www.osteology-cannes.org

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To promote the active scientifi c exchange the Osteology Foundation invited researchers and clinicians within the fi eld of regenerative dentistry and dental tissue engineering to submit poster abstracts of original investigations for the Osteology Poster Presentation.

We have invited the following six expert clinicians and researchers to participate in the poster abstract committee:Tord Berglundh, SwedenJean-Louis Giovannoli, FrancePaul Mariani, FranceFrancis Mora, FranceIsabella Rocchietta, ItalyEric Rompen, Belgium

The poster committee evaluated more than 160 poster abstracts. The fi ve best abstracts in each of the categories clinical research and basic research are invited to present their work verbally to the poster committee.

Osteology poster price

The prize for the best poster in each of the two categories will be awarded on Friday, april 15, 2011 at 16.40 at the beginning of the Osteology Research Session.

poster Exhibition

The poster exhibition will take place in the exhibition hall.The accepted poster abstracts are subdivided into four different topics which can be distinguished by the different numbering:

Clinical research:Case Reports – 101, 102, 103,… (red)Clinical Studies – 201, 202, 203,… (green)

Basic research:In Vitro Studies – 301, 302, 303,… (blue)Pre-Clinical Studies – 401, 402, 403,… (grey)

The poster authors will be presenting their work on Friday, April 15, 2011 from 12.30 to 13.45 and on Saturday, April 16, 2011 from 13.30 to 14.30.

oSteology foundation PoSter PreSentation

PoSter abStractS

Pascal Valentini franck bonnet

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CliNiCal rESEarCH, CaSE rEpOrTS

101 i Secondary intention Surgical Wound HealingWith Biomaterials in damaged Extraction Sockets

Emanuele Tamburini (italy)

Objectives: The objectives of the “ridge build-up technique” are to simplify the hard tissue augmentation procedure and to reduce discomfort for the patient. In damaged extraction sockets it is better to wait some weeks until the infected site has healed. The biological approach of the post-extraction protocol is to augment the alveolar bone with biomaterials in the early phase of the healing process.Methods:The surgical protocol provides for the avulsion of irredeemable teeth because of abscess. Three to six weeks from extraction, the augmen-tation procedure is carried out using current biomaterials only. The volume of biomaterials, membrane included, exceeds the volume of original alveolus in order to provide for resorption of bone substitutes. The surgical protocol is designed in such a way as to make the exposed surface of the surgical site resemble a post-extractive alveolus. It is possible to recover and rotate the abundant repair connective tissue from the alveolar defect on the colla-gen membrane. Bacterial wound proliferation is controlled with clorexidine mouthwashes and application of hyaluronic acid. After 1 year, the implant and fi xed crown are inserted into the augmented bone (baseline) and observed for 1–4 years of follow-up.results: Soft tissue results: the exposed surface of the membrane is covered after 1–2 weeks and is sealed by soft tissue after 4–6 weeks. Hard tissue aug-mentation. The greatest linear horizontal and vertical bone gain are detected by cone-beam computed tomography. Clinical evaluations are performed be-fore extraction, 3–6 weeks after extraction (“control” wound healing), 1 year af-ter the augmentation procedure and 1–4 years after implant of the prosthesis. No implant or prosthesis loss, biological complication or patient discomfort is observed.Conclusions: Like the ridge preservation technique, surgical secondary inten-tion wound healing with current biomaterials is also possible without problems 3–6 weeks from extraction. Bone volume after 1 year is enough to insert a suc-cessful implant into the augmented site. The limitation of this technique lies in the diffi culty of precisely predicting the fi nal coronal shape of bone and soft tissue. In any event, it is possible during implant surgery to correct bone and gingival contour with biomaterials or a connective tissue graft.

