abstract book92-9-12

International Associationfor Dental Research

Iranian Division of IADRIADR

www.iadr-iran.com11-13 Dec 2013 Olympic Hotel -Tehran-Iran

WHO Collaborating Center for Training and Research in

Dental Public Health, Tehran, I.R. Iran

Dorsunteb Pars

AbstractBook

9th Iranian & 13th Kuwaiti

Divisions of IADR Joint Congress

Abstract Book

9th Iranian & 13th Kuwaiti Divisions of IADR Joint Congress, 11-13 Dec 2013 - Abstract Book

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IndexOrganizing Committee Messages ........................................................10Organizing Committee ................................................................................16Iranian IADR Officers ...................................................................................17Scientific Committee & Abstract Reviewers ...................................17Sessions Chairs ...............................................................................................18Featured Presentations ..............................................................................19Workshops ........................................................................................................27IADR-WHO Symposium ..............................................................................38Oral & Poster Presentation .....................................................................41Abstracts in order of ID numbersH. BAGHERI GBiomimetic Synthetic Enamel: A Potential Remineralizing Agent for Enamel Repair ...........................42M. BONABIAdherence of Iranian Dentists to Information Technology ..........................................................43A. BAGHALIANFracture Resistance of Posts in Full-Coverage Restorations of Primary Incisors .................................44A. KESHVADHuman and Animal Bone Substitutes for Augmentation before Implant Placement ...........................45A. PARHIZBone Debris vs. Allografts in Repairing Implant Buccal Bone Dehiscence ........................................46O. MOGHADDASRole of Titanium Mesh in Reconstruction of Ridge Deficiencies ...................................................47F. FARSHCHIReverse Contrast Digital Radiography in Root Fracture Diagnosis .................................................48


Divisions of IADR Joint Congress

Abstract Book

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N. NOURBAKHSHThe Effect of OTC Bleaching Products on Enamel Microhardness .................................................49F. FARAJIEffect of GC Tooth Mousse and MI Paste Plus on Dental Plaque Acidity ..........................................50A. DARNAHALPorcelain Laminate Fracture Resistance on Incisal Reduction less than 2mm ...................................51D. NIKNAMEffect of Fluoride and Chlorhexidine Varnishes on Interproximal Plaque pH ....................................52A. NAJAFPOURThe Role of HIV Infection on Oral Pigmentation ......................................................................53H.-. MOOSAVIClinical Effectiveness of Laser on Postoperative Hypersensitivity ..................................................54T. HOOSHMANDDegree of Conversion of Low-Shrinkage Composites Photo-Activated by LED and Halogen ..................55E. JAFARPOURInvestigation of Implant Width on Distribution of Stress in Adjacent Bone ......................................56F. NILCHIANQuality Assessment of the Information Related to Fissure Sealant ................................................57S. ALIREZAEIFormulation of New Mucoadhesive Containing Phenytoin on Wound Healing .................................58N. MOHAMMADZADEH AKHLAGHIResidual Root Thickness Evaluation after Pre-Flaring Using Gates Glidden Drills ...............................59S. SADEGHIEffects of bonding agent and sealant viscosity on sealant microleakage ........................................60A. MESGARANIAccuracy of Two Radiographic Methods in Diagnosis of Root Resorption........................................61N. RAHSHENASRelationship between Art (Painting) with Stress, Anxiety, Depression in Dentists ..............................62H. RAHIMIEffect of Stress on Salivary Ion Content in Orthodontic Patients ...................................................63A. PAHLEVANSEM Evaluation of Intracanal Dentin Changes in Endodontically Treated Teeth: ...............................64S. AZADNIAA Biocompatibility Comparison of Nanosilver Coated Gutta-Percha and Standard Gutta-Percha ............65L. RANJBAR OMRANIInternal Evaluation of Operative Dentistry Department of Tehran University ...................................66S. KHAZAEIEffects of Different Prosthesis Materials on Stress Distribution of Implant ......................................67S. ASEFIIntroduction of Iranian 3D Dental Cast Simulator.....................................................................68A. PAKFETRATRemoval of Refractory Erosive Lichen Planus by CO2 Laser ........................................................69A. SEDIGH NIAComparison Of Apically Extruded Debris Between Hero And Race Systems .....................................70R. HAMEDIThe Effect of Bone Metabolic Alterations on Orthodontic Tooth Movement ....................................71M. ABBASICoronal Leackage Of Gutta-percha Or Resilon Using An Intraorifice Barrier .....................................72M. MINAMathematical Beta Function for Maxillary Arch Form Prediction ..................................................73H. YOUSEFIInterleukin-10 Gene Polymorphisms in Patients with Recurrent Aphthous Stomatitis.........................74


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M. NEJADKARIMStress Distribution at the Internal Surface of Dental Implants .....................................................75N. MOHEBBIANDebonding of Ceramic Brackets Using Er-YAG Laser ..................................................................76J. ORANGIEnhance Socket Preservation with Combination of Bio-Oss with Silk ............................................77L. KHEIRIThe Osteoregenerative Effects of PDGF-BB with MSCs Loaded on FDBA .........................................78S.R. HABIB ABADIImplant Location Influence on Stress Distribution in Implant Assisted RPDs ....................................79S. SEYEDZADEH SABOUNCHISearch for Evidence Behavior among Dental Faculty Members in Iran ...........................................80A. ALBUJEERHIV/AIDS Awareness Among Iraqi Medical and Dental Students ..................................................81A. EBN AHMADYDesigning an Oral Health Surveillance System in Iran ................................................................82S. SHAHRABI FARDEvaluation of Zirconia Post and Zirconia Coated FRC Post ...........................................................83S. ARAGHIPH Changes of Intracanal Materials in Simulated Root Surface Defects ..........................................84G. NAHVIApical Transportation of Waveone File with Full-Rotation versus Reciprocation Movement .................85M.T. BAGHANIMesenchymal Stem Cells Delivery in Maxillofacial Bone Regeneration: Systematic Review ..................86M. SHABANILaser Assisted Monitoring of Dental Caries in Early Childhood Caries Prevention ..............................87S.S. HASHEMI KAMANGAREffect of Bleaching on the Microhardness and Color of Composites ..............................................88S. ETEHADIEH KOOCHAKThe Effect of Firing on Marginal Integrity of Zirconia Core ..........................................................89N.S. MATINIInvisible Dental Injuries (Cracks) due to General Anesthesia Intubation .........................................90B. TAHANIAttitude and Practice of Dentists regarding Tobacco Cessation in Iran ............................................91B. DADRESANFAREffectiveness of Reciproc and iRace on Canal Wall Cleanliness (SEM) ............................................92A. AHADIHistocompatibility and Setting Time of Endodontic Cement .......................................................93A. ZIADLOUEndodontic Cements Influence on Odontogenic Differentiation of Pulp Stem Cells ............................94M. MOJAHEDILaser Assisted Pain Reduction after Vital Pulp Therapy ..............................................................95M. GHASEMIAssociation of Periodontal Condition with Serum PSA Level .......................................................96H. BAHRAMIANIs Anxiety Affecting Iranians’ Oral Health Behavior? .................................................................97P. MEHRIAREffect of Magnesium on Bonding Strength of MTA Based Cement ................................................98G. AZARBAKHSHEvaluation of Oral Medicine New Lesson Plan, Requirement and Questionnaire ...............................99A. FARZANA New Grading System for Orthodontic Treatment Quality Assessment ........................................100









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S. TOOPCHIEffect of Enoxolone on Dental Plaque, Gingival Inflammation, and Bleeding ...................................101P. MEHRVARZFARAntimicrobial Comparison of Green Tea Extract and Calcium Hydroxide ........................................102H. BAKHTIARRegenerative Endodontic Treatment of Immature Permanent Teeth by Using PRP ...........................103M. KARCHEDReal-Time PCR Quantification of Periodontal Pathogens in Diabetic Kuwaiti Children ........................104L. ATASH BIZ YEGANEHCBCT and Periapical Radiography in Diagnosis of Strip Root Perforations .......................................105D.S. MAHOUTCHIDiagnosis of Gingival Biotype by Probing Technique vs. Visual Method .........................................106M. BOSKABADYFissure-Sealants Microleakage Based on the Type of Solvent in Bonding-Agents ..............................107M. AZARIANThe Influence of Implant Dimension on Stress Frequency Responses ...........................................108R. BARDALAccuracy of Different Image Modalities in Detection of Bone Lesions ...........................................109N. JAMEIEvaluation of One Iranian Probiotic Yogurt’s Effect on Salivary S. Mutans Count ..............................110M.T. BAGHANIEvaluation of Silicone Effect on Implant Abutment Interface Microbial Leakage...............................111Y. REZVANIThe Effect of Intranasal Midazolam with/without N2O/O2 on Children’s Behavior ...........................112M. KARIMIKnowledge of Dentists About Stepwise Excavation and Pulp Capping ...........................................113J. MEHRANI SABETSelective Alveolar Decortication Technique for Facilitating Orthodontic Tooth Movement ..................114Z. SHAKIBAEIAccuracy of Two Radiographic Techniques in Diagnosis of Root Fractures ......................................115M. MALEKI GORJISEM Evaluation of Etching Pattern of 18%HCL: A Pilot Study ......................................................116G. RADAFSHARPlacebo Medication for Pain Relief During Scaling and Root Planning ...........................................117A. FAYAZDetermining Depth and Radius of Curve of Spee: A Pilot Study ..................................................118N. NAGHAVIEvaluation of Genotoxic Effects of Two Endodontic Cements .....................................................119G. RADAFSHARLong Term Survival Rate of teeth Requiring Multiple Treatment Procedure ....................................120N. SOLTANIANOsteoblast Survival during Different Bone Harvesting Techniques: An Animal Study .........................121F. SARLATIPeriodontal Flap and Osseous Resective Surgery Techniques: Computer Assisted Learning .................122S. ALIJANIComparison of Single and Double Jaw Surgery in ClII Patients ....................................................123H. SHEKARCHIZADEHSelf-perceived Oral Health of Addicts in Rehabilitation in Tehran, Iran ..........................................124M. KASHKULIHome Bleaching Relapse in Patients with and without Recall Treatment .......................................125N. DABIRIFrequency of Oral Connective Tissue Lesions in Children ..........................................................126








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S. ZOKANIEffect of Coffee on Discoloration of Three Nano Composites......................................................127F. SHIRBANEn-Mass Distalization of Maxillary Posterior Teeth with Mini-Screw Supported Hyrax .......................128N. MAHINFARThe Effect of Bleaching on the Microleakage of Silorane-Based Composite ....................................129S. RAZEGHIMedical Emergency Management Among Iranian Dentists ........................................................130F. BASTAMIDemographic Factors Affecting the Survival Rate of Dental Implants ............................................131P. MOHEBBIMineral Trioxide Aggregate X-Ray Diffraction Analysis at Different pH Values ..................................132N. BAYATIEffect of Zeolite on Sealing Ability of Mineral Trioxide Aggregate ................................................133P. OMIDSALARAnticariogenic Effect of Some Herbs ...................................................................................134S. RABIEIPrimary Care Nurses’ Perspective on Children’s Oral Health ......................................................135P. VARESCorrelation between the Gingival Embrasure Space and Interdental Papilla ...................................136N. YOUSSEFIInfluence of Cavity Size Modification on Microleakage of Bulk-Cured Composites ............................137R. POURABBASEffects of Plasma Rich in Growth Factors in Extraction Sockets ...................................................138M. NOURBAKHSHEffect of Polishing and Glazing on Color Stability of Porcelain .....................................................139S. ASHNAGARPrevalence of Oral Lesions in AIDS and HIV Positive Patients ......................................................140N. MOHAMMADZADEH REZAEIGreen Tea Mouthwash in Postoperative Pain Following Third-Molar Extraction ...............................141S. JAFARNIAEffect of Lip Line on Anterior Teeth Proportion Preference ........................................................142M. BROOKHIMEvaluation of Ki-67 and PCNA in Subtypes of Amelonlastoma ....................................................143Z. TEHRANILow-Level Laser Effect on Pain after BSSO Surgery ..................................................................144A. HASSANIImplant Placement Simultaneous Alveolar Ridge Augmentation with Block Bone Graft .....................145S. BABAZADEHSocial Capital and Self-Perceived Oral Health, Urban HEART Study ..............................................146T. SAFAIEEffect of CPP-ACPF on Oral Symptoms of Patients under Chemotherapy .......................................147A. ORUMCHIDouble Taper and Simple Taper Fiber Posts ..........................................................................148M. SHIRYANComparison of Two Adhesive Systems on FRC Post Bond Strength ..............................................149Z. MOMENIDental Pain and Self Perceived Oral Health, Urban HEART .........................................................150N. BAHROLOLUMICytotoxicity Evaluation of Four Intracanal Medicaments on L929 Fibroblasts ..................................151M. SAFAIE YAZDIStepwise Excavation Using MTA: A Randomized Clinical Trial .....................................................152







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S. SABBAGHInfluence of Spatial Resolution on Detection of Non-Cavitated Proximal Lesions .............................153S.S. FAKHR TABATABAIEAssessment of the Electromyographic Activity and Vertical Dimension (VDR) .................................154A.H. NEJATDental Bleaching Induced Redox Perturbation .......................................................................155N. PAHLAVANFive Years Epidemiology Study on Oral Cancers in Tehran (2001-2006) .........................................156M. GHOLAMIAssessment of Adults’ Periodontal Knowledge Following a Mass Media Campaign...........................157S. NEMATI ANARAKIEffect of Fluoride on Enamel Roughness after Home Bleaching...................................................158M. DEHGHANIEffect of Combined Fluoride-Chlorhexidine Mouthrinse on Orthodontic Patients’ Oral Health .............159M. HAJIHASANIEffect of Irradiation Time and Distance on Nano-Hybrid Composites Microhardness .........................160S. MARANDI Assessing the Knowledge of Senior Dental Students towards Antibiotic Prescription ........................161F. AFKHAMIRadiographic Localization of Mandibular Foramen in an Iranian Population ...................................162S. BANAVAComparison of CalciumHydroxide, MTA, and CEM Cement in Stepwise Excavation: Final Results ..........163E. KOSARIEHComparison of Penetration Depth of Two Different Photosensitizers in Root Canal Wall ...................164N. KOOHESTANIANAssessment of Retentive Strength Orthodontic Bands Cemented with ACP-Modified GI ....................165A.S. MOSTAFAVIInternal Connection Reverse Torque Values in 3 Types of Abutments ...........................................166M. HASSANPOUR SHATERPrevalence of Different Techniques used in Implant Supported Fixed Prosthesis ..............................167Z. RAHMANIGeometric Parameters of Implants and stress distribution in Partial Overdenture ............................168A. ANSARIPotential Psychological Effect of GA on Pediatric Dental Patients.................................................169N. PASDAROral/Intramuscular Ketamine, Midazolam, Atropine for Dental Sedation .......................................170G. ANSARIPrimary Teeth Pulpotomy with C.E.M/LLLT, Two Years Result .....................................................171M. MIRMicroleakage Analysis of Resilon Obturation Material in Laser Assisted RCT ...................................172M. ZARE JAHROMIEffect of Triple Antibiotic and Chlorhexidine on Shear Bond of Composite ....................................173H. NOJEHDEHYANPLGA Microspheres Containing Minocycline as Drug Delivery System ...........................................174N. ALASVANDPreparation of Gelatin-Hydroxyapatite Microspheres as Cell Carrier ............................................175K. SARGERANDental Visit and Number of Missing Teeth among Tehrani Elderly ...............................................176S. HAMIDIAVALCephalometric Assessment of Jaws Growth in 9-11yrs Normal Subject .........................................177A. JAFARI NAEIMIForce Relaxation of Three Different Orthodontic Latex Elastic Products .........................................178








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S.M. MOAZZAMISelf-Sealing Ability of High Copper Amalgams with Self-Etch Adhesives ........................................179A. AZIZIPreventive Effect of Zinc Sulfate on Oral Mucositis ..................................................................180M.H. KHOSHNEVISANOral Hygiene Behavior in Iran: National NCD Risk Factor Surveillance ...........................................181J. SARABADANIStudy Experiences of Staff and Faculty Members of Oral Medicine ..............................................182B. HOJJATIEComputational Models for Temperature/Stress Prediction in Layered Dental Porcelains ....................183S. HONKALAIs Toothbrushing Associated with Other Oral Health-Related Habits in Kuwait? ...............................184P. LUCASTooth Wear Studied via Single-Particle Interaction with an Enamel Surface ....................................185E. HONKALAThe Effect of 5Weeks Xylitol Consumption on Oral Microflora ....................................................186A. VAN CASTERENThe Role of Dust, Grit and Phytoliths in Tooth Wear ................................................................187A.J. MOULEResidual Active Chlorine in Sodium Hypochlorite Solutions after Tissue Dissolution..........................188Congress Contributors ...............................................................................189Congress Sponsors .......................................................................................191Diamond Sponsor .........................................................................................................192Platinum Sponsor..........................................................................................................193Gold Sponsor ...............................................................................................................194Silver Sponsor .............................................................................................................195






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Iranian Division of IADR President Professor Ghassem Ansari

Dear Valued Delegates, Presenters, Colleagues

It is a great pleasure for me as the President of IADR-Iranian Division to welcome you to the uniquely organized first joint congress of Iranian and Kuwaiti Divisions. This congress has shaped in such a wonderful scale under the leadership of Dr. Sepideh Banava (Congress Chair and one of the leading national researchers) and enthusiasm of her team in association to all of you who made this to happen by your contribution. I like to high light that as most of the other international events, this congress has also taken such an enormous amount of work and communications in order to allow this to happen. All preparation and arrangement steps of this congress were made possible by individual courage and enthusiasm of each and every member of the organizing team which deserves my personal appreciation.

As the nature of the IADR congresses provides unique opportunities for researchers in various fields, this one is no exception. Being engaged and responsible in almost all of the Iran’s IADR history, I am confident to say that this year’s event is planned as one of the most active and well covered research products of the two divisions. This is clearly highlights the position of the research status in this region and the potential role could be played by the two divisional members within the IADR network. I also like to emphasis that this year’s event illustrates the research capacity of our nationwide dental scientists.

As the main policy of the IADR Iranian Division is to use all of its potential research opportunities it is hoped that within the next couple of years this country can find its deserved international position. A nationwide plan is on to engage all of the national dental research active members. Herewith I urge everyone to register with us and let us keep our files updated with all research activities going on in every corner of our great country. Being the largest in dental population size, academic facilities and research institution numbers which inevitably provide massive potentials for research production compare to other nations of the region in EMRO and most probably AMER groups, I am confident that we are impatiently moving towards our goals. This will eventually reveal the actual role of Iran in the world of Dental Research.

Another unique aspect of this congress is collaboration of the WHO and their offices

Organizing Committee Messages


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in the region. With the leadership of Prof Khoshnevisan who has headed his Iranian counterparts, we will have several symposiums and group discussions in the field of Community Oral Health and their hot topics. With the presence of WHO active representatives in the region in these discussions I am sure these meetings will provide valuable outcomes for their group and their communities.

I am fully aware as there have been massive efforts and courageous in our dental fair team which resulted in their collaboration with several supporting companies and dental agents who offered their full support to make this year’s dental exhibition different. This is why I like to express my personal appreciation to their directors and engaged team in the congress in advance.

The IADR Headquarter team is thanked for their support and help throughout the course of congress preparation and in particular the CONFEX facility providers who made the online submission, review and registration of the congress possible, Special thanks to Dr. Christopher Fox, Ms Marissa Napinsky and Ms Denise Steszoff for their valued helps.

Last but not least, I like to say that it is of great value to me and my colleagues to share this year’s congress with the Kuwaiti colleagues. The Iranian team’s highest appreciation is expressed to Prof Jawad Behbehani president of AMER and Prof Eino Honkala who were fully supportive of this event from start. Without their generous help and support such collaboration would not form to this level. I also like to express my appreciation to all other international colleagues who have contributed to this congress. I can reassure everyone that this rather small but unique community, when compared to other Dental Associations, has a lot to say and will bring valued ideas, research results and courage to those involved in the field of Dental and Medical research. I hope that you enjoy your time here in Tehran and have a wonderful scientific occasion to remember for years to come.

With Best regardsProfessor Ghassem AnsariPresident of the IADR Iranian Division


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Congress President

Dear Distinguished Colleagues, Researchers, Dentists, and Students,

This is a great opportunity for me to express my deep gratitude to you and welcome you to the 9th Iranian and 13th Kuwaiti divisions of IADR Joint Congress.

In every IADR congress around the world, the latest research results are presented. For those students, dentists, and researchers who put a lot of effort into moving along with developments in the realm of knowledge, technology and research, IADR is the best way to keep themselves up-to-date.

In the field of science and research, every single question matters and can inspire new studies. A researcher becomes GLOBAL instantly by presenting his/her research in any of the IADR congresses.

In my opinion, IADR congress builds a strong bridge between science, knowledge, research, technology and dental clinics. Therefore this scientific and prestigious congress connects all the people in these areas.

The 9th Iranian division of IADR congress is so special this year due to several reasons; the Kuwaiti division has joined and a close collaboration has happened between the two divisions; WHO Collaborative center in Iran has organized a symposium to connect the oral hygiene leaders in the region. A hard effort was made by the organizing committee since almost a year ago to acquaint dental students, general dentists, and specialist with the scientific and research basis of the IADR Another positive point of this congress is having a close and scientific collaboration of dental companies with IADR.

This great event was not possible without tremendous efforts of my valued team and their supports. I’m really grateful of Dr. Omid Moghaddas, Dr. Arash Rahimi, Dr. Mohammad Safaie Yazdi and Ms. Azin Kazemi who stood by me during the organization of the congress. Last but not the least I want to express my special thanks to Dr. Ghassem Ansari who trusted me for holding this congress.

I wish you all great days in this international congress.

Dr. Sepideh Banava 9th Iranian IADR Congress President


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Head of Scientific Committee

Dear Colleagues,

It is an honour and a great pleasure to welcome you all to the 9th Annual Meeting and Scientific Congress of IADR Iranian Division in Tehran, Iran from December 11-13, 2013. This is a joint program with 13th Kuwaiti Division and WHO collaborating Center for Training and Research in Dental Public Health in Iran.

I am proud and thankful for the considerable extent of scientific contribution this year. This meeting consists of 11 scientific workshops, 68 oral and 78 poster presentations on current dental and collateral research findings selected from 250 submitted articles. Furthermore, a 3-day WHO symposium will run concurrently with scientific sessions. This would be a unique opportunity to exchange valuable knowledge and recent advances in the field of dental research among scientists in this region and we hope this event will facilitate more communication and application of the research findings. The scientific presentations will be scheduled according to the IADR scientific groups and the final outline will be presented in the congress program.

On behalf of the scientific committee, I would like to express my sincere gratitude toward those who collaborate with us in different committees and concerned authorities, in addition to our 30 valuable referees and other dental research centers for their dedication and support.

I would like to welcome you all to this event with the hope for contribution towards improvement of Oral Health Researches.

Sincerely,Dr. Azita TehranchiHead of Scientific Committee


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Head of Executive Committee

Dear colleagues and friends

It is my great pleasure to welcome you to the 9th annual congress of Iranian division of IADR in Tehran. The members of Executive, Organizing and Scientific committees of Iranian Division of IADR worked so hard to prepare an outstanding program, and we are all grateful to them for their efforts.

The scientific program of IADR will cover all the major aspects of dentistry, presented by prominent scientists and clinicians and researchers. The conference is also a unique social opportunity to make new acquaintances, meet colleagues from other countries and better know the different National Dental Societies of Iran. This year the congress is joint with 13th annual congress of IADR Kuwaiti division and we are honored to have special guests from Kuwait.

I am honored and privileged to be the Head of the Executive committee in this congress and I would like on this occasion to express my gratitude to all people that have contributed to the success of the Iranian division of IADR : Past and present Presidents, General Secretaries,Treasurers and National Delegates. Special thanks to our friends from the Industry, true partners and supporters of the IADR goals.

I wish you all a wonderful and memorable experience.

Dr. Omid MoghaddasHead of the Executive Committee


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Head of Exhibition Committee

Dear Colleagues,

It is a great pleasure to welcome you to this international congress with a different exhibition.

In this congress, different companies participated to express themselves with their R&D sections to scientifically communicate with the participants. We are thankful to all companies who play an important role in making congresses glorious.

In this congress, unlike the past Iranian IADR congresses, some dominant companies have participated as financial sponsors of diamond, platinum, gold, and silver.

I am deeply grateful because of their companionship and hopeful to have their support in the future.

Sincerely yoursDr. Arash RahimiHead of Exhibition Committee


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Organizing CommitteeCongress President: Dr. Sepideh BanavaHead of Scientific Committee: Dr. Azita TehranchiHead of Executive Committee: Dr. Omid MoghaddasVice Executive Director: Dr. Mohammad Safaie YazdiHead of Exhibition Committee: Dr. Arash RahimiVice Exhibition Director: Babak MamizadCongress Advisors: Dr. Ghassem Ansari, Dr.Mahtab Nouri, Dr. Haleh Heshmat, Dr. Ebrahim Aminsalehi, Dr.Ali Saghiri, Dr.Keivan SaatiPoster Committee: Dr. Haleh Heshmat (Director), Dr. Pooneh Mohebbi, Dr. Raha TafarojiWorkshop Committee: Dr. Ehsan Esnaashari (Director), Dr. Arezou Pezeshkfar, Dr. Mansoureh Emami Arjmand, Dr.Ali Mansouri Public Relations & International Affairs Secretory: Azin KazemiIADR-WHO Symposium Committee: Dr. Mohammad Hossein Khoshnevisan, Dr. Arezoo Ebn Ahmady, Dr. Sepideh RabieiRegistration Committee: Dr. Sima Alizadeh, Dr. Mona Kashkuli, Shahla Hamidi, Mahsa Hamidi, Jamileh Toghi, Termeh Shemirani, Haniye Tehrani, Janet ShahverdiWebsite Designing & Support: Flying Feathery GroupPublication Committee: Azin Kazemi, Ehsan ShamsGraphic & Design: AfraviGroup (Foroozan Kheiri, Bahram Afravi) VIP & Ceremonial Committee: Dr.Vida Dolati, Dr. Mehrnoush Ghobadi, Dr. Linda Nematollahian, Leila PourjafarAudio-Visual & Media Committee: Zhoubin GhazianiCE Credit Committee: Zeinab MozafartashStudent Executive Members (in alphabetic order): Haniyeh Haeri Araghi (Head), Sahar Abdollahzadeh, Mina Aghabeygi, Elnaz Alavi, Nazanin Allahyari, Mahsa Amjad, Hamidreza Alimoradi, Parmida Ariaei, Saghar Bahmani, Alireza Darnahal, Nafiseh Farajian Zadeh, Ehsan Farjad, Seyed Hesamodin Haeri Araghi, Zohreh Heydari, Zahra Jabari, Marjan Javadzadeh, Omid Javadzade, Zohreh Kazemi, Peiman Kermaniha, Keikhosro Khosraviani, Donya Sadat Mahoutchi, Negar Manouchehri, Pegah Mirmalek, Nima Mohahegh Dolatabadi, Mehrdad Moradi, Azin Orumchi, Shabnam Pourhaghani, Shadi Poursoltani, Shima Rashidi, Mahdieh Sahrakari, Niloufar Saleh, Mahsa Shadi, Targol Shafizade, Masoud Shahhoseini, Zahra Shakeri, Hamed Shojaei, Negar Soltanian, Sedigheh Toraji, Peyman Vares, Bahareh Yousefian, Mahsa Zeinali, Negin Zokaie, Kaveh Zolfaghar Nasab


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Iranian IADR OfficersGhassem Ansari: PresidentSepideh Banava: President-ElectRaheleh Hassanizadeh: SecretaryMohammad Jafar Eghbal: Treasurer Ghassem Ansari: CouncilorMahtab Nouri: Immediate Past President

Scientific Committee & Abstract ReviewersGhassem Ansari Arash Azizi Sepideh Banava Katayoun EsfahanizadehAli Hassani Raheleh HassanizadehHaleh Heshmat Eino Honkala (Kuwait) Sisko Honkala (Kuwait)Tabassom HooshmandMohammad Reza Khami Mandana KhatibiArash Khojasteh Mohammad Hossein Khoshnevisan

Sandra MehralizadehHesam Mirmohammadi(Netherlands) Omid Moghaddas Nahid Mohammadzadeh Akhlaghi Faramarz MojtahedzadehMahtab NouriReza PourabbasArash Rahimi Alireza Sadr (USA)Mohammad Ali SaghiriJavad Sarabadani Farhad ShafieiAzita Tehranchi


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Sessions Chairs

Dr. Ali KangarlooDr. Mohammad Hossein NekoofarDr. Mohsen Amin SobhaniDr. Ezzatollah KhamesiDr. Ebrahim MajidiDr. Ali KhaderDr. Mohammad Reza KhamiDr. Haleh HeshmatDr. Tabassom HooshmandDr. Amir NazariDr. Seyed Mohammad Reza SafaviDr. Majid GhasemianpourDr. Fariborz AminiDr. Mahtab NouriDr. Mohammad Hossein KhoshnevisanDr. Amjad MatouqDr. Arezoo Ebn AhmadyDr. Sisko HonkalaDr. Soodabeh SargolzaieDr. Kaveh OloomiDr. Hossein Bagheri Dr. Arash RahimiDr. Emad KosariehDr. Mahkameh MoshfeghiDr. Ahamad RezaTalaeepourDr. Sandra MehralizadehDr. Saeid Mostafa MoazzamiDr. Tahereh Sadat Jafarzadeh KashiDr. Fatemeh Sadat TabatabaieDr. Salahudeen AlBulushiDr. Fatemeh MashhadiabbasDr. Farnaz MahdisearDr. Mehdi Valizadeh

Dr. Kiumars Nazari MoghaddamDr. Saied NematiDr. Arash KhojastehDr. Alireza Jafari NaeimiDr. Hamid MoghaddasDr. Mohammad JafarianDr. Kaveh SeyyedanDr. Hossein BehniaDr. Katayoun EsfahanizadehDr. Payman MehrvarzfarDr. Haleh Kazemi YazdiDr. Eino HonkalaDr. Ghassem AnsariDr. Mojtaba Vahid Golpayegani Dr. Lida ToumarianDr. Javad SarabadaniDr. Masoud EjlaliDr. Faramarz MojtahedzadehDr. Alireza keshvadDr. Nasrin EsfahanizadehDr. Afsaneh PakdamanDr. Nahid Mohammadzadeh AkhlaghiDr. Shahram AzimiDr. Alexander John MouleDr. Peter LucasDr. Khosrow GolshanDr. Ahmad NajafiDr. Hassan Torabzadeh Dr. Mahdi NasibiDr. Hossein HesariDr. Suleiman MohammadDr. Abdolhamid Zafarmand

9th Iranian & 13th Kuwaiti Divisions of IADR Joint Congress - Abstract Book

Featured Presentations


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Dr. Ayoub Pahlevan, DDS, MSAssociate ProfessorTehran University of Medical Sciences, Dental FacultyRestorative Department, Iran

A General Look to Dentin Bonding Systems

Nowadays dentists are really confused about the type of the Dentin Bonding Agents (DBA) they are going to select and apply in different clinical cases. Bonding to enamel has been approved for many years and is very reliable but the issue is different with bonding to dentin.

There are different factors that make the bonding to dentin more questionable. Nature of the substrate, tag formation, etching pattern and chemical composition are different from enamel and these make the bonding to dentin very technique sensitive.

New DBAs are developed to fulfill the whole area but there is need to further research regarding the type of DBA that is suitable and more reliable in different clinical situations. Future needs clinical research and clinical evidence for successful, reliable and non-degradable bond to tooth structure.


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Nelson R. Pinto, MDUniversity of Concepcion, Chile

Graduatefrom, Faculty of Dentistry ,University of Concepcion, Chile 1985.Residence in Oral Implantology Ohio State University Faculty of Dentistry, USA, 1990. Residence in Oral Implantology Friburg University Faculty of Dentistry, Germany, 1992. Head of Clinica San AgustinRestorative Implant Department 1993 - 2013Private Practice exclusive in Oral Implantology. 1989 - 2013National and International Lecturer in Oral Implantology ( morethan, 200 conferences)National and International Lecturer of Courses in Oral Implantology (more than, 100 courses)Nobel Biocare Key Clinician Consultan 2006 - 2013Intra-lockInt. Key Clinician Consultant 2005- 2013Professor, Post GraduateProgram in Oral Impantology and Periodontics, Facultad de Odontología. Universidad de los Andes, Chile 2010 -2013Visitant Professor: University of Concepcion, Faculty of Dentistry, Implant ProgramSeveral Prizes in Clinical Research PresentationsDeveloper of a novel technique for the management of Chronics Wounds with Leucocytes - Platelet Rich Fibrine, Best Oral Research Presentation PrizeL-PRF: Technique Overview to Clinical Applications

This Symposium will present the background, science, applications and methodologies regarding the use of L-PRFTMmembranes. Clinical cases will be shown to further illustrate the techniques and results that can be derived from its use. The hands-on workshop will enable the participants to become familiar with the membrane-forming apparatus and the various techniques that are utilized when creating and manipulation L-PRFTMmembranes.Upon completion of this hand-on workshop, the participants will have a better understanding of the physiological mechanisms that are pertinent to membrane formation and that take place during augmentation procedures. They will be more familiar with the strategies that enable L-PRFTMto be such a beneficial aid during the healing process. During the hands-on exercises, the participants will have the opportunity to work with the membrane-forming armamentarium and to employ the techniques necessary for the fabrication of L-PRFTMmembranes and for their correct clinical placement.


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Dr. Mohammad H. Nekoofar Endodontist, DDs MSc DoIBoE PhD Vice Dean (Global Strategies & International Affairs) School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Honorary Clinical Lecturer School of Dentistry, Cardiff University, UK

Basic Requirements of Dental Biomaterials in Endodontics

The launching of mineral trioxide aggregate in 1995 can be considered as the initiation of the rocketed development of new biomaterials in the field of endodontics.

Imperatively, any new biomaterial must not be used for human being until subjected to various defined independent experiments.

Obviously manufacturers of new materials cannot postpone marketing of their materials and waiting for the results of the time consuming academic experiments. Therefore they try to bypass some of the basic experiments. It becomes worse when the inventor and the manufacturer of a material are same. In addition, the essential physical and chemical properties of a material may ignore to expedite their marketing.

In this presentation, basic and general requirements of dental biomaterials in the field of Endodontics will be discussed and the lack of information about some of the newly introduced biomaterials will be highlighted.


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Dr. Shahram Azimi, DDS, MsEndodontist, Iran

Pain Control

Effective pain control during and after endodontic treatment is an essential key for the success of root canal therapy and also professional practice. One of the challenging occasions for a clinician is to control and obtain deep anesthesia when the patient has urgently been referred because of sharp and diffused pulpalgia. Even experienced clinicians might face challenges to achieve deep numbness in case that are so called ‘Hot tooth “.

Various theories such as decrease in PH, morphologic changes of neuron, expression of new receptors on axon surface are among those that are currently debated.

While reviewing these theories as the probable causes of resistance against achieving anesthesia, clinical solutions to overcome such problem would be discussed.


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Dr. Masoud Mojahedi, DDS, MSc, PhDAssociate Professor, Adjunct faculty member of RWTH Aachen University- GermanyPhD in Laser in Dentistry

Research in LASER Field

These days due to increasing the number of LASER users and dentists interests also the lack of new research and evidence bases in this field so It is very important to know how we should plan a research and how we can reach to the scientific target and hope this short course can help to all dentist and students which are interested to have scientific and academic activates.


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Dr. Amir Nazari, DDS, Ph.DCariology and Operative Dentistry, Tokyo Medical and Dental UniversityNICOPE Corporation, JAPAN

Toward Perfection in Operative Dentistry: Optical Coherence Tomography

Achieving perfection in operative dentistry requires perfection in diagnosis. Optical Coherence Tomography (OCT) is a unique diagnostic modality which obtains real-time 2D and 3D high-resolution scans of internal structures using non-ionizing near infra-red spectra. Various applications of OCT have been suggested.

OCT may be used during caries diagnosis to detect shallow lesions; during examination of a previously restored tooth to evaluate the condition of the restoration; during cavity preparation to check the remaining dentin thickness over the pulp chamber; during placement of resin composite into the cavity to check the proper adaptation of the composite to the cavity surfaces; during post-operative stage to check for any defects at the margins or presence of voids within the restoration.

The OCT technology is rapidly developing, and with no doubt, OCT can bring us closer to perfection.


Dr. Babak BehboudiVice President of Middle East and Oceania, International Institute of Marketing Professionals (IIMP®)

The Applications of Marketing Research in Dental Research & Clinics

Despite of its attributes, marketing researches and studies have vast applications in dental researches. There are a wide range of similarities in both researches and studies that are looking for solving the key problems of patients. Whether we call them clients or patients, the focus point of both marketing researches and dental researches is human being; one is looking for understanding the needs, wants and demands of a patient as a client for receiving better dental care services and cure, and another is looking for exploring new cure for dental damages and ailments.

Every clinical research aims to develop a new solution for old or newly found ailments and the successful solutions are those that can be commercialized in a manner that could be applicable cost effectively by dentists.