102 i aesthetic and Functional reconstruction Of Severeatrophic Maxillary alveolar Crest By autogenous Bone Graftand dental implants

Sermet Sahin (Turkey), Metin Sencimen, Hasan Ayberk Altug, Aydin Gulses

Objectives: Although many osseous augmentation techniques have been de-veloped, autologous bone grafting remains the gold standard in maxillofacial reconstruction. Various donor sites for bone grafting have been investigated and described in the literature, including the tibia, fi bula, calvarium, scapula, clavicula and ilium. In addition, local bone grafts from the maxilla and man-dible have also been used. The obvious advantages of local bone graft are con-venient access, low morbidity, short healing periods, minimal graft resorption and maintenance of high bone density. The aim of this report is to describe the treatment and rehabilitation of severe bone loss with autogenous graft and dental implants.Methods: This paper demonstrates the surgical and prosthetic rehabilitation process of a patient with excessive bone loss in the anterior maxilla, secondary to a gunshot injury.results: The use of autologous bone grafts with osseointegrated implants is a well-accepted procedure in oral rehabilitation. Bone harvesting can cause postoperative complications such as donor site morbidity and sometimes does not provide a suffi cient quantity of bone. Therefore, synthetic biomateri-als have been investigated to be used in conjunction with autogenous bone grafts.

Conclusions: Extensive loss of bone and teeth in the anterior maxilla presents a complex problem for reconstruction, especially in patients with severe bone loss in the horizontal and vertical planes. This technique is valuable for the reconstruction of severe bone loss.

103 i using postauricular Split Thickness Skin Graft forVestibuloplasty and prosthetic rehabilitation Of Fibula FreeFlap reconstructed Mandible With dental implants

Sermet Sahin (Turkey), Metin Sencimen, Hasan Ayberk Altug, Gurkan Rasit Baykar

Objectives: This case report describes the surgical and prosthetic rehabilita-tion process of a case of excessive bone and soft tissue defect secondary to a facial gunshot injury.Methods: A 34-year-old male patient who had received a vascularized fi bula fl ap secondary to a gunshot injury involving the left side of the mandible presented to the Gülhane Military Medical Academy, Department of Prosthodontics, com-plaining of diffi culty in chewing and distorted physical appearance. According to the patient’s history, the fi bular grafting had been performed two years previous-ly and healing had been uneventful. Dental implants were subsequently inserted. Due to inadequate vestibular sulcus depth, vestibuloplasty combined with split-thickness skin grafts harvested from the post auricular area was performed.results: The surgical process produced satisfactory functional and aesthetic outcomes.Conclusions: The posterior split thickness skin grafts are useful in the treat-ment of cases with inadequate vestibular sulcus depth. We believe that this is an effective and reliable technique for composing attached gingival. As a result, our patient demonstrated successful prosthetic and functional results.

104 i alveolar Bone regeneration using anorganicBone Matrix and platelet-rich plasma

antonin Fassmann (Czech republic), Peter Augustin, Jan Vokurka, Lydie Iza-kovicova Holla, Jiri Vanek

Objectives: Tissue engineering is a progressive regeneration procedure and is used in several medical specializations such as periodontology, implantology and orofacial surgery.Methods: Platelet-Rich Plasma (PRP), autologous growth factors concentrate, can signifi cantly enhance the physiological regeneration of tissues. PRP is ac-tivated by adding thrombin and calcium and is applied together with anorganic bone matrix as a composite gel during guided tissue regeneration procedures.results: Alveolar augmentation in a patient with severe periodontitis is pre-sented. After multiple extractions, only a narrow alveolar ridge remained, with little retention for a partial denture. After alveolar ridge treatment and removal of granulomatous tissue, osteoplasty was performed. A composite gel was implanted and covered with resorbable collagen membrane. A temporary re-movable denture was given to the patient after the procedure. After 6 months, endosseous implants were placed in the maxilla and a metal ceramic bridge was cemented on to the osseointegrated implants.Conclusions: The procedure leading to the full cosmetic, functional and social rehabilitation of the patient using this progressive surgical approach will be presented step by step .

105 i immediate implants in The aesthetic zone.a Technique to preserve The Buccal Wall

Celia alves (portugal), André Correia, professor, Manuel Neves

Objectives: The aim of this paper is to present a novel technique for preserv-ing the buccal wall dimensions when performing an immediate implant in the aesthetic zone. Immediate implants in the aesthetic zone are a challenge to the clinician due to the possibility of buccal wall loss with direct consequences in the fi xed rehabilitation function and aesthetics. Evidence in the literature suggests that immediate placement does not prevent vertical or horizontal re-sorption and that bone regeneration techniques should be applied to ensure preservation of the shape of the alveolar ridge.