However, there is a gap between the approaches of a solid dental care study and research and those of marketing approaches to the same problem which can be considered as the dark continent of commercialization of dental research and studies. There is no doubt that if a dental care study or research can produce commericializable solution, such a solution can be successfully developed to benefit both dentists and their patience.

Every dental care solution should be considered as a product (or customer solution) and, by considering the patient as a customer, needs to be delivered through a precise marketing mix including the critical elements of customer solution, cost to customer, convenience to customer, communication to customer, considering the culture of customer, customer care process and context of the solution for the customer.

This article strives to clarify the common context of clinical researches and studies with marketing research and studies in dental care context and the key factors that should be considered in commercializing the dental care solution and products.

Workshops


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Dr. Haleh Heshmat, DDS, MSSpecialist in Restorative DentistryAssistant Professor Azad Dental University, Dental Branch, Iran

All About Resin Cements

Clinicians might be familiar with the quality and indications of conventional dental cements that historically have been used frequently.

But it appears that many yet become confused when it comes to handling self-etch or self-adhesive cements.

In this workshop an extensive presentation of resin cements and recent generations of self-adhesive resin cements shall be given. Chemical composition, its effect on the setting reaction and adhesion to various substrates, physical and biological properties and other material aspects along with clinical points and handling guidelines shall be discussed.


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Faramarz Mojtahedzadeh, DMD, MS, MMed Orthodontist, Iran

Forced Eruption

Forced eruption (FE) is a simple orthodontic movement which basically intends to extrude the tooth structure. FE can be carried out in different occasions and with different intentions, and once a dentist becomes familiar with it, he or she could take advantage of it in many fields as an adjunctive treatment. The method presented in this workshop has the advantage that it requires minimum a recall of orthodontic knowledge. As it does not require conventional fixed orthodontic appliances and designs, the complex biomechanical interactions seen with brackets can be easily bypassed.


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Dr. Sepideh Banava, DDS, MSSpecialist in Restorative DentistryAssistant Professor Head of Dental Materials DepartmentAzad Dental University, Dental Branch, Iran

All About Adhesive Systems

Different adhesive systems in the market make us so confused. Various classifications, different application steps and compositions are so compromising. Selection between total etch and self etch adhesive systems is a question for dentists.

Newly introduced adhesive generations are more self-etch with better properties claims. Dentists Need to be aware of adhesive systems, properties, method of application to make a proper decision in their clinical cases.

In this workshop all questions about the new generation of adhesives will be covered.


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Dr. Shahram Azimi, DDS, MsEndodontist, Iran

Rotary Instrument in Dentistry

In this hands-on workshop the clinical tips on application of rotary instruments in endodontics will be discussed.


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Dr. Arash Rahimi, DDS, MScIran

Application of Diode Laser in Dentistry

Laser technology is quickly evolving with the presence of newer lasers, along with new indications, that are constantly being introduced. The use of lasers has become a major discipline and is currently practiced in dentistry.

This workshop offers practical usage of diode laser in dentistry.


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Omid Moghaddas, DDS, MSPeriodontist, , DentalXP Expert, Iran

Ridge Splitting with Piezosurgery

Inserting dental implants in a proper position is one of the most influential factors in achieving success not only from the biomechanical point of view but also from prosthetic and esthetic. In some patients there is not enough available bone so different modalities in ridge augmentation have been proposed for recreating a proper bony bed. Ridge splitting is one of the techniques for increasing the width of the available bone present and has its own criteria. In the workshop the indications, contraindications and probable complications that may happen intra-operatively will be discussed and participants will have a hands on training on animal models.


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Dr.Haleh Kazemi Yazdi, DDS, MSSpecialist in Restorative DentistryAssistant Professor Azad Dental University, Dental Branch, Iran

Management of Tooth Wear, Functionally & Aesthetically with Supra-Occlusion Composite Restorations

According to the latest epidemiological survey, prevalence of tooth wear is increasing significantly among young and elder patients. Restorative management of worn dentition is a great challenge in general dental practice when tissue loss involves the articulating surface. Short clinical crown height of worn teeth and inadequate space to accommodate a proper restoration can compromise the vitality of worn teeth and resistance of restorations. Using supra-occlusion restorations to restore tooth wear is both reliable and predictable .Reliability and predictability of direct bonding to residual tooth tissue, widened the indication of direct composite restorations from just a single tooth build up to a practical option for full mouth rehabilitation. In spite of a few problems such as discoloration and chipping of restorations; a stable occlusion can be achieved with this treatment. The objective of this brief will be illustrating techniques and considerations of restoring worn teeth utilizing supra-occlusion composite restorations.


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Dr.Fariba Motevasselian, DDS, MSSpecialist in Restorative Dentistry, Iran

Management of tooth wear

The term tooth wear is a general term that can be used to describe the surface loss of dental hard tissues from causes other than dental caries, trauma or as a result of developmental disorders.

It is subdividing into those where the severity of tooth wear may be considered to be normal or physiological for that person’s age, or excessive, pathological to the extent that it is associated with functional or aesthetic concerns and is disproportionate for the age of the patient and symptoms of discomfort are present.

Treatment plan includes the management of any acute conditions, prevention, stabilization of any underlying dental pathology, placement of definitive dental restorations and final stage involves monitoring and maintenance. It is important to institute review stages in passing from one stage to the next one. While for many cases of pathological tooth wear, a passive management and monitoring may suffice, for a proportion of cases active restorative intervention will become necessary. Active restorative intervention will be subdivided into that for localized wear (Maxillary anterior teeth, Mandibular anterior teeth, localized posterior teeth) and generalized wear.

The restorative intervention in three localized tooth and one generalized tooth wear cases are presented.


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Dr.Ebrahim Aminsalehi, DDS, MSSpecialist in Restorative DentistryAssistant Professor Azad Dental University, Dental Branch, Iran

The Clinical Tips on Ceramic Restorations

Nowadays request for esthetic restorations increase more and more. The main reason is that people knows about our capability to create a beautiful and particularly natural smile. Ceramic laminates and crowns are ideal restorations for anterior and posterior teeth but when they can show their ideal performances that practitioner have enough knowledge about composition, variety, advantages, disadvantages, indications and contraindications of these materials.


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Dr. Brigitte Douaihy, DDSProfessional Service ManagerGC Middle East

Composite Restorations: New Concepts and Applications

In modern dentistry, composite restorations occupies a major place in our daily practice. This workshop covers all new concepts and techniques in anterior esthetic restorations and in posterior cases.

Minimum Intervention: A way to Go

Prevention and conserving tooth structure are of a major importance for both dentists and patients.

During this workshop we will propose a new way to take in charge the patient and to assess the risk factors all this in order to put in place the optimal treatment plan.


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This symposium is a cooperation between WHO Collaborative Center, SBMU, Tehran, Iran and Iranian Division of IADR.

Dr. Ali Khader: How can we develop comprehensive preventive strategies at the regional level: what should the specific time line priorities be, should these be disease specific? Which social and environmental health determinants should be incorporated and how?

Dr. Suleiman Mohammad: How can we measure oral health inequalities and who should undertake this at the regional level? How can we establish a knowledge base that uses a standard set of reporting criteria?

Dr. Mohammad H. Khoshnevisan: Upstream strategies- how best can researchers and public health practitioners work together to develop, implement and evaluate the effectiveness of upstream oral health improvement strategies?

Dr. Amjad Matouq: Promoting oral health advocacy - what opportunities exist at local, national and international levels in developing oral health advocacy activities?

Dr. Salahudeen AlBulushi: Future research priorities -what are the future priorities in oral health inequalities research? What are the training needs for the next generation of dental researchers to equip them to work effectively on inequalities agenda?

IADR-WHO Symposium


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Dr. Keivan Saati, DDS, MSSpecialist in Restorative DentistryAssistant Professor Azad Dental University, Dental Branch, Iran

All About Bleaching

Dental bleaching, also known as tooth whitening, is a common procedure in general dentistry. According to the FDA, whitening restores natural tooth color and bleaching whitens beyond the natural color. There are many methods available, such as brushing, bleaching strips, bleaching pen, bleaching gel, and laser bleaching. Bleaching methods use carbamide peroxide which reacts with water to form hyDr.ogen peroxide. Carbamide peroxide has about a third of the strength of hyDr.ogen peroxide.. The peroxide oxidizing agent penetrates the porosities in the rod-like crystal structure of enamel and breaks down stain deposits in the dentin.

Causes of tooth discoloration : A child’s deciduous teeth are generally whiter than the adult teeth that follow. As a person ages the adult teeth often become darker due to changes in the mineral structure of the tooth, as the enamel becomes less porous and phosphate-deficient. Teeth can become stained by bacterial pigments, food-goods and vegetables rich with carotenoids or xanthonoids. Certain antibacterial medications (like tetracycline) can cause teeth stains

Other causes: Tetracyclines Enamel hypoplasia Fluorosis Age of the tooth Tea Coffee Tobacco ( tar ) Mate Wine and cola Dr.inks consumed in excess Other foods and oral tobacco products with strong content of pigments Chlorhexidine

Method :According to the American Dental Association, different whitening methods include in-office bleaching, which is applied by a professional dentist; at-home bleaching, which is used at home by the patient; over-the-counter, which is applied by patients

The ADA recommends to have one’s teeth checked by a dentist before undergoing any whitening method. The dentist should examine the patient thoroughly: take a health and dental history observe hard and soft tissues, placement and conditions

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of restorations, and sometimes x-rays to determine the nature and depth of possible irregularities.

. Bleaching is not recommended if teeth have decay or infected gums. It is least effective when the original tooth color is grayish and may require custom bleaching trays. Bleaching is most effective with yellow discolored teeth.

In-office : In-office bleaching procedures generally use a light-cured protective layer that is carefully painted on the gums and papilla to reduce the risk of chemical burns to the soft tissues. The bleaching gel typically contains between 10% and 44% carbamide peroxide, which is roughly equivalent to a 3% to 16% hyDr.ogen peroxide concentration.

Internal bleaching :Internal bleaching procedures are performed on devitalized teeth that have undergone endodontic treatment (a.k.a. “Root Canal”) but are discolored due to internal staining of the tooth structure by blood and other fluids that leaked in. Bleaching the tooth internally involves Dr.illing a hole to the pulp chamber, cleaning, sealing, and filling the root canal with a rubber-like substance, and placing a peroxide gel or sodium perborate tetrahyDr.ate into the pulp chamber so they can work directly inside the tooth on the dentin layerIn this variation of whitening the whitening agent is sealed within the tooth over a period of some days and replaced as needed, the so-called “walking bleach” technique

At-home :Commercial whitening products intended for home use include gels, chewing gums, rinses, toothpastes, among others. The ADA has published a list of accepted over-the-counter whitening products to help people choose appropriate whitening products.

High-concentration home bleaching uses carbamide peroxide. Whitening is performed by applying a high concentration of oxidizing agent to the teeth with thin plastic trays for a short period of time, which produces quick results. The application trays ideally should be well-fitted to retain the bleaching gel, ensuring even and full tooth exposure to the gel. Trays will typically stay on the teeth for about 15–20 minutes. Trays are then removed and the procedure is repeated up to two more times.

Low-concentration whitening is far less effective. Low-concentration whitening involves purchasing a thin mouth guard or strip that holds a relatively low concentration of oxidizing agent next to the teeth for as long as several hours a day for a period of 5 to 14 days. Results can vary, depending on which application is chosen, with some people achieving whiter teeth in a few days, and others seeing very little results or no results at all.


Oral & Poster Presentation Abstracts in order of ID numbers


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181423Biomimetic Synthetic Enamel: A Potential Remineralizing Agent for Enamel Repair

H. BAGHERI G1, F. SHAFIEI2, T.S. JAFARZADEH KASHI3, and M. BEHROOZIBAKHSH3,1Institue for research in Dental Sciences/School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, 2Tehran University of Medical Sciences, Tehran, Iran, 3Research Center for Science and Technology in Medicine; Tehran University of Medical Sciences, Tehran, Iran

Objectives: Currently, remineralizing agents are being considered as a preventive strategy to stop the mineral loss process and to alter the oral conditions toward remineralization. Up to now, fluoride or calcium phosphate containing systems have been introduced to remineralize the defected enamel tissue. Recently polypeptides have been used for regulation of the mineralization process. The aim of this study was to evaluate the regulatory capacity of leucine-rich amelogenin peptide (LRAP) on the calcium phosphate mineralization.

Methods: Mineralization solutions were prepared to yield final concentration of 2.5 mM Ca+2, 1.5 mM phosphate, and 2 mg/ml LRAP (GL Biochem China) (pH=7.2). 1 ppm F- was added to the selected solutions to study the effect of fluorine ion. Calcium phosphate or fluorine-containing (1 ppm) solutions were used as the controls. The solutions were incubated at 37°C for 72 h. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and selected electron area diffraction (SAED) techniques were used to study the mineralization characteristics.

Results: SAED analysis revealed diffraction patterns corresponding to the apatite structure in all solutions. TEM analysis showed that in LRAP-containing solutions fibers of hydroxyapatite or fluoroapatite arranged in bundles, while in solutions without LRAP, the crystallization occurred without that arrangement. AFM imaging showed the hierarchical prismatic assembly of HA and FA crystals, similar to the enamel structure.

Conclusions: LRAP can regulate the crystallization of calcium phosphate and produce prismatic structures like dental enamel. Therefore, LRAP-CP has the potential to be used as a remineralizing agent for enamel reconstruction.



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181508Adherence of Iranian Dentists to Information Technology

S. MOHEBBI, M. BONABI, M.R. EBRAHIMPOUR, M. SAHEBJAMEE, and A.J. ABBASI, Tehran University of Medical Sciences, Tehran, Iran

Objectives: In the health field, there have been fast development and expansion of use of information and communication technology (ICT) such as navigation portals, telemedicine and dentistry, remote medicine and dentistry, and patient data-storing. This study aimed to assess the knowledge and usage of professional IT applications among dentists.

Methods: The data were collected by a self-administered validated questionnaire distributed among dentists participating in the 52nd International Congress of Iranian Dental Association and a random sample of dentists working in Tehran. It included 7 questions about knowledge, 8 questions on backgrounds, 10 questions on general usage of IT, and 3 questions on the professional usage of IT. The data were entered into SPSS version 18 and the statistical analyses were performed by ANOVA, NPAR test, and regression modeling.

Results: From the total of 303 general practitioners, 30.4% were male and 11 dentists (3.6%) indicated that they had no access to a personal computer. Some of the most popular sites used by dentists were Google (94.3%) and social network of Facebook (69.8%). Those with higher scores in general usage of IT had more consulted with their patients through the Internet. The practice of professional IT was more in men and among those with higher general usage of IT.

Conclusions: This study was a preliminary evaluation of the topic among oral health professions indicating IT to be almost available to most but not all dentists in Iran. Dentists participating in the study had insufficient knowledge and their professional IT usage is defective and weak, needing more consideration and training.


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181684Fracture Resistance of Posts in Full-Coverage Restorations of Primary Incisors

A. BAGHALIAN1, M. RANJPOUR2, T. HOOSHMAND3, and A. EBRAHIMI2, 1Qazvin University of Medical Sciences, Tehran, Iran, 2Qazvin University of Medical Sciences, Qazvin, Iran, 3School of Dentistry/Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran

Objectives: The purpose of this study was to evaluate the fracture resistance of 4 different posts in full-coverage restorations of severely decayed primary incisors.

Methods: 50 primary incisors were selected for this study and all the teeth were sectioned 1 mm above the CEJ. After filing and irrigation of root canal space, the canals were obturated with metapex and 3 mm of post space was prepared inside the canals. Intact glass fiber post, split-ended glass fiber post, composite resin post, and orthodontic wire γ post were used as intracanal posts. The final composite resin restoration was done by using pedodontic strip crown. After thermocycling the specimens, the fracture resistance was measured using a universal testing machine.

Results: The mean fracture resistance of split-ended glass fiber posts was higher than that of other posts; however, there was no significant difference between any of the groups (P>0.05).

Conclusions: Split-ended glass fiber posts seem to be a more appropriate option for full-coverage restorations in primary incisors.


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182551Human and Animal Bone Substitutes for Augmentation before Implant Placement

A. KESHVAD, Shahed University, School of Clinical Dentistry, Tehran, Iran, and T. HOOSHMAND, School of Dentistry/Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran

Objectives: The aim of this study was to compare 2 commercially available human and animal derived bone grafts to augment partially edentulous human bone prior to implant placement for those volunteers with insufficient host bone.

Methods: According to the exclusion and inclusion criteria, 12 healthy volunteers (6 in each group) who accepted our protocol and consented for the study were selected. Similar or identical bone particle sizes were selected from the two products, namely Bio-Oss™ (as an animal derived bone) and Faraz-Kish™ (as a human derived bone), in each surgical approach to augment the partially edentulous areas that had insufficient width or height for placing implants of 10 mm or more. The decision of bone quantity was based on the cone beam computerized tomography (CBCT) obtained in one center by only one radiologist. One edentulous area for each patient on the same jaw was left non-grafted to act as a control group and one edentulous area was grafted with one material for comparison. Xenograft and allograft groups were compared with each other and with their corresponding control groups using before and after values reported on the digital CBCTs.

Results: To obtain post grafting results, 6 months laps’ period was considered as a proper time before the grafted area was subjected to control CBCT. This and the number of subjects necessary to draw a conclusion took 3 years for the study to complete. Data were analyzed using Kruskal-Walis test and the level of significance was set at P<0.05. The results showed significant differences between the grafted and non-grafted areas. Comparison between the xeno and allografts also showed significant differences in the amount of bone obtained after grafting.

Conclusions: Human derived bone grafts showed better bone quality and quantity after 6 months of grafting as opposed to animal derived bone substitutes.


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182850Bone Debris vs. Allografts in Repairing Implant Buccal Bone Dehiscence

A. PARHIZ, and M. JAFAR GHOLIZADEH, Tehran University, Tehran, Iran

Objectives: Assessment of success rate of use of bone debris and allograft biomaterial in reducing gingival complications in implants in which some threads are exposed.

Methods: In this randomized clinical trial, 17 patients (9 male, 8 female) and 30 implants, with collar thread exposure, were entered. Patients with systemic disease (even controlled disease) and poor oral hygiene were excluded. Selection of grafted material for each patient was done randomly using flash cards. After implantation and putting the grafted material on the exposed threads, a collagen membrane was put on it and the surgical site was sutured tightly. In 14 implants bone debris was used and in 16 implants allografts (DBA+MBA, TBI) to cover the exposed threads. The second stage was done at least 2 months later. To save the keratinized gingiva, the tissue punch was not used. Three and 12 months after cementing the crown, three clinical complications were assessed: Collar exposure, Thread exposure, Metal shadow

Results: Data were analyzed using SPSS software, Pearson Chi-square test, and Fisher’s Exact test. In the first follow-up there was no complication. In the second follow-up, there was thread exposure in three implants (18.8%) of allograft group which was not seen in the bone debris group. However, these differences were not statistically significant (P=0.228). There was metal shadow in two implants (14.3%) of bone debris group after 12 months while it was seen only in one implant (6.3%) of allograft group. This difference was not statistically significant (P=0.586). Collar exposure was seen in seven implants (50%) of bone debris group and (43.8%) of allograft group. This difference was not significant either.

Conclusions: Although results of using bone debris and allograft had no statistical difference, in 14 (46.6%) implants one of the mentioned complications arose.


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182855Role of Titanium Mesh in Reconstruction of Ridge Deficiencies

O. MOGHADDAS, Islamic Azad University, Dental Branch, Tehran, Tehran, Iran

Objectives: Sufficient quality and quantity of bone is mandatory for achieving success in implant dentistry from biomechanical and esthetic points of view.

Methods: 25 patients (16 male, 9 female) with horizontal and vertical deficiencies enrolled in this study. Titanium mesh plus freeze-dried bone allograft (FDBA) were utilized to augment the deficient areas. Evaluations were done at baseline (pre-op) and 8 months after, during a reentry surgery for implant placement with periodontal probes and caliper. Independent t-test was used to compare the differences.

Results: Bone graft materials were almost completely incorporated with the vital bone and mean gain in width of 4.6 mm and in height of about 3.2 mm were achieved.

Conclusions: Utilizing titanium mesh with low turnover rate bone grafts is a good alternative with great tissue compatibility, low risk of contamination and easy handling, especially in advanced cases.


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182883Reverse Contrast Digital Radiography in Root Fracture Diagnosis

F. FARSHCHI, Azad Dental University, Tehran, Iran

Objectives: The purpose of this study was to evaluate the diagnostic precision of reverse contrast option from Cygnus Ritter CCD Intra-oral Digital sensor, compared to original digital radiographs, in detection of vertical root fracture.

Methods: 100 extracted single-rooted human teeth (50 non-fractured and 50 fractured) were placed singly in a skull socket. The radiographs were taken in 2 methods: Digital radiographs using a Cygnus Ritter CCD sensor and then reverse contrast option was applied to the original radiographs. 2 maxillofacial radiologists and an endodontist observed the original digital radiographs and their reverse contrast option counterparts to detect vertical root fractures and recorded them in a 5-grade scale. The data were analyzed with a proportion test and processed with SPSS 14.

Results: Statistical analysis showed a sensitivity of 84.7% with CI: 95% for the Reverse contrast option to detect vertical root fractures (P>0.05). The specificity was shown as 61.3% (P>0.05). The Positive Predictive Value was calculated as 77.8% (P>0.05) and Negative Predictive Value as 68.6% (P>0.05).The Accuracy was 73% (P>0.05)

Conclusions: The Reverse contrast option of Cygnus Ritter CCD Sensor did not show a significantly higher diagnostic accuracy compared to original digital radiographs made with that sensor.


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182884The Effect of OTC Bleaching Products on Enamel Microhardness

N. NOURBAKHSH1, E. JAFARPOUR1, and S. NEMATI ANARAKI2, 1Islamic Azad Dental university of Tehran, Tehran, Iran, 2Islamic Azad Dental university, Tehran, Iran

Objectives: OTC bleaching materials which have been accepted in society may affect properties of enamel microhardness. The aim of this study was to compare the effect of three kinds of OTC bleaching materials (White strip, paint on, and toothpaste) one enamel microhardness of human third molar before and after bleaching treatment.

Methods: In this experimental study of enamel specimens, 45 freshly extracted human third molar were prepared and divided in to three groups of white strips, paint on, and toothpaste. Each material was used according to the manufacturers (Crest and Rapidwhite) instructions. Vickers microhardness test was performed for all groups. Data were analyzed by repeated measure ANOVA and LSD test.

Results: Microhardness values of white strips, paint on, and tooth paste groups before and after bleaching treatment were 305.60±51.70 and 289.20±54.24/286.53±62.10&276.13±61.75/256.60±39.77&253.06±38.62, respectively. One-way ANOVA showed significant differences among three OTC groups (P<0.001). There was also significant difference among the value of enamel microhardness before and after the bleaching in each group (P<0.001).

Conclusions: Whitening OTC products affect enamel microhardness. White strips and paint on decreased the microhardness more than whitening toothpaste. Consumers should be aware of these OTC products side effects and use them conservatively.


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182902Effect of GC Tooth Mousse and MI Paste Plus on Dental Plaque Acidity

H. HESHMAT, Department of Restorative Dentistry and Dental Materials, Islamic Azad University Dental Branch, Tehran, Iran, Tehran, Iran, H. ABDIAN, Dentist, Tehran, Iran, and F. FARAJI, School of Dentistry,Islamic Azad University.Tehran.Iran, Tehran, Iran

Objectives: Reduction in plaque pH after consuming sugary materials is effective in dissolving minerals on enamel surface. Casein phosphopeptid-Amorphous Calcium Phosphate (GC Tooth Mousse), is a paste with available type of Calcium Phosphate rather than ions of calcium and phosphate that is in the saliva. The new composition of this paste called MI Paste Plus is presented with 900 ppm fluoride (CPP-ACPF). Utilizing this paste can help neutralize the pH of bacterial plaque. In this study the effect of CPP-ACP and CPP-ACPF were evaluated on neutralizing the plaque pH during different times.

Methods: This clinical study has been done on 40 students. Plaque acidity (pH) at distal of first molar were evaluated before and 10 minutes after 10% sucrose consumption. In the next step, CPP-ACP and CPP-ACPF pastes were used as directed on tooth surface. Plaque pH was assessed 30 and 60 minutes, 24, 48, 72 and 96 hours after application, data were recorded and analyzed by Repeated Measure ANOVA statistical method (P<0/05) .

Results: Both CPP-ACP and CPP-ACPF increased plaque pH levels, identically for the first 48 hours. The pattern differed after this period.

Conclusions: The effect of CPP-ACP and CPP-ACPF were identical until 48 hours, but CPP-ACPF can be increased the pH until 96 hours.


53

182903Porcelain Laminate Fracture Resistance on Incisal Reduction less than 2mm

E. AMINSALEHI, K. SAATI, A. DARNAHAL, and S. NEJAD KARIMI, Islamic Azad University Dental Center, Tehran, Iran

Objectives: In the past decade, the demand for more durable and esthetic anterior restoration like porcelain laminate veneer has increased. The main reason for failure in this treatment is porcelain fracture. Therefore, tooth preparation plays an important role in fracture resistance of porcelain laminate veneer. Obviously proper choice of incisal reduction is an important factor to increase fracture resistance. The aim of this in vitro study was to evaluate the fracture resistance of porcelain laminate veneer dependent on the size of incisal reduction at less than 2 millimeter.

Methods: In this experimental study, 40 caries-free maxillary central incisors were divided into four groups (n=10). While the control group remained unprepared, in the second, third, and fourth groups the preparation included 1 mm, 1.5 mm and 2 mm of incisal edge respectively. 30 feldespatic ceramic veneers were bonded by light cure luting cement (Choice 2). After that, specimens were loaded by universal testing machine under increasing force (1 mm/min cross head speed – 135 force angle degree) 0.5 mm lower than incisal edge until fracture was accrued. Finally, fracture loads were recorded on newton unit.

Results: The mean fracture forces for control, 1 mm, 1.5 mm and 2 mm groups were 1089.4±276.49, 921.56±399.78, 894.46 ± 538.35, and 877.28±371.5 respectively. Besides, cohesive fracture in second, third, and fourth groups were 6, 6, and 4 respectively. Also, adhesive fractures (between cement and porcelain) were 1, 1, and 2 and adhesive fractures (between cement and tooth) were 3, 2, and 3 respectively. However, in third and fourth groups one crack in porcelain without fracture was seen.

Conclusions: Under limitations of this study from fracture resistance point of view there was no significant difference between control group and the three other groups (P>0.05).


54

182909Effect of Fluoride and Chlorhexidine Varnishes on Interproximal Plaque pH S. BANAVA1, S. ASKARZADEH2, D. NIKNAM3, and S. ABDOLLAHZADEH2, 1Islamic Azad University Dental Branch, Tehran, Iran, 2Dental Branch , Islamic Azad University, Tehran, Iran, 3Islamic Azad University Dental Center, Tehran, Iran

Objectives: Dental plaque characteristics are responsible for occurrence of dental caries. If the plaque pH reduces to 5.2-5.5 the demineralization procedure will start. Increasing the plaque pH could be effective on slowing down the demineralization process. The aim of this clinical study was to evaluate the effect of fluoride and chlorhexidine varnishes on plaque pH of children aged 2-15 years old.

Methods: In this triple-blind randomized controlled clinical trial 46 children aged 2-15 who met the inclusion criteria entered the study and were divided into two age groups of 2-6 and 6-15 by Stratified Randomization. Participants were randomly allocated in the three following groups: Group 1 (Control): No varnish application, Group 2: Chlorhexidine varnish (Cervitec Plus, Ivoclar V), and Group 3: Fluoride varnish (Fluor Protector, Sultan Healthcare Inc, USA). In the first session, the baseline pH of inter-proximal dental plaque of all participants was measured by pH Plaque Indicator Kit (GC America, USA) and then the related varnishes were applied according to the manufacturer instructions in each group. The application of varnishes was done by dental floss into the proximal surfaces. After 1 and 3 months, the interproximal plaque pH was measured again. The data were analyzed by Kruskal wallis test and set to 0.05.

Results: Statistical analysis showed that once application of none of the varnishes could change the interproximal plaque pH significantly in different groups and different times (P>0.05).

Conclusions: Applying fluoride varnish or chlorhexidine varnish did not cause any changes in the interproximal pH plaque in different groups in comparison to the control group. Varnish application of more than once is recommended and needs further research.


55

182913The Role of HIV Infection on Oral Pigmentation

S. LESAN, M. SADAT KHODAEI, M.A. OUSIA, A. AZIZI, and A. NAJAFPOUR, Islamic Azad University,Dental branch,Tehran,Iran, Tehran, Iran

Objectives: Diffuse or Multifocal Mucocutaneous pigmentation has been frequently described as a clinical feature of HIV+/AIDS person. The purpose of this study was to determine the role of HIV+/AIDS on oral pigmentation in Tehran Imam Khomeini hospital’s patients and their control group during 2009-2010.

Methods: In this historical cohort study (cross sectional study) 35 HIV+ patients (case group) and 35 HIV- patients (control group) who referred to the infectious, surgery, or gynecology department of Tehran Imam Khomeini hospital were examined and evaluated. Both groups were matched for age, sex, cigarette smoking, alcohol consumption, OCP using, and pregnancy. The study was done by observation, clinical examination, and interviewing the patients in addition to reviewing their medical files and completing the questionnaire. Oral pigmentation was recorded. The data were analyzed by chi-squared, exact fisher test.

Results: In this study 70 individuals were examined which were equally divided into case and control groups. The prevalence of oral pigmentation was 22.9% (N=8) in the case group and 17.1% (N=6) in the control group. The prevalence of melanin pigmentation in control group was less than healthy individuals but there was no statistically significant difference between the case and control group (P=0.5).

Conclusions: Since there was no significant difference in oral pigmentation in HIV+ and HIV- patients, it can be concluded that in this study, HIV infection does not have any role on oral pigmentation.


56

182923Clinical Effectiveness of Laser on Postoperative Hypersensitivity

H.-. MOOSAVI1, F.-. MALEKNEJAD2, M.-. SHARIFI1, and F.-. AHRARI1, 1Dental Materials Research Center, Mashhad, Iran, 2Dental Material Research Center, Mashhad, Iran

Objectives: Postoperative hypersensitivity may be one of the drawbacks of every tooth operation. The aim of this study was to evaluate the efficacy of Indium Gallium Aluminum Arsenide Phosphate laser on postoperative hypersensitivity in cervical lesions.

Methods: In this randomized controlled clinical trial, 31 patients were included. Teeth were assigned randomly two groups of with or without irradiation by laser. In the experimental group the same clinical procedure was used as the control group, except applying laser emission before filling. Self-etch adhesive; Clearfil SE Bond, was applied and cavities restored with composite resin; Clearfil APX. Preoperative and 1-day, 2-, and 4-week-postoperative hypersensitivity were recorded for both groups using an 11-point visual analog scale filled out by subjects. The analyses were conducted to determine whether any correlation or association existed between with or without laser irradiation during several follow-ups. Data were analyzed by Wilcoxson and Friedman test.

Results: Laser irradiation had a significantly higher desensitizing effect compared with the control group after treatment. Significant differences were observed between the laser and control groups at every follow-up examination. For the laser and control group, the differences between baseline and all time points following the treatment were statistically significant.

Conclusions: Laser irradiation is an effective method in the reduction of postoperative sensitivity compared with non-irradiated treatment.


57

182924Degree of Conversion of Low-Shrinkage Composites Photo-Activated by LED and Halogen

T. HOOSHMAND, School of Dentistry/Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran, K. FAMILI, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, and A. KESHVAD, Shahed University, School of Clinical Dentistry, Tehran, Iran

Objectives: To assess and compare the degree of conversion and micohardness of different resin-based restorative materials consisting of conventional methacrylate-based, silorane-based, and new urethane dimethacrylate-based composites as a function of light curing units (Quartz-Tungsten-Halogen (QTH) and Light Emitting Diode (LED)).

Methods: To obtain the specimens, a circular matrix of stainless steel was used. Composite materials (Tetric Nceram, Filtek Silorane and Kalore GC) were put into the mold and pressed under 500 gr siker. The specimens were cured by either Bluephase LED for 20 s, or Coltolux halogen for 40 s. Degree of conversion was measured using FT-IR spectroscopy. Vickers microhardness of top and bottom surfaces was also evaluated. To compare the degree of conversion and microhardness between composites, Kruskall-Wallis test and pairwise comparison were used. Mann-Whitney U test was used for comparison of efficacy between the two light curing units.

Results: The degree of conversion or microhardness between bottom and top surfaces of all test groups were significant (P<0.05). The degree of conversion or microhardness for all the specimens polymerized by LED was significantly higher than that of halogen (P<0.05). Filtek Silorane exhibited a better degree of polymerization compared with that of other composites polymerized either by QTH or LED light (P<0.05).

Conclusions: Silorane-based composite showed a better degree of polymerization than that of other methacrylate-based composites. The degree of conversion and Vickers microhardness were affected by the type of resin composite material, light curing units, and curing depths.


58

182926Investigation of Implant Width on Distribution of Stress in Adjacent Bone

E. JAFARPOUR1, N. NOURBAKHSH1, and E. JALALIAN2, 1Azad university of dentistry of Tehran, Tehran, Iran, 2Islamic Azad University Dental Center, Tehran, Iran

Objectives: Implant width has a significant role in distribution of stress and many different studies have suggested different outcomes. The purpose of this study was to determine the optimum width of implant for distribution of stress.

Methods: The current experimental research was implemented using photo elastic method with wide variety of implant width including 3.3,3.7,5,6, 3.5 mm and similar length equal to 10 mm. Plexiglass block with the same length and height of 33.5 and 35 mm and different width of implant were prepared so as there would be 1.5 mm width around each implant. They were placed under the force of 157 and 65 N in 90 and 30 degree angles respectively by photo elastic device. The obtained images were assimilated using Photoshop 650 x 760 and evaluated by image.

Results: Using the image J software colored analyzed images were obtained. The analysis procedure was based on three color (red –white –blue) separation technique. Three color separations resulted in a more investigation of spots which later categorized into stress focused, stress free and modest stress groups. The highest amount of stress focus was associated to 6 mm depth, 30 degree angle and under 100 N force with partial fraction of ¼ or 25/100 and the lowest amount of stress focus was associated with 3.7 mm depth, 90 degree angle and under the N force.

Conclusions: With the increase of implant depth from 3.2 to 5 mm, the stress amount of adjacent bone decreased and with increase in stress occurred. In the case of using higher depth, the optimum depth seems to be 5 mm.


59

182929Quality Assessment of the Information Related to Fissure Sealant

F. NILCHIAN, School of Dentistry, Isfahan University of Medical Sciences, Esfahan, Iran, and L. GHASEMI, University of Isfahan, Isfahan, Iran

Objectives: The aim of this study was to evaluate the quality of information related to pit and fissure sealant in general Persian Internet websites.

Methods: In this cross-sectional study, by searching in Google engine, the websites providing information about fissure sealant were found. The key words were “patient education and fissure sealant”, checked by MeSH database. From 500 initial links, the inadequate ones were eliminated according to exclusion criteria, and 37 websites remained. These websites were evaluated through a checklist designed by the researchers, the validity and reliability of which had been evaluated and confirmed.

Results: The average score of the quality of information was 22.46. The minimum and maximum of obtained scores were 16 and 30, respectively. The total and ideal number was 38.

Conclusions: Overall the quality of information related to fissure sealant in general Internet sources was good, yet they did not cover the entire required information which could be improved. The main problem of information was that they did not provide creditable/credible and up-to-date sources.


60

182944Formulation of New Mucoadhesive Containing Phenytoin on Wound Healing S. ALIREZAEI, resident, tehran, Iran, and M. BAHARVAND, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: Several studies have shown the wound healing effect of topical phenytoin, which is applied by its effect on connective tissue intracellular matrix. However, there are still some controversies about its effect on various kinds of wounds. This study evaluated the effect of mucoadhesive paste compared to phenytoin mucoadhesive paste on wound healing after oral biopsy. The importance of this study is that no systemic treatment is used; therefore, side effects of such a treatment.

Methods: This study was a randomized double blind clinical trial. Parameters included age, gender, tissue inflammation, degree of pain, and size of the ulcer. After entering the study, patients were randomized into two groups. Both groups had oral biopsy ulcers ranging between one and two centimeters. Patients in the first group were treated by simple mucoadhesive paste, while patients in the second group were treated by phenytoin mucoadhesive paste. Both pastes were applied for 5 days after the biopsy. Statistical analysis was done using Mann-Whitney test.

Results: After the second and third appointments, it was observed that the rate of wound healing and decrease in the size of the ulcers were significantly quicker in the second group (P=0.001 and P=0.003 respectively) and the patients in the second group reported less pain. Diameter of the inflammatory halo was not significantly different between the two groups.

Conclusions: Applying phenytoin mucoadhesive paste on biopsy ulcers resulted in accelerated wound healing and decrease in pain, but had no effect on the diameter of the inflammatory halo.


61

182961Residual Root Thickness Evaluation after Pre-Flaring Using Gates Glidden Drills

N. MOHAMMADZADEH AKHLAGHI1, A. NAGHDI2, L. MOHAMMADIAN2, and E. BEHROUZ2, 1Islamic Azad University Dental Branch, Tehran, Iran, 2Islamic Azad University Dental Center, Tehran, Iran

Objectives: To evaluate the residual root thickness in mesiolingual (ML) canals of mandibular molars after pre-flaring using different sequences of Gates-Glidden (GG) drills.

Methods: Computed tomography (CT) scans of the ML canals of 60 mandibular first molars were provided from areas within 1, 2, 3, and 4 mm of the furcation area and minimum initial root thickness (MIRT) of concave areas was measured at each level. The samples were divided into two groups (G1 and G2) which were prepared by the step-back and crown-down techniques, respectively. In both groups, anti-curvature filing was used. On secondary CT images of the samples in the same position, the minimum residual root thickness (MRRT) and the amount of removed dentin were analyzed by t-test and ANOVA.

Results: There was no significant difference for MIRT between the two groups. The MRRT was greater in the G2 group in all the sections, with no significant difference between them. The average of MRRT was not less than 0.5 mm in any of the groups or sections.

Conclusions: Based on the results of this study when the root thickness is appropriate at first, GG drills used in any sequence may be suitable, safe, and cost effective for pre-flaring of mesial canals of mandibular first molars with preserving the root thickness of furcation areas.


62

182962Effects of bonding agent and sealant viscosity on sealant microleakage

S. SADEGHI, Assistant professor, Department of Orthodontics, Kerman Dental School, Kerman University of Medical Sciences, Kerman, Iran, F. MAZHARI, Associate professor, Department of Pediatrics, Mashhad Dental School, Mashhad University of Medical Sciences, Mashhad, Iran, and M. MEHRABKHANI, Assistant professor, Department of Pediatrics, Mashhad Dental School, Mashhad University of Medical Sciences, Mashhad, Iran

Objectives: Pit and fissures are susceptible to caries and this accounts for approximately 80-90% of all permanent posterior teeth decay. Sealant placement culminates in a 80% caries reduction after one year. An issue of concern in dentistry is proper sealing following sealant placement. The purpose of this study was to evaluate the effect of enamel bonding agent, dentin bonding agent, and sealant viscosity on sealant microleakage occurrence.

Methods: 60 extracted human premolars were randomly divided into two equal groups and each group was divided to three subgroups of 10 teeth. In Group 1, Subgroup 1 after prophylaxis, enameloplasty, etching of occlusal surfaces with 38% phosphoric acid gel, rinsing and drying, low viscosity sealant was applied and cured. Group 1, Subgroup 2 received enamel bonding agent prior to low viscosity sealant placement and cured. In Group 1, Subgroup 3 before low viscosity sealant placement, dentin bonding agent was applied and cured. In Group 2 similar procedures were performed except for applying high viscosity sealant. Specimens were thermocycled for 500 cycles at 5°C and 55°C with dwell time of 10 second. Microleakage was scored according to distance of dye penetration as: 0 = no dye penetration and 3 = dye penetrates to underlying fissure.

Results: Statistical Analysis showed significant effect of sealant viscosity and bonding agent on the microleakage scores (P=0.037). There was no significant difference between dentin bonding agent and enamel bonding agent and no bonding agent subgroups in the microieakage scores in both groups. Significant differences between low viscosity sealant without applying bonding agent subgroup and high viscosity sealant without applying bonding agent subgroup (P=0.041), and between dentin bonding agent in low viscosity and high viscosity sealant subgroups (P=0.002) were found.

Conclusions: The results of this study indicated that concurrent use of low viscosity sealant and dentin bonding agent reduces the microleakage of pit and fissures.


63

182963Accuracy of Two Radiographic Methods in Diagnosis of Root Resorption

A. MESGARANI, and M. EHSANI, Assistant Professor, Faculty of Dentistry of Babol, Babol, Iran

Objectives: The aim of the current study was to evaluate the diagnosis accuracy of external root resorption with conventional intraoral film radiography, CCD sensor, and PSP sensor.

Methods: This in vitro study was performed on 80 extracted human sound premolars. Artificial external root resorption were simulated using 0.8 mm, 1 mm, 1.2 mm, and 1.4 mm diameter round burs by drilling to the entire depth at apical half of the mesial, distal, and buccal surface. Two dosages of radiography were used (0.16 and 0.08 second in the conventional radiography, 0.08 and 0.04 in the digital radiography).Three observers (one radiologist and two endodontists) examined the images. Data were statistically analyzed by SPSS 17 software.

Results: Higher proportion of correct reading were obtained with the CCD receptor (P=0.39). The best results were obtained when surfaces were without resorption (P=0.001).The observers detected more cases with increasing the dose of radiography and the size of cavity.

Conclusions: The CCD sensor was better than conventional intraoral film radiography and conventional radiography is better than PSP sensor in detecting external root resorption, although, there is no significant difference.


64

182964Relationship between Art (Painting) with Stress, Anxiety, Depression in Dentists

N. RAHSHENAS1, M.S. NAZARI1, K. NASIRI1, O. HAJ AGHAIE1, A. NAZARI2, and S. SHAHIDI3, 1Islamic Azad University Dental Center, Tehran, Iran, 2Ahvaz Jundishapour University of Medical Sciences (ajums), Ahvaz, Iran, 3Shahid Beheshti of University, Tehran, Iran

Objectives: Art (painting) and its effects on reducing the stress, anxiety, and depression of dentists were the aim of this research.

Methods: The research was done as historical cohort. Initially by using the list of artist physicians association and artistic societies, the names of dentists engaged in an artistic field (painting) were received. In this research, 80 samples were examined from the viewpoints of stress, depression, and anxiety. After visiting these dentists, their artistic activity and some specifications including age, gender, marital status, engagement in a field of specialty, existence of a stressed and depressed person in the family, and existence of specific events (divorce, death of a family member etc) in life were examined and registered in the information form. Then a sample was then taken from the non-artist group. These two groups were examined using a DASS-42 questionnaire and were statistically assessed by profiting from Mann-U-Whitney and Chi-Square tests.

Results: There was a meaningful difference between the two groups of dentists (two 40-persons groups; 40 dentists who had artistic activity (painting) and 40 dentists who did not). Among dentists who had artistic activity (painting), 32 persons (80%) had normal stress, 40 persons (100%) had normal depression, and 40 persons (100%) had normal anxiety. However, among dentists who did not have artistic activity, 7 persons (17.5%) had normal stress, 10 persons (25%) had normal depression, and 17 persons (42.5%) had normal anxiety.

Conclusions: The findings showed that dentists who did not have artistic activity (painting), had more stress, anxiety, and depression than those who had artistic activity. Some examinations of stress, depression, and anxiety in other artistic fields is recommended.


65

182965Effect of Stress on Salivary Ion Content in Orthodontic Patients

H. RAHIMI, and F. AMINI, Islamic Azad University Dental Center, Tehran, Iran

Objectives: Psychological stress can alter the environment in favor of corrosion of orthodontic alloys by changing the properties of saliva. This study aimed to assess the effect of stress induction on salivary nickel and chromium content in fixed orthodontic patients.

Methods: 30 patients were enrolled in this experiment. Saliva sample collection was performed at four time points: T1, before insertion of orthodontic appliances; T2, 3 months after the initiation of orthodontic treatment, before induction of stress; T3, 15 min following the induction of stress by Trier Social Stress Test; T4, 30 min following the induction of stress. Ion content was measured by atomic absorption Spectrophotometry. The obtained data were analyzed by repeated-measures analysis of variance (ANOVA) and post hoc Bonferroni test.

Results: The mean amount of salivary nickel increased from 11.88 ± 5.11 µg/L at T1 to 14.11 ± 5.31 µg/L at T4. This increase was found significant only at T4 compared to T1. The average salivary chromium content changed from 4.09 ± 2.33 µg/L at T1 to 5.10 ± 3.28 µg/L at T4. None of the differences was significant for chromium.

Conclusions: In this study induction of stress led to a significant increase in nickel release from orthodontic appliances into saliva. The salivary chromium content, however, was not significantly altered, yet gradually increased.


66

182970SEM Evaluation of Intracanal Dentin Changes in Endodontically Treated Teeth:

M. MIRZAEI, department of operative devtidtry, Tehran University of medical science, tehran, Iran, A. PAHLEVAN, department of operative dentistry,Tehran university of medical science, tehran, Iran, F. MOTEVASELIAN, specialist in restorative dentistry, Tehran, Iran, and M. SHAMSEDDIN, dentist, Tehran, Iran

Objectives: In recent years, different kinds of posts have been used in dentistry that were manufactured according to bonding to intracanal dentin and can be used by resin adhesive to root canal system. The aim of this study was to evaluate the morphlogical structure of different parts of root dentin in endodontically treated teeth and untreated teeth.

Methods: 18 human central incisors were selected for this study. 14 teeth were divided into two groups of 7 in each control or experimental group. 4 central incisor teeth were used to assess the histomorphologic view of dentin of crowns. After endodontic treatment in the experimental group, the roots were cut in both experimental and control group. The filling materials inside the canal including gutta-percha and sealer were removed by pluggers. Root samples were cut from cervical and middle part of root with diamond disc. Also, 4 crown samples were cut into two halves by diamond disc to assess the dentin from upper and lateral view. The samples were assessed by scanning electron microscope. The photographs were taken from one third of apical, one third of middle of root canal, and the sections of crowns to calculate the percentage of area occupied by dentinal tubules using Adobe Photoshop software.

Results: The Mann-Whiteny test in analysis of dentinal tubule surface in different parts of dentin surfaces showed statically significant difference (P=0.005).

Conclusions: It can be concluded that in treated teeth that a suitable substrate for bonding is not available due to the presence of debris and residual of filling materials.


67

182976A Biocompatibility Comparison of Nanosilver Coated Gutta-Percha and Standard Gutta-Percha

M.A. MOZAYENI, Shahid Beheshti University of Medical Sciences, Tehran, Iran, S.O. DIANAT, Assistant Professor, Dept. of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences,Tehran, tehran, Iran, and S. AZADNIA, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Iran

Objectives: Gutta-percha has been the most widely used root canal filing material because of its well-known low toxicity. A new kind of gutta-percha with nanosilver coating has been synthesized by Iranian researchers and claimed to have antibacterial and antifungal properties. The aim of this study was to compare biocompatibility of nanosilver coated gutta-percha with normal gutta-percha in subcutaneous tissue of rats.

Methods: In this in vivo study, biocompatibility was evaluated on subcutaneous tissue of rats. The test materials were inserted into subcutaneous of two groups of 20, and histopathological examinations were done 7 and 30 days after the implantation. In each time period, 10 test cases and 1 negative control were used and inflammation was evaluated using conventional transmitted light microscopy. The results of the inflammatory reactions were tested with Mann–Whitney U-Test, Wilcoxon Signed Ranks Test, Fisher Exact Test, and Mc Nemar Test.

Results: In 7 days period, inflammation induced by nanosilver coated gutta-percha was significantly more than normal gutta-percha (P<0.001). After 30 days, inflammation response of two test groups were significantly different (P<0.001). There was no sign of inflammation in normal gutta-percha group, whereas mild inflammation was reported in test cases associated with nanosilver coated gutta-percha. In both time periods formation of collagenized-fibrous tissue was observed.

Conclusions: Considering the fact that inflammation response decreased in both test groups, and after 30 days in test cases associated with silver coated gutta-percha mild inflammation was present, and also the presence of collagenized-fibrous tissue in both groups which is a sign of healing, it can be concluded that there is no contraindication in clinical usage of nanosilver coated gutta-percha.


68

182979Internal Evaluation of Operative Dentistry Department of Tehran University

L. RANJBAR OMRANI, Assistant Professor, operative dentistry department, Faculty of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, and M. MIRZAEI, department of operative dentistry, Tehran University of medical science, Tehran, Iran

Objectives: Internal evaluation is the measurement of abilities and potentials. The aim of internal evaluation is promoting the quality of education, research, health, and treatment. The goal of education is creating appropriate and growing changes in students. The aim of this research was to determine the effective factors in the operative dentistry department and determining points of strength, weakness, opportunities and threats of this department in order to improve programs and activities after this research.

Methods: This research was a descriptive and analytical study. The method of study was cross sectional. In this evaluation, 11 important factors were taken into account. Data were collected by questioner. Research was analyzed and was expressed as raw data and percentage.

Results: The score of the restorative and esthetic dentistry department as the main factor is 3.45 out of 5 that is (69.11%). Factors were scored as follows: 1 – Mission and goals: 3.77 (75.6%), 2 – Management and organization: 3.13 (62.75%), 3 – Faculty members: 3.53 (70.7%), 4 – Students: 2.99 (59.9%), 5 – Teaching and learning process: 3.21 (64.27 %), 6 – Training courses and curriculum: 3.32 (66.52%), 7 – Graduate students: 3.78 (75.6%), 8 – Educational and research facilities and equipments: 3.08 (61.7%), 9 – Research: 2.73 (55.64%), 10 – Patients satisfaction of services: 4.67 (93.55%), and 11 – Students’ capabilities: 3.95 (79.1%). Therefore, according to the results, weaknesses of the department were research, educational and research facilities and equipments. Graduated students, patients’ satisfaction of services, and students’ capabilities were the strengths of the department.

Conclusions: An analysis of the findings of this research study led to the understanding that the operative dentistry department was desirable.


69

182985Effects of Different Prosthesis Materials on Stress Distribution of Implant

S. KHAZAEI1, P. IRANMANESH2, E. GHASEMI2, and A. ABEDIAN3, 1School of Dentistry, Kermanshah University of Medical Sciences, Kermanshah, Iran, 2Isfahan University of Medical Sciences, Isfahan, Iran, 3Isfahan University of Technology, Isfahan, Iran

Objectives: The finite element method (FEM) was used to investigate the effects of different types of prosthesis material on stress distribution of bone surrounding implants and to evaluate the stress distribution in three-unit implant supported fixed partial denture (FPD).

Methods: A three-dimensional finite element FPD model of the maxillary second premolar to the second molar was designed. Three load conditions were applied statically on functional cusps in horizontal (57.0 N), vertical (200.0 N) and oblique (400.0 N, è=120°) directions. Four standard framework materials were evaluated: polymethyl methacrylate, base-metal, porcelain fused to metal and porcelain. All materials were considered to be linear elastic, homogeneous and time independent.

Results: The maximum of von Mises stress in oblique direction was higher than vertical and horizontal directions in all case studies. In crestal bone section, the maximum von Mises stress was observed in polymethyl methacrylate through oblique direction of the load with the value of 53.78 MPa. The numerical results demonstrated that maximum stress was generated at the connector region of the FPD in all case studies.

Conclusions: A noticeable difference between bone stress distribution using different prosthesis materials were not observed. Although higher stress value could be seen in polymethyl methacrylate, all types of prosthesis yielded the same stress distribution pattern in FPD. More clinical studies are needed to evaluate the success and failure of these materials.


70

182990Introduction of Iranian 3D Dental Cast Simulator

M. NOURI, Dentofacial Deformities Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, S. ASEFI, Resident of Orthodontics Shahid Beheshti University of Medical Sciences, Tehran, Iran, A. AKHBARZADEH BAGHBAN, Associate Professor, Department of Basic Science Faculty of Rehabilitation Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran, A. AMINIAN, Assistant Professor of Orthodontic Department of Dental School, Kerman University Of Medical Science, Kerman, Iran, and R. MASSUDI, Professor of Laser institute, Shahid Beheshti University, Tehran, Iran

Objectives: Plaster study models are “gold standard” in diagnosis and treatment planning in orthodontic. Because of their drawbacks, alternative methods have been suggested for reconstruction of dental occlusion.

Methods: In this descriptive study, a software was developed for dental cast simulation and analysis. This software was developed by Visual Basic. The features of this software were: High speed; Real-time rotation of the cast; Moving, translation and zooming the cast by the selected range; Cutting and removing different parts of the cast; Clip far that is the omission of the points until reaching the cusp tip; Distance measurement with 0.1 mm accuracy; Ease of application and training; Small size of the program (less than 400 KB). For assessing the simulator accuracy, 3 variables (intercanine width, intermolar width, and arch depth) were measured on 20 plaster study casts with 5 categories. The parameters were measured in the simulator and on the cast manually by digital caliper. They were compared by means of ICC and Dahlberg.

Results: Reliability coefficients between the two methods for maxillary intercanine, intermolar widths, and also arch depth were 0.98, 0.98, and 0.87, respectively. However, for mandible, they were 0.94, 0.77, and 0.92 respectively.

Conclusions: The average maximum absolute difference between the two methods was less than 0.5 mm, provided system was indeed clinically acceptable. The laser scanner and its software were clinically accurate in measuring arch depth and width in canine and molar areas.


71

182999Removal of Refractory Erosive Lichen Planus by CO2 Laser

A. PAKFETRAT, Associate professor, Mashhad, Iran, F. FALAKI, Assistant professor, Mashhad, Iran, F. AHRARI, Assistant Professor, Mashhad, Iran, and S. BIDAD, dentist, Mashhad, Iran

Objectives: The erosive-atrophic form of Oral lichen planus (OLP) is often associated with severe pain and burning sensation. This study investigated the efficacy of CO2 laser surgery for management of refractory erosive-atrophic OLP.

Methods: 10 patients with 13 erosive-atrophic OLP resistant to standard therapy participated in this study. The size and clinical score of the lesions and the level of pain/discomfort were recorded before treatment. The lesions were then removed with a CO2 laser device (10600 nm, continuous wave, 5 W). The patients were evaluated 1 month and 3 months later and the response rate was assessed according to the decrease in sign and pain scores and size of the lesions.

Results: There was a significant reduction in pain symptom and lesion size at 1 and 3 months following laser treatment (P<0.05). The sign scores of the lesions were also significantly improved at follow-up periods compared to the pretreatment state (P<0.05). At the end of the follow-up period, 54% of the lesions showed 3 or 4 degrees of improvement in the clinical score and 23% improved 1 or 2 degrees.

Conclusions: The present results indicate that the CO2 laser surgery is an effective modality for management of erosive-atrophic OLP.


72

183020Comparison Of Apically Extruded Debris Between Hero And Race Systems H. AKHAVAN*, Department of endodontics, Islamic Azad University Dental Center*, Tehran, Iran, A. SEDIGH NIA**, Shahid Beheshti University Dental Center, Tehran, Iran, and A. MIRKAZEMI*, Islamic Azad university dental center, Tehran, Iran

Objectives: The purpose of this in vitro study was to determine the quantity of extruded apically debris using the proper Hero rotary system compared to Race rotary system.

Methods: In this experimental study, 40 disto-buccal root canals of human maxillary first molars were selected and divided into two groups of 20 canals. One group was instrumented with Hero rotary system and the other with Race rotary system according to the manufacturer instructions. A standard amount of irrigant was used for each canal. Apically extruded debris and irrigant were collected in pre-weighted vials. Then the vials were located in the desiccator and after removing the irrigant, the weight of dry debris was estimated. The mean weight of the extruded debris for each group was analyzed using one sample Kolmogorov-Smirnov test and independent sample test.

Results: The weight of extruded debris showed that the Race rotary system resulted in less debris extrusion (0.0043485 gr) compared to Hero rotary system (0.0072135 gr). The difference was statistically significant (P=0.004).

Conclusions: Under the conditions of this study, the Race rotary system extruded less debris than the Hero rotary system.


73

183021The Effect of Bone Metabolic Alterations on Orthodontic Tooth Movement

M. SEIFI, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, R. HAMEDI, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and Z. KHAVAND, 3- Dentist, Tehran, Iran

Objectives: The aim of this study was to determine the effect of administration of cholecalciferol, Thyroid Hormone, calcium gluconate as bone metabolies on orthodontic tooth movement.

Methods: In this study, 40 male albino wistar rats were selected and divided into 5 groups: 1- 20 ug/kg thyroxine was injected intraperitoneally after installation of the orthodontic appliance. 2- 3 I.U thyroxine with cholecalciferol was injected intraperitoneally after installation of the orthodontic appliance. 3- 200 um/kg Thyroxine with calcium gluconate 10% was injected intraperitoneally. 4- thyroxine, cholecalciferol, and calcium gluconate were administered. 5- distilled water was used in control group. In order to calculate the tooth movement, the distance between the upper right first and second molars was measured. The statistical ANOVA test was used in this study.

Results: The average of tooth movement was 0.45±0.13 for group 1, 0.48±0.07 for group 2, 0.37±0.04 for group 3, 0.8±0.20 for group 4, and 0.2±0.066 in control group.

Conclusions: Increased tooth movement was observed for Thyroxine, cholecalciferol, and calcium gluconate group with significant difference (P<0.05).


74

183023Coronal Leackage Of Gutta-percha Or Resilon Using An Intraorifice Barrier

M. ABBASI1, A. KOLAHDOUZAN2, N. REZAYI2, S. ARAGHI3, and D. SADEGHI4, 1Azad Medical University, Tehran, Iran, 2Qazvin Medical University, Qazvin, Iran, 3Department of endodontics,Qazvin Medical University, Tehran, Iran, 4Shahid Beheshti Medical University, Tehran, Iran

Objectives: The prevention and control of coronal microleakage after root canal therapy is critical for successful endodontic outcomes. The aim of this study was to compare coronal microleakage between Resilon and Gutta-percha using Glass ionomer as an intraorifice barrier.

Methods: In this experimental study, 64 extracted human teeth were decoronated to a standardized length of 16 mm and instrumented with protaper rotary system according to manufacturer’s instructions. The teeth were randomly divided into 4 experimental (n=14) and 2 control (n=4) groups (+/-).Then, the roots in negative control and experimental were obturated with either Resilon or Gutta-percha alone or with a 2 mm glass ionomer intraorifice barrier. In the negative control groups, all teeth surfaces were coated with 2 layers of nail polish. In the positive control groups, canals were not obturated. After setting of the sealers, microleakage was evaluated with microbial analysis. Data were evaluated with chi-square test one-way analysis of variance and Tukey.

Results: Positive control leaked within 24 hours, whereas none of the negative control leaked. Resilon and gutta-percha with intraorifice barrier showed less leakage than Resilon and Gutta-percha without any barrier, although the difference was not statistically significant (P>0.05).

Conclusions: Under conditions of this study, all 4 groups showed leakage in some specimens, but Glass ionomer might be an effective intraorifice barrier.


75

183026Mathematical Beta Function for Maxillary Arch Form Prediction

A. TEHRANCHI, Shahid Beheshti University of Medical Sciences, Evin, Tehran, Iran, M. NOURI, Dentofacial Deformities Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and M. MINA, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: To evaluate dental arch size and form changes in 12 to 16-year-old Iranian adolescents and generate a regression formula to predict maxillary dental arch form.

Methods: This study was conducted on 36 adolescents (14 male, 22 female), with normal occlusion. The depths and width of the dental arches at the first molar region were measured with a laser scanner device. Molar Facial-Axis Point (FA Point) was used as a reference point on the casts. The Kolmogorov-Smirnov Test, paired and unpaired t–test were used for statistical analysis. Statistical package for Social Sciences version 17.0 for Windows (SPSS Inc, Chicago, Ill) was used to perform all of the statistical analyses.

Results: The mean value for maxillary and mandibular inter molar width was 60.16 mm and 57.20 mm respectively. The mean value for maxillary and mandibular inter molar depth was 31.91 mm and 28.72 mm respectively. It was concluded that gender dimorphism does exist only for maxillary inter molar width (P<0.008).

Conclusions: A beta function formula for maxillary arch form prediction was generated using mandibular inter molar width and depth data.


76

183027Interleukin-10 Gene Polymorphisms in Patients with Recurrent Aphthous Stomatitis S. NAJAFI, MSc in Oral Medicine,Dental School,Tehran University Of Medical Sciences,Tehran,Iran, Tehran, Iran, M. MOHAMMADZADE, Department of Oral Medicine, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, A.Z. BIDOKI, Molecular Immunology Research Center; and Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran, H. YOUSEFI, Faculty of Dentistry,Azad University of Medical Sciences, Tehran, Iran, E. FARHADI, Hematology Department, School of Allied Medical Science, Tehran University of Medical Sciences, Tehran, Iran, G. MEIGHANI, Pediatrics Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, and N. REZAEI, Research Center for Immunodeficiencies, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Molecular Immunology Research Center; and Department of Immunology, School of Medicine,Tehran University of Medical Sciences, Tehran, Iran

Objectives: Recurrent aphthous stomatitis (RAS) is a common oral inflammatory disease with unknown etiology in which the immune system seems to have a role in oral tolerance. Interleukin (IL)-10 is a cytokine synthesis inhibitory factor, the production of which could be affected by single nucleotide polymorphisms (SNPs) of IL10 gene. This study was performed to investigate genotype frequencies of IL10 in a group of individuals with RAS.

Methods: Genomic DNA of 60 Iranian patients with RAS were typed for IL10 gene (C/A -1082, C/T -819, and C/A -592), using polymerase chain reaction with sequence-specific primers. The frequency of each allele and genotype was compared to a group of healthy individuals.

Results: A significantly higher frequency of T allele at position -819 (P=0.006) and A allele at position of -592 (P<0.001) were found in the group of patients with RAS, when compared to the controls. IL-10 GA genotype at position -1082 (P=0.007), CA genotype at position -592 (p=0.001), and CT genotype at position -819 (p=0.001) were significantly higher in the RAS patients.

Conclusions: The results of this study suggest that certain SNPs of IL10 gene have an association with predisposition of individuals to RAS. However, further multi-center studies are needed to confirm these findings.


77

183029Stress Distribution at the Internal Surface of Dental Implants

M. NEJADKARIM, DDS student in shahid beheshti univercity.member of talented division, tehran, Iran; 3rd position of the10th karazmi fair, tehran, Iran, and M. KADKHODAZADEH, Dental Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: The aim of this study was to determine the stress patterns within an implant and the effect of different types of connections on load transfer.

Methods: Three different types of implant-abutment connections were selected for this study. Sample A: 1.5 mm deep internal hex corresponding to a lead-in bevel, sample B: a tri-channel internal connection, and sample C: internal Morse taper with 110 degrees of tapering and 6 anti-rotational grooves. Four types of loading conditions were simulated in a finite element model and the maximum Von Mises stress set as output variables.

Results: The maximum stress concentration at the inner surface of the fixtures was higher than the stress value in bone in all of the samples. Stress values in sample B were the lowest amongst all of the models. Any alterations in amount and direction of the 100 N axial load resulted in an increase in fixture surfaces stress. Overall, the highest amount of stress (112 MPa) was detected in sample C at the inner surface of the fixture under a non axial load of 300 N.

Conclusions: Stress concentration could be reduced when the internal surface area increased. Creating three or six stops in the internal surface of the fixtures resulted in a stress reduction.


78

183031Debonding of Ceramic Brackets Using Er-YAG Laser N. MOHEBBIAN, dentist, rhoon, Netherlands

Objectives: This study sought to evaluate the enamel surface characteristics of teeth and patient response after debonding of ceramic brackets with Er:YAG laser light.

Methods: 64 frontal and premolars were bonded using 4 different ceramic brackets and later debonded through a Er:YAG laser (600mJ, 2 Hz, no air, no waterspray). The laser was applied for 0.5s with no movement and just the middle point in the slot of the brackets. After debonding, the adhesive remnant index (ARI), the incidence of bracket failure and enamel fracture, and patient response were compared among the groups.

Results: There was no case of enamel fracture or bracket fracture in the clinical examination of the debonded group. Significant high ARI scores were observed in the groups. Laser debonding caused a significant decrease in the frequency of enamel cracks. Patient did not feel any pain and sensitivity during and after treatment. They had follow-up for 3 months without any experience of discomfort.

Conclusions: Laser-assisted debonding of ceramic brackets without using any external load could reduce the risk of enamel damage and bracket fracture. It also produces the more desirable ARI scores without causing thermal damage to the pulp.


79

183039Enhance Socket Preservation with Combination of Bio-Oss with Silk

M.A. SAGHIRI, Kamal Asgar Reserch Center, Encino, CA, J. ORANGI, Post graduate Student of Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, Iran, and N. TANIDEH, DVM, MPH, Shiraz University of Medical Sciences, Shiraz, Iran

Objectives: To evaluate the histological and dimensional changes followed by tooth extraction without Bio-Oss and with Bio-Oss and silk mixture in dental socket.

Methods: 40 subject requiring tooth extraction and implant placement were selected. Patients were randomly divided into control (without Bio-Oss) and case (Bio-Oss and silk mixture) groups. The parameters of plaque index, gingival index, bleeding on probing, horizontal ridge width and vertical ridge changes were measured, immediately and 6 month after extraction. A bone biopsy was taken from the extraction site in both groups 6 months after surgical treatment. Histological study was performed on all biopsy samples. Paired t-test was used for data analysis and significance level considered as P<0.05.

Results: In the control group, a significantly greater horizontal absorption was observed compared with the case group. The ridge height reduction in control group was 4.1±1.9 mm and 2.9±1.3 mm at buccal side and lingual site, respectively. However, in the case group it was 3 mm in buccal side. Biopsies taken from the grafted sites showed the presence of trabecular bone which was highly mineralized and well structured. Histological examination revealed that the amount of connective tissue was significantly higher in the control group compared to the case group.

Conclusions: Results confirmed that dental socket preservation approach using Bio-Oss in combination with silk significantly reduce the resorption of dental socket after tooth extraction.


80

183041The Osteoregenerative Effects of PDGF-BB with MSCs Loaded on FDBA A. KHOJASTEH, Assistant Professor of Oral and Maxillofacial Surgery Shahid Beheshti University of Medical Sciences, Tehran, Iran, S.G. DASHTI, Doctor of Dental Surgery, Dental Research Center, Research Institute of Dental Sciences of Shahid Beheshti University of Medical Sciences, Tehran, Iran, M.M. DEHGHAN, Veterinary Surgeon, Associate Professor, Department of Surgery and Radiology,Center of Excellence for Cell Therapy and Tissue Engineering,Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran, and L. KHEIRI, Student, Gifted and Talented Dental Students Division, Dental School, Shahid Beheshti University of Medical Sciences, tehran, Iran

Objectives: Due to shortcomings associated with autogenous bone graft, the gold standard of craniofacial grafting, investigators seek alternatives that are accessible, efficient, and affordable. Accordingly, in the present pilot study, bone regeneration was induced using Bone Marrow derived Mesenchymal Stem Cells (BMCS) loaded onto Freeze Dried Bone Allograft (FDBA) blocks in the presence or absence of recombinant platelet-derived growth factor-BB (rhPDGF-BB). Treatments were tested on critical sized defects created in canine mandible.

Methods: 8 weeks after the bilateral extraction of premolars of 4 mongrel dogs, 25×10 mm defects were created at both sides of the mandible. The right mandible received autogenous-BMSC loaded on FDBA (control), whereas the left mandible received cellular blocks impregnated with rhPDGF-BB (experimental). Animals were euthanized 8 weeks after grafting. Mandibles were harvested and transferred to the laboratory for micro-computed tomography (micro-CT) and histomorphometric analysis. The Mann-Whitney test was used for data analysis and statistical significance was set at P<0.05.

Results: Although differences were not statistically significant, micro-CT and histomorphometric analysis demonstrated higher levels of bone formation for the test group (5.34%±0.20 and 16.63%±3.14 respectively) when compared to the control group (4.20%±0.20 and 11.38%±5.11).

Conclusions: According to the performed micro-CT and histomorphometric analysis, adding 0.5 mg rhPDGF-BB (0.3 mg/ml) to the combination of BMSC/FDBA might have amplified bone formation in critical sized defect in dog mandible.


81

183050Implant Location Influence on Stress Distribution in Implant Assisted RPDs

Y. MEMARI, Associate professor,Prosthodontics department,Dental School,Shahid, Tehran, Iran, A. GERAMI, Tehran University of Medical Sciences, Tehran, Iran, A. FAYAZ, Associate professor,Prosthodontics department,Dental School,Shahid, tehran, Iran, S.R. HABIB ABADI, Post graduate student,Prosthodontics department,Dental School,Shahid Beheshti University of Medical Sciences,Tehran,Iran, Tehran, Iran, and Y. MANSOURI, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: DERPD is a situation with lack of distal dental support and 13 times difference in resiliency between the mucosa and the periodontal ligament, resulting in levers during compression forces that are potentially destructive to the abutments and the surrounding tissues. The aim of this study was to assess the effect of implant location on stress distribution, in distal extension implant assisted Removable Partial Dentures.

Methods: A three-dimensional model of a bilateral distal extension partially edentulous mandible containing anterior teeth and first premolar in both sides of the arch, a partial removable denture and an implant (4×10 mm) were designed. With the aid of the finite element program ANSYS 8.0, the models were loaded and von Mises stresses were evaluated.

Results: When implant was placed in second premolar region, presented with highest stress on implant, abutment tooth and cancelous bone were shown. The lowest stress was shown on implant and bone in 1st molar area.

Conclusions: Locating the implant in first molar area positively influenced the distribution of stresses on the analyzed models.


82

183054Search for Evidence Behavior among Dental Faculty Members in Iran S. SEYEDZADEH SABOUNCHI, Community Oral Health Department, Hamadan Dental School, Hamadan, Iran, M.H. KHOSHNEVISAN, Preventive Dentistry Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, M. NOURI, Dentofacial Deformities Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, N. ERFANI, Psychiatry Department, Payame Noor University, Hamadan, Iran, and B. HOUSHMAND, Periodontics Department, Shahid Behehti Dental School, Tehran, Iran

Objectives: Despite great achievements and evidence developments in the field of dentistry, searching and retrieving evidence seems to be not very well applied and effective in academic settings. The aim of this study was to assess search for evidence behavior among dental faculty members in Iran.

Methods: A cross-sectional study was conducted on dental faculty members in Iran. To obtain a representative sample a stratified cluster random sampling approach was used. 8 dental schools were randomly selected from existing 17 public and 2 private schools in 2009. Self-administered questionnaires were used to gather data from faculty members on their use of high and low level evidence resources, studying scientific article habits, and frequency of reading articles. Demographic and educational information were also collected in the background part of the questionnaire. To test the association of gender and specialty with different components of search for evidence behavior Chi-square test was used. Also Pearson correlation test was conducted to assess association of other background characteristics with search for evidence behavior and multiple regression was also conducted.

Results: In total 377 dental faculty members returned completed questionnaires. Their mean age was 39±7.64 (min=27 and max=69) and also their mean years of research experience was 6.74±4.9. The most evidence resources used were textbooks (7.62±1.87) and original articles (6.73±1.97) according to visual analogue scale (VAS: range: 0-10). The least used source of evidence was Cochrane library 2.76±2.7 (VAS). Also 66.1% of faculties studied more than one scientific article in a week.

Conclusions: According to the results of this study, overall use of high level evidence resources was low. However, according to the positive correlations among search for evidence behavior components improving reading article, habits and knowledge may improve search for evidence behavior. This abstract is based on research that was funded entirely or partially by an outside source: This study was founded by I.R. Iran’s National Institute of Health Research, Tehran University of Medical Sciences (Contract No: 241/m/303).


83

183055HIV/AIDS Awareness Among Iraqi Medical and Dental Students A. ALBUJEER, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran; students’ scientific research Centre ,Tehran university of Medical Sciences, Tehran, Iran, and A.R. SHAMSHIRI, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran

Objectives: The aim of this study was to evaluate the knowledge and attitude among medical and dental students (4th and 5th year of their education) from Iraq, a country with actually low HIV/AIDS frequency, which is presented as a first report.

Methods: A cross sectional study of HIV/AIDS knowledge and attitude designed covering 526 students in four medical universities (Kufa, Babylon, Karbala, and Qadissiya) in March 2013. Data collection was done by a questionnaire containing knowledge and attitude questions (11 questions for each part) in addition to some demographic questions.

Results: 526 questionnaires (319 from medical students and 207 from dental students) were received. The knowledge of medical students were about 54.8% (n=190) intermediate (were defined as score 51-75), 27.1% (n=94) good (were defined as score 76-100) and dentistry students about 68.2% (n=150) intermediate, 10.5% (n=20) good. Estimated level of attitude of medical students were 14.7% (n=51) intermediate and dentistry students 21.4% (n=47) intermediate. None of them was put in “good” attitude category. Knowledge and attitude are not affected by age, gender, and marital status, but it was statically significant difference between medical and dental students.

Conclusions: Overall knowledge and especially attitude are not in good situation among medical and dental students, which potentially threatens healthcare workers and patients considering HIV and other blood-borne infections. It is also important for Medical Learning Programmers to put greater emphasis on controlling blood-borne infections, especially HIV.


84

183056Designing an Oral Health Surveillance System in Iran

A. EBN AHMADY, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and M.H. KHOSHNEVISAN, Preventive Dentistry Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: The concept of oral health surveillance is derived from disease surveillance, and means “to watch over oral health status”, in order to make decisions that lead to improvements in oral health status in populations. The aim of this study was to design an oral health surveillance system for country to aid long-term planning in oral health system and its development, to provide input for program management and evaluation, and to give timely warning of the need for intervention to prevent critical deteriorations in oral health condition. Timely warning requires earlier indicators of the possibility of oral health access, and risk factor indicators are often the most appropriate.