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Methods: Methods: After the immediate implant drilling phase, the socket is filled up with Bio-Oss Collagen® (Geistlich Pharma AG® Switzerland) trimmed with a cone form, in order to closely adapt it to the socket buccal wall. Then, the implant is placed with a low rotation speed (15rpm) into the drilled socket, pushing the Bio-Oss Collagen® buccally and making it more condensed.results: Results: The technique presented uses a material that is mouldable and easy to place into the extraction socket just before implant. As Bio-Oss® (Geistlich Pharma AG® Switzerland) particles are linked by the porcine col-lagen, the material condenses better during the implant insertion. At the 6 months follow-up visit, the Cone-beam CT scan (I-CAT® Imaging Sciences) showed both vertical and horizontal stability of the buccal bone. No clinical changes were observed in the facial soft tissues of the immediate implants and peri-implant soft tissues showed normal values for pocket depth and at-tachment loss.Conclusions: Conclusion: In immediate implant cases in the aesthetic zone, this technique may be very helpful in order to reduce resorption of the buccal wall, since it promotes excellent biomaterial compaction between the implant and the alveolar wall.

106 i deproteinized Bovine Bone Matrix in periodontal regeneration in Organ Transplant patients

peter augustin (Czech republic), Augustin Fassmann, Jan Vokurka, Lydie Iza-kovicova Holla, Hana Poskerova, Jarmila Celerova

Objectives: Organ transplant patients are successfully treated with complex immunosuppressive therapy.Methods: Drug-induced gingival overgrowth (DIGO) is an unwanted side effect of the therapy. Drugs inducing DIGO are Cyclosporine A, Azathioprin, Myco-phenolate, Verapamil and Nifedipine. Many other etiological factors contribute to the condition and are further aggravated by oral biofilm accumulation. Fi-brosis, inflammation and cell accumulation depend on doses, time and type of drug administrative, oral hygiene and individual reaction of organism.results: We are using our treatment protocol: After patient hygiene instruc-tions, scaling and root planing (SRP), the surgical treatment (gingivectomy) is performed. After six months, regenerative periodontal therapy using tissue en-gineering with deproteinized bovine bone matrix (DBBM) and platelet rich plas-ma (PRP) is started. After activation with thrombin and calcium, a composite gel is prepared for implantation into periodontal defects. The gel is covered with resorbable collagen membrane. Degranulation of thrombocytes and release of growth factors significantly improve the quality of periodontal regeneration.Conclusions: The poster demonstrates the use of this method in patients with drug-induced periodontitis following transplantation of heart and kidney. This therapeutic practice is performed successfully.

107 i The use Of Mucograft® Collagen Matrix To augmentThe zone Of keratinized Tissue around Teeth

Soo-Woo kim (uSa), David Kim, Peter Schupbach, Marc Nevins

Objectives: The importance of a functional and healthy mucogingival complex to underlying osseous stability around teeth is evident by the increasing atten-tion given to soft tissue augmentation procedures in clinical practice. An intact attached band of keratinized gingiva is seen as a critical component to the pro-tective function of the mucogingival complex, although minimum width require-ments of this tissue type remain controversial. The exact quantity of attached gingiva necessary for maintaining periodontal health has not been defined, but a number of studies suggest that it necessary to have a minimum of 2 mm of ke-ratinized gingiva for sustainable periodontal health. The purpose of our prospec-tive split-mouth case series was to evaluate the safety and efficacy of Mucograft® (Xenogenic porcine bilayer collagen matrix) as an alternative to the autogenous gingival graft in procedures designed to increase the zone of attached gingiva.Methods: Five healthy patients presenting with 2 mm or less bilaterally of at-tached keratinized gingiva on the buccal aspect of mandibular posterior teeth were recruited. Plaque and Gingival Indices as well as probing pocket depth, gingival recession, and the amount of attached gingiva were determined at the buccal aspect of each test (Mucograft) and control (autogenous gingival graft) tooth and again at 12 months. Both the test and control procedures were per-