Methods: In this study, the basic steps that are involved in designing and building an oral health surveillance system were described. Both qualitative and quantitative seven steps approaches were used to design an oral health surveillance system.

Results: After stakeholders’ analysis and selecting oral health stakeholders at country level, the most important, feasible and fundable Oral Health Surveillance Indicators (n=32) were selected, divided and prioritized into five areas and agreed by well-established structured, multistep facilitated group techniques. Through a situation analysis and comparative study two data sources were identified. The proposed system confirmed as part of identified Delphi process consisted of three round of electronic surveys.

Conclusions: This was the first consensus study of Iranian oral health experts to identify key areas for improving oral healthcare programs and interventions. By this study, necessary steps to design an effective system for oral health surveillance system have been highlighted. The designed system is composed of understanding the current surveillance system of non-communicable diseases, analyzing effective strategic factors of oral health care system, determining oral health priorities and measurable indicators of surveillance system, and patient management profile and hold records.



85

183058Evaluation of Zirconia Post and Zirconia Coated FRC Post

M.H. SALARI1, E. JALALIAN1, S. SHAHRABI FARD2, and S. RASHIDI3, 1Islamic Azad University Dental Center, Tehran, Iran, 2dental student of dental branch of Islamic Azad University, Tehran, Iran, 3student of dental branch of Islamic Azad university, Tehran, Iran

Objectives: One of the problems in preparation of root canal treated teeth is debonding of post from root dentin; which correlates to post type. If measures are not taken to avoid this problem, mortal outcomes will appear during treatment. One of the new post that is used nowadays is the zirconia coated FRC posts, that are the next generation of aesthetic posts, ice light features 70% fill of zirconia enrinched, parallel glass fiber for exceptional strength. Its flexibility is close to dentine, so stress is distributed. The aim of this study was the evaluation of post types (zirconia post and zirconia coated FRC post)

Methods: The research method was experimental. 20 extracted human premolar teeth with 14 mm root length were selected. After post space preparation, the teeth were randomly divided into two groups (20 mm length and 1.4 mm diameter posts). Group 1: zirconia coated FRC post (Danville), Group 2: zirconia post (Ivoclar vivadent). All posts were cemented with dual-cure resin cement (Kuraray Panavia). All samples were mounted in acrylic cylinders. Samples were divided to 3 mm length parts. Make stress in apical to coronal direction with 0.8 mm diameter rod and inscripted pressure percentage. The push-out test was done by means of universal testing machine (Instron 5500R) with 1 mm/min speed. Data were analyzed through t-test.

Results: Retention average for the zirconia coated FRC post in coronal are as follows in Mpa: 79.22±12.93, middle:71.76±16.79, apical: 48.64±13.85 for the zirconia post in coronal: 131.80±32.52, middle:93.17±5.27, apical: 40.57±6.51.

Conclusions: Zirconia post provided significantly increased post retention compared with the zirconia coated FRC post. The retention of both post type reduced from coronal to apical.


86

183060PH Changes of Intracanal Materials in Simulated Root Surface Defects

S. ARAGHI, Department of Endodontics, Qazvin Medical University, Tehran, Iran, A. KOLAHDOUZAN, Qazvin Medical University, Qazvin, Iran, and M. ADEL, Qazvin University of Medical Sciences, Qazvin, Iran

Objectives: The aim of this study was to compare the diffusion of hydroxyl ions from intracanal calcium hydroxide (CH), Mineral trioxide aggregate (MTA), EndoSequence Root Repair material (ES), CEM cement and Biodentine (BD) in simulated root surface resorptive defects.

Methods: In this experimental study, 72 extracted human permanent maxillary central incisors were decoronated to a standardized length of 10±1 mm. After preparation of root canals, 1 mm depth cavities were prepared on the root at 3 and 6 mm from the apex. The teeth were randomly divided into 5 experimental groups and a control group (n=12). Root canals of experimental matched pairs were filled with either MTA, CH, BD, ES, or CEM cement; control teeth were filled with distilled water. The pH in root surface cavities was measured at 4, 24, and 48 hours, and 1, 2, 3, and 4 weeks. Repeated measurement ANOVA was used for statistical analyses. Significant was set at (P<0.05).

Results: In experimental groups the pH at 6 mm was statistically higher than 3-mm level (P<0.05). Overall, pH in all groups gradually reduced during 4 weeks; CH had the highest PH and MTA, CEM cement, BD, ES respectively. There were no significant differences between MTA and CEM cement, ES and BD at 24 and 48 hours, 2, 3, 4 weeks (P<0.05).

Conclusions: All of the material could increase the pH level on surface resorptive defects during 4 weeks.


87

183064Apical Transportation of Waveone File with Full-Rotation versus Reciprocation Movement

M. NASERI1, S.O. DIANAT2, A.K. KANGARLOO3, P. PEIMANPOUR4, and G. NAHVI5, 1Assistant Professor , Department of Endodontics and Endodontic Research Center, Dental School of Shahid Beheshti, Tehran, Iran, Tehran, Iran, 2Assistant Professor, Dept. of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, 3, Professor, Department of Endodontics and Endodontic Research Center, Dental School of Shahid Beheshti, Tehran, Iran, Tehran, Iran, 4Private Practice, Tehran, Iran, 5Dental student, Dental School of Shahid Beheshti, Tehran, Iran, Tehran, Iran

Objectives: The aim of this study was to evaluate apical transportation and centering ability of newly marketed single-file instruments, WaveOne, with Full-Rotation versus Reciprocation movement by virtue of CBCT analysis in severely curved mesiobuccal human mandibular molars.

Methods: According to the type of instrument movement, mesiobuccal canal of thirty mandibular molars were divided into 2 groups (n=15): Group 1, Reciprocation/WaveOne; Group 2, Full-Rotation/WaveOne. After coronal access preparation, a #15 K-file was used for working length determination (1 mm short of apical foramen). Pre- and post-instrumented CBCT scans were used for assessment of apical transportation and centering ability (1 mm, 3 mm, and 5 mm short of WL) in both groups. Statistical analysis of the data was performed using Man-Whitney, Friedman and T-test (α=0.05).

Results: There was no statistically significant difference between the two experimental groups in terms of apical transport and centering ratio at 1, 3, and 5 mm level (P>0.05). Preparation time and practitioner’s convenience were not significantly different between the two groups (P>0.05). No separation of instruments occurred in either groups.

Conclusions: Apical transportation and centering ability of WaveOne reciprocating instrument did not significantly differ between Reciprocation and Full Rotation movement.


88

183080Mesenchymal Stem Cells Delivery in Maxillofacial Bone Regeneration: Systematic Review

A. KHOJASTEH1, P. IRANPARVAR2, and M.T. BAGHANI2, 1Assistant Professor of Oral and Maxillofacial Surgery Shahid Beheshti University of Medical Sciences, Tehran, Iran, 2Student, Gifted and Talented Dental Students Division, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: The concept of tissue engineering holds huge promise for the future treatment of osseous defects. For bone tissue engineering, stem cells are applied on supporting scaffolds under controlled stimulation with growth factors. Scaffolds have a role in delivery of cells, growth factors, and blood supply. Different techniques and materials have been used for scaffold construction. In the present study, different scaffolds in craniofacial bone engineering were introduced.

Methods: Systematic search in Pubmed database was performed using keywords “bone engineering” and “bone tissue engineering” and also by manual search in selected journals until March 2012. Studies which had analyzed craniofacial defect treatment in human or animal models, and also related in vitro studies using scaffolds and stem cells were included in this study.

Results: According to these 69 articles, which were completely read and analyzed, there are 4 main categories of scaffolds: ceramic, non-ceramic or polymer, composite (ceramic + polymer), and metal. Ceramic scaffolds are either natural or synthetic

Conclusions: Based on the results of this systematic review, ceramics and polymers have been two most used scaffolds in these years. Bone marrow stromal cells (BMSCs) have been used frequently.



89

183089Laser Assisted Monitoring of Dental Caries in Early Childhood Caries Prevention

M. SHABANI, and M. MOJAHEDI, Rwth International Academy, Aachen, Germany

Objectives: Early childhood caries (ECC) is of the most common health problems in children under 6 years old. Periodical monitoring of caries risk assessment (CRA) and the oral care measurements can be one of the effective methods for prevention of ECC. Unfortunately visual and tactile periodical examinations cannot be confident as an index concerning CRA management and caries process prevention. It seems that laser assisted monitoring of caries process progression can be an effective adjunct tool to evaluate CRA management in children for prevention of ECC.

Methods: 20 children took part in this study and were divided into two groups. Laser group received CRA management, periodical visual and tactile examination and laser assisted caries process progression with Diagnodent device. Non-laser group received CRA management, periodical visual and tactile examination. For Diagnodent scanning, at first, the flat surface was divided into four portions and the midpoint of each quadrant was chosen for Diagnodent scanning. The midpoint of each proximal surface was chosen for Diagnodent scanning of the proximal surfaces. Finally, the mean score of Diagnodent scale was chosen as an index to determine the patient cooperation in control of dental caries progression.

Results: Diagnodent scale after 1 year and 2 years of the study in the two groups were different, so that in the laser group the Diagnodent scales for both proximal and flat surfaces were better than non-laser group (P=0.00). DMFS index in the two groups after 1 year was not significantly different, but after 2 years follow-up the DMFS index was significantly different (P=0.02).

Conclusions: Diagnodent scanning for monitoring of dental caries progression is an effective device in management of CRA.


90

183092Effect of Bleaching on the Microhardness and Color of Composites

S.S. HASHEMI KAMANGAR, Tehran university of medical sciences, International campus, Dental school, Operative department, Tehran, Iran, M. MIRZAII, Tehran University of Medical Sciences, Dental school, Operative department, Tehran, Iran, and K. KIAKOJOORI, Tehran university of medical sciences, International campus, Tehran, Iran

Objectives: The aim of this study was to determine the effect of 40% hydrogen peroxide on microhardness and color change of a silorane-based composite in a comparison of two metecrylate-based composites.

Methods: 12 disc shaped specimens (A3 shade) of each composite (Filtek P90, Filtek Z350XT Enamel, Filtek Z250 (3M-ESPE, St Paul MN USA)) were fabricated according to the manufacturer’s instructions using a stainless steel mold and were polished with SiC paper. Then the specimens were stored in 100% humidity for 24 hours. The samples of each type of composites were randomly divided into two groups (n=6). [Control: 2 weeks storage in distilled water at room temperature, experimental: exposure to Opalescence Boost (Ultradent, S Jordan UT, USA)]. Vickers microhardness and the color of samples were evaluated before and after each treatment. A spectrophotometric analysis was used to measure the following color parameters in the CIE L*a*b* color space: deltaa*, deltab*, deltaL*, deltaH, deltaC, and deltaE. Data were analyzed using repeated measure ANOVA.

Results: The baseline microhardness of Filtek P90 was significantly lower than the two other composites (P=0.001), but there was not any difference between Z250 and Z350XT (P=0.293). Opalescence Boost significantly decreased the microhardness of Z250 and Z350XT (P<0.001), but no significant change was observed in either the experimental or control groups of P90 (P>0.05). After bleaching, deltaE was evaluated 3.12 (1.97), 3.31 (1.84) and 3.7 (2.11) for P90, Z250, and Z350 respectively with no significant difference.

Conclusions: Using 40% H2O2 decreased the microhardness value of metacrylate-based composites but not the silorane-based composite. Although there was not any difference between the deltaE of composites, the deltaE of P90 remained in the range of clinical acceptance (deltaE<3.3).


91

183093The Effect of Firing on Marginal Integrity of Zirconia Core

E. JALALIAN, Islamic Azad University Dental Center, Tehran, Iran, S. MASUMI, Dentistry student , Islamic Azad University Dental Center, Tehran, Iran, S. ETEHADIEH KOOCHAK, Dentistry student, Islamic Azad University Dental Center, Tehran, Iran, and M. MALEKI GORJI, Dentistry student ,Islamic Azad University Dental Center, Tehran, Iran

Objectives: Marginal integrity of full-coverage restorations is one of the most important agents of the long-term success. The aim of this study was to evaluate the effect of porcelain firing on marginal integrity of all-ceramic restorations by an in vitro method.

Methods: This study was performed in single blind experimental method. At first, a standard brass die with 7 mm length and 5 mm diameter was made and then it was prepared by an accurate machine in a classic chamfer form with 0.8 mm depth and 10 degrees of convergence. Copings were made on die with CAD/CAM method: One group of 10 samples with 0.5 mm thickness. Then the copings were placed on the die and were numbered randomly. The vertical gap of marginal zone was measured in microns in 10 different points by SEM microscopy. After firing, the porcelain restorations were placed on the die and vertical gap of the marginal zone in the previous points were measured again by SEM microscopy. After recording the data and determining the mean and standard deviation, ANOVA test was used for comparing the data before and after the firing process.

Results: The amount of marginal gap in porcelain with 0.5 mm thickness was 79.55±39.32 µ before porcelain firing and 82.50±22.40 µ after porcelain firing .Test showed that there is no significant difference between the marginal gap of this thickness before and after porcelain firing.

Conclusions: Porcelain firing process does not affect the amount of marginal gap in all-ceramic zirconia core with 0.5 mm thickness.


92

183094Invisible Dental Injuries (Cracks) due to General Anesthesia Intubation

M. YAGHMAEI, professor, Department of oral and maxillofacial surgery, Dental school, Shahid Beheshti University of Medical sciences, Tehran, Iran, N.S. MATINI, under graduate student, Student’s research committee, Dental School, Shahid Beheshti University of Medical sciences, Tehran, Iran, and F. SHAHABIAN, Dentist, Private Practice, Tehran, Iran

Objectives: Administration of general anesthesia necessitates certain amount of manipulation or instrumentation within the mouth that may cause dental and oral tissue trauma during and after receiving general anesthesia. This study sought to assess invisible dental trauma (cracks) due to general anesthesia intubation and related risk factors.

Methods: This observational prospective study was conducted on 112 patients (12 anterior maxillary and mandibular teeth in each patient) in Taleghani hospital (Tehran, Iran). Patients were under general anesthesia by oro-endotracheal intubation. They were examined for old and new cracks, pre and post intubation, before and after the intubation using a light cure unit (Sanyi, SLC-35C, ZHE, China).

Results: Maxillary incisors had the highest incidence of new cracks (28.58%). The left quadrant was more susceptible in traumas (17.9%), than the right quadrant (10.7%). Gender, BMI, ASA class, Angles classification, and the experience of the operator who inserted the tube had no association with higher frequency of new cracks.

Conclusions: Dental cracks due to intubation are highly prevalent. These injuries are mostly disregarded by the anesthesiologist since they are not visible and do not cause any complication or problem during anesthesia. Enhancing the knowledge of anesthesiologist about dental anatomy, physiology, and pathology and use of the teeth-guard (prefabricated or customized) are necessary measures to prevent such injuries.


93

183096Attitude and Practice of Dentists regarding Tobacco Cessation in Iran

M.S. RAZAVI, Isfahan University of Medical Sciences, Isfahan, Iran, B. TAHANI, Oral Public Health Department, Isfahan University of Medical Science, Isfahan, Iran, B. ZOLFAGHARI, Department of Pharmacognosy, Pharmacy School, Isfahan University of Medical Science, Isfahan, Iran, and M. EMAMI DOOST, dental school, Isfahan University of Medical Science, Isfahan, Iran

Objectives: The aim of the current study was to assess Iranian dentists’ practice and attitude toward tobacco cessation programs.

Methods: A valid and reliable questionnaire was designed and piloted. To assess the practice profile, some questions were developed based on the expected 5A tobacco cessation protocol. Statements on attitudes focused on professional responsibility towards smoking cessation and were analyzed using a five-point Likert scale. 150 dentists were randomly selected from those working in Isfahan-Iran. Chi-square, ANOVA, and t test were used.

Results: 139 valid questionnaires were finally obtained. Most of the dentists were male (62.5%, n=87) and were practicing in private setting (72%). The cessation program in dental settings covers a small group of patients (about 18%). About 69.1% (n=96) of dentists reported to ask their patients about tobacco use. About 86.5% (n=83) of them indicated to advise their patients to quit, 33.8% (n=47) assessed their patients readiness and willingness to quit and just about 20% (n=28) of them reported to help their patients in planning for quit. A far lower percentage reported active involvement in arranging assistance (4.3%, n= 5). There was no significant difference between male and female dentists except for those who asked their patients (82% vs. 60%, P<0.01). Just about 26% of dentists disagreed or strongly disagreed with the tobacco cessation programs as part of dentists’ professional responsibility. 40% of dentists believed that encouraging patients to quit would make them feel uncomfortable.

Conclusions: Iranian dentists ask and advise at much higher rates than they assist, assess, and arrange with patients’ quit attempts. They indicated that they were not familiar with the clinical guidelines and suggested that lack of training is the major reason for non-adherence. Therefore, planning to encourage dentists to follow the protocol such as conducting continuous educational programs is needed.



94

183099Effectiveness of Reciproc and iRace on Canal Wall Cleanliness (SEM)

B. DADRESANFAR1, A. AKBARI2, and N. MOHAMMADZADEH AKHLAGHI1, 1Islamic Azad University Dental Branch, Tehran, Iran, 2dentist, Tehran, Iran

Objectives: Reciproc is a newly developed NiTi instrument which claims to clean the root canal walls with just one instrument. Root canal wall cleanliness can be evaluated by the amount of the remained debris and smear layer. The aim of this ex-vivo study was to compare cleaning effectiveness of Reciproc and iRace instruments in mesiobuccal canals of maxillary molars by SEM analysis.

Methods: A total of 34 MB canals of maxillary first molars with angle of curvature (20-40) degrees were divided into 4 groups. Samples in group A (n=15) were prepared with Reciproc #25 and taper of 0.08. Samples in group B (n=15) were by iRace sequence (#15/0.06, #25/0.04 taper).Two samples served in negative and positive control groups. Final irrigation consisted of 17% EDTA and 5.25%NaOCl followed by distilled water. The specimens were examined under SEM and scored on the basis of numerical evaluation scale for the amount of remained debris and smear layer in 3 different thirds of the canals. Data were subjected to Kruskal-Wallis test.

Results: There was no significant difference in regard to the smear layer between the two groups A and B. Reciproc left significantly less debris in apical and middle third of the canal (P<0.03, P<0.07 respectively).

Conclusions: Based on the findings of the present study Reciproc can result in clean walls in apical and middle thirds of maxillary mesiobuccal canals.



95

183100Histocompatibility and Setting Time of Endodontic Cement M.A. SAGHIRI1, A. AHADI2, and A. ZIADLOU2, 1Kamal Asgar Reserch Center, Encino, CA, 2private practice, Tehran, Iran

Objectives: To evaluate the effect of mixing techniques on Histocompatibility and the setting time of MTA and Biodentine.

Methods: The samples (n=24) of Wistar albino rats weighing 250±30 g received subcutaneously polyethylene tubes filled with biodentine and MTA which were mixed by titration and conventional technique. 15, 30, and 60 days after implantation, the animals were sacrificed and specimens were prepared for microscopic analysis. The setting times of cements were analyzed using Gilmore needles according to the ISO 6876 specification. Data were analyzed by ANOVA and Tukey’s test (P≤0.05) for setting time and Kruskal-Wallis and Dunn test for biocompatibility.

Results: Histologic observation of dental cements 30 and 60 days revealed no statistically significant difference (P>0.05) among the materials in the subcutaneous tissues but it was significant on day 15. The initial setting time for MTA and Biodentine regarding the method of mixing (40, 32 min) were (28, 12min) for MTA and biodentine respectively.

Conclusions: All the cements represent good histocompatibility but it seems that the method of mixing may improve this initial setting time so may have influenced the release of some ingredients of cements like Ca+ and physiological characteristics.


96

183101Endodontic Cements Influence on Odontogenic Differentiation of Pulp Stem Cells

M.A. SAGHIRI1, A. ZIADLOU2, and A. AHADI2, 1Kamal Asgar Reserch Center, Encino, CA, 2private practice, Tehran, Iran

Objectives: The regeneration of pulp is a major problem in endodontics. Therefore, it is desirable to develop new cement to provide infrastructure for pulp regeneration. Dental pulp stem cells (DPSCs) are appropriate cells for evaluating the ability of Odontogenic differentiation of endodontic cements. The current investigation evaluated the ability of Odontogenic differentiation of mineral trioxide aggregated (MTA) and Biodentine.

Methods: In the present study, isolated pulp stem cells from human molars were cultured and expanded. The cells from passage 3 were then loaded onto (MTA) and Biodentine cement plugs and treated with odontogenic supplements (OSs) that included vitamin D3 for a period of 7 days. DPSCs cultivated on cement plugs and normal pulp tissue were the controls. These groups were compared in terms of odontogenic differentiation markers.

Results: The activity of Alkaline phosphatase (ALP) and the levels of dentine sialophosphoprotein (DSPP) expression and dentine matrix acidic phosphoprotein 1 (DMP1) genes tended to be significantly higher in the MTA and control (P<0.05). 3D culture on endodontic cement without OS showed a level of differentiation indicating an odontogenic property of the endodontic cement.

Conclusions: Regenerative endodontic is now considered a facile therapy to efficiently restore tooth function. After a tooth injury, dental pulp is involved in reparative dentinogenesis and may be exposed to endodontic cement including MTA and biodentne. The present study revealed the differentiation level of the cells is significantly lower than that of odontoblasts present in pulp tissue. Both MTA and Biodentine cements possess an odontogenic-inducing property.


97

183105Laser Assisted Pain Reduction after Vital Pulp Therapy

M. MOJAHEDI, and M. SHABANI, Rwth International Academy, Aachen, Germany

Objectives: Preservation of the pulp vitality is essential to increase the pulp life and the tooth surveillance. After involvement of pulp during advanced caries or trauma accidents, many different pulp therapies may be chosen based on the pulp condition. Nowadays a novel material called CEM (calcium enrichment material) cement is used in Iran for vital pulp therapy. In some cases with vital pulp therapy using the CEM cement (for example in the partial pulpotomy), sometimes the patient experiences pain and needs to take OTC (over the counter) medication for pain relief. Low-level laser has pain reduction effect and seems to be an effective method to control pain in patients with vital pulp therapy, particularly partial pulpotomy.

Methods: After collecting medical and dental history data and also clinical examination, 20 molar and premolar teeth were allocated randomly in laser and non-laser groups. For patients who had to receive VPT, the standard procedure was done, but in laser group, after creation of clot and control of bleeding, low-level laser (diode laser 980 nm, 2j) was irradiated through the pulp chamber or pulp horn orifice in non-contact mode and finally, pulp dressing with CEM cement and permanent filling were done. Patient’s discomfort based on visual analogue scale (VAS) method and based on need to take any medication (OTC) was measured for the same day and a day after. SPSS software was used for statistical analysis.

Results: The results of this study showed that pain reduction in laser group was significantly (P=0.00) better than non-laser group the same day and a day after (P=0.04).

Conclusions: Low-level laser therapy can be used for pain reduction in patients’ VPT to remove any OTC pain relief medication.



98

183108Association of Periodontal Condition with Serum PSA Level

M. GHASEMI, Islamic Azad University Dental Center / Associate Professor, Tehran, Iran, N. SHAKHSSALIM, Urologist, Associate Professor, Shahid Beheshti University of Medical Science, Tehran, Iran; Iranian Urology and Renal Transplantation center, Tehran, Iran, and H. SADEGHI, Private Practice, Tehran, Iran

Objectives: Cytokine imbalance toward increased pro-inflammatory and decreased anti-inflammatory cytokines has been implicated in the pathogenesis of both periodontitis and prostitis. The aim of this study was to evaluate any relationship between periodontitis and PSA level in chronic prostitis patients.

Methods: In this historical cohort study 40 volunteers were divided into two groups based on their PSA levels. Group I had PSA level≤4 ng/dl and group II≥4 ng/dl. Plaque and gingival index, probing depth and clinical attachment level (CAL) were determined. Statistical analysis between the two groups was done using Leven and independent T test.

Results: There was statistically significant difference in PSA levels between the two groups. Also, all the periodontal parameters had higher value for the group with PSA level≥4 ng/dl and the differences were significant (P<0.001).

Conclusions: Subjects with more severe periodontitis had higher PSA level. Periodontal conditions may be considered as a factor in increasing the serum PSA level.


99

183112Is Anxiety Affecting Iranians’ Oral Health Behavior?

H. BAHRAMIAN1, S.Z. MOHEBBI1, R. YAZDANI1, A.A. NOORBALA2, and H. HESSARI1, 1Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, 2Department of Psychosomatic Diseases, Tehran University of Medical Sciences, Tehran, Iran

Objectives: There is an increased risk for impaired dental health among those who have symptoms of anxiety. This study aimed to determine the association between anxiety as a component of mental health and oral health behavior of population in Tehran, Iran.

Methods: The target population included 15 to 64 year-old adults (n=21039) reached to by a randomized clustered sampling within all 22 districts of Tehran city in 2012 during URBAN HEART survey by Municipality of Tehran. Anxiety among the population was measured by 7 questions of anxiety domain of GHQ-28 questionnaire. A sum variable of anxiety was calculated for each person, later dichotomized as being normal or disordered according to Goldberg classification. Frequency of tooth brushing was inquired as an indicator of oral health behavior and age and gender as demographic features. Chi-square test and Linear regression were applied by SPSS version 20 software for statistical analysis.

Results: The questionnaires were completed by 20105 individuals (response rate 95%) in all districts of Tehran. The mean age of the study group was 39.1 (SD=13.0) and 45% were men. The sum for anxiety ranged between 0 and 7 with a mean of 1.6 (SD=2.1). As regards to anxiety level, 63% of the population were categorized as normal and the others as disordered. Females and older adults revealed more anxiety than others (P<0.001). Tooth brushing on a daily basis was more frequent among females, younger, and normal adults in comparison to males, older and anxious ones (P<0.001).

Conclusions: Females and older age groups of society are more susceptible to mental health disorders, such as anxiety, which might influence on their health behaviors and must be tackled with to achieve better oral health outcomes among the population.


100

183114Effect of Magnesium on Bonding Strength of MTA Based Cement M.A. SAGHIRI, Kamal Asgar Reserch Center, Encino, CA, and P. MEHRIAR, Kamal Asgar Research Center, Encino, CA

Objectives: Several cements have been suggested for root canal treatment. Among these, the Mineral Trioxide Aggregate (MTA) has unique characteristics including sealing and osteopromotion. In addition, many studies confirm the effect of Magnesium components on osteopromotion of medical cements. The main objective of this work was to assess the dentin-bonding strength and antibacterial activity of adding 2% Magnesium as Magnesium carbonate to MTA based cement.

Methods: In the current research, 2% Magnesium as Magnesium carbonate was mixed mechanically with MTA and then mixed according to manufacturer’s instructions. At this level, 20 extracted human single-rooted teeth were used. The crowns were removed and spaces were mechanically enlarged using K-files and Gates Glidden burs. Cements including experimental (n=10) and Control Group were filled in dentine slices. The filled specimens were then soaked in (37°C) water for 24 h. The specimens were glued to Instron machine and then microtensile bond strengths to root canal dentin were measured with this device.

Results: The mean bond strengths of each group, with and without 2% Magnesium carbonate were (8.11±3.21), (6.21±5.01) respectively. Statistically significant differences were observed among the Magnesium carbonate contained group and the control group (P≤0.05).

Conclusions: Chemical reaction between cement and dentine fully demanded and may impede the leakage properties of endodontic cement. The present study confirmed that adding 2% Magnesium as Magnesium carbonate might improve the bonding strength of MTA cement.


101

183118Evaluation of Oral Medicine New Lesson Plan, Requirement and Questionnaire

Z. JABERIANSARI1, G. AZARBAKHSH1, Z. MALEKI2, and N. HEIDARI3, 1Shahid Beheshti University of Medical Sciences, Tehran, Iran, 2Associated Prof., Dept. of Oral Medicine, Dental School, Shahid Beheshti University of Medical Sciences. Tehran, Iran, Tehran, Iran, 3Dentist, Tehran, Iran

Objectives: Requirement is the minority of what students must do and lesson plan is a written description of the learning process, both are necessitated for the improvement of clinical competency. Recently a new lesson plan, requirement, and questionnaire of Oral Medicine (3) was suggested in dental school of Shahid Beheshti Medical Sciences University and the present study determined the attitudes of final year dental students about that.

Methods: In this descriptive study, a new questionnaire, requirement, and lesson plan for oral lesions were designed using previous lesson plans and opinions of the department members of staff. The new and previous questionnaires were assessed by 60 senior dental students in this school. The comments were classified using a 5-scaled Likert measure and statistically analyzed by nonparametric Wilcoxon signed ranks tests.

Results: 98.4% of the students believed in the comprehension of the new questionnaire in the diagnosis of oral lesions, 91.7% considered the new measure as a complete guide to lead the students to the lesions’ diagnosis, and 93.3% suggested the use of the new questionnaire for the patients with oral lesions along with the previous one.

Conclusions: It seemed that the use of new questionnaire in addition to the previous one was potentially useful to improve student’s clinical performance and knowledge regarding oral lesions’ diagnosis.



102

183121A New Grading System for Orthodontic Treatment Quality Assessment

S.M.R. SAFAVI, Dental Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and A. FARZAN, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: Several methods for assessing the quality of treatment outcomes in orhtodontics have been developed including Peer Assessment Rating (PAR) Index, American Board of Orthodontics Objective Grading System (ABO OGS), and Comprehensive Clinical Assessment (CCA). These methods, however have several limitations, such as the absence of weight for their criteria and assuming an individual ideal as a reference for all the possible clinical situations. In this regard, considering these limitations, the current study has tried to introduce a new commitment based model.

Methods: In preliminary phase of this study, holding several academic panel discussion sessions were held to recognize possible limitations of the mentioned methods. Also, the new model was discussed based on clinician’s commitments according to a prioritized problem list (involving patient demands, accessibility of treatment goals, cost-benefit ratio etc.) and it was tried to develop a new grading system for outcome assessment of orthodontic treatments in this regard. Moreover, 5 faculty member orthodontists were asked to rank 10 selected cases (including common malocclysion and treatment plans) in an ordered list using ABO OGS and also by their own experience in a separate list. A ranking was made by the new model as well. The new model was then compared with previous ones in assessing 10 selected cases as a preliminary step in model development.

Results: In this preliminary project, several controversies among skilled orthodontists were recognized on use of available methods such as ABO OGS for outcome assessment. Also a better compatibility between the proposed model and skilled orthodontists’ ranking in the selected cases was found.

Conclusions: A commitment oriented grading system may better be recognized for assessing the quality of treatment provided by orthodontists, especially in academic settings. Further investigations including a larger group of experts and cases are needed for developing a mature model.



103

183123Effect of Enoxolone on Dental Plaque, Gingival Inflammation, and Bleeding

H. MOGHADDAS, Professor, Department of Periodontology, Shahid Beheshti University of medical sciences, Tehran, Iran, O. MOGHADDAS, Islamic Azad University, Dental Branch, Tehran, Tehran, Iran, and S. TOOPCHI, Islamic Azad University Dental Branch, Tehran, Iran

Objectives: Enoxolon is a natural licorice and its formula is similar to cortisone. In this double blind randomized match control clinical trial the effect of Arthrodont toothpaste containing 1% Enoxolone was tested.

Methods: 40 patients who had gingivitis were selected. They were assigned to brush their teeth twice daily for three minutes then massage the gums with pastes for one minute and then wash their mouth. The patients were divided into two groups: Arthrodont toothpaste that contains Enoxolon, was given to the test group and Crest toothpaste which does not have Enoxolon, was given to the control group. At the beginning of the study and after 21 days, plaque, gingival, and bleeding indices were measured. The statistical analyses were done by Paird T test, T test and nonparametrical analysis of Wilcoxon and Mann-Whitney.

Results: Statistical analyses showed that in both groups, the three indices had decreased significantly and in comparison between the two groups, the gingival and bleeding indices had significantly decreased in the test group.

Conclusions: The results of this clinical study showed that Enoxolon has anti-inflammatory effect on gingivitis.



104

183128Antimicrobial Comparison of Green Tea Extract and Calcium Hydroxide

P. MEHRVARZFAR, Islamic Azad University, Dental Branch, Tehran, Tehran, Iran, M. VATANPOUR, Azad University Dental Branch, Tehran, Iran, B. DADRESANFAR, Islamic Azad University Dental Branch, Tehran, Iran, and B. MADANI, Dentist, Tehran, Iran

Objectives: The elimination or reduction of bacteria from root canal system using intracanal medication is an important step during endodontic therapy. In this regard, the purpose of this study was to compare the antibacterial effect of a Green Tea Extract (GTE) and calcium hydroxide as intracanal dressings in the dentinal tubules.

Methods: In this ex vivo study, 44 extracted human single rooted teeth were prepared with rotary nickel-titanium instruments and irrigated with EDTA 17% and sodium hypochlorite 5.25% to remove smear layer. All canals were inoculated with an Enterococcus Faecalis suspension for 2 weeks, then the samples were divided into two experimental groups (20 canals in each group) and two positive and negative controls. The infected canals in group 1 and 2 were dressed by GTE and calcium hydroxide creamy pastes, respectively. All restored samples were kept in incubator at 37°C humid environment for a week. Then, dentinal shavings were harvested from each root canal wall the following day and transferred to Bile Esculin Agar plate to culture and count colony forming units of E.Faecalis. The CFU/ml data were statistically analyzed by Mann U-Whitney test.

Results: Significant statistical difference was observed between each experimental group and control group (P<0.05). The percentage of bacterial reduction in group 1 and 2 was 92.47% and 99.86 %, respectively (P<0.05).

Conclusions: It seems that intracanal dressing of both calcium hydroxide and Green Tea Extract (GTE) may exert an effective antimicrobial action against E.Faecalis inside the dentinal tubules. Regarding other benefits of herbal green tea, it might be used as a suitable alternative for disinfecting canal medication.



105

183129Regenerative Endodontic Treatment of Immature Permanent Teeth by Using PRP

H. BAKHTIAR, Assistant Professor of Endodontic Department, Islamic Azad University, Dental Branch,Tehran, Tehran, Iran, and AREZOO RAYANI

Objectives: The alternative regenerative endodontics versus traditional endodontic techniques will have lots of favors for the patients in order to maintain their natural teeth functions. Considering the disinfection of the root canal systems using the three mixed antibiotics (metronidazol, minociclyne, and cyprofloxacyne), this study presented a new hypothesis that using an accelerator for proliferation of progenitor will lead to development of open apexes in these teeth.

Methods: There were 5 immature non-vital teeth with apical periodontitis in this research. After doing the radiographic and clinical testing and access cavity preparation, the pulp champers were irrigated with copious amount of 0.5% hypochlorite followed by 10 cc normal saline. The three mixed antibiotic were then placed in pulp champers and the teeth were temporary restored. After two weeks the teeth were mechanically irritated to bleeding with a large file to bleeding and the activated PRP with cacl2 which was extracted from the own penitents, were rinsed to the pulp chambers to form the blood clot and teeth were temporarily restored again. Two weeks later considering no sign and symptoms a double sealed crown filling were placed on the teeth and the 3, 6, and 9-month follow-ups were done in all patients.

Results: In the first 3-month follow-up in all cases increase of the dentinal walls thickness and closing the apex in at least one case was observed. In the 6-month follow-up increasing the dentinal walls thickness in one case and closing all the other apexes were reported and in the 9-month follow-up continuing the increasing of the dentinal walls thickness were mentioned.

Conclusions: The results of this in vivo research confirmed the hypothesis that “using an accelerator for proliferation of progenitor will lead to development of open apexes in non-vital immature teeth”.


106

183133Real-Time PCR Quantification of Periodontal Pathogens in Diabetic Kuwaiti Chil-dren

M. KARCHED1, S. GEORGE1, R. BHARDWAJ1, P. PHILIP1, A.R. INBAMANI1, S.E. ASIKAINEN1, and A.K. AL-KHABBAZ2, 1Oral Microbiology Section, Department of Surgical Sciences, Faculty of Dentistry, Kuwait University., Kuwait, Kuwait, 2Department of Surgical Sciences, Faculty of Dentistry, Kuwait University., Kuwait, Kuwait

Objectives: Prevalence of type-1 diabetes in children is increasing worldwide. A link has appeared between diabetes and periodontal diseases. Although diabetes in Kuwaiti children is common, no information is available of their periodontal microbiota. The aiom of this study was to assess the levels of major periodontal pathogens in diabetic and non-diabetic Kuwaiti children with gingivitis.

Methods: 6 children (14-18 years old) were included; 3 diabetics (HbA1C>7%) and 3 controls (HbA1C≤5.5%). None had received antibiotics during the preceding 3 months. 8 subgingival paper point samples were collected per child. Bacterial DNA was purified using DNeasy kit (Qiagen) and quantified on ABI Fast 7900 HT RT-PCR machine using Power SYBR Green” kit and species-specific primers. The detection limit for all target species was 102 CFU/ml.

Results: The detection rates among diabetics versus controls were for Aggregatibacter actinomycetemcomitans (Aa; 2 vs. 3), Porphyromonas gingivalis (Pg; 2 vs. 3), Prevotella intermedia (Pi; 2 vs. 1), Prevotella nigrescens (Pn; 2 vs. 2), Fusobacterium nucleatum (Fn; 3 vs. 3), Campylobacter rectus (Cr; 3 vs. 3), and Parvimonas micra (Pm; 2 vs. 2). Pg, Fn and Cr quantities were low (≤103 CFU/ml) in all children and did not significantly (P>0.05) differ between the groups. Aa and Pm neither differed (P>0.05) between the groups, although their mean quantities were higher in children with [(Aa: 1.15x105 (1.9x105), Pm: 2.4x104 (3.4x104) CFU/ml] than without [(Aa: 1.6x104 (7.3x103), Pm: 1x104 (9x103) CFU/ml] diabetes. Mean (SD) quantities of Pi and Pn were elevated [5x105 (7x105) and 5.6x105 (7x105) CFU/ml] in 2 of 3 patients in the diabetes group, but the difference from the non-diabetes group did not reach statistical significance. The diabetic with the lowest number of target bacteria also had the lowest HbA1C.

Conclusion: While the target species seem common, diabetics may support the peak quantities. The results encourage analyzing larger study populations.


107

183134CBCT and Periapical Radiography in Diagnosis of Strip Root Perforations

L. ATASH BIZ YEGANEH1, M. ADEL2, and M. TOFANGCHIHA2, 1Qazvin University of Medical Sciences, Endodontics department, Tehran, Iran, 2Qazvin University of Medical Sciences, Qazvin, Iran

Objectives: To compare the accuracy of conventional periapical radiography (PR) and CBCT in detecting strip root perforations in the absence and presence of gutta-percha root fillings.

Methods: In this in vitro experimental study, mesial root canals of 97 extracted human mandibular molar teeth were prepared. Distal wall of the mesiolingual canals were thinned in the danger zone. Then 51 teeth were randomly perforated. Before and after obturation, PR (3 horizontal angulations: 20 degree mesial, straight and 20 degree distal) and CBCT were performed and evaluated by two observers. Chi square and Fisher Exact tests were used for statistical analysis, with significance level set at P=0.05.

Results: In the absence of root filling, sensitivity, specificity, and accuracy of CBCT was superior to PR (P<0.05). In the presence of root filling, the sensitivity of PR was significantly higher (P<0.05), although specificity and accuracy were not significantly different. After root canal obturation, the sensitivity, specificity, and accuracy of CBCT were significantly dropped (P<0.05). However, the sensitivity, specificity and accuracy of PR were significantly increased (P<0.05).

Conclusions: Under the conditions of this in vitro study, in the absence of root filling, CBCT was superior to PR. In the presence of root filling, PR was more sensitive. The presence of root filling reduced the ability of CBCT and increased the ability of PR in detecting strip root perforations.


108

183136Diagnosis of Gingival Biotype by Probing Technique vs. Visual Method

R. SHARIATMADAR AHMADI, department of periodontics, dental branch, Islamic Azad University, Tehran, Iran, Tehran, Iran, R. TAVASSOLI, dentist, Tehran, Iran, D.S. MAHOUTCHI, dental student, dental branch, Islamic Azad university, Tehran, Iran, and A. ORUMCHI, dental student ,dental branch, Islamic Azad University, Tehran, Iran

Objectives: this study evaluated the reliability of visually assessing the facial gingival biotype of maxillary and mandibular teeth with and without the use of a periodontal probe in comparison with direct measurements.

Methods: 100 teeth in 67 patients (42 male, 25 female) with mean age of 36.02 (range 18 to 66 years) with maxillary and mandibular teeth participated in this study. Three methods were used to evaluate the thickness of the gingival biotype of the failing tooth: Visual, periodontal probing, and direct measurement. Prior to extraction, the gingival biotype was identified as either thick or thin via visual assessment and assessment with a periodontal probe. After tooth extraction, direct measurement of the gingival thickness was performed to nearest 0.1 mm using tension free caliper. The gingival biotype was considered thin if the measurement was ≤1.0 mm and thick if measured >1.0 mm. The assessment methods were compared using MacNamer test at a significance level of α=0.05

Results: The mean gingival thickness obtained from direct measurements was 0.96±0.25 mm. The MacNemer test showed a statistically significant difference when comparing the visual assessment with assessment using a periodontal probe (P=0.001). However, there was no statistically significant difference when comparing the assessment with a periodontal probe and direct measurement (P=0.607).

Conclusions: Assessment with a periodontal probe is an adequately reliable and objective method in evaluating gingival biotype, whereas visual assessment of the gingival biotype by itself is not sufficiently reliable compared to direct measurement.


109

183140Fissure-Sealants Microleakage Based on the Type of Solvent in Bonding-Agents

H. NEMATOLLAHI1, M. EBRAHIMI1, and M. BOSKABADY2, 1Assocated professor of Pediatric Dentistry, Department of pediatric dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran, Mashhad, Iran, 2Assistant Professor of Pediatric Dentistry, Dental Material Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran, Mashhad, Iran

Objectives: Despite the proposed application of bonding agents during salivary contamination before sealant, no study that evaluates the impact of the bases of this agents on microleakage of fissure sealants has been done yet. Studies about adherence of new bonding agents on wet enamel have not shown conceiving results. The aim of this study was evaluation of the effect of enamel surface conditions (wet, dry, and saliva contamination) and dentin bonding agents with acetone or ethanol bases on the microleakage of sealants.

Methods: 150 maxillary premolars were divided into 3 groups after etching: dry, wet with water, and contaminated with saliva. Each of them was divided to 3 subgroups: use of ethanol base bonding (Single Bond), use of acetone base bonding (Solobond), and without bonding (N=15). Eventually, the fissures were covered with Clinpro sealant. After thermocycling, the amount of microleakage was assessed using dye penetration technique qualitatively. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests.

Results: The use of Solobond significantly decreased microleakage compared to Single Bond (P<0.001) and without bonding (P=0.001). Regarding surface conditions, the microleakage of wet and dry enamel were significantly lower than contaminated enamel (P<0.001), but there was no significant difference between dry and wet enamel (P=0.11). The highest microleakage was found in saliva contaminated-without bonding sealants and the lowest microleakage in dry-without bonding and dry-Solobond groups. Conclusions: Acetone base bonding compared to ethanol base bonding showed considerable superiority in reducing microleakage under salivary contamination. But the best method was applying sealant directly on the dry enamel without intermediate bonding layer.


110

183142The Influence of Implant Dimension on Stress Frequency Responses

M. AZARIAN, Dental Faculty of Islamic Azad University Khorasgan (Isfahan) Branch, Isfahan, Iran

Objectives: Chewing forces on the dental implants make undesirable stresses around surrounded implant bone. These stresses result in bone defect and implant failure. The aim of this study was to do harmonic analysis and evaluate the effect of implant dimensions on the stress distribution by means of finite element method.

Methods: The present study included three dimensional mandibular bones in the second premolar, ITI implant, rigid connector, and chewing force that were analyzed in ABAQUS software program by three dimensional finite element method. In this evaluation dental implant and jawbone had to exactly be modeled in the software program.

Results: There were not any modulations in the different frequencies. Increasing of frequencies from 0 to 30 HZ did not have any effect on the dental implant. Maximum stress was made in the neck of narrow neck implant and stress was decreased by the increasing of diameter.

Conclusions: Regarding to the results of this study, frequencies on the dental implant in compared with resonance frequencies had difference. Natural implant frequencies were not stimulated by chewing frequencies. So different implant failures in different frequencies were not related to implant frequencies. The best choice for each patient could be implant with maximum diameter regarding to anatomic condition.


111

183146Accuracy of Different Image Modalities in Detection of Bone Lesions

R. BARDAL, Assistant Professor, Department of Radiology, Qazvin University of Medical Sciences, ghazvin, Iran, M. DEHGHANI, Assistant Professor, Department of Radiology, Shahid Sadoughi University of Medical Sciences, Yazd, yazd, Iran, H. JAHANIHASHEMI, associate professor, Department of Biostatistics, Qazvin University of Medical Sciences, Qazvin, Iran, Qazvin, Iran, M. MOSTAFAVI, assistant professor, Department of Oral and Maxillofacial radiology , Uromie University of Medical Sciences, Uromie , Iran;, uromie, Iran, E. KALHOR, .S Shahidbolandian Health Centre, Qazvin, Iran, Qazvin, Iran, and M. TOFANGCHIHA, Qazvin University of Medical Sciences, Qazvin, Iran

Objectives: Radiography is one of the most useful methods in dentistry. The optimal goal of radiography is providing high quality diagnostic images with the least radiation. The aim of this study was to evaluate the accuracy of cone-beam computed tomography (CBCT) and intra oral photostimulable phosphor plate (PSP) and film in detection of artificial cancellous bone lesions.

Methods: 7 dried human mandibles were used for this study. The mandibles were put inside water bath made of Plexiglass plates. Then PSP and CBCT imaging were performed. Mandibles were struck by a coping saw in buccolingual shape and dimensions of the oval lesions in 6.1 °Á 6.1 mm, 3 °Á 6.1 mm and 4 °Á 4 mm were created by milling into the spongy bone. After fixing the two parts together (buccal and lingual) imaging was repeated again. Presence or absence of lesions on images were obtained and then evaluated and recorded by two observers. Using SPSS 16, compatibility level, sensitivity, and specificity and ROC analysis were determined for each observer.

Results: Internal agreement of observers in all three imaging methods was low to moderate (kappa≤0.613). The external agreement in all three imaging methods was moderate (kappa=0.406). The area under the curve (AZ) of imaging techniques in each observation was not significantly different. In addition, the area under the lesion size curve (AZ) for the two observers was not significantly different.

Conclusions: The lesions confined to spongy bone could be identified on film, PSP, CBCT. But interpretation of PSP and CBCT images needed more skills and training.


112

183151Evaluation of One Iranian Probiotic Yogurt’s Effect on Salivary S. Mutans Count

P. MOEINI, Assistant Professor, Islamic Azad university. dental branch-pediatric department, Tehran, Iran, N. JAMEI, dentist, Ahwaz, Iran, and M. MOHAMADI, dentist, Karaj, Iran

Objectives: Nowadays production and consumption of probiotics are growing. Yogurt is one of the most common vehicles for probiotics. In recent years, potential of these products for reduction of salivary counts of Streptococcus mutans has been the subject of many studies. In this study, the influence of one type of local probiotic yogurt and an ordinary yogurt (Pegah Company) on the salivary counts of S. mutans has been examined.

Methods: In the present study that was conducted as “clinical trial double-blind randomized crossover”, 30 healthy dental students participated. Salivary counts of participants’ Streptococcus mutans were determined by using the mitis salivarius agar environment at the base time, after 3 weeks run in period, (T1), after the completion of 3 weeks consumption (T2), and 3 weeks after discontinuity (T3) of probiotic yoghurt, ordinary yogurt (C1) or none of them (C2) by considering 3 weeks washout period. The data were analyzed in terms of intra-group and inter-groups differences by Repeated Measures and Paired-Samples T respectively. Statistical significant level was established at P<0.05.

Results: The results showed significant differences in the salivary counts of S. mutans between probiotic and control groups C1 (P=0.009 ) and C2 (P=0.012 ) at T2. However, there was no difference between C1 and C2 measures at any of the time points. Besides, a significant count reduction in the salivary S. mutans was noticed duringT1-T2 period (p= 0.028) within the probiotic group, but there was no significant difference during T2-T3 period.

Conclusions: It seemed that a 3 weeks period of probiotic yogurt consumption had an ability to reduce the number of salivary Streptococcus mutans and this effect remained 3 weeks after discontinuity.


113

183153Evaluation of Silicone Effect on Implant Abutment Interface Microbial Leakage

M.R. TALEBI ARDAKANI1, G. ESLAMI2, M.J. KHARAZI-FARD3, M.T. BAGHANI4, S. SHIDFAR4, S. SALAHI5, and M. MEYMANDI6, 1Associate Professor, Department of Periodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, 2Associate Professor of Microbiology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, 3Dentist, Member Dental Research Center, Tehran University / Medical Sciences, Tehran, Iran, 4Student, Gifted and Talented Dental Students Division, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, 5Resident of periodontics, Department of periodontics, Shahid Beheshti university of medical sciences, Tehran, Iran, 6department of periodontics, school of dentistry, Shahid Beheshti university of medical sciences, Tehran, Iran

Objectives: Soft tissue inflammation and bone resorption around the implants have always been one of the complications associated with implant treatments. The microbial leakage of implant-abutment interface has been considered as a cause for this phenomenon in many pieces of research. The purpose of this study was to evaluate the effect of silicone on implant abutment interface microbial leakage in 5 different systems including 3i, Astra, Replace, Swissplus, and SPI of which each one has special connection between implant and abutment.

Methods: 50 samples of systems mentioned above were evaluated in 2 phases: outward and inward. In the first stage, after the injection of silicone into the implant hole, connection screw was inoculated with E.Coli solution and the abutment was connected to the implant according to the manufacturer’s protocol. Then the samples were placed in cryo-tubes which contained semi-solid simple gelose environment and feeding solution. Microbial leakage was evaluated after 24 hours in these samples. In the second stage, the samples were placed in cryo-tubes after the injection of silicone same as the first stage. The only difference was that E.Coli solution was used instead of feeding solution and leakage was evaluated after 72 hours in these samples.

Results: In the first stage because of the outer surface contamination, many of the samples were excluded. Finally, leakage was evaluated between the rest of the samples and there was no significant statistical difference between groups (P=0.465). In the second stage, leakage was evaluated after 72 hours and the Astra group showed significantly lower leakage than others (P=0.039). However, the difference of leakage between the other groups was not statistically significant (P=0.127).

Conclusions: The usage of silicone gel is not able to completely seal the implant-abutment interface. The most efficacy of this gel is reducing the leakage in those systems that have tapered connection (as Astra).



114

183155The Effect of Intranasal Midazolam with/without N2O/O2 on Children’s Behavior

Y. REZVANI, Assistant Professor of pediatric dentistry, Shahid Beheshti university of medical sciences, Tehran, Iran, N. ASKARIZADEH, associate professor of pediatric dentistry , Azad university of medical sciences, Tehran, Iran, F. DEHGHAN, assisstant professor of pediatric dentistry , Azad university of medical sciences, Tehran, Iran, and M. MIRESKANDARI, associate professor of anaesthesiology , Tehran university of medical sciences, Tehran, Iran

Objectives: Managing children with behavioral problems remains a major challenge for pediatric dentists. Children do not have capability to fully cope with stressful situations due to reasons such as limited coping skills, immature reasoning, and anxiety/fear resulting from lack of experience. Sedation can be helpful in minimizing stress in an uncooperative child. The aim of the present research was to evaluate the effect of intranasal midazolam with/without inhalation sadation (N2O/O2) on children’s behavior under dental treatment.

Methods: In this clinical trial, 28 samples, were sedated randomly, once by the combination of intranasal midazolam with nasal drops of lidocaine hydrochloride 2% without inhalation sedation (A). In the next session, inhalation sedation (N20/02) with intranasal (lidocaine/midazolam) was administered (B). In the second session two protocols were randomly changed. To evaluate the patient’s behavior and depth of sedation, Houpt scoring system was used. To compare the redundancy of the items with regard to cross-over design of the study, Wilcoxon-sign Rank test was used.

Results: Of the 28 samples analyzed, group B showed significant difference in the index of general behavior compared to group A only after 15 minutes and at the end of treatment (P<0.05). No significant differences were seen at the time of onset and discharge (P>0.05). Index of movement and crying in group B showed a significant difference compared to group A, only after 15 minutes and at the end of treatment (P<0.05). No significant differences were seen at the time of onset and discharge (P>0.05). Index of drowsiness did not significantly differ between the two groups and at all times (P>0.05).

Conclusions: It is recommended to use inhalation sedation combined with intranasal midazolam to manage the behavior of children undergoing dental treatments.


115

183157Knowledge of Dentists About Stepwise Excavation and Pulp Capping

S. BANAVA, Islamic Azad University Dental Branch, Tehran, Iran, M. KARIMI, Islamic Azad University -Dental Branch, Tehran, Iran, and M. SAFAIE YAZDI, Islamic Azad University-Dental Branch, Tehran, Iran

Objectives: Dentist’s knowledge of new dental treatments and conservative restorative methods to preserve the pulp vitality is of great importance. The object of this descriptive study was to evaluate the knowledge of the dentists about Stepwise Excavation (SE) and pulp capping techniques.

Methods: In this descriptive study, 89 dentists who had participated in the recently held dental congress of Iranian Dental Association (IDA) were randomly enrolled. A self-administered questionnaire including personal (age, gender, academic level) and scientific information about pulp capping and SE was individually handed to the participants. The reliability and validity of this questionnaire was previously evaluated. The data were analyzed by statistical tests with significance of 0.05.

Results: 89 participants (41 male, 48 female) ranging from 23 to 62 years old, were enrolled in the research, 20 of which were students, 63 general practitioners and 6 specialists (oral and maxillofacial surgeon, endodontist, prosthodontist, oral pathologist and periodontist). Only 14% of the participants were aware of SE, 28% of whom reported prior application of SE. In case of deep caries occurrence, 39% of participants believed in removing the caries completely even when pulp exposure happened, while 48% preferred to leave some caries behind followed by restoration and sealing the cavity, and finally 15% chose the root canal therapy. Regarding the knowledge rank, only 1.1% (one person) showed a medium awareness of SE, indirect pulp capping (IPC) and direct pulp capping (DPC) and the remaining 98.9% achieved low marks. Also 78% reported applying calcium hydroxide as the most common liner in the pulp capping technique.

Conclusions: According to the results of this study and weak knowledge of dentists about SE, IPC and DPC techniques, it seems crucial to consider continuing education courses in this field.


116

183158Selective Alveolar Decortication Technique for Facilitating Orthodontic Tooth Movement

J. MEHRANI SABET, Assistant professor, Department of Periodontics, Dental faculty, Mazandaran University of Medical Sciences, Sari, Iran

Objectives: Demineralization of a thin layer of bone covering a root prominence after performing alveolar decortication surgery can facilitate the response to applied orthodontic forces, which leads to rapid tooth movement and is in accordance with the regional acceleratory phenomenon seen in bone augmentation.

Methods: Since alveolar decortication technique has been introduced as a new approach for accelerating orthodontic tooth movement and based on the articles reviewed, the aim of this review was to describe the mechanism and benefits of this technique over traditional tooth movement with orthodontic forces.

Results: Selective alveolar decortication was reported to increase the turnover rate of alveolar spongiosa, leading to acceleration of remodeling of the bone, which could describe the mechanism underlying the rapid tooth movement after selective alveolar decortication observed in clinical trials.

Conclusion: The selective alveolar decortication technique provides for efficient and stable orthodontic tooth movement. Compared with traditional orthodontic treatment, this treatment has the main advantage of shortening the treatment times, which is beneficial for many patients.


117

183159Accuracy of Two Radiographic Techniques in Diagnosis of Root Fractures

Z. SHAKIBAEI, Assistant Professor , Department Of Oral And Maxillofacial Radiology, Faculty Of Dentistry , Hamadan University Of Medical Science, Hamadan, Iran

Objectives: This study was performed to compare the diagnostic accuracy of cone beam computed tomography (CBCT) scans and digital radiography (PSP) for detecting experimentally induced different root fractures (longitudinal and transverse) in extracted human teeth.

Methods: 44 extracted single rooted premolars mounted in a dry human mandible for assessment of longitudinal root fractures were endodontically prepared and divided into 2 groups. The teeth in group A were artificially fractured and those in group B were not. Longitudinal fractures were induced in 22 of 44 premolars. For horizontal root fracture, 44 maxillary central incisors were used that in 22 of which, fractures were created in horizontal plane by a mechanical force with hammer and fragments were relocated. They were placed in the respective empty maxillary anterior sockets of a human dry skull. Intraoral radiographs were obtained by a PSP sensors (Digora Optime). Cone beam CT images were taken with a unit (Promax 3D, Planmeca Helsinki Finland). 4 observers evaluated the CBCT scans and PSP images.

Results: Sensitivity and specificity for longitudinal root fracture detection of CBCT were 0.48, 0.92 and for PSP were 0.29, 0.87, respectively and in horizontal root fracture were 0.97, 0.73 for CBCT and 0.89, 0.85 for PSP. The results showed an overall higher accuracy for CBCT (0.70) scans higher than PSP (0.59) for detecting longitudinal root fractures and slightly overall higher accuracy for PSP (0.87) scans than CBCT (0.85) for detecting horizontal root fractures.

Conclusions: CBCT outperformed the digital radiography in detecting simulated longitudinal root fractures but not in horizontal root fractures.


118

183160SEM Evaluation of Etching Pattern of 18%HCL: A Pilot Study S. BANAVA, Islamic Azad University Dental Branch, Tehran, Iran, M.A. SAGHIRI, Kamal Asgar Reserch Center, Encino, CA, M. MALEKI GORJI, Islamic Azad University-Dental Branch, Tehran, Iran, and S. ETTEHADIE, Islamic Azad University -Dental Branch, Tehran, Iran

Objectives: Resin Infiltration Technique (RIT) has been suggested to prevent the progression of incipient caries and sealing the demineralized tooth structure. In this technique, 15% HCL is applied for 120 seconds to erode the enamel surface followed by application of a special resin to seal the demineralized parts. The aim of this study was to evaluate the effect of 18% HCL, made in Iran on etching pattern of enamel and compare it with 15% HCL by SEM in different times.

Methods: In this pilot study, some extracted human anterior teeth were selected to provide sound enamel surface. Samples were randomly divided into the following groups of 3 as follows; Group1: 15%HCL (Icon, DMG, Germany) – 120 s (control). Group2: 18%HCL (Kimia, Iran) – 60 s. Group3: 18%HCL (Kimia, Iran) – 90 s. Group4: 18%HCL (Kimia, Iran) – 120 s. The samples were prepared for SEM evaluation. The etching pattern and line scanning were evaluated and compared with significance of 0.05.

Results: SEM evaluation indicated that Group2 resulted in partial etching pattern on enamel in comparison to control group; no homogenous patterns in the surface erosion were observed. 90 s application of this acid was more aggressive than 120 s of 15%HCL with demineralization of interprismatic parts more than control group. In Group4 the mean demineralization depth was 19 micron.

Conclusions: Results of this pilot study revealed that 60 s application time of 18%HCL (made in Iran), caused partial etching of enamel which will be not appropriate for diffusion of resin in next step. It seems that a research should be conducted on evaluating a time between 60-90s for acceptable etching pattern of enamel for resin diffusion.


119

183162Placebo Medication for Pain Relief During Scaling and Root Planning

G. RADAFSHAR, Associate Professor of periodotology, Oral and Maxillofacial Developmental Disease Research Center, School of Dentistry, Guilan University of Medical Sciences. Rasht, Iran, Rasht, Iran, S. HAJIZADEH, General Dentist, Private practice, Rasht, Iran, E. KAZEMNEZHAD, Assistant Professor of Biostatistics, Oral and Maxillofacial Developmental Disease Research Center, Guilan University of Medical Sciences. Rasht, Iran, Rasht, Iran, and N. MIRFARHADI, MSc in Nursing Education, Oral and Maxillofacial Developmental Disease Research Center, School of Dentistry, Guilan University of Medical Sciences. Rasht, Iran, Rasht, Iran

Objectives: One-stage full mouth scaling and root planning (SRP) should be performed together with pain control modalities of low risk and side effects. This investigation aimed at evaluating the placebo effect on pain perception during SRP.

Methods: 182 patients participated in this double-blind, randomized, controlled clinical trial. Having signed an informed consent, each patient filled a modified dental anxiety index upon entry. Based on random blocks, 91 patients received one placebo capsule 30 minutes before SRP as a potent painkiller, and 91 control subjects received SRP alone. Base-line periodontal and confounding variables were measured in each sextant by a blind examiner. Pain was recorded using a 10 cm line VAS as well as a 5-point verbal Likert scale (VRS-5) during SRP for each sextant of dentition. Statistical analysis was accomplished by SPSS version19.

Results: There was no statistical difference between placebo and control groups regarding VAS and VRS-5 scores using Mann-Whitney test. Multiple linear regression model controlling for co-variables revealed a statistical significant lower pain perception mean in placebo compared to control group based on VAS (β= 0.6, 95%CI=-0.3, -0.88, P<0.0001). Moreover, multiple ordinal logistic regression model showed lower mean of pain reported through VRS-5 by placebo group than controls (β=0.24, 95%CI=0.007, 0.465, P<0.043). Spearman rank test disclosed correlation between the two pain measuring methods (rsp=0.917, P<0.0001).

Conclusions: Within the limitation of this study, placebo effect was capable of reducing pain during SRP compared to control. Significant confounders for pain perception during SRP are age, anxiety, mean probing pocket depth, sub-gingival calculus, symptomatic dentin defects, and faulty restorations.


120

183163Determining Depth and Radius of Curve of Spee: A Pilot Study

A. FAYAZ, Assistant Professor, Tehran, Iran, M. HEMMATI, pedodontics department, Hamedan, Iran, and F.S. MIRHASHEMI, PhD student, Mechanics of Agricultural Engineering, Ferdowsi University of Mashhad, Mashhad, Iran; Dental Research Center, Research Institute of Dental Sciences of Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: The purpose of this study was to examine and analyze the depth and radius of curve of spee in maxilla in a group of Iranian specimens.

Methods: 44 dentistry students (21 male, 23 female) with permanent healthy dentition participated in this study. After making impression of maxilla and preparing maxillary casts, they were transferred to a semi adjustable articulator using air-bow. The tip of cusp of cupid and tips of buccal cusps of first and second premolars and molar teeth were determined by means of a coordinated measuring machine in three dimensions. The depth and radius of curve of spee of maxillary cast were analyzed by computer software (mechanical auto desk 2007). SPSS and T test were used for statistical significance (P<0.05).

Results: The curve of spee in maxilla showed a mean radius of 102.90 mm and had a depth of 1.64 mm. This curve was significantly deeper in subjects with oval face form and was not influenced by the gender.

Conclusions: In determining and reconstruction of plane of occlusion it seemed that to make a more precise curve of spee, the facial form of the patient must be considered.


121

183164Evaluation of Genotoxic Effects of Two Endodontic Cements

N. NAGHAVI1, and J. GHODDUSI1,2, 1Dental Research Center, Faculty of Dentistry, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran, Mashhad, Iran, 2professor of endodontics, Mashhad, Iran

Objectives: Recently, a novel endodontic cement has been introduced to dentistry: calcium enriched mixture (CEM) cement. In the present study, the genotoxic and cytotoxic effects of this cement were evaluated compared with ProRoot MTA on L929 mouse fibroblasts.

Methods: The genotoxic and cytotoxic effects of MTA and CEM were compared using MTT as well as single-cell gel (comet) assays with 9 serial ascending concentrations (0 to 1000 µg/mL) of tested materials.

Results: In terms of cytotoxicity, there was no significant difference between CEM and MTA at all concentrations except for the full concentration (1000 µg/mL); CEM had lower cytotoxicity (P=0.019). Genotoxic effects were more evident with CEM at concentrations of 15.6 and 250 µg/mL compared with MTA; however, this toxicity was less than that of MTA at concentrations of 500 and 1000 µg/mL. When the concentration of both materials was gradually augmented, the cytotoxicity and genotoxicity effects of the 2 experimental groups generally increased.

Conclusions: Under the conditions of this in vitro study, CEM was more effective than MTA in full concentration. This novel endodontic cement is biocompatible in terms of cyto- and genotoxicity. CEM appears to be an alternative to MTA as an endodontic biomaterial offering several advantages.


122

183166Long Term Survival Rate of teeth Requiring Multiple Treatment Procedure

G. RADAFSHAR, Associate Professor of periodotology, Oral and Maxillofacial Developmental Disease Research Center, School of Dentistry, Guilan University of Medical Sciences. Rasht, Iran, Rasht, Iran, A. SHAHBAZI MOGHADDAM, Dentist, Private Practice, Rasht, Iran, Rasht, Iran, M. TARAMSARI, Department of Endodontics, School of Dentistry, Guilan University of Medical Sciences, Rasht, Iran, Rasht, Iran, F. DARABI, Department of Operative and Esthetic Dentistry, School of Dentistry, Guilan University of Medical Sciences, Rasht, Iran, Rasht, Iran, and N. MIRFARHADI, MSc in Nursing Education, Oral and Maxillofacial Developmental Disease Research Center, School of Dentistry, Guilan University of Medical Sciences. Rasht, Iran, Rasht, Iran

Objectives: Preservation or replacement of teeth requiring multiple treatment procedures is still a common dilemma for practitioners especially with emerging trends in implant dentistry. This study sought to determine the 3 to >10-year survival rate of teeth that had undergone combined endodontic, periodontal, and prosthodontic treatments.

Methods: 245 teeth in 87 patients were clinically and radiographically evaluated. The patients were contacted by phone. All the teeth had received crown lengthening surgery (CLS) by a single periodontist. Root canal therapy and prosthehetic procedures were rendered either by specialists or experienced general dentists. Aside from lost teeth, the criteria for a hopeless tooth was defined and applied at the time of examination. Survival rate was determined using the Kaplan-Meier estimator. Clinical indices including pocket depth (PD), bleeding points index, C/R ratio, position of the restoration margin relative to the gingival margin (RM-GM), and presence of intra-canal post were compared between different survived groups (<3, 3-5, 5-10, and >10 years) using one-way Analysis of Variance (ANOVA). Potential predictors of failure were determined using the Cox regression model.

Results: The mean±SD of 3, 5, 10 and 13-year survival rates were 98±1%, 96±1.6%, 83.1±4.5%, and 51.9±14.5%, respectively. The mean PD (P<0.013), as well as C/R ratio in the mesial (P=0.003) and distal (P=0.007) surfaces were significantly higher in the >10 year survived teeth. BPI and RM-GM showed no significant differences among the groups. C/R ratio and sub-gingival placement of restoration margins appeared to be the major determinants of tooth loss.

Conclusions: The long-term survival rate for compromised teeth that have undergone combined endodontic, periodontic, and prosthodontics therapies, was 83-98%.


123

183167Osteoblast Survival during Different Bone Harvesting Techniques: An Animal Study

N. SOLTANIAN, Shahid Beheheshti university of medical sciences, tehran, ON, Iran, R. AMID, shahid Beheshti university of medical sciences, Tehran, ON, Iran, and M. KADKHODAZADE, shahid beheshti university of medical sciences, Tehran, Iran

Objectives: Autogenous bone graft is still the gold standard in bone regenerative procedures. However, there are no data about the effectiveness of bone harvesting methods on the viability of osteoblasts. The aim of this study was to assess the osteoblasts survival in autogenous bone grafts which were harvested through three different popular techniques.

Methods: This experimental animal study was performed on five laboratory pigs. After sedation and scrubbing the surgery zone with Chlorhexidine 1%, bone was harvested from calvaria via three different devices: trephine bur, bone scraper, and rotating bone collector. Bone chips were collected in PBS and transferred to the cell biology laboratory. The viability of osteoblast cells was evaluated by a blinded examiner under light microscopy images.

Results: 15 bone samples were obtained from five pigs with a mean weight of 500 gr. Examinations of cell morphology and viability showed that there was no intact osteoblasts in bone scraper and bone collector groups. There was some evidence of identifying osteoblasts in the samples of terephine bur group.

Conclusions: There was a great difference in osteoblast viability in bone grafts collected through different harvesting techniques. It seemed that a less traumatic technique such as trephine bur could be used for maintaining the viability of osteoblasts in a safer manner. Physical and thermal shock damages are probably two major causes of cell destruction which had happened in more traumatic procedures such as bone scraper and collector.


124

183171Periodontal Flap and Osseous Resective Surgery Techniques: Computer Assisted Learning

F. SARLATI, Z. ZARE, and N. LAIJI, Islamic Azad University, Dental Branch,Department of Periodontics, Tehran, Iran

Objectives: Computer Assisted Learning (CAL) can present approaches in new and innovative ways, while it allows approaches to be reviewed multiple times anytime and anywhere. CAL also has the potential of helping students develop skills and knowledge. The aim of this study was to compare knowledge of students exposed to two different instructional modalities for periodontal flap and resective osseous surgery techniques.

Methods: In this experimental study, 50 dental students (20 male, 30 female), within the age range of 24-27 years that did not have any experience about periodontal flap techniques or resective osseous surgery techniques, were randomly assigned in a prospective study to either use the CAL program (n=25) or traditional methods (n=25). CAL group had self-directed learning at a computer class. A university professor (Department of Periodontics) taught the traditional group. Both groups participated in an equal examination consisting of 15 true/false questions. Chi–square and independence samples T test were used for data analysis.

Results: Students in the CAL program scored higher (12.88 for periodontal flap and 12.6 for resective osseous surgery) than those in the traditional group (10.24 for periodontal flap and 9.48 for resective osseous surgery) and this difference was statistically significant (P<0.001).

Conclusions: This study showed that CAL is more effective than traditional methods and can be used as an adjunct to traditional education or as means of self-instruction in teaching periodontal flap and resective osseous surgery techniques.



125

183175Comparison of Single and Double Jaw Surgery in ClII Patients

M. NOURI1, S. ALIJANI2, M. JAFARI3, and A. AKBARZADEH BAGHEBAN2, 1Dentofacial Deformities Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, 2Shahid Beheshti University of Medical Sciences, Tehran, Iran, 3Orthodontic Department, Shahid Beheshti University of Medical Sciences, tehran, Iran

Objectives: The aim of this study was to compare one year follow-up craniofacial changes after mandibular advancement, with and without maxillary impaction surgery in ClII patients.

Methods: In this retrospective quasi experimental study, 51 patients were evaluated (25 patients had isolated mandibular surgery and 26 patients had simultaneous maxillary impaction and mandibular advancement). Lateral cephalograms were taken immediately before surgery and at one year follow-up. The cephalograms were superimposed on SN and registered on S point. The changes of 47 variables were assessed based on analysis introduced by Solow. The significance of changes in each group and between the groups were demonstrated by paired t-test.

Results: In both jaw surgery groups, mandibular hard and soft tissue landmarks (especially B point, lower Incisal edge and Pogonion), moved superiorly and anteriorly reflecting the upward and forward rotation of the Mandible that occurred as a result of the maxillary impaction. In mandibular advancement group, soft and hard tissue mandibular structures were positioned anteriorly and superiorly. On average, the SN-Pog angle increased 5.0° (SD=3.5°) and the ANB angle decreased 4.0° (SD=1.6°), the mandibular plane to SN angle decreased significantly (P<0.04). No statistically significant difference was observed between the two types of surgery.

Conclusions: The craniofacial changes after maxillary impaction and mandibular advancement surgery were similar to those seen in only mandibular advancement procedure.



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183177Self-perceived Oral Health of Addicts in Rehabilitation in Tehran, Iran

H. SHEKARCHIZADEH1, M.R. KHAMI2, S.Z. MOHEBBI1, and J.I. VIRTANEN3, 1Tehran University of Medical Sciences, Tehran, Iran, 2Tehran University of Medical Sciences, Dental Research Center, Tehran, Iran, 3University of Oulu, Oulu, Finland

Objectives: Self-perceived oral health, which is the subjective measure of an individual’s oral health, is affected by both objective indicators of oral disease and the impact of oral health on individual’s life. It reveals the patient’s value to oral health and the likelihood of seeking dental services. This study aimed to evaluate self-perceived oral health of drug addicts in addiction treatment in Tehran, Iran.

Methods: In 2011, a close-ended questionnaire was administered to a random sample of in-treatment addicts from the three main socioeconomic areas of the city utilizing a stratified cluster random sampling method. Moreover, participants provided their backgrounds and addiction history during an in-person interview. A linear regression model served for statistical analysis.

Results: Among the participants (n=813; mean age of 40.5 years, SD 11.5; 4% women), 16% were totally edentulous. Mean duration of addiction was 10.8 years (SD 7.9). Nearly half of the dentate addicts rated their oral health as poor or very poor. Education, employment status, area of residence, and duration of addiction were factors significantly associated with individual’s perception of oral health (P<0.05). Compared to dentate addicts, more edentulous patients rated their oral health as good (44% vs. 16%). Among the edentulous addicts, women, late starters of drugs, and users of opium or drugs other than crystalline heroin users revealed better perception of oral health.

Conclusions: Evaluation of self-perceived oral health, as an inexpensive and non-invasive way, is important in monitoring oral health situation of drug addicts. Most addicts in this study were not satisfied with their oral health. Differences in demographics and addiction history of the patients should be considered when planning oral health promotion activities.



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183180Home Bleaching Relapse in Patients with and without Recall Treatment

M. KASHKULI, Dental research center,Shahid Beheshti University of Medical Sciences, Tehran, Iran, A. GHASEMI, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and M. ABDO TABRIZI, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: Major controversies still exist over the relapse time of bleaching treatments and the period necessary until re-bleaching of the teeth in the dental literature. Therefore, the present study clinically compared the relapse of the home-bleaching treatments with and without recall bleaching in a 9-month follow-up period.