formed at the same visit and the preparation of the recipient bed and suturing techniques were similar. Test and control treatments were randomly assigned to either recipient sites, and they were sized similarly to cover the wound bed and stabilized with sutures. Patients were seen in follow-up at 2, 4, 6, 8 and 13 weeks and then recalled for long-term examination at 12 months. A soft tissue biopsy was obtained from both test and control sites at 13 weeks from four patients for histological examination.results: All patients healed uneventfully without any graft-related adverse events. The test and control sites exhibited normal healing, with excellent co-lour and texture at the test sites equalling tissue maturation at the control sites. The 12-month examination revealed that the increase zone of attached gingiva remained stable for both groups. Unlike the control sites, the tissue contour, colour and texture of the test sites blended nicely with the native adjacent soft tissues. The Wilcoxon signed rank test for pre and postoperative measurements revealed a statistically significant increase in the amount of keratinized gingiva for the test (P = 0.041) and the control group (p = 0.042). No statistically sig-nificant differences were found on all other measured parameters. The Mann-Whitney U Test did not find statistically significant differences between the test and control groups on any examined variable, including changes in keratinized gingiva and epithelial thickness. The histological findings between test and con-trol sites were remarkably similar for each patient. Mature connective tissue was covered by well-formed keratinized epithelium, over which a small band of dense orthokeratin was consistently found. The rete peg morphology of test and control specimens appeared similar for each patient. In all instances inflamma-tory cells were notably absent. Small fibrous remnants of collagen matrix were the only evidence that a graft material had previously been placed.Conclusions: The results of this study comparing Mucograft to autogenous gingival graft identified the likelihood of the Mucograft being a viable alterna-tive when the goal of therapy is to increase the zone of keratinized tissue and obviate the need for palatal harvest. This is especially true in areas of reason-able vestibular depth and minimum musculature.

108 i platelet-rich Fibrin in The Treatment Of Bilateral Gingival recessions

Gulnihal Eren (Turkey), Gul Atilla

Objectives: Coronally advanced flap (CAF) + connective tissue graft (CTG) has been suggested as the most predictable technique for correction of recession defects. However, CTG technique necessitates a second surgical site and in-creases the risk of morbidity linked with harvesting the autogenous palatal do-nor mucosa. Platelet-rich fibrin (PRF), containing autologous growth factors, has been thought to accelerate soft tissue healing. The use of PRF in treatment of gingival recessions eliminates the requirement for a donor site. The aim of this case report is to evaluate the clinical effectiveness of coronally advanced flap CAF+PRF combined technique and also to compare its results with CAF+ CTG in the treatment of bilateral gingival recessions.Methods: This case report concerns the surgical treatment of a 22 year old pa-tient with bilateral gingival recessions in maxillary canine incisors. Sites were randomly assigned into CAF+PRF (test) or CAF+CTG (control) groups. Clinical periodontal parameters were recorded at baseline and at 1, 3 and 6 months. Clinical photographs were taken at baseline and at 1, 3 and 6 months and the recession area analyzed by digital image analysis (ImageJ Windows, National Institutes of Health, Bethesda, MD). Soft tissue thickness was also evaluated at baseline and at 6 months.results: Root coverage amount, soft tissue thickness levels, increase in kera-tinized tissue depth, clinical attachment level and probing depth were improved for both study groups. The test group showed better wound healing than the control group at the 10th day. Fewer complications were also recorded in the test group, due in particular to the fact of not having a donor site.Conclusions: Based on the results, CAF+PRF technique is a predictable treat-ment for gingival recessions. PRF may accelerate wound healing and cause less patient discomfort in the treatment of gingival recessions.

109 i use Of Nanocrystalline Hydroxypatite in Blocks For Bone Graft in atrophic areas. Clinical, Tomographic and Histological analysis

Sergio Gehrke (Brazil)

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Objectives: The objective of this study was to evaluate the performance of the nanocrystalline hydroxyapatite in blocks NanoBone® (Artoss GmbH, Germany) for the recovery of atrophic areas to allow subsequent placement of dental implants.Methods: Performance was assessed through clinical and tomographic follow-up as well as histological examination to evaluate the osteogenic potential of the material in six patients.results: The samples showed a large bone formation inside the blocks. Clini-cally we observe a proper consistency of newly formed tissue, allowing stabi-lization of the implants. Tomographically, the grafted blocks showed adequate radiopacity, enabling control and evaluation to be carried out.Conclusions: The results show that nanocrystalline hydroxyapatite in blocks NanoBone® is very promising for use as a graft material to obtain volume, be-cause it promotes higher cellular activity and bone substitution.