Methods: In this prospective single-blind randomized clinical trial, 44 patients with the least mean shade of A3 at their anterior teeth were selected and instructed to use carbamide peroxide (Opalescence 15% gel) into the trays nightly for 14 days. After 3 months, half of subjects received recall bleaching treatments (intervention group) while the other group did not receive recall treatment (control group). Digital images were obtained from the teeth in the baseline, after the bleaching, prior to the recall treatment, immediately after the recall and at 6 and 9-month follow-ups. L*a*b* parameters and overall color changes were calculated on the images by means of Photoshop and CIEL*a*b* system. The data were subjected to analysis of variance for repeated measurements test.

Results: Opalescence 15% gel administration resulted in significant improvement of teeth colors (whiteness) after 9-month follow-ups. The mean overall color changes (∆ E) in the intervention and control groups were 23.84 and 21.57 on 14 days after the initial bleaching, 22.92 and 21.45 before the recall treatment, 27.24 and 23.25 after the recall, 22.61 and 20.45 on the 6-month and 20.46 and 18.2 on the 9-month follow-ups as compared to the baseline values. Therefore, recall bleaching treatments following the initial bleaching was not associated with the increased teeth whiteness until 9 months.

Conclusions: Home bleaching with carbamide peroxide 15% gel showed successful results in teeth whiteness and re-bleaching of the teeth is not recommended up to 9 months after the initial bleaching due to the constant achieved results.


128

183182Frequency of Oral Connective Tissue Lesions in Children

S. ATARBASHIMOGHADAM, and N. DABIRI, faculty of dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: The frequency of oral connective tissue lesions of children in the literature is largely incomplete. The purpose of this study was to obtain the prevalence of these lesions and to compare the data with previous reports.

Methods: Files from the Oral and Maxillofacial Pathology registry of Shahid Beheshti University of Medical Sciences from 2003 to 2013 were searched for cases recorded as “soft (connective) tissue tumors and tumor-like lesions” in children. This study included 51 cases based on location within the oral region, diagnosis of soft tissue tumor, clinical information, and age≤12.

Results: Of the 51 cases, 30 tumors occurred in males, 21 in females (ratio 1.4:1). The mean age was 8.17 years. The common location was gingiva (80.39%). Peripheral giant cell granuloma was the commonest lesion (n=19), followed by pyogenic granuloma (n=14) and focal fibrous hyperplasia (n=6). All the lesions were benign.

Conclusions: Peripheral giant cell granuloma and pyogenic granuloma were the most common oral soft tissue tumor in children. The gingiva was the commonest site. The relatively high incidence of inflammatory and reactive lesions in pediatric patients implies the importance of careful oral hygiene in children. Fortunately, the frequency of benign soft tissue tumors in children was much more than the malignant counterpart.


129

183184Effect of Coffee on Discoloration of Three Nano Composites

F. MAHDISIAR1, A. GHAFFARI2, S. SOLEYMANI3, S. ZOKANI4, M. SHADI KIVI3, and N. NASOOHI3, 1Islamic Azad University- Dental Branch- Tehran - Iran, Tehran, Iran, 2Islamic Azad University- Dental branch - Tehran - Iran, Tehran, Iran, 3Islamic Azad University dental branch Tehran, Iran, 4Aslamic Azad University dental branch, Tehran, Iran

Objectives: Discoloration of dental composites over time is one of the important impact factors which plays a role in the process of refurbishment. Changing of color in resin composite could result in discontent of the patient over time and lead to the downfall of treatment process. The purpose of this study was to evaluate the influence of coffee on solubility and stability of color of nanocomposite in the process of spectrophotometry.

Methods: In this experimental study, 30 disc models (8.5 x 2 mm2) of three composites Z350XT, Grandio, and Herculite XTV Ultra were prepared (from every composite 10 models in two categories for keeping in coffee and distilled water).All specimens were kept in specific solutions for 72 hours. Color measurement was evaluated with spectrophotometry (MINOLTA-Japan) before and after immersion in solution. The results were evaluated with two-way ANOVA and Repeated Measure ANOVA.

Results: The rate of color change in each of the three composites which had been immersed in coffee was significant (P<0.05) and regarding to clinical aspect it was unacceptable rate ( E>3.3). The rate of color changing after immersion in distilled water relating to baseline was not significant(P>0.05).

Conclusions: Based on the methodology and the obtained results, Herculite XRV Ultra showed significantly the least color changes and it is more suitable restorative material in esthetic zone.


130

183191En-Mass Distalization of Maxillary Posterior Teeth with Mini-Screw Supported Hyrax F. SHIRBAN, DDS, Post graduate student, Dental Student Research Center, Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran, S. ALAVI, DDS, MS. Associate Professor, Torabinejad Dental Research Center, Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran, and S. NOOROLLAHIAN, , DDS, MS. Assistant Professor, Torabinejad Dental Research Center, Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran

Objectives: Maxillary posterior teeth distalization is a routine treatment approach for patients with Class II malocclusion who do not select extraction treatments or have had previous extractions. Up to now, techniques have tried to distal movement of these teeth separately. Regardless of anchorage type they have used, the common and greatest disadvantage of them is increasing the treatment time. The present technique tried to distalize all the maxillary posterior teeth simultaneously to reduce time and extend treatment options for special cases.

Methods: Case #1 was a 26-year-old female with Class I skeletal and dental relationship, bi-maxillary dento-alveolar protrusion with previous extraction of first upper premolars. Case #2 was a 19-year-old female with Class I skeletal and end to end molar relationship who did not accept to extract her first premolars. The treatment plan included distalization of all maxillary posterior teeth simultaneously. The posterior arms of modified Hyrax appliance were attached to the dentition with bands on first molars and bonding to other posterior teeth. Anterior arms had been formed as eyelets with 2 mm internal diameter and were attached to anterior palate with two mini-screws (2 mm×10 mm, Jeil Medical, Korea) at para-median regions. The vector of expansion of appliance was parallel to mid-palatal suture and occlusal plane. Before and after distalization, lateral cephalograms were used to evaluate the results.

Results: In case #1 3.6-mm and in case #2 3.45-mm distalization of entire maxillary posterior teeth were achieved in five months. Bodily distal movement with no significant unwanted rotations and anchorage loss was seen. The anterior face height did not change significantly.

Conclusions: This technique can be used for en-mass distalization of maxillary posterior teeth. The greatest advantage is reducing the treatment time. Other advantages are skeletally anchorage, patient comfort and no unwanted dental tipping and rotations.


131

183192The Effect of Bleaching on the Microleakage of Silorane-Based Composite

S.S. HASHEMI KAMANGAR1, M. GHAVAM1, and N. MAHINFAR2, 1Tehran University of Medical Sciences, International campus, Dental school, Operative department, Tehran, Iran, 2Tehran university of medical sciences , International campus, Dental School, Tehran, Iran

Objectives: The aim of this study was to determine the effect of 38% carbamide peroxide on microleakage of class 5 restorations filled by a silorane-based composite in a comparison of two metecrylate-based composites.

Methods: A total of 96 standardized class 5 cavities (1.5×2×3 mm) were prepared on the buccal surface of sound extracted human premolars and molars with both enamel and dentin margins and were randomly assigned to three groups as follows: Group A, Filtek P90 (silorane) with its dedicated adhesive system (P90 system adhesive); Group B, Adper Prompt L-Pop with Filtek Z250; Group C, Adper Prompt L-Pop with Filtek Z350XT. The teeth were subjected to thermocycling regime (1000×, 5–55ºC) and half of them received bleaching (38% carbamide peroxide, 15 min, twice a day, 14 days) and half of them received no bleaching (Control). Then dye penetration of tooth sections were evaluated following 24 hours immersion in 2% basic fuschin. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U test at 95% significance level.

Results: There was not any significant differences between composites in control groups either in enamel (P=0.867) and dentin (P=0.59) margins. After bleaching, microleakage of Z250 and Z350 did not significantly change (P>0.05) in relation to control but the microleakage of P90 significantly increased in both enamel (P=0.042) and dentin (P=0.002) margins. Bleaching increased the microleakage of Z350 and P90 more than Z250 (P<0.05).

Conclusions: There was not any significant difference between bleaching and control subgroups of two metacrylate-based composites either in enamel or dentin margins. Microleakage of silorane-based composite significantly increased after bleaching.


132

183193Medical Emergency Management Among Iranian Dentists

M.R. KHAMI1, S. RAZEGHI2, R. YAZDANI2, M. AFZALIMOGHADDAM3, and A. MOSKOWCHI4, 1Department of Community Oral Health, Dental Research Center, Tehran University of Medical Sciences, Tehran, Iran, 2Department of Community Oral Health, Tehran University of Medical Sciences, Tehran, Iran, 3Department of Emergency Medicine, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran, 4Dentist, Tehran, Iran

Objectives: About 18000 patients need medical emergencies management in dental offices in Iran annually. The present study investigated medical emergencies management among Iranian dentists in terms of knowledge, self-reported practices, and availability of necessary equipments and drugs in dental offices.

Methods: The target population of the study was all dentists working in public and private offices in the city of Tehran, Iran in 2011. From the list of their cell phone numbers, 210 dentists were selected randomly. A self-administered questionnaire was used as the data collection instrument. The questionnaire requested information on personal and professional characteristics of the dentists, as well as their knowledge and self-reported practice in the field of medical emergency management, and availability of required drugs and equipments to manage medical emergencies in their offices. T-test and linear regression models served for statistical analyses. This study was approved and supported by World Health Organization Patient Safety Project.

Results: Totally, 177 dentists (84%) completed the questionnaire. While most of the respondents were knowledgeable about such conditions as vasovagal syncope, diabetes, and myocardial infarction, less than 60% were aware of characteristics of hypoglycemic patients, chest pain with cardiac origin, and true cardiopulmonary resuscitation (CPR) practice. Certain shortcomings existed in the respondents’ ability to diagnose and manage emergency conditions, as well as in availability of necessary drugs and equipments in their offices to manage emergencies. In regression models, while knowledge, diagnosis and practice of the dentists were not associated with any of the professional characteristics, higher diagnosis and practice scores were significantly associated with higher knowledge scores (P<0.001).

Conclusions: The results call for a need to further education on the subject for dentists. Continuing education and changing dental curriculum in different forms seems to be useful in enhancement of the self-reported knowledge and practice of practicing dentists.



133

183198Demographic Factors Affecting the Survival Rate of Dental Implants H. SEMYARI1, N. JALAYER NADERI2, and F. BASTAMI1, 1Dental School of Shahed University of Medical Science, Tehran, Iran, 2Pathology, Dental School of Shahed University of Medical Science, Tehran, Iran

Objectives: Demographic factors can have an effect on failure of dental implant treatments. The aim of this retrospective study was to analyze the relationship between demographic factors and survival rate of dental implants.

Methods: A total of 235 Implants placed in 103 patients between January 2008 and December 2010 at the selected dental treatment centers of Tehran, were investigated with the following data collected from the dental records and radiographs: patient’s age, gender, location of implant placement , systemic disease, need for bone grafting and periodontal conditions before treatment. Then correlations between these data and survival rate were analyzed by SPSS and Chi-square analysis.

Results: 9 of 235 implants were failed, and implant survival rate was 96.2%. Maximum failure was observed in fifth and sixth decades of life (8 implants). The most frequent cause of implant failure was fibro osseous integration (7 implants). 16% and 49.5% of the patients had systemic disease and periodontitis before treatment respectively; moreover, 33.5% of implants needed bone grafting. A significant correlation between survival rate and need for bone grafting and periodontal conditions was shown (P=0.000); Still, there was no correlation between other demographic factors and survival rate significantly (P<0.05). In addition, there was a significant correlation between age and location of implant placement (P<0.001).

Conclusions: Consequently, it is important to consider demographic factors, such as need for bone grafting and periodontal conditions, before treatment to increase the survival rate of dental implants.


134

183204Mineral Trioxide Aggregate X-Ray Diffraction Analysis at Different pH Values

P. MOHEBBI, Islamic Azad University, Dental branch, Tehran, Tehran, Iran, and H. AKHAVAN, Dental School of Azad university of Tehran, Tehran, Iran

Objectives: In most clinical conditions, the materials used as root end filling, perforation or resorption repair are in close contact with infectious tissue with acidic pH and in case of calcium hydroxide therapy in contact with alkaline pH. The aim of this study was to compare the crystallographic structures of ProRoot White mineral trioxide aggregate (WMTA) at different pH values.

Methods: Both hydrated and unhydrated cements were mounted for XRD analysis. An X-ray diffractometer using Cu Ká radiation was set to run at 40 KV and 30 mA in a continuous mode. The scan range was 5-60 ̊ 2è with a scan speed of 2 ̊/min. X manager evaluation software was used for the analysis.

Results: In powder pattern, the sharpest peak was related to bismute oxide, followed by tricalcium silicate. The peaks reduced in intensity in the hydrated phases. The sharpest peak was related to bismute oxide. Portlandite was identified in the set forms. However, it was not observed in the powder forms. Peaks related to Portlandite were more intense in neutral pH in comparison with acidic and alkaline pH.

Conclusions: WMTA was best hydrated in neutral and then alkaline environments.


135

183208Effect of Zeolite on Sealing Ability of Mineral Trioxide Aggregate

M.A. SAGHIRI, Kamal Asgar Reserch Center, Encino, CA, A. ASATOURIAN, Islamic Azad University Dental Center, Tehran, Iran, and N. BAYATI, Private Practice, Tehran, Iran

Objectives: Natural zeolite is a type of mineralogical material containing large quantities of reactive SiO2 and Al2O3. It is widely used in the cement industry. In addition, many studies have confirmed the effect of zeolite components on physicochemical properties of constructive cements. The main objective of this work was to assess the sealing ability of adding 2% zeolite as Clinoptilolite (Na, K, Ca)2-3Al3 (Al,Si) 2Si13O36•12H2O to MTA based cement.

Methods: In the current research, 2% Zeolite as Clinoptilolite was mixed mechanically with MTA and then mixed according to manufacturer’s instrcutions. In this part, Root-end cavities were filled with white MTA plus Clinoptilolite in the experimental groups. In the control groups, root-end cavities were filled just with MTA. Microleakage was evaluated by using bovine serum albumin.

Results: The evaluation was conducted at 24-hour intervals for 30 days. Data were analyzed by using SPSS software. The earliest bovine serum albumin microleakage was observed in control group. There was a significantly longer time necessary for leakage to occur in experimental group (P<.000).

Conclusions: Chemical reaction between MTA and Zeolite must be addressed and may amend the leakage properties of endodontic cement. The present study confirmed that adding 2% Zeolite as Clinoptilolite may improve the sealing properties of MTA cement.


136

183210Anticariogenic Effect of Some Herbs

S. NEMATI ANARAKI, Islamic Azad University Dental Center, Tehran, Iran, R. GHOSEIRI, Islamic Azad University, Tehran, Iran;and P. OMIDSALAR, Islamic Azad university, Tehran, Iran

Objectives: Dental caries, this infectious and transmissible disease, is the most common disease that affects humans. The main factors causing tooth decay are the increase in the S.mutans and Lactobacillus acidophilus. Studying the effects of plants on teeth caries due to the increasing interests on using herbal medicines, their accessibility, low cost, and effectiveness, has led the researchers to one of the most effective ways of preventing this infectious disease. In this in vitro study, the antibacterial effect of black pepper (Piper nigrum L.) and garlic (Allium sativum L.) extracts on standard Streptococcus mutans and Lactobacillus acidophilus were reviewed.

Methods: This experimental study was conducted in two stages. At the first stage, alcoholic extracts of black pepper and garlic were prepared by Percolation extraction method and the concentrations of 256 and 512 mg⁄ml of them were diluted by Serial dilution method. Then, at the second stage, the evaluation of minimum inhibitory concentration of the extracts on Streptococcus mutans and Lactobacillus acidophilus was performed by Broth macrodilution method. Furthermore, in order to test the susceptibility of these microbes to extracts, Zone of Inhibition of these extracts was evaluated by Agar well diffusion method.

Results: In all repetitions of the test, for the concentrations of 256 and 512 mg⁄ml of extracts, in all tubes, a few turbidity related to the presence of microbes was seen, so, no measures for MIC were determined. Also in Agar well diffusion method, for the concentrations of 256 mg⁄ml of both extracts, no Zone of Inhibition was observed. However, for the concentration of 600 mg⁄ml of black pepper, for both of microbes, a very small Zone of Inhibition, about 1 mm, was observed around the wells.

Conclusions: Plant extracts of black pepper and garlic available in Tehran markets, with extraction method of Percolation, have no significant effect on oral standard Streptococcus mutans and Lactobacillus acidophilus. It is worth mentioning that many factors can affect the outcome of this research.


137

183211Primary Care Nurses’ Perspective on Children’s Oral Health

S. RABIEI1, S.Z. MOHEBBI1, R. YAZDANI2, and J.I. VIRTANEN3, 1Tehran University of Medical Sciences, Tehran, Iran, 2Department of Community Oral Health, Tehran University of Medical Sciences, Tehran, Iran, 3University of Oulu, Oulu, Finland

Objectives: The majority of young children receive no early dental examination while attending primary health care for routine check-ups. Our aim was to study primary care nurses’ knowledge of oral health care (OHC) and their attitudes toward delivering OHC, as well as to assess their willingness to obtain OHC information.

Methods: The current study is a cross-sectional survey of all primary-care nurses working in the public health centers of Tehran city. An anonymous self-administered questionnaire queried their knowledge in pediatric-, general and medicine-related areas of dentistry, providing knowledge scores for three domains. The nurses’ attitudes toward OHC and their willingness to obtain OHC information underwent evaluation with statements utilizing a five-point Likert scale. Altogether 680 nurses took part in the survey. The Chi-square test, t-test, one-way ANOVA and logistic regression model served for statistical analyses.

Results: The mean score for the pediatric dentistry domain (3.6, SD: 1.5) was lower than those of medical (4.4, SD: 2.3) and dental domains (5.8, SD: 1.5). Obtaining higher scores in the pediatric (OR=1.2) and dental (OR=1.3) domains, and a greater willingness to receive OHC information (OR=5.3) were associated with a positive attitude toward OHC. Nurses with lower education level (OR=1.9) and better oral health behavior (OR=1.1) as well as those working in a non-affluent region (OR=1.6) had a more positive attitude toward OHC.

Conclusions: Primary care nurses’ low level of knowledge in OHC and their positive attitude and willingness to obtain more information point to the need for appropriate training.



138

183212Correlation between the Gingival Embrasure Space and Interdental Papilla

P. VARES1, M. KADKHODAZADEH2, R. AMID1, and F. HAJIZADEH1, 1Shahid Beheshti University of Medical Sciences, Tehran, Iran, 2Dental Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: Interdental papilla, especially in anterior segment of maxilla, is one of the most crucial determining factors in esthetics. In addition, interdental crestal bone height is significantly correlated with the position of interdental papilla. The aim of current study was to determine the correlation between the height, width, and surface area of gingival embrasure space and interdental papilla.

Methods: 60 cases (aged of 20 to 30 years) participated in this cross-sectional study. For each case, five areas including: interdental papilla between centrals, centrals and laterals, and premolars were evaluated through parallel periapical radiography and impression. The height, base, and surface area of the radiographic and clinical surface of each papillary area was measured by using radiography and casts. Correlation coefficient between radiographic and clinical variables was measured in the whole data and each region separately. The database was evaluated through SPSS software with Pearson correlation test.

Results: Totally, 216 regions were studied. Correlation between clinical and radiographic papilla height was significant. Correlation between radiographic height and clinical base between central incisor and lateral incisor, and correlation between radiographic height and papillary clinical surface area were weakly significant. Correlation between the clinical and radiographic papillary surface area was not significant.

Conclusions: It seems that the relationship between radiographic and clinical dimensions of papilla has to be evaluated in both vertical and horizontal directions. Due to different correlations, all data obtained from anterior teeth should not be calculated together.



139

183214Influence of Cavity Size Modification on Microleakage of Bulk-Cured Composites

A. GHASEMI, and N. YOUSSEFI, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: The aim of this in vitro study was to evaluate the amount of polymerization shrinkage of the recently introduced composites, investigating the claims that these restorative materials work efficiently and credibly in any cavity size. Therefore, two different brands of these bulk-cured composites were chosen for this microleakage evaluation study.

Methods: 40 samples were prepared with class II cavities in mesial and distal sides of human molar teeth and were divided into four groups. Group1: 3mm buccolingual width cavity (to be known as the smaller cavity) filled with Tetric Bulk Fill composite. Group2: 6 mm buccolingual width cavity (larger cavity) filled with Tetric Bulk Fill composite. Group3: 3 mm buccolingual width cavity filled with X-tra base composite. Group4: 6 mm buccolingual width cavity filled with X-tra base composite. Thereafter, the specimens were thermally stressed for 500 cycles in water bath at 5 and 55°C, protected with nail polish, colored with 1% methylene blue dye, cut into sections, and finally evaluated.

Results: The data were submitted to ANOVA and the results showed the highest degrees of microleakage in larger cavity of X-tra base among four groups and there was a significant statistical difference (P=0.012) between larger and smaller cavity of X-tra base (Groups 3 and 4) while there was no statistical difference between two cavity sizes of Tetric-filled groups.

Conclusions: The recent advancements in restorative dentistry have come up with a variety of achievements which need a precise and delicate approach to make the finest choices. According to this experiment, Tetric bulk fill composite lies in a strongly superior position compared with X-tra base composite when it comes to microleakage and polymerization shrinkage.



140

183218Effects of Plasma Rich in Growth Factors in Extraction Sockets

R. POURABBAS, Dental and Periodontal Research Center-Tabriz Univ. of Medical Sci., Tabriz, Iran

Objectives: The positive effects of plasma rich in growth factors (PRGF) in the healing of extraction sockets have been shown in some studies. The aim of the present study was to evaluate the effect of PRGF alone or in combination with other biomaterials in a dog model in extraction sockets.

Methods: Distal roots of upper second and third premolars were extracted bilaterally in six mongrel dogs. Buccolingual (BL) and Apico-coronal (AC) dimensions of extraction sockets were measured. The extraction sockets were randomly grafted with autogenous bone grafts (ABG) with and without PRGF, DBBM with and without PRFG, and clot with and without PRGF. The dogs were sacrificed after 3 months and the extraction sockets were evaluated from clinical and histological points of view.

Results: There were significant differences in post extraction vertical dimensions of the sockets among the study groups. The mean AC changes were 5.27±2.32 (ABG), 6.12±2.12 (ABG+PRGF), 6.25±2.13 (DBBM), 6.83±1.83 (DBBM+PRGF), 3.83±1.63 (clot), 3.85±1.67 (clot+PRGF), respectively (P=0.02). The mean BL dimension reductions were 1.68±0.45 (ABG), 1.23±0.76 (ABG+PRGF), 2±1.09 (DBBM and DBBM+PRGF), 2.66±1.47 (clot), 2.03±1.23 (clot+PRGF) that expressed a significant differences (P=0.01). The control groups (clot with and without PRGF) exhibited a complete bone fill and bone formation rate which was more than that in the other groups.

Conclusions: The findings of this study indicate that using DBBM or ABG with and without PRGF might successfully maintain socket dimensions.


141

183219Effect of Polishing and Glazing on Color Stability of Porcelain M. NOURBAKHSH, Islamic Azad University dental center, department of fixed prosthodontics,Tehran, Iran, M.H. SALARI, Islamic Azad University Dental Center, Tehran, Iran, and M. NOURBAKHSH, Dental student of dental branch of Islamic Azad University, Tehran, Iran

Objectives: In the past twenty years, using synchronous dental restorations were very common, even in restoring molar teeth. This raised many questions regarding to the method of preparing the surface of the restoration in order to decrease discoloration in long-term use. One of the common problems in using synchronous restoration is their discoloration. Many researchers have studied the different types of materials for making restoration and their procedure. The purpose of this study was to compare the color of glazed and polished NORITAKE A1 porcelain using spectrophotometer.

Methods: This experimental study was conducted under in vitro condition. 20 disc-shaped specimens, 10 mm in diameter and 2 mm thick were prepared. All of the specimens had opaque layer and A2 shade was used for them. In order to have similar specimens, the same plaster mold and technician were used. The samples were randomly divided into two groups, each containing 10 specimens. One group received glazing powder and the other was prepared by polish kit. Specimens from each group were immersed in 0.2% chlorhexidine mouthwash solution for 30 days. Differences in color before and after 30 days were calculated using spectrophotometric analysis. Overall color difference was determined using the CIE Lab system for measuring small color differences.

Results: After 30 days of immersion in solution, ΔE value was 0.78±0.19 in polish group and 0.76±0.16 in glaze group (P<0.05). The result of this study showed a little difference in color stability between the polished and glazed specimens. This was not statistically significant.

Conclusions: It can be concluded that all of the color stability in both groups were acceptable clinically, and there was not a significant difference between the two groups.


142

183225Prevalence of Oral Lesions in AIDS and HIV Positive Patients

A. MANSOURIAN, Oral Medicine Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, NY, Iran, S. ASHNAGAR, Students Scientific Research Center, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, J. MOMEN BEITOLLAHI, Oral Medicine Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, and N. FARHANGI, School of Dentistry, Tehran University of Medical Sciences, Tehran, NY, Iran

Objectives: Oral lesions are common in HIV infected patients. Several studies have been conducted to the entire world in order to determine the prevalence of oral lesions in AIDS/HIV infected patients. Since few studies have been conducted in this issue in Iran, the current study aimed at evaluating the prevalence of oral lesions relating to HIV/AIDS in patients referring to Imam Khomeini Hospital. The presence of oral lesions was correlated with biologic and behavioral risk factors.

Methods: 203 patients with AIDS/HIV+ were recruited in this study and oral examination was performed for each individual. The oral lesions were diagnosed based on clinical appearance using EEC-Clearing house criteria on oral problems related to HIV infection (1993). Oral lesions were managed by routine therapeutic protocols.

Results: 77.3% patients were male. 186 oral lesions were diagnosed in association with HIV in 109 patients (53%). The most common oral lesions were Erythematous Candidiasis (24.1%), Angular Cheilitis (22.2%), Hyperpigmentation (18.2%), and Pseudomembranous Candidiasis (14.3%) respectively. Other oral lesions which were seen included: Hairy Leucoplakia (3.4%), Herpes Labialis (3.4%), Hyperplastic Candidiasis (2.5%), Minor Aphthous ulcers (1.5%), common Wart (1 case), Facial palsy (1 case), and Steven Johnson disease (1 case). Smoking addicted participants and patients using mobile dental prosthesis were more likely to have oral candidiasis. Patients who were on HAART had a significantly lower risk of pseudomembranous candidiasis. No significant relationship was found between use of HAART and presence of oral pigmentation. Pseudomembranous Candidiasis was significantly associated with AIDS condition.

Conclusions: The prevalence of oral HIV lesions in the present study was high. A comprehensive oral examination plays an important role not only in the management of the patients, but also in assessing the immune status and their follow-up. There are many biological and behavioral risk factors that influence the development of oral lesions in AIDS/HIV+ patients.


143

183226Green Tea Mouthwash in Postoperative Pain Following Third-Molar Extraction

M. ESHGHPOUR, Mashhad University of Medical Sciences, Mashhad, Iran, H. MORTAZAVI, Shahid Beheshti University of Medical Science, Tehran, Iran, N. MOHAMMADZADEH REZAEI, General Dentist, Mashhad University of Medical Sciences, Mashhad, Iran, and A.H. NEJAT, Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran

Objectives: Pain following surgical removal of impacted molars has remained an important concern among practitioners. As green tea possesses anti-inflammatory and antibacterial properties, the aim of the current study was to evaluate the effectiveness of green tea mouthwash in controlling postoperative pain.

Methods: In a study with split-mouth and double blind design, 44 patients in need of bilateral removal of impacted third molars underwent randomized surgical extraction. Following one surgery, patients rinsed with a green tea mouthwash from the first to seventh postoperative day and after other extraction rinsed with placebo mouthwash for the same duration. Both patients and surgeon were blinded to the type of mouthwash. The predictor variable was the type of mouthwash and primary outcome variable was postoperative pain measured by visual analogue scale (VAS) during the first week after surgery. In addition, the number of analgesics patients used after surgery recorded. To analyze data, repeated measures with confidence interval of 95% was performed.

Results: Total of 43 patients with mean age of 24 years underwent total of 86 surgeries. VAS value had no statistically difference prior rinsing among groups (P>0.05). However, the mean value of VAS following rinsing with green tea was statistically lower than placebo in postoperative days of 3-7 (P<0.05). In addition, while rinsing with green tea, patients took significantly lower number of analgesics after surgery (P<0.05). No side effects were reported.

Conclusions: Green tea mouthwash could be an appropriate and safe choice to control postoperative pain after molar surgery.


144

183230Effect of Lip Line on Anterior Teeth Proportion Preference

H. KERMANSHAH1, S. JAFARNIA2, L. RANJBAR OMRANI1, and R. NEJATBAKHSH3, 1Restorative Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, NY, Iran, 2Sudents’ Scientific Research Center, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, 3School of Dentistry, Tehran, NY, Iran

Objectives: Considering the importance of acceptability of esthetic treatments, the aim of this study was to evaluate the effect of lip line on different proportions of central to lateral.

Methods: After taking photos of smile of two female and two male participants, changes were made in “lip line” and “proportion of visible width of maxillary anterior teeth” by computer graphic program (Adobe Photoshop) to provide 9 various modes of these factors for the selection of evaluators. Photos were printed as a questionnaire for evaluation of attractiveness. 20 male and 20 female dental students in their second or third year of education were interviewed and the factors were analyzed according to the results.

Results: Two assessed factors were not independent to be reviewed separately. In upper line, 70% proportion and in average lip line, 62% proportion and in lower lip line, 54% proportion were the most attractive width proportions. Totally, the average lip line was the most attractive lip lines in all width proportions. Gender of evaluator and cases had no significant effect on the rating.

Conclusions: In restorative treatments of maxillary anterior teeth, lip line should be considered before selecting a particular width proportion.


145

183235Evaluation of Ki-67 and PCNA in Subtypes of Amelonlastoma

F. MASHHADI ABBAS, Dental Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Z. NAJI RAD, Shahed University of Medical Sciences, Department of Orthodontics, Iran, Tehran, Iran, and M. BROOKHIM, Shahid Beheshti University of Medical Sciences, Iran, Tehran, Iran

Objectives: Ameloblastoma is the most important Odontogenic neoplasm, particularized by its local invasion. The aim of this research was to clarify the possible relation between the two markers, PCNA and Ki-67, and different types of Ameloblastomas.

Methods: This research was a descriptive retrospective study and was performed on 33 specimens of Ameloblastomas, 4 of which were excluded due to the loss of expression of the markers. As a result, the specimens were dropped to 29 (17 benign, 5 recurrent, 7 malignant). They were examined Immunohistochemically using the Streptavidin-Biotin method with anti-PCNA and anti-Ki-67 antibodies.

Results: The Ki-67 was expressed below 10% in 75.9% of the cases (22 cases), below 39% in 20.7% (6 cases) and above 3% in 3.4% (1 case). This showed that there was no significant relationship between the type of ameloblastoma and presence of Ki-67 (P<0.927). The average positivity percentage of PCNA expression was 42.05% in benign types, 65% in malignant types, and 25% in the recurrent types. The average positivity of PCNA expression in the malignant type was higher than the recurrent and benign types, but there was no difference between the recurrent and the benign types. This showed a statistically difference in PCNA expression among different types of Ameloblastomas (P<0.023).

Conclusions: There was no statistically significant difference between different types of Ameloblastomas and expression of Ki-67, so it cannot be used as a diagnosis means for different types of Ameloblastomas, but there is strong relation between the positivity percentage of PCNA and different types of Ameloblastomas; therefore, it can be used to differentiate between the different types.


146

183236Low-Level Laser Effect on Pain after BSSO Surgery

A. HARAJI, Islamic Azad University , Dental Branch, oral & maxillofacial surgery Department, Tehran, Iran, and Z. TEHRANI, Islamic Azad University, dental Branch, Tehran, Iran

Objectives: Pain controlling is a serious challenge after surgical operation, especially in orthognatic surgery. The aim of this research was assessing the pain control after BSSO surgery by use of irradiation of diode low power laser.

Methods: The study was done as a double blind, split mouth, clinical trial. 38 regions were operated symmetrically. Exclusion criterion was systemic disease that contrandication the BSSO. In each patient, the jaw was divided into control and experimental group. In experimental group, after surgery, diode laser 810 nm, power 100 mv, energy 4 J/cm2 and 80 s was irradiated. In control group, laser was only showed, but did not irradiated (placebo).The pain evaluation was done 6, 12, 24, and 48 hours after surgery. The data were analyzed with Wilcson signed ranks test.

Results: Patients with mean, 20.4±1.7 years of age, 6 male and 13 female, where selected. The jaw was divided into 2 groups (control-experimental) randomly. The experimental group showed more pain decreasing than the placebo (control group) (12 h after surgery P=0.003, 24 h after surgery P<0.001).

Conclusions: Low power laser application can cause pain control, more significantly than the placebo group, after the BSSO.


147

183237Implant Placement Simultaneous Alveolar Ridge Augmentation with Block Bone Graft

A. HASSANI, Oral and Maxillofacial Department, Islamic Azad University, Dental Branch, Tehran, Iran, Tehran, Iran, and S. SAADAT, Craniomaxillofacial Research Center, Tehran University of Medical Sciences, Shari’ati Hospital, Tehran, Iran

Objectives: Successful osseointegration of dental implants requires sufficient bone surrounding the implant. Delayed or simultaneously implant placement after maxilla/mandibular reconstruction is controversial. Despite the overall progress in dental implantology, the placement of implants in the atrophic maxilla/mandible is already considered to be challenging. On the basis of previous criterion, several studies have shown successful results for implants placed in the block bone graft. The aim of the present study was to demonstrate the outcome of implants placement simultaneously in block bone graft.

Methods: This Study was designed as a cross sectional study. Consecutive patients affected by jaw’s atrophy and treated with implants placement, simultaneous block bone graft between 2008 to 2011, were recalled. 87 patients (42 male, 45 females) aged between 22 and 70 years were enrolled. A total of 194 implants were inserted in 110 surgery sites. During the recall, new X-Rays were requested and a clinical evaluation was performed. The outcome measures were “Implant Success”, “Implant Satisfactory Survival”, “Implant Compromised Survival”, and “Implant Failure”. The follow up period was 19.7±6.2 months.

Results: Of the 194 implants placed simultaneous with block bone graft, 178 implants in 84 patients carried ideal conditions. The amount of crestal bone loss of 10 implants in 7 patients was evaluated 2.6±0.5 mm. 4 mm C.B.L occurred for 3 implants in 3 patients, also a slight to moderate peri-implantitis was observed. 3 implants failed in 3 patients. The outcome was recorded as follows: Implant Success rate: 91.8%; Implant Satisfactory Survival rate: 5.2%; Implant Compromised Survival rate: 1.5%; and Implant Failure rate: 1.5%.

Conclusions: Based on the results, with necessary precautions, it can be concluded that implant placement in conjunction with block bone graft simultaneously represents a safe modality of treating the atrophic maxilla/mandible.


148

183239Social Capital and Self-Perceived Oral Health, Urban HEART Study

S. BABAZADEH1, R. YAZDANI2, S.Z. MOHEBBI1, A. MONTAZERI3, and H. HESSARI1, 1Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, 2Department of Community Oral Health, Tehran University of Medical Sciences, Tehran, Iran, 3department of mental health , Iranian institute for health sciences research, Tehran, Iran

Objectives: There has recently been much debate about the influence of social capital on health outcomes. This study determined the association between social capital and self-perceived oral health, in Tehran.

Methods: In 2011, a cross-sectional survey was performed within all 22 districts, by municipality of Tehran, URBAN HEART survey. A questionnaire served as the tool to measure social capital in randomly selected clustered subjects (n=21039) within households. Social capital consisted of two main components, structural and cognitive, and in six categories of participation, voluntary help, sense of community, social network, trust, reciprocity; All were measured in nine layers from close family member to other groups. The responses were based on Likert scale. The total score was calculated through the sum of all factors. Self-perceived oral health was measured by a single question. Descriptive statistics, contingency table, analysis of variance ANOVA, and post-hoc test were used to detect differences. P<0.01 was considered as significant.

Results: The mean age of the study population was 39.1 years (SD:13), 45% were male and 72% were married. Among the respondents, 41% perceived their oral health to be very good or good. The total social capital mean score was 42 (SD:11.9). Respondents with a higher level of social capital revealed a better perception of their oral health (P<0.0001).

Conclusions: Individuals with a higher social capital had a better perception of oral health. This calls for more focus on social capital supports throughout the communities to improve health conditions.


149

183240Effect of CPP-ACPF on Oral Symptoms of Patients under Chemotherapy

S. BANAVA, Islamic Azad University Dental Branch, Tehran, Iran, and M. HOSHYARI, Shohadaye Tajrish Hospital, Tehran, Iran T. SAFAIE, Islamic Azad University Dental Center, Tehran, Iran,

Objectives: Oral status of patients undergoing chemotherapy is affected by the drugs they received. A suitable substance with all positive properties to prevent oral complications has not yet been introduced. So, the aim of this study was to evaluate the effect of CPP-ACPF paste on oral status of patients undergoing chemotherapy.

Methods: This research was a clinical randomized parallel double blind trial. 20 patients with treatment plan of chemotherapy who met the inclusion criteria entered the study and were randomly divided into the two following groups: Group 1 received routine medication of cancer therapy center, Group 2 used CPP-ACPF (MI paste, GC USA) paste twice a day. The baseline status of oral conditions of patients (mucositis, dry mouth, infection, diminished tasting sense, difficulty in food intake, and burning sensation of mucosa, were recorded and re-evaluated after 21 and 42 days. The data were analyzed with Mann-Whitney U-test.

Results: Mann-Whitney test showed that using CPP-ACPF paste twice daily did not cause any significant difference in oral complication of subject group compared to the control (P>0.05).

Conclusions: Using CPP-ACPF paste before starting chemotherapy and during it, could not significantly improve the oral status of patients undergoing this treatment.



150

183241Double Taper and Simple Taper Fiber Posts Z. MAHDAVI IZADI1, E. JALALIAN1, M.H. SALARI2, M. SHIRAZI3, A. ORUMCHI4, and D.S. MAHOUTCHI5, 1Islamic Azad University Dental Center, Department of Fixed Prosthodontics, Iran, Tehran, Iran, 2Islamic Azad University Dental Center, Tehran, Iran, 3dentist, Tehran, Iran, 4dental student ,dental branch, Islamic Azad university, Tehran , Iran, Tehran, Iran, 5dental student ,dental branch, Islamic Azad University, Tehran, Iran

Objectives: Since the precast non-metal posts are used more frequently these days in dentistry, while there are no confident data showing stress distribution across the root canal, the purpose of this research is comparison of the stress distribution on the walls of the root canal for two types of fiber posts, double and simple taper, employing photo-elastic method.

Methods: This research was conducted by experimental method in photo-elastic system. Posts used in this research were two types of Fiber posts called Simple Taper and Double Taper with 0.9 mm diameter and 20 mm length and the applied resin was Epoxy. The research was started by making two photo-elastic models with dental dimensions and installing the mentioned posts in them and the core was made up over each post. Then colorful rings developed by loading each model in Plariscope were photographed.

Results: By loading to 100 N with 90 degree angle the simple taper fiber post had fringe order equal to 1.39 and 2.5 in cervical and apical zones respectively, while these figures were 1.39 and 2.35 for the same conditions and same zones for double taper post. 150 N loading with 30 degree inclination, the simple taper post had fringe order magnitudes in cervical and apical zones equal to 4 and 2.65 respectively while double taper showed 4 and 2.5 fringe order at the similar condition.

Conclusions: In vertical forces, the double taper posts have better stress distribution compared to simple taper ones.


151

183242Comparison of Two Adhesive Systems on FRC Post Bond Strength

F. BALOUCH1, M. SHIRYAN2, M. SHAHNEH SABET2, T. LESSAN2, and E. MOHAMMADDIAN AMIRI2, 1Islamic Azad University Dental Center, Tehran, Iran, 2Islamic Azad university, Dental faculty, Tehran, Iran

Objectives: One of the most important concerns in dentistry is endodontically treated teeth restorations. Recently, fibers and use of adhesive and resin cement for post cementation have increased. Two cementation systems are available: Separate acid etch adhesive and Self-adhesive. To evaluate the post retention, the push out technique was used. The purpose of this in vitro study was to evaluate the effect of self-adhesive and separate acid etch adhesive on regional bond strength on a kind of fiber reinforced post.

Methods: 20 endodontically treated teeth were randomly divided into two groups (n=10); in one group Self-adhesive system without using etch and bond technique, and in the other group Separate acid etch adhesive system after etching (Phosphoric acid 32%) and bonding cements were applied into the root canal space. 12 mm of each cemented post within root canal sectioned in equal thirds using a 0.1 mm diamond disk. Each slice was polished with soft and wet abrasive paper to obtain 2 mm thickness. Loading was performed by a testing machine with a speed of 1 mm/min. until these posts were dislodged. The obtained data were statically analyzed using one sample Kolmogorov-Smirnov, T-test, and ANOVA test.

Results: Significant differences were found on all tooth regions. In separate acid etch adhesive group, the bond strength was stronger at coronal and middle regions. In self-adhesive system group, the bond strength was stronger at apical region. Bond strength was significantly increased from coronal to apical in self-adhesive system. In contrast, this bond strength rate reduced in coronal to apical in other group.

Conclusions: According to the increase of bond strength obtained in separate acid etch adhesive compared to self-adhesive, it seems convenient to use separate acid etch adhesive system for cementation of fiber reinforced post instead of self-adhesive system.


152

183243Dental Pain and Self Perceived Oral Health, Urban HEART

Z. MOMENI, A. PAKDAMAN, and H. HESSARI, Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran

Objectives: To assess the prevalence of dental pain and to investigate the association between dental pain and self-perceived oral health among Tehrani adults (15-64 years old, 2011).

Methods: Using a self-administered questionnaire, data were collected on dental pain experience in the past 12 months (present pain, pain within past 12 months, pain lasted for three months) in a sample of 21039 (9418 were male) 15- to 64-year-old adults. Data were from a large population-based cross-sectional survey conducted in the city of Tehran, using the Urban Health Equity Assessment and Response Tool (Urban-HEART) 2011. Chi-square tests analysis was used to assess the associations between dental pain experience and self-perceived oral health.

Results: The questionnaire was completed by 21039 individuals between 15 and 64 years old with a mean age of 39 (SD=13.02 - Range= 49). The response rate was 95%. 19% of adults reported having dental pain at the present, 14% reported having dental pain in the past 12 months and 5% reported having dental pain that lasted for 3 months. Females had pain more than males (P<0.001). Self-reported oral health presented poor and very poor by most of the subjects.

Conclusions: Findings indicated that age, education, poor and very poor self-perceived oral health were related to dental pain in this group.


153

183245Cytotoxicity Evaluation of Four Intracanal Medicaments on L929 Fibroblasts

Y. SHANTIAEI, Associate Professor, Dept. of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, O. DIANAT, Assistant Professor, Dept. of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, N. BAHROLOLUMI, Undergraduate Student, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and S. YAGHMAEI, Postgraduate Student, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: Endodontic therapy is performed in multiple sessions in many occasions with the use of different intracanal medicaments to eradicate the existing microorganisms and prevent the growth of new bacteria. Besides anti-microbial activity, their histocompatibility would be of great significance. The aim of this study was to compare the cytotoxicity of calcium hydroxide, calcium hydroxide reinforced with chlorhexidine, 2% chlorhexidine solution, and 2% chlorhexidine gel.

Methods: In this in vitro study, cytotoxicity was evaluated by fibroblast cell culture and its direct contact with the test materials. Cell survival fraction was estimated by MTT test after 1, 12, 24, 48, and 72 h. The corresponding data were analyzed statistically using One way ANOVA test.

Results: By gradually increasing concentrations and time, an increased cytotoxicity was observed for each agent. 2% chlorhexidine gel had the highest toxicity in all concentrations and time durations, while calcium hydroxide had the least. After 1 hour, calcium hydroxide had the lowest cytotoxicity. However, no significant differences were observed between the three other agents (P>0.05). The same trend was observed in other time durations.

Conclusions: Calcium hydroxide is the least toxic intracanal medicament. Agents containing chlorhexidine should be used with caution in tooth canals due to their great potency of cytotoxicity. Calcium hydroxide reinforced with chlorhexidine with less cytotoxicity than chlorhexidine can be used as dressing between endodontic sessions with caution.


154

183246Stepwise Excavation Using MTA: A Randomized Clinical Trial

M. SAFAIE YAZDI1, S. BANAVA2, and H. HESHMAT3, 1Islamic Azad University-Dental Branch, Tehran, Iran, 2Islamic Azad University Dental Branch, Tehran, Iran, 3Department of Restorative Dentistry and Dental Materials, Islamic Azad University-Dental Branch, Tehran, Iran

Objectives: It has been proved that pulpal exposure could be avoided in deep carious lesions, using Stepwise Excavation (SE). The lining material that covers the remaining caries plays an important role in this technique. Mineral Trioxide Aggregate (MTA) is a biocompatible cement with appropriate characteristics such as antibacterial effect, sealing ability, and induction of dentine formation. The aim of this randomized clinical trial was to investigate the effect of using MTA liner on the success of SE with no re-entry after 12 months.

Methods: 48 patients participated in this study according to inclusion criteria. Patients were randomly assigned into 2 groups: Group 1 (Control): 22, no liner applied, Group 2: 26, MTA. After evaluating responses of each tooth to cold, percussion, and pressure, a cavity was prepared and caries were excavated completely from the periphery of the cavity, except the pulpal floor or the axial wall. The liner was applied according to manufacturing instructions. Restoration of the cavity was done with EQUIA System (Posterior Glass Ionomer, GC Co., USA). The cavity was conditioned with polyacrylic acid, restored with a capsule of posterior glass ionomer and coated with a special nano-hydrophobic light-cured resin (G Coat, GC Co., USA). Clinical and radiographical evaluations were done on certain periods up to 12 months.

Results: The results of this study revealed that there was a significant difference between the two groups regarding the symptoms (P>0.05). Three cases in Group 1 resulted in irreversible pulpitis after SE, which needed RCT while eight cases experienced sensitivity to cold during clinical examinations (P<0.05). Only one patient in Group 2 experienced sensitivity to cold (P<0.05).

Conclusions: MTA can be used as a lining material over the remaining caries in SE technique without re-entry. However, longer evaluation time is suggested.


155

183248Influence of Spatial Resolution on Detection of Non-Cavitated Proximal Lesions

S. NIKNESHAN, Shahid Beheshti University of Medical Sciences, Tehran, Iran, F. MASHHADI ABBAS, Dental Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and S. SABBAGH, Dental Student, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: This in vitro study aimed at comparing the diagnostic accuracy of two digital radiographic systems with three spatial resolution settings in the detection of non-cavitated proximal lesions.

Methods: 70 non-restored, extracted human premolars were used in this experimental study. The teeth were mounted in 14 plaster blocks. Two blocks were simultaneously used to simulate a bitewing radiograph and digital images were taken by two digital systems: Digora Optime (PSP) at two resolution settings (high and super) and Trophy RVG Access (CMOS) at one. Six observers evaluated 105 proximal surfaces for caries on a 4-point scale in two sessions for each setting. The teeth were sectioned and actual extent of caries was coded on the same scale by an oral pathologist. The results of the histological examination were served as gold standard. Finally, the data were transferred to SPSS version 18 and analyzed using Kruskal-Wallis test; P<0/05 was regarded as significant.

Results: There was no statistical difference between the spatial resolution settings assessed in this study for detection of proximal lesions (P>0.05). Overall, Trophy RVG Access showed the highest specificity, 87.7%, and Digora Optime images scanned with high resolution had the lowest specificity, 84.2%.

Conclusions: The results indicated the comparable performance of both digital systems and their three spatial resolution settings in the detection of non-cavitated proximal caries.




156

183250Assessment of the Electromyographic Activity and Vertical Dimension (VDR)

S. LAWAF, Assistant professor of prosthetic department-Islamic Azad University/Dental Branch, tehran, Iran, A. AZIZI, Associate professor Of Islamic Azad University>Dental Branch.Oral medicine department, tehran, Iran, M. PAKRAVAN, Islamic Azad University -Dental Branch, Tehran, Iran, and S.S. FAKHR TABATABAIE, Islamic Azad University/Dental Branch, Tehran, Iran

Objectives: the purpose of this study was to compare the electromyographic (EMG) activity of the anterior temporal and masseter muscles using habitual methods such as swallowing of saliva, phonetic and absolute rest to determine the clinical rest position.

Methods: In this experimental study, 30 healthy subjects with natural dentition and healthy muscles were tested. Having located the Bipolar surface electrodes on the right anterior temporal and masseter muscles, EMG (MT8, MIE British Company) record was taken. Vertical dimension of rest position (VDR) was measured while performing the following jaw posture tasks: during and after pronouncing the word “Maryam”, during and after swallowing of saliva, and while maintaining their mandible in a relaxed posture.

Results: The mean voltage of masseter and anterior temporal muscle shows that there is a significant difference between mean voltage of swallowing method and phonetic, absolute rest (P<0.05); but there is no significant difference between mean voltage of phonetic and absolute rest (P>0.05). Also mean VDR shows that there is significant difference between all mentioned methods (P<0.05). The most measured rate is related to absolute rest, phonetic and rest posture after swallowing respectively.

Conclusions: The results provide scientific evidence that all mentioned methods can be used; and if there is difference, mean measured rates will be applied.


157

183251Dental Bleaching Induced Redox Perturbation

M. AKBARI1, A.H. NEJAT2, N. FARKHONDEH1, S. MEHRABAN MOGHADAM3, and S.I. HASHEMY4, 1Dental Research Centre Mashhad University of Medical Sciences, Mashhad, Iran, 2Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran, 3Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran, 4Addiction Research Centre, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

Objectives: At-home bleaching is one of the techniques in which carbamide peroxide or hydrogen peroxide is utilized as tooth whitening agent. However, there exists no clinical data regarding systemic safety of this technique. The aim of the current study was to investigate the systemic effect of home bleaching on serum oxidative-antioxdative status.

Methods: 29 healthy volunteers in demand of tooth whitening participated in this study. Specified bleaching trays were built for maxilla and mandible. Two syringes containing hydrogen peroxide 9% gel were given to each participant to use for 30 min/night for 14 consecutive nights as instructed. To evaluate the oxidative-antioxdative status, the serum concentration of malondialdehyde (MDA) as marker of serum oxidative level, total antioxidant capacity (TAC), and prooxidant-antioxidant balance (PAB) were measured. Data were collected and analyzed in SPSS version 11.5 using the paired sample t-test. The confidence interval was set on 95%.

Results: 23 subjects completed the study. MDA, PAB, and TAC were increased significantly after bleaching period (P=0.001, 0.001 and 0.002, respectively). Although the magnitude of TAC change was not as big as MDA and PAB changes, the effect size of all measures was big (Eta square>0.16).

Conclusions: Results of the current study revealed that tooth whitening with dentist-supervised home bleaching technique could induce detectable oxidative stress in human serum, which must be considered as a serious safety concern.



158

183253Five Years Epidemiology Study on Oral Cancers in Tehran (2001-2006)

N. PAHLAVAN, Tehran, Iran, N. GOLMOHAMMADI, Tehran University, Tehran, Iran, and S. NAJAFI, MSc in Oral Medicine, Dental School, Tehran University Of Medical Sciences, Tehran, Iran

Objectives: These days, oral and pharyngeal cancer is one of the main causes of death and disability which is differently prevalent depending on geographic region. In Iran, it is the 13th and 17th most common cancer among men and women respectively. The aim of this study was to investigate epidemiologic factors related to oral and pharyngeal cancers, during 5 years, (2001-2006), in clinical and educational centers in Tehran.

Methods: In this retrospective study, 256 cases were selected from 5 cancer centers of clinical and educational. The forms were filled in by two methods. The first, information were collected from completed medical records and in the other method, incomplete files were completed via calling patients by phone. ICDO-Coding system was used to determine the kind of malignant lesions. SPSS software was used for statistical data analysis.

Results: Among 256 cases, squamous cell carcinoma (S.C.C) was the most common lesion (70.3%) followed by moucco epidermoid carcinoma (M.E.C). The most common site in mouth was the tongue (25.8%) and in pharynx was larynx (15.2%). The mean age of patients was observed in the fifth to eighth decades. S.C.C and M.E.C had the most recurrence rate. In 23 cases (11.3%) metastasis were reported from which 14 cases were S.C.C.

Conclusions: The results of this study showed that the most common malignancy in oral and pharynx was S.C.C and men almost were involved two times more than women. Therefore, it is necessary that the authorities be ware about referring patients to specialized centers for control and management as soon as possible.


159

183254Assessment of Adults’ Periodontal Knowledge Following a Mass Media Campaign

M. GHOLAMI1, A. PAKDAMAN2, A. MONTAZERI3, A. JAFARI1, and J.I. VIRTANEN4, 1Tehran University of Medical Sciences, Tehran, Iran, 2Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, 3department of mental health , Iranian institute for health sciences research, Tehran, Iran, 4University of Oulu, Oulu, Finland

Objectives: To assess the effect of a national TV campaign on knowledge of periodontal health among Iranian adults in Tehran.

Methods: A before-after survey among adults aged 18-50 was conducted using a stratified multistage sampling method in the 22 districts of Tehran city in 2011. All participants were interviewed at two points in time: baseline (before launching the campaign) and follow-up (after the campaign was finished) using a validated instrument. The campaign included an animation clip about periodontal health and disease that was telecasted in a ten-time interval for ten days from five channels of national TV. The instrument included items related to aetiology and signs of gum disease. Knowledge level was determined as sum score of periodontal knowledge and changes in knowledge score was calculated. Chi-square test, Wilcoxon Signed Ranks Test and logistic regression analysis served for statistical analysis.

Results: 791 individuals (mean age: 32.6 years) were interviewed before launching the campaign, 543 of whom responded on the follow-up session. 245 indicated that they had seen the campaign (30%) and the rest reported that they had not. The mean age of the individuals who participated in the follow-up was 33 years. Improvement of the knowledge score was statistically significant in those who had seen the campaign (0.61±0.96) compared to those who had not (0.29±0.85) (P<0.001). In the regression model, the variables significantly predicted improvement of periodontal knowledge score were seeing the campaign (OR=2.20, %95 CI=1.37-3.54), female gender (OR=1.59, %95 CI=1.05-2.43), being in the age group of 25-34 (OR=1.76, %95 CI=1.00-3.08), having higher education (OR=2.34, %95 CI=1.23-4.43) (OR=3.33, %95 CI=1.66-6.64) and having higher baseline knowledge score (OR=0.25, %95CI=0.17-0.36).

Conclusions: The findings of this study demonstrated a positive impact of the TV campaign on Iranian adults’ knowledge regarding periodontal health and disease.



160

183255Effect of Fluoride on Enamel Roughness after Home Bleaching

S. NEMATI ANARAKI, Islamic Azad Dental University, Tehran, Iran and S. AZIMZAD, Islamic Azad Dental University, Tehran, Iran

Objectives: Increased enamel roughness is one of the main problems which occurs after bleaching that can cause an increase in caries occurrence, plaque accumulation, and discoloration. Some materials were found useful to decrease these effects, such as HA, calcium and phosphate, fluoride etc.

Methods: 20 samples (newly extracted intact premolars) were included in this experimental study. They were divided into two groups of 10. First the enamel roughness of each group of samples was measured before treatment by profilometer device (RT200 Roughness profilometers, USA ).Then one group was bleached twice daily for 14 days and each time for 1 h by Opalescence (Ultradent, USA) 22%CP and the other group was bleached by Whiteness Perfect (FGM, Brazil) 20%CP. Immediately after bleaching, the enamel roughness of each sample was measured again. The samples were immersed in artificial saliva throughout the study. After bleaching, fluoride (Flor Opal1.1%) was applied on each sample for 8 hours and the enamel roughness of each sample was measured. One Way ANOVA was used to compare the difference between groups.

Results: In both groups after bleaching the enamel roughness was increased and the enamel roughness was decreased after fluoride therapy and it was even lower than the enamel roughness before treatment. There was no significant difference between these two groups.

Conclusions: According to this study, it was shown that bleaching will increase the enamel roughness but artificial saliva and fluoride therapy after bleaching not only remove the harmful effects but also improve the enamel roughness even before than baseline.



161

183256Effect of Combined Fluoride-Chlorhexidine Mouthrinse on Orthodontic Patients’ Oral Health

M. DEHGHANI, assistant orthodontist, dental research center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran, M. ABTAHI, associate orthodontist, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran, H. SHAFAEE, senior resident of orthodontics, , School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran, and B. TANBAKOUCHI, Senior resident of orthodontics, , School of Dentistry, orthodontics department, Mashhad University of Medical Sciences, Mashhad, Iran

Objectives: The purpose of current study was to investigate whether combined mouthrinse containing both fluoride and chlorhexidine would improve clinical oral hygiene parameters and could be efficacious in reducing total bacterial level, and cariogenic bacteria.

Methods: In this double blind clinical study, 60 fixed orthodontic patients aged 15-25 years who had mild gingivitis were randomly assigned to one of the following 4 mouthrinses groups: 1- Combined fluoride and chlorhexidine, 2- Chlorhexidine 0.12%, 3- Fluoride 0.05%, 4- Placebo. Following baseline examination, the members of each group were instructed to use the assigned mouthrinse twice daily for 1 min. Their usual oral hygiene procedures were continued. They were also encouraged to continue their usual oral hygiene practices. Bleeding index (BI), marginal gingival index (MGI) and plaque index (PI) were determined at baseline (T0) and after 3 weeks of mouthrinsing (T1). Also, supragingival plaque samples were obtained and assessed for total bacterial, lactobacillus, and streptococcus mutans colony counts.

Results: BI and MGI: Both combined and chlorhexidine mouthrinses significantly reduced the mean amounts of BI and MGI (P<0.05). Fluoride mouthrinse was less effective than the those two, but more efficient than placebo. PI: combined and chlorhexidine mouthrinses reduced PI significantly (P<0.05) and fluoride and placebo did not improve PI. Total bacterial count: Except placebo, other mouthrinses reduced total bacterial count, but the effect of combined one was significantly better. The order of efficiency was combined>chlorhexidine>Fluoride. Lactobacillus count: Combined one was significantly better than the others. Streptococcus mutans count: All, except placebo reduced colony count. The order of efficiency was combined>chlorhexidine, Fluoride. Chlorhexidine and Fluoride difference was not significant.

Conclusions: The new combined mouthrinse had similar to better effects compared to chlorhexidine mouthrinse on improving clinical parameters of orthodontic patients while could take advantage of fluoride. However, further studies are recommended to assess the effect of new combined mouthrinse in reducing white spot lesions.


162

183259Effect of Irradiation Time and Distance on Nano-Hybrid Composites Microhard-ness

T.S. JAFARZADEH KASHI1, M. HAJIHASANI2, S. HEIDARI1, K. KHOSHROO1, and R. MASAELI1, 1Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, 2School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran

Objectives: The aim of this study was to evaluate the microhardness of top three nano-hybrid resin based composites polymerized by QTH for different irradiation times and distances.

Methods: A total of 180 disk-shaped samples were prepared from three nano-hybrid resin based composites: Grandio (VOCO), Tetric N-ceram (Ivoclar Vivadent), Simile (Pentron) in a teflon mold (diameter of 10 mm and height of 2 mm). 90 specimens for different distances were divided in three groups: (0 m, 3 mm, 9 mm). For each group, 10 specimens were made. Metal rings were used to control the distances. 90 specimens for different curing times were divided in three groups: (10 s, 20 s, 40 s). For each group 10 specimens were made. Vickers microhardness was measured on top and bottom surfaces. ANOVA test was used for statistical analysis.

Results: There was statistically significant difference in the microhardness between the groups with different times and distances (P<0.001). For all specimens top surface values were greater than bottom surfaces, but the ratio was different in three composites, ranging from 0.66 to 0.94. The highest top and bottom microhardness was measured for Grandio.

Conclusions: The results revealed that microhardness improves significantly by increasing the irradiation time or reducing the irradiation distance.


163

183260Assessing the Knowledge of Senior Dental Students towards Antibiotic Prescrip-tion

S. MARANDI, DDS, Master student in MSc program in Global Health, Karolinska Institute, Stockholm, Sweden, G. MARRONE, PhD, Div of Global Health, IHCAR, Karolinska Institute, Stockholm, Sweden, and H. GHASEMI, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: The aim of this study was to assess the knowledge of senior dental students in four dental schools in Iran in regards to antibiotic prescription and antibiotic resistance.

Methods: In this cross-sectional study, the pre-tested questionnaire was given to all the 181 senior dental students in four universities. Of the 72 surveys returned, 69 were accepted as follows: University no. 1: 23 students, University no. 2: 18 students, University no. 3: 16 students and University no. 4: 12 students. The questionnaire consisted of demographic, behavioral, and background questions and knowledge and attitude questions. Both ways of distributing the questionnaires, by hand in three universities and in one university by email, were examined. For statistical analysis T-test, Chi-square, and ANOVA were conducted.

Results: The mean of the total knowledge score was 30.98 out of 43. Only 49.1% of the students had acceptable knowledge (knowledge score≥33) in regards to antibiotic prescription and antibiotic resistance. More than 50% of the students chose to prescribe antibiotics prophylactically in case of Mitral valve prolapse. Nearly half of the students did not know that antibiotic resistance can spread from human to human. There was not a significant difference in the knowledge scores based on the gender and studying in the newly or old established universities (P>0.05). The lowest response rate was observed in the university in which the questionnaires were sent to the students via email.

Conclusions: Dental students’ knowledge about antibiotic usage and antibiotic resistance seems inadequate. As the knowledge foundation of dental students about medication is laid and improved by the offered courses during undergraduate studies, further education and more comprehensive courses covering the antibiotic prescription for orofacial infections are recommended to update the students.


164

183265Radiographic Localization of Mandibular Foramen in an Iranian Population

F. AFKHAMI, assistant professor of Tehran University of Medical Sciences, International Campus, Tehran, TX, Iran

Objectives: Precise information about location of mandibular foramen is very important in maxillofacial surgery and blocking inferior alveolar nerve. Knowing the location of mandibular foramen in relation to different skeletal landmarks may help successful anesthesia and surgery in this region. Therefore knowing the normal range of possible locations is essential. The objective of this study was to determine the position of the mandibular foramen based on panoramic radiographs in a selected Iranian population.

Methods: The 250 panoramic radiographs of adult patients who needed for different reasons and taken with Planmeca panoramic set (model PM 2002 CC) were evaluated in radiology department. The position of the mandibular foramen relative to the superior, inferior, and posterior borders of the mandibular ramus and sigmoid notch were measured. The diameter of the mandibular foramen was also determined using caliper with 0.05 mm accuracy. The panoramic film magnifications were also measured and the real distances were estimated.

Results: Average distance of mandibular foramen was 15.17±3.64 mm from ramus anterior border, 32.21±4.39 mm from ramus posterior border, 13.40±2.20 mm from inferior border of ramus, and 13.71±2.99 mm from sigmoid notch. In addition, the mandibular foramen diameter was 4.38±1.08 mm.

Conclusions: This information can be used to perform safer inferior nerve block during surgical interventions.


165

183267Comparison of CalciumHydroxide, MTA, and CEM Cement in Stepwise Excavation: Final Results

S. BANAVA, Islamic Azad University Dental Branch, Tehran, Iran, M. SAFAIE YAZDI, Islamic Azad University-Dental Branch, Tehran, Iran, H. HESHMAT, Islamic Azad University Dental Center, Tehran, Iran, and M.J. KHARRAZIFARD, Tehran University of Medical Sciences- Dental Faculty, Tehran, Iran

Objectives: Stepwise excavation is a conservative approach to treat the deep carious lesions in which pulpal exposure is probable. Different materials have been suggested as liners over the remained caries. Calcium hydroxide is the most common material. The aim of this clinical randomized trial was to compare the effect of calcium hydroxide, MTA, and CEM cement in stepwise excavation of deep caries lesions with no re-entry up to 12 months after restoration.

Methods: 96 patients participated in this study. Inclusion criteria were as follow: existence of at least one tooth with deep caries, no evidence of irreversible pulpitis and PDL widening, and presence of a radiopaque zone at the pulpal wall. Participants were randomly divided into 4 groups: Group 1 (Control): No liner applied, Group 2: Calcium Hydroxide, Group 3: MTA, Group 4: CEM cement. After baseline evaluation of response of the involved tooth to cold, hot, percussion, and pressure, a cavity was prepared and caries excavated completely from the periphery of the cavity, but it was remained on the pulpal floor or the axial wall. The liner was applied; the cavity was conditioned with polyacrylic acid, and restored with posterior glass ionomer (Fuji 9 plus, GC Co., USA). Clinical symptoms of patients were evaluated at specific times until 12 months and x-rays were taken after 2, 6, and 12 months.

Results: Results of this study showed that only one case in group 2 resulted in irreversible pulpitis after stepwise excavation, which needed RCT. There has been no evidence of clinical symptoms in the remaining cases in all groups until now.

Conclusions: Preliminary results of this clinical study indicate that all the materials are promising in stepwise excavation of deep caries with no re-entry, but longer evaluation time is required.

This abstract is based on research that was funded entirely or partially by an outside source: Dental Research Center, Shahid Beheshti University of Medical Science


166

183269Comparison of Penetration Depth of Two Different Photosensitizers in Root Canal Wall E. KOSARIEH, Department of Peridontics Zanjan Faculty of Dentistry, Zanjan, Iran, S. SATTARI KHAVAS, Department of Endodontics, Zanjan Faculty Of Dentistry, Zanjan, Iran, and A. RAHIMI, Private Practice, Karaj, Iran

Objectives: The main objective of this study was to evaluate the penetration depth of suggested photosensitizers in the lateral wall of the human root canal.

Methods: 40 extracted single-rooted human teeth with straight canals that had been extracted for periodontal reasons were collected and stored in the sterile saline until employment in the experiment. The teeth were decoronated to a standard 12 mm root segment using diamond disc. After instrumentation of specimens, the external root surface was sealed with two layers of nail polish to avoid environmental contamination. The apical foramen was subsequently closed with composite material. The teeth were randomly divided into two major groups consisting of indocyanine green solution (ICG) and tolonium chloride solution (TCH) with and without EDTA in their subgroups. Specimens in all groups were grooved longitudinally with a diamond disc and were split in two halves with a stainless steel chisel. The measurements were done by the stereo microscope under 20X magnification in three zones of each specimen and the penetration depth of dye was measured.

Results: The results of this study showed that the mean of lateral penetration depth of ICG (224.04 µm) was significantly (P<0.05) higher than TCH (70.15 µm). Regarding to the influence of EDTA, in ICG group without consideration to the different regions, the usage of EDTA improved the mean of lateral penetration depth of ICG, but this improvement was not statistically significant (P>0.05). However, in the TCH group, the mean of lateral penetration depth of TCH into the lateral wall of the canal was significantly improved by EDTA usage (P=0.004).

Conclusions: Further to the findings of this study, it could be assumed that ICG could kill bacteria in deeper regions of the root canal wall. Therefore, it could be used as an alternative to the tolonium chloride in PDT.


167

183274Assessment of Retentive Strength Orthodontic Bands Cemented with ACP-Modi-fied GI

N. KOOHESTANIAN1, F. HERAVI2, M. OMIDKHODA3, N. GHAFFARI1, and FARZIN HERAVI, MARYAM OMIDKHODA,NEGIN GHAFFARI, 1Dentist, faculty of dentistry, Mashhad University of Medical sciences, Mashhad, Iran, Mashhad, Iran, 2Mashhad University of Medical Sciences, Mashhad, Iran, 3Assistant professor, department of orthodontic, Mashhad dental school, Mashhad University of Medical Sciences. Mashhad, Iran, Mashhad, Iran

Objectives: One of the problems concerning banding in orthodontics is the formation of decalcified areas around the bands. In addition, the bands are likely to loosen during the treatment, thus the cement is required to provide efficient bond strength and retention. In order to prevent demineralization of enamel, amorphous calcium phosphate (ACP)-containing cements have been introduced recently. The aim of this study was to evaluate the retention strength of ACP-containing glass-ionomer cement (GIC) for band fixation.

Methods: 120 extracted human mandibular third molars were embedded in acrylic resin blocks, leaving the buccal surface of the crowns parallel to the base of the molds. The teeth were randomly divided into four groups containing 30 teeth each. Groups 1 and 3 were banded using conventional GIC and groups 2 and 4 were banded using ACP-containing orthodontic cement. Thereafter, the samples were maintained in the incubator in stilled water and at a temperature of 37°C for 48 hours. Groups 1 and 3 immediately, and groups 2 and 4 after thermo cycling (5000 cycles,5° to 55°C),were examined for retention strength, using universal testing machine (cross-head speed of 1 mm/min).The data were analyzed using variance analysis (ANOVA) and Tukey test via SPSS.

Results: The highest retention strength (mean: 1.5140 MPa) belonged to group 1 (with conventional GI cement and without thermo cycling), and the lowest retention strength (mean: 1.1695 MPa) belonged to group 2 (ACP-containing GI cement with thermo cycling). According to Tukey test results, the difference between group 1 and groups 2 and 3 was significant (P<0.05). The difference between group 2 and groups 1 and 4 was also significant (P<0.05).

Conclusions: Although retention strength decreased when ACP was added to GI cement,after thermo cycling,retention strength of the samples banded by ACP-containing GI was remarkably higher to a point that it had no significant difference with the retention strength of GI cement group without thermo cycling.It seems that in the oral cavity ACP-containing GI cement has sufficient strength to endure the forces upon posterior teeth.


168

183281Internal Connection Reverse Torque Values in 3 Types of Abutments

A.S. MOSTAFAVI1, S. NOKAR2, and H. HAJIMIRAGA2, 1assistant professor, prosthodontic department, dental faculty of Zahedan university, tehran, Iran, 2assistant professor, prosthodontic department, dental faculty of Tehran University, Tehran, Iran

Objectives: Biomechanical complications associated with dental implants have caused problems for both dentists and patients; in addition, they are time-consuming and need extra cost. Screw loosening and fracture are among these problems, which are still faced in clinical practice. The purpose of this study was to evaluate the reverse torque values of three different types of abutments in Implantium dental implant system.

Methods: 18 internal hexagonal implants (6 for each type of abutment) were divided into three groups, 2-piece abutment (group 1), 1-piece abutment (group 2), and Screw abutment (group 3). Abutments were tightened by digital torque gauge and after 15 minutes, the reverse torque values were recorded.

Results: The mean reverse torque values of studied groups were as follows respectively: 20.65±1.92 N.cm, 37.88±4.28 N.cm, 30.76±3.92 N.cm, which showed a significant difference between three groups. The samples in group 3 showed the highest reverse torque values after group 2 and both were significantly higher than group 1 (P=0.000).

Conclusions: More surface area in implant -abutment connection causes more adaptation between adjacent surfaces and may increase the cold weld probability. Consequently, it may reduce screw abutment loosening.


169

183285Prevalence of Different Techniques used in Implant Supported Fixed Prosthesis

A. ZARBAKHSH, Assistant Professor, Department of Prosthodontics, Islamic Azad University of Tehran, dental branch, Tehran, Iran, K. SEYYEDAN, Assistant Professor, Department of Fixed Prosthodontics, Shahid Beheshti University, dental branch, Tehran, Iran, A. MAZAHERI TEHRANI, Assistant Professor, Department of Removable Prosthodontics, Islamic Azad University of Tehran, dental branch, Tehran, Iran, and M. HASSANPOUR SHATER, Student Islamic Azad University of Tehran, dental branch, Tehran, Iran

Objectives: Introducing dental implants in dentistry is the reason for lots of progresses in this field. Differences in pattern and structures of dental implant result in different treatment options, so that clinicians use several techniques and materials for implant restorations. The aim of this study was to determine prevalence of techniques used for treating partially edentulous patients with implant supported prosthesis.

Methods: A questionnaire was designed containing all the variety of different techniques used to treat patients with implant supported prosthesis. The reliability and validity of this questionnaire was evaluated by 2 prosthodontists. Copies of the questionnaire were sent to105 professors of Iranian Dental Schools via Email.

Results: In analysis of the 78 questionnaire that were sent back, 67 of the participants (85.9%) preferred Cement.R and 6 (7.7%) preferred Screw.R. 59 of the professors (75.6%) used restorations jointed together and 10 (12.8%) preferred separate restoration. Most of them, (67 people, 85.9%), used Delayed loading for maxillary and mandibular implants. Also, most of them used Coping open and Stock tray technique for impression. Solidarization technique was the least preferred. Addition silicon was the most preferred material. 73 people (93.6%) preferred Metal ceramic restorations and 50 of the participants (64.1%) used precious and 17 of them (21.8%) used nonprecious alloys. Only 31 people (39.7%) preferred Metal Free restorations anf 26 of them (33.3%) preferred using Ceramic restorations and 4 of them (5.1%) preferred Composite restorations. Finally, 65 of the respondents (83.3%) were against using Mini Implants in treatment of patients with implant supported prosthesis and only 9 of them (11.5%) agreed with the treatment.

Conclusions: The most preferred final restoration type was Cement.R, Delayed loading was the most used loading technique in Maxillary and Mandibular implants, Metal Ceramic Restoration was the most preferred and used restoration material. The majority of the respondents were against using Mini implants.


170

183291Geometric Parameters of Implants and stress distribution in Partial Overdenture

Z. RAHMANI, Postgraduate Student of Prosthodontics, Department of Prosthodontics, School of Dentistry, Shahid Beheshti University of Medical Science, tehran, Iran, A. FAYAZ, Assistance professors, Department of Prosthodontics, School of Dentistry, Shahid Beheshti University of Medical Science, teharn, Iran, A. GERAMY, Tehran University of Medical Sciences, Tehran, Iran, and Y. MEMARI, Assistance professors, Department of Prosthodontics, School of Dentistry, Shahid Beheshti University of Medical Science, Tehran, Iran

Objectives: The present study aimed to assess the effects of length and inclination of implants on stress distribution on implant and terminal abutment teeth in an implant assisted-removable partial denture based on three-dimensional finite element analysis.

Methods: In an in vitro trial, a 3D finite element model of a partial dentate mandible with designed DERPD and dental implants was established to analyze stress distribution in bone around terminal abutment teeth and implants with different lengths and angles.

Results: The stress in the PDL of first premolar teeth ranged between 0.133 MPa in 10 mm implants with the angle of 15 degree and 0.248 MPa in 7 mm implants with the angle of 0 degree. The minimum analyzed stress was specified to the implants with 10 mm length with the angle of 0 degree with the stress of 19.33 MPa and was maximized in 25.78 MPa for implants with 10 mm length with the angle of 15 degree. In implants with the fixed length of 7 mm, with the increase of transplanting angles, the stress on implants was gradually elevated. Similarly, in implants with the fixed length of 10 mm, increasing transplant angles resulted in quantize increase in the stress on implants.

Conclusions: With respect to minimizing stress on implants, not only the length and diameter of implant could be considered, but also the angle of implantation is concurrently necessary. Results showed vertical implanting resulted in lower stress on implant and therefore by increasing this angle, the distribution of stress could be gradually increased.


171

183294Potential Psychological Effect of GA on Pediatric Dental Patients

M.V. GOLPAYEGANI1, G. ANSARI2, M. AALI3, and A. ANSARI3, 1Professor of Pediatric Dentistry, Tehran, Iran, 2Shahid Beheshti University of Medical Sciences, Tehran, Iran, 3Shahid Beheshti Medical University, Tehran, Iran

Objectives: The necessity for using anesthesia in dentistry for disobedient children and medically compromised ones is widely accepted as a path to ultimately deliver dental treatment to them. Based on the limited experience of such conditions in Iran and the fact that it has many unknown points yet to be outlined, this experience was conducted in order to assess the possible psychological effects of general anesthesia on the behavior of children under 6 years old after receiving treatment at Mofid Children’s hospital during 2009-2010.

Methods: This longitudinal study was carried out on 90 children who received dental treatment under general anesthesia. A prepared questionnaire was used including 25 questions on child behavior before the anesthesia with similar number of questions for changes 30 days after the treatment, answered by parents. Data were processed by SPSS version 15.0.

Results: Overall, 30 girls and 60 boys were included in the current study. The mean age of the patients was 46.6±12.3 months. The mean weight of the subjects was 15.3±2.78% kgs. The anesthesia led to small but meaningful behavioral changes in 7 cases, among which 2 individuals improved while 5 reported remaining behavioral changes for some time.

Conclusions: Most negative behavioral changes seen in children were anger and excitement in comparison to before the anesthesia, and the most positive behavioral change was ease in eating behavior.



172

183296Oral/Intramuscular Ketamine, Midazolam, Atropine for Dental Sedation

G. ANSARI, Shahid Beheshti University of Medical Sciences, Tehran, Iran, M. VAHID GOLPAYEGANI, Shahid Beheshti University of Medical Sciences, Tehran, Iran, N. PASDAR, Assistant professor, Babol, Iran, and A. MAHDAVI, Assistant professor, Tehran, Iran

Objectives: The purpose of this study was to evaluate the efficacy and safety of a mixture of ketamine, midazolam and atropine while comparing oral and intramuscular routes for sedation of pediatric uncooperative dental patients.

Methods: In this crossover randomized clinical trial, 31 pediatric patients, 1-4 year(s) old were classified as definitely negative (Frankl 1969). Cases were randomly assigned for one of the two groups receiving either oral (ketamine 10 mg/kg, midazolam 0.2 mg/kg and atropine 0.02 mg/kg) or intramuscular (ketamine 6 mg/kg, midazolam 0.05 mg/kg and atropine 0.02 mg/kg) in the first visit followed by the other route in the second visit. Sedation score was recorded along with behavior rating (Houpt behavioral rating scale), physiological parameters, and side effects. Dental treatment was performed in all the cases when they were judged sedated by two independent pedodontists.

Results: Intramuscular route showed a significantly deeper level of sedation in patients when placed on dental chair (P=0.035) with less onset time (P<0.05). There were no significant differences in sleep, movement, cry and, overall behavior scores or even physiological parameters between the two treatment groups (P>0.05). Success rate at the first 15 minutes was 80.7% in the oral and 87.1% in the intramuscular routes. Despite an increase in blood pressure and heart rate, there were no cardiovascular or central nervous system difficulties. Only 9 cases presented small degree of desaturation due to laryngospasms (2 cases) and airway mal-alignments (7 cases). Practitioner and parents’ satisfaction of the oral and intramuscular routes did not differ significantly (P>0.05).

Conclusions: Despite variable efficacy in some cases, oral ketamine, midazolam and atropine given orally provided sedation similar to that produced by the same drugs given intramuscularly.


173

183297Primary Teeth Pulpotomy with C.E.M/LLLT, Two Years Result

G. ANSARI, Shahid Beheshti University of Medical Sciences, Tehran, Iran, S. ASGARI, Professor of Endodontics, Tehran, Iran, B. ERFANIAN, Shahid Beheshti Medical University, Tehran, Iran, and M. VAHID GOLPAYEGANI, Shahid Beheshti Medical University, Tehran, Iran

Objectives: There are increasing concerns over the use of Formocresol in pulpotomy of primary teeth. Several alternatives have been introduced including C.E.M and laser. The purpose of this investigation was to evaluate the clinical and radiographic success of a novel material known as C.E.M associated with a low-level laser energy in pulpotomy of primary teeth.

Methods: This randomized crossover clinical trial was conducted on a group of 20 children aged 2 to 7 years with 3 similar teeth needing pulpotomy. Cases were randomly allocated into 3 groups for test and control. To enable same day treatment for all teeth, cases were selected from those scheduled to receive full mouth treatment under general anesthesia. Following conventional pulp amputation and hemostasis, group I received C.E.M and group II received low-level laser and C.E.M while group III received Formocresol and served as control. All teeth were restored using stainless steel crown. Patients were reviewed in 6, 12, 18, and 24 months follow-ups. Clinical and radiographic examination of the treated teeth was conducted to enable a comparison on the differences. Data were then calculated statistically using basic statistics.

Results: 18 patients completed 6, 12, 18, and 24 months follow-ups. No clinical or radiographic complications were observed in any of the cases or controlled teeth. However, close radiographic assessment showed a possible initial signs of P.C.O formation in only one case of the C.E.M group.

Conclusions: Findings of this investigation showed that C.E.M with LLLT could be used safely in pulpotomy procedure of primary molars. Longer follow-up periods are recommended to investigate their long-term effects.


174

183307Microleakage Analysis of Resilon Obturation Material in Laser Assisted RCT

M. MIR1, M. MAZANDARANI2, and N. GUTKNECHT2, 1UCI, Tehran, Iran, 2RWTH-Aachen University, Aachen, Germany

Objectives: The purpose of this study was to analyze the microleakage of Resilon/Epiphany obturation material in different types of laser assisted root canal therapy procedures.

Methods: 72 bovine incisor root canals were prepared. They were randomly divided into 6 groups of 12. Canals in one group were just obturated with Resilon filling material, without any EDTA rinsing or laser irradiation as control. In the second group, canals were rinsed with EDTA only, 12 canals irradiated with Nd:YAG laser (1.5 W, 15 Hz) only as the third group and other 12 canals received both mentioned treatments as 4th group. 12 canals with no EDTA rinsing but Er,Cr:YSGG and Nd:YAG lasers irradiation counted as the 5th group. The last twelve canals were treated using all three procedures. Obturation with Resilon root filling material was done by the same investigator. Also, roots were covered by polish except apical parts. After dye penetration process during 5 days as stimulation of apical leakage condition in incubator, histological measurements were done. The extent of leakage was scored as following: penetration of dye measured less than 500 um, between 500 and 1000 um, and more than 1000 um (1 mm). Data analysis was made by Stat view software and the extent of leakage in each group was investigated in both vertical and horizontal cuts. Kruskal-Wallis test was used to determine the significance of leakage differences between groups.

Results: Microleakage in all samples was less than 1 mm. The group with EDTA and both lasers showed less leakage (P<0.5). No significant difference was resulted between other treatment modalities.

Conclusions: Resilon showed very low leakage, especially when canals were rinsed with EDTA and lased.


175

183308Effect of Triple Antibiotic and Chlorhexidine on Shear Bond of Composite

M. ZARE JAHROMI, Assistant Professor of Endodontic Dept.Faculty of Dentistry-Khorasgan Azad University (Isfahan), ISFAHAN, Iran, P. MIRZAKOUCHEKI BOROUJENI, Khorasgan branch.Islamic Azad University, Isfahan, Iran, and S. DANESHPOUR, Khorasgan dental School, Isfahan, Iran

Objectives: The aim of the present study was to investigate the effect of chlorhexidine gel (2%) and three antibiotic pastes as intra-canal medication on shear bond strength of composite resin to dentin.

Methods: In this in vitro study, 36 freshly extracted adult human premolars were used. Then specimens were divided into three groups of 12 as follows: normal saline (group 1), chlorhexidine gel 2% (group 2), and triple antibiotic paste (group 3). All specimens were stored for 10 days at 37°C in incubator, and then dentin bonding system was applied to the dentin surfaces. Shear bond strength was measured after 24 h incubation. Then data were analyzed with Kruskal-Wallis Test.

Results: The mean shear bond strength in saline, chlorhexidine, and antibiotic groups were 17.25, 25.75 and 13.93 respectively. There was no significant difference between studied groups (P>0.05).

Conclusions: There were no noticeable changes in shear bond strength of experimental groups. Also, chlorhexidine increased the mean shear bond strength slightly.


176

183316PLGA Microspheres Containing Minocycline as Drug Delivery System

R. KARIMI SOFLOU, Department Of biomedical engineering, Science And Research Branch, Islamic Azad University, Tehran, Iran, H. NOJEHDEHYAN, Department of Dental Materials, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran, M. TORSHABI, Department of Dental materials, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and F.S. TABATABAEI, Dental Material department; Dental School;Shahid Beheshti University of Medical Sciences, Tehran, Iran Objectives: Poly (lactic-co-glycolic acid) (PLGA) has been one of the most used polymers for drug delivery and tissue engineering applications. PLGA is a biodegradable polymer with great potential for pharmaceutical applications due to its favorable properties, such as good biocompatibility, biodegradability, and mechanical strength. Also, it has been approved by the Food and Drug Administration (FDA) for drug delivery system. Among different forms of PLGA-based drug delivery systems, microspheres or microparticles are the most common.

Methods: The microspheres containing Minocycline were prepared by the w/o/w double emulsion solvent evaporation method. Microsphere formulations were morphologically characterized by scanning electron microscope (SEM). Minocycline loaded PLGA microspheres were subjected to an in vitro release test under static conditions.

Results: The SEM images showed that the size of microspheres containing Minocycline was in the range of 10 microns. The in vitro release experiment showed that the release time was over 26 days. The release profile of Minocycline from PLGA microspheres showed a constant and controlled release. Furthermore, the curve showed that there was a burst release on the eighth day.

Conclusions: In conclusion, the biodegradable PLGA microspheres containing Minocycline were successfully prepared by double emulsion solvent evaporation method. Various factors related to the preparation process influenced the drug encapsulation efficiency and the cumulative drug release was subsequently investigated. Ultimately, spherical PLGA microparticles with encapsulation efficiencies higher than 90% and prolonged Minocycline release over 30 days were obtained.

This abstract is based on research that was funded entirely or partially by an outside source: This work was supported financially by a grant (NO:310-3685) from dental school of Shahid Beheshti university of Medical Sciences, Tehran, Iran



177

183322Preparation of Gelatin-Hydroxyapatite Microspheres as Cell Carrier

N. ALASVAND, Department of biomaterial,School of Biomedical Engineering, Azad University Science and Research Branch, Tehran, Iran, and H. NOJEHDEHYAN, Department of Dental Materials, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: Microspheres have many biological applications such as drug delivery, cell carrier, etc. Bone extracellular matrix included two phases of mineral and organic. Hydroxyapatite (HAp) is the main mineral component of bone. HAp directly bonds with natural bone and is an osteoconductive and bioactive material. Gelatin is a natural polymer that increases attachment and differentiation of cells. Since these materials are components of bone extracellular matrix (ECM), they were used as microcarrier for bone cell delivery in the current study.

Methods: In this study, for making gelatin and hydroxyapatite microspheres, the method of emulsion (water in oil) was used. In this experiment, the aqueous solution was dispersed by mechanical stirrer, homogenizer, and ultrasonic homogenizer. Aqueous solution including polymer and ceramic was added dropwise into oil and was stirred. After 30 min, the solution temperature was lowered to 10°C with constant stirring. Then chilled acetone was added to stirring solution to solidify microspheres. After that, glutaraldehyde was added to the solution as crass linking agent. The microspheres were washed several times to remove residual oil. Their characteristics were followed by optical microscopy, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR).

Results: The results showed that the use of ultrasonic homogenizer fabricated smaller and more uniform particles than the use of homogenizer, but the use of mechanical stirrer did not produce any microspheres. The FTIR result showed that several times washing microspheres removed residual oil and glutaraldehyde from microspheres.

Conclusions: This study showed that dispersion of the aqueous phase by different tools effects the size of particles. Since these particles are used as cell carrier, the size and distribution of microspheres is important. The methods which make smaller and more uniform microspheres are better than those for cell culture and cell carrier.


178

183323Dental Visit and Number of Missing Teeth among Tehrani Elderly

K. SARGERAN, Tehran University of Medical Sciences, Tehran, Iran, and H. HESSARI, Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran

Objectives: The purpose of this study was to assess the relationship between number of missing teeth and dental visit among Tehrani elderly people.

Methods: The study population covered 64+ year old adults (n=2480) participated in a large population-based cross-sectional survey sponsored by Municipality of Tehran, using the Urban Health Equity Assessment and Response Tool (Urban-HEART) in 2011. Original sampling method was stratified multistage cluster randomized design, conducted within all the districts of Tehran. Self-reported number of remaining teeth and the history of dental visit in the past year were asked and recorded by a trained surveyor. Statistical analysis was done by t-test and ANOVA.

Results: Of all the participants, 63% were male with the mean age of 72.4 (SD 5.9; range 65-90 years). The mean number of missing teeth was 12.6 (SD 11.5) with no difference by gender. Older adults who had no dental visit in the past year (55% of total) had more missing teeth (P<0.001).

Conclusions: Findings of the current research indicated that oral health programs should be focused on the encouragement of older people to have regular dental check-ups, at least once a year, to improve their oral health and maintain more teeth during their lifetime.



179

183325Cephalometric Assessment of Jaws Growth in 9-11yrs Normal Subject

S. HAMIDIAVAL, department of radiology, Shahid Beheshti University of Medical Sciences, Tehran, Iran, M. NOURI, Dentofacial Deformities Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, and A. AKBARZADEH, Iran Center for Dental Research, Iranian Center for Endodontic Research, Tehran, Iran

Objectives: This study was designed to evaluate the vertical and sagittal changes in the jaws due to growth.

Methods: A sample group was chosen of 85 individuals with normal occlusion, consisting of 42 females and 43 males between the age of 9 and 11. A series of cephalometric parameters (related to Mcnamara analysis such as SNA.Facial axis angle, mandibular plan angle) and lineal parameters (also related to Mcnamara analysis such as mandibular length, midfacial length, ANS to Me, U1 to Apoint, L1 to Apoint) were traced in computed programmed cephalometric analysis. Superimpositions of the initial and final cephalometries in the Ba-N plane and in the Nasion fixed point were carried out to measure growth. An analytic statistical analysis was applied using Mann-Whitney U for independent samples in order to evaluate the differences found according to sex. An analysis of variance followed by Wilcoxon signed ranks was done to study the evolution of each variable throughout the duration of the experiment.

Results: In parameters such as U1-Ap, mandibular length, midfacial length, sup/inf airway the P-value was 0.001, and in Ans-Me, Max/Mand diff the P-value was 0.0001 which were statistically significant. In assessment, the influence of sex just in Na-Pog the P-value was 0.34 which was significant in comparison with the girls.

Conclusions: In light of the results obtained, the following points were concluded: in samples there are significant increase in 9 to 11 years old in most of the parameters except for Na-Pog distance, SNA angle, and facial axis angle. In assessment of the effect of the sex there is only a significant difference in Na–Pog between two groups during growth, which was more significant in boys.

This abstract is based on research that was funded entirely or partially by an outside source: Shahid Beheshti Dental Resaerch center


180

183391Force Relaxation of Three Different Orthodontic Latex Elastic Products

A. JAFARI NAEIMI, Assistant Professor, Islamic Azad University, Dental Branch, Tehran, Iran

Objectives: The objective of the present study was to determine the force-extension and force degradation characteristics of different commercially available orthodontic latex elastics.

Methods: To determine the force-extension in dry state, elastics were stretched by continuous extension from slack condition to 60 mm at 25°C. Resultant forces versus length changes were recorded. To determine the force-degradation in wet conditions, elastics were stretched to 20 mm and 40 mm and were stored in artificial saliva at temperature of 37°C in a moisture oven. Force measurements were made at 3 intervals: 1, 24, and 72 hours with universal strength testing machine (Hounsfield, UK). Multiple group comparisons were made by ANOVA and pair wise comparisons by t-test.

Results: In dry test, overall, elastics did not perform according to specifications marketed by different companies. In general, the loads at three times the internal diameter were larger than the manufacturer’s specified loads. The result of the present study, also, showed a force decay of a 12.38% and 20.5% during the first hour and this decay increased to 20.1% and 28.5% at 24 hours, and to 28.0% and 34.4% up to 72 hours, when extended to 20 and 40 mm respectively. Significant differences between comparable sizes of elastics among all manufacturers were noted.

Conclusions: It is concluded that from mechanical perspectives, though the initial elastic forces were higher than what has been prescribed, they reduce to a clinically acceptable range within hours.


181

183392Self-Sealing Ability of High Copper Amalgams with Self-Etch Adhesives

S.M. MOAZZAMI, Mashhad University of Medical Sciences, Mashhad, Iran, H. MOOSAVI, Dental Materials Research Center, Department of Operative Dentistry, Mashhad University of Medical Science, Mashhad, Iran, M. MODDABER, Operative and Esthetic Dentistry Department, yazd, Iran, M.H. MOAYED, Department of Materials and Metallurgical Engineering, Ferdowsi University, Mashhad, Iran, R. PARVIZI, School of Engineering, Faculty of Science and Technology, Deakin University (DU), Geelong, Australia, N. MOKHBER, Department of Orthodontics, Academic Center of Education, Culture and Research (ACECR), Mashhad, Iran, R. KAZEMI, Associated Professor, Farmington, CT, and M. MEHARRY, Loma Linda University, Loma Linda, CA

Objectives: It takes time that microleakage of high copper amalgams being sealed by corrosion products. Acidic self-etched adhesives make better conditions for interfacial corrosion for amalgam restorations. The aim of this study was to evaluate the effect of self-etched adhesives with different pH on interfacial corrosion potential of high-copper amalgams and its self-sealing ability in the early hours using Electro-Chemical Tests (ECTs).

Methods: 30 premolars were cut to make a slice with a cylindrical cavity of 4.7x4.5 mm with a 0.3 mm floor thickness. All surfaces were sealed with resins, except the cavity floor and its opposite surface. There were five main groups based on Adhesive Resin (AR)/liner used. The control group was left without any AR/liner (No). In other testing groups, (AR)/liner that were used included: I-Bond (IB), Clearfil S3 (S3), Single Bond (SB), and Varnish (V). Each group was divided into two subgroups based on the type of the amalgams (ANA and Tytin) used. (ECTs) like Open Circuit Potential (OCP) of each specimen and the linear Polarization Resistance (LPR) test were performed in artificial saliva.

Results: Except Ana-No, the mean OCP values reached steady after 18 hours. OCP values of the Tytin-No and Tytin-IB were the highest and lowest respectively. In LPR tests, Rp values of Ana-V and Tyt-V were the highest (i.e. lowest corrosion rates). Ana-IB and Tyt-IB samples represent the lowest Rp values (i.e. highest corrosion rates).

Conclusions: I-Bond with the lowest pH showed the highest corrosion whilst the Varnish with the highest pH value revealed the lowest corrosion. Clearfil S3 and Varnish demonstrated lower corrosion rates compared to the control groups, therefore, these agents are not proposed for reducing microleakage in amalgam restoration.



182

183393Preventive Effect of Zinc Sulfate on Oral Mucositis

A. AZIZI, Department of Oral Medicine, Islamic Azad University, Dental Branch, Tehran, Iran

Objectives: Mucositis is one of the most common complications of chemotherapy that may cause ulceration and pain in oral mucosa. Side effects of mucositis consist of debilitating, difficulty of mastication, and pain. Conservative and preventive treatments are used to decrease mucositis during chemotherapy. On the other hand, zinc is an inorganic element, which has been proved to increase the healing rate of wounds. Due to physiological effects of zinc, in this study the effects of zinc in decreasing severity and pain of mucositis were evaluated.

Methods: This double-blind, case-control trial was carried out on 73 leukemic and lymphoma patients who underwent chemotherapy. Patients in the case group were administered one 220 zinc sulfate capsule daily until one week after the end of their chemotherapy treatment. Two weeks after starting chemotherapy and three months after its ending, severity and quantity of pain were checked and recorded in both groups. Data were analyzed by ANOVA test.

Results: The mean and standard deviation of mucositis severity was 1.1±0.2 in the case group and 2.7±0.3 in control group, and there was a significant difference between case and control groups (P=0.00). The mean and standard deviation of VAS in case group was 2±2.52 and 6.2±3.6 in control group two weeks after treatment. There was a significant difference between case and control groups (P=0.00). Three months after the end of chemotherapy, the mean and standard deviation of mucositis severity was 0.5±0.03 in case group and 1.5±0.3 in control group and there was a significant difference between case and control groups (P=0.00). The mean and standard deviation of VAS in case group was 5.5±0.7 and 1.5±0.7 in control group. There was a significant difference between case and control groups (P=0.00).

Conclusions: It can be concluded that zinc sulfate might decrease the intensity of mucositis.



183

183449Oral Hygiene Behavior in Iran: National NCD Risk Factor Surveillance

M.H. KHOSHNEVISAN1, K. ETEMAD2, J. KOOHPAYEHZADEH2, A. RAFEI2, F. ASGARI2, and A. EBN AHMADI1, 1Shahid Beheshti University of Medical Sciences, Tehran, Iran, 2Tehran University of Medical Sciences- Dental Faculty, Tehran, Iran

Objectives: Non-communicable diseases are increasingly recognized as a major cause of morbidity and mortality at the global level. Oral health is an integral and critical component of general health and oral diseases are among the non-communicable diseases of public-health importance. The Government as well as the Ministry of Health and Medical Education are greatly concerned about the rapidly increasing burden of oral diseases in Iran.

Methods: A representative sample of 12,075 non-institutionalized Iranian individuals aged 6-70 years was extracted though a Multi-Stage Cluster Random Sampling scheme. Households’ addresses were obtained from the national zip code databank. The kish randomization method was used to select participants within the households. After receiving an informed consent, individuals were interviewed at their homes by trained health workers from 51 Medical Science Universities across the country. Brushing and flossing habits were inquired from participants using a standard WHO questionnaire designed for NCD Risk Factors. Complex Sample Survey Analysis was utilized to estimate prevalence and related 95%CI. Odds Ratio as a measure of association was computed using weighted Binary Logistic Regression Model.

Results: Generally, the results reflected that brushing and flossing status in Iran was better in females compared to males (Brush; Male: 13.9%, Female: 26.5%), (Floss; Male: 13.8%, Female: 19.8%). Moreover, urban dwellers care more about their oral hygiene than people who lived in rural areas (Urb: 22.3%, Rur: 15.1%). Both the level of education and socioeconomic status were positively associated with oral hygiene conditions in Iran.

Conclusions: Given that brushing and flossing are the two most important oral health promotion activities, it seems there is a lot of room for improvement in Iran. Special attention must be paid to oral health education, oral hygiene instruction, education level as well as any other mechanism that could especially target the low SES individuals.



184

183486Study Experiences of Staff and Faculty Members of Oral Medicine

J. SARABADANI, A. PAKFETRAT, Z. DELAVARIAN, H. KARIMI MOUNAGHI, and M. MEIBODI SANI, Mashhad Dental Faculty, Mashhad, Iran, Iran

Objectives: Assessment in the setting of clinical training is not well developed, but methods based on observation of routine encounters like CBD and mini-CEX offer a feasible and rich alternative. This study aimed to explore oral medicine faculty and residents’ experiences on new workplace assessment methods.

Methods: In the first step of this qualitative study, a workshop was conducted for residents and staff entitled “Workplace Assessment”. After that, during 6 months in 2011, assessment tools such as mini-CEX and CBD were applied for assessing the judgment and clinical reasoning. By these methods, it was possible to get an opportunity for educational feedback. Interview was conducted and the data were recorded, transcribed, and then categorized.

Results: Advantages and disadvantages of new methods based on observation were as follows; Advantages: These new methods were valid and could qualify the residents’ ability better than traditional methods, the new methods could be weak points of residents in each diagnostic field of oral lesions, each resident could present his/her clinical competencies in a quantitative manner at the end of the course. Disadvantages: Considerable time consumption for residents and staffs, lack of inter rater reliability.

Conclusions: Although time consuming, the new approach was useful for qualifying the clinical competency of residents. It seems that both staff and residents must be trained for achieving better results.


185

183749Computational Models for Temperature/Stress Prediction in Layered Dental Porcelains B. HOJJATIE1, C. PONCE2, T. MINH2, L. HALE2, and C. SHEN3, 1Faculty member of Physics/Engineering, Valdosta State University, Valdosta, GA, 2Undergraduate student, Physics/Engineering, Valdosta State University, Valdosta, GA, 3Faculty member of Restorative Dentistry, University of Florida, Gainesville, FL

Objectives: In order to determine the magnitude of transient stresses developed in dental ceramics during firing and cooling, one should first determine the temperature distributions and the cooling profiles of the structures subjected to various cooling conditions. The objectives of this study were to develop analytical and computational models to predict temperature and stress distribution behavior of layered dental porcelain disk samples during cooling.

Methods: A two dimensional conduction model was developed and solved analytically. A computer program in MATLAB was developed, based on the analytical solutions to predict the cooling profiles for each disk.

Results: For a body porcelain disk, 2 mm in thickness and 16 mm in diameter subjected to free convective cooling from an initial temperature of 800°C, the maximum value of principal tensile stress was 39 MPa. However, for a bi-layered ceramic disk with a thermal mismatch level of 1.5 ppm/°C, the corresponding stress value increased to 55 MPa.

Conclusions: Comparison of the results from the analytical model, with those from the models based on finite element analysis, showed a good agreement, which supported the validity of analytical solutions and computational models used in this study. Thermal contract mismatch of porcelain layers had a significant impact on the magnitude of transient thermal stresses developed with the samples during cooling. The finite element analysis and 3-D printing/prototyping techniques are being applied to develop simulated and physical models of the restorations to analyze the strength behaviors of the porcelain samples and compare them with the experimental data. This study was supported by a Quality Enhancement Program (QEP) Grant from Valdosta State University.

This abstract is based on research that was funded entirely or partially by an outside source: This study was supported by a Quality Enhancement Program (QEP) Grant from Valdosta State University.


186

184520Is Toothbrushing Associated with Other Oral Health-Related Habits in Kuwait?

S. HONKALA, M.J.M. BEHBEHANI, and E. HONKALA, Kuwait University, Safat, Kuwait

Objectives: This study aimed to find out if toothbrushing frequency is associated with other oral health-related habits among 13-year-old schoolchildren in Kuwait.

Methods: Nationally representative sample of schoolchildren (n=1,292) at the age of 13 years (SD±1.04) participated in this study by filling a structured questionnaire anonymously in the school classrooms. The questionnaire of the WHO Collaborative (HBSC) study was used after modifying it for the Kuwaiti situation. The Ethical Committee of the Faculty of Dentistry, Kuwait University approved the study. Variables for oral health-related habits included: eating or drinking sugar-containing products, smoking tobacco, and visiting a dentist. Chi-square tests and logistic regression model were used in the analyses.

Results: Smoking tobacco (ever tried) and drinking sugared tea were statistically significantly associated with unfavorable toothbrushing: Children who had never tried tobacco (P<0.001) and did not drink sugared tea on a daily basis (P=0.001) brushed their teeth more frequently. More-than-once-a-day toothbrushing was significantly more common among girls (P<0.001), among children who performed very well at school (P<0.001), whose family was financially well-off (P<0.001), if father (P=0.038) or mother (P=0.003) had university education, and who were Kuwaitis (P=0.017). In the logistic model, the strongest predictors for twice-a-day toothbrushing were good financial status of the family (OR 2.2, 95% CI 1.438–3.266) and female gender (2.1; 1.617–2.793), following by very good school performance (1.8; 1.269–2.555) and never tried smoking (1.6; 1.045–2.551).

Conclusions: Toothbrushing of schoolchildren was more associated with socio-demographic and -economic factors than other oral health-related habits. When controlling all the background variables, only smoking tobacco had a significant association with toothbrushing frequency.

Acknowledgements: This study was supported by Kuwait University Research Grant No. [DD1/02].



187

184523Tooth Wear Studied via Single-Particle Interaction with an Enamel Surface P. LUCAS, R. OMAR, A. HENRY, J. WATZKE, A. AL-MUSALLAM, K. FADHALAH, S. MICHAEL, L. AROKYTHAI, and A. ATKINS, Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University,, Kuwait, Kuwait

Objectives: The aims were to establish the pattern of microscopic marks made on dental enamel by natural particles.

Methods: A longitudinal section of an orangutan (Pongo pygmaeus) molar was set in resin and polished. Quartz grit particles and silica phytoliths (extracted from Ampelodesmos mauritanicus leaf tissue), <100 µm in size and of known mechanical properties, were mounted on a flat-ended titanium probe. This probe was placed in a nanoindenter (Hysitron Ubi1) to permit ‘scratching’ of the molar enamel surface. Fixed vertical forces of between 0.6-1.8 mN were employed for 10-15 µm lateral displacements, while lateral forces were monitored. The enamel surface was then examined by AFM (Agilent 5500) in tapping mode.

Results: Four tests were made with each particle type. Contacts produced marks of differing shapes. Those produced by phytoliths were U-shaped in cross-section, while grit particles formed sharper, more V-shaped, marks associated with enamel chipping. Lateral forces were 30-80% of vertical forces.

Conclusions: The shape of marks reflects the relative hardness of the materials. Quartz is sufficiently hard enough to make rigid plastic contacts with enamel, the contact reflecting the geometry of the quartz particle. In contrast, a phytolith and enamel mutually deformed to produce a smooth impression on the enamel without tissue loss. It can be concluded that phytoliths are not wear agents, but grit particles are. Very low forces may be involved with variable frictional contributions.

Acknowledgements: This study was supported by General Facilities Project GE01/07 from Kuwait University.


188

184525The Effect of 5Weeks Xylitol Consumption on Oral Microflora

M. ELSALHY1, S. HONKALA2, E. HONKALA2, A. VARGHESE2, and E. SODERLING3, 1Ministry of Health, Kuwait, Kuwait, 2Kuwait University, Safat, Kuwait, 3Institute of Dentistry, Turku, Finland

Objectives: Xylitol is a naturally occurring polyol shown to have anti-caries effects on Str. mutans. However, its effects on other oral bacteria are less well-known. The aim of this study was to evaluate the short-term effects (5 weeks) of xylitol chewing gum consumption (three times a day) on some oral bacteria.

Methods: Altogether 122 children aged 12-13 years were screened with the Dentocult SM® (Orion Diagnostica, Turku, Finland) test. Those children with high (>100000 CFU/ml) MS counts in saliva or plaque were included in the intervention. The children were randomly allocated to the xylitol and control groups (sorbitol chewing gum), using classrooms as clusters. The following bacterial species were quantified from stimulated saliva samples using Real Time PCR: Streptococcus mutans, Streptococcus sobrinus, Lactobacillus plantarum, Lactobacillus paracasei, and Aggregatibacter actinomycetemcomitans. Species-specific forward and reverse primers were used. Changes in the salivary microbes before and after the intervention were evaluated.

Results: There were no statistically significant differences between the groups at the beginning or at the end of the study. However, the saliva samples showed statistically significant reductions in the counts of all 5 studied bacteria both in the xylitol and the control groups, but none of them were statistically significant.

Conclusions: It seems that both groups were benefiting from the chewing gum interventions. The study-associated improved oral hygiene in both groups might explain the significant reduction in the determined bacteria.

Acknowledgements: This study was supported by the Kuwait University grants DD02/10, GD01/11, SRUL02/13. This study was registered in clinical trials.gov with ID: NCT0528969.


189

185044The Role of Dust, Grit and Phytoliths in Tooth Wear

A. VAN CASTEREN1, P. LUCAS1, K. FADHALAH1, A. AL-MUSALLAM1, S. MICHAEL1, A. HENRY2, J. WATZKE3, D. REED4, T. DIEKWISCH5, D. STRAIT6, and A. ATKINS7, 1Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University,, Kuwait, Kuwait, 2Plant Foods in Hominin Dietary Ecology Group, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany, Leipzig, Ghana, 3Plant Foods in Hominin Dietary Ecology Group, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany, leipzig, Germany, 4Department of oral biology, chicago, IL, 5University of Illinois at Chicago, Chicago, IL, 6Department of Anthropolgy, Albany, Albania, 7Department of Mechanical engineering, London, England

Objectives: Particles poising a wear threat to teeth must be both harder than enamel and possess the correct angle of attack. Most natural ‘grit’ particles possess sufficient hardness, while effective attack angles may be generated during mastication. Plants produce particles of opaline silica called phytoliths that are embedded in their tissues. These appear not to be hard enough to wear tooth enamel, but evidence suggests they are a form of defense against herbivores. Here the hypothesis that phytoliths mimic grit in the mouths of mammalian herbivores and therefore provide plant protection by deception is investigated.

Methods: Phytoliths were obtained from two grasses Dactylis glomerata and Ampelodesmos mauritanicus, with dust and grit extracted from the Kuwaiti landscape. Particles were subjected to nanoindentation to obtain estimates of hardness (H), elastic modulus (E), and toughness (KIC). Individual dust particles were also subjected to compression tests and their failure strengths calculated.

Results: For grit (n=15): E=94.16±2.29 GPa, H=13.53±0.19 MPa and KIC=0.68±0.08 MPa.m½. For phytoliths: Dactylis glomerata (n=17) E=20.2±1.19 GPa, H=2.76±0.11 MPa and KIC=0.28±0.04 MPa.m½. Ampelodesmos mauritanicus (n=12) E=21.6±2.51 GPa; H = 3.03±0.10 MPa and KIC=0.22±0.05 MPa.m½. Grit particles (n=22) of differing diameters failed at forces of 0.9–150 N, giving a range of failure strengths between 52.6–283.5 GPa.

Conclusions: Grit seems to be the most likely wear agent due to its high hardness. Compression tests prove that they fracture at low forces, rendering fragments with dangerous attack angles. Given that mammals seem capable of detecting particulate fractures in the mouth, it is possible that the fracture of phytoliths during plant consumption resembles that of the natural agents of wear. Therefore, it is suggested that phytoliths could represent an example of mimicry, forming an example of a feeding deterrent operating by deceit.

Acknowledgements: This study was supported by General Facilities Project GE01/07 from Kuwait University.


190

185059Residual Active Chlorine in Sodium Hypochlorite Solutions after Tissue Dissolution

R. CLARKSON1, T.K. SMITH2, B.A. KIDD1, G.E. EVANS1, and A.J. MOULE3, 1School of Dentistry, University of Queensland, Australia, Queensland, Australia, 2Research and Development, Multitrator Pty Ltd, Brendale, Queensland, Australia, Queensland, Australia, 3Faculty of Dentistry Kuwait University, Kuwait; School of Dentistry University of Queensland Australia, Kuwait, Kuwait

Objectives: In previous studies, surfactant-containing brands of sodium hypochlorite solutions (Hypochlor: Dentalife Pty Ltd, Victoria, Australia) showed better tissue solubilizing abilities than a commonly used endodontic irrigating solution (Milton: Milton Australia Pty Ltd, Queensland, Australia); differences were not explained by original active chlorine content or presence of surfactant. It was postulated that exhaustion of active chlorine content could explain these differences. This project aimed to assess whether exhaustion of active chlorine content explained difference in tissue dissolving abilities of some sodium hypochlorite solutions. Parallel experiments assessed the influence of titration methods, and the presence of chlorates, on active chlorine measurements.

Methods: Time required to dissolve one or groups of ten samples of porcine incisor pulp samples in Milton was determined. Residual active chlorine was assessed by thermometric titration. Iodometric and thermometric titration was carried out. Chlorate content was also measured.

Results: Dissolution of single and ten pulp samples caused a mean loss of 1 and 3% respectively of active chlorine, not being proportional to tissue dissolved. Thermometric ammonium ion titration resulted in 10% lower values than iodometric titration. Chlorate accounted for much of this difference.

Conclusions: Depletion of active chlorine is not the reason for differences in tissue dissolving capabilities of sodium hypochlorite solutions. Thermometric ammonium ion titration gives more accurate measurement of active chlorine content than iodometric titration.

This abstract is based on research that was funded entirely or partially by an outside source: Australian Dental Research Fund project number 35/2008


191

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