110 i Bone regeneration in Maxillary anterior regionBy Microplate and Non-resorbable Membrane

Jung-Bae dan

Objectives: Block bone grafts have been widely used in the reconstruction of the maxillary anterior region. Recent advances have enabled clinicians to deal with various situations. The author attempted to regenerate the bone in the maxillary anterior region using a microplate and non-resorbable membrane.Methods: The 45 year old female came to WooJung Dental clinic in Seoul, Ko-rea with a left central incisor displaying severe mobility.After extraction of the left central incisor, the bone graft was delayed for 2 months until the soft tissue had matured. After soft tissue maturation, the bone graft procedure was performed. There was severe bone destruction in the buccal plate.About 5 mm vertical loss was observed in the buccal plate. A 5-hole-length microplate (Jeil Medical Corporation,Korea)was bent to fi t the contour of the facial bone and fi xed with bone tack (Frios®,Germany). BioBarrier (Imtec®,USA: non-resorbable, non-porous type) was fi xed from the lingual side with bone tack.Irradiated cancellous bone and marrow (Rocky Mountain Tissue Bank, USA) 0.25g and Cerasorb (Curasan,Germany) 0.5cc mixed with PRGF (Platelet Rich in Growth Factor) were placed under the membrane. Finally, bone tack was fi xed to the covering membrane to stabilize the bone graft.results: After 8 months, re-entry was performed and the implant installation carried out. At this time, the core of the graft site was taken out by trephine burr. Though some Cerasorb particles maintained their integrity in macroscop-ic appearance, primary stability of the implant was good. The microscopic ap-pearance of the graft core showed some degree of bone formation. The second operation was performed 3 months later. A papilla-saving incision helped to conserve papillae. Though some degree of bone resorption was observed in the crestal region, the replacement of Cerasorb by bone had progressed relative to the previous state (i.e. at installation).Final restoration shows good harmonious appearance with adjacent tooth and soft tissue. The soft tissue has a fi rm and healthy appearance.The author experienced the benefi t of soft tissue maturation. Thick, fi rm and healthy soft tissue is important in order to avoid membrane exposure and for the success of the bone graft and long-term maintenance in the anterior re-gion, where aesthetics are a major concern. The author recommends a staging approach for graft sites with weak soft tissue. Furthermore, even soft tissue enhancement is needed for successful implant. Most clinicians have major concerns for bone in GBR and for the coupling action of osteoblast and os-teoclast: the author likes to use the term “coupling action of bone and soft tissue”. The microplate technique is a non-invasive, time-saving procedure without bone harvesting.Conclusions: 1. The staging approach to soft tissue maturation was benefi cial and contributed to the success of the GBR and to the aesthetic aspect.2. GBR through microplate was a non-invasive and time-saving procedure compared with block bone graft.3. Suffi cient bucco-lingual bone dimension was secured through use of the microplate.

111 i Gain Of Bone Height and Thickness in The posteriorMandible using Bilateral reconstruction With autogenous GraftOf ramus Mandibular and Mentum

Guilherme piragine, Marco Pontual, Hedilberto Sousa, Danielle Lima, Marco Bianchini

Objectives: To demonstrate through Cone Beam CT image the horizontal and vertical gain in bone volume 6 months after grafting surgery with functional prosthetic rehabilitation on implants of different diameters in the posterior mandible.Methods: Patient MR, 53, female, leukoderma, came complaining of diffi culty in chewing due to lack of teeth in the posterior region of mandible, failing to make use of removable partial denture. Cone beam tomography of the man-dible showed initial marked loss of bone volume to be deployed in the regions (34-36, 44-46). Due to the length and proximity of donor and recipient sites, the surgery, which involved reconstruction of bilateral mandibular bone height and thickness with autograft taken from the symphysis mandibular and left ramus mandibular, was performed in a hospital environment. During the reconstruc-tive surgery, the bone blocks were stabilized to the recipient site and fi xed 1 mm above the crest to induce bone height gain. After six months of the new cone beam tomography grafted region was ordered after surgery to install 05 implants (Straumann SLA-active). After 4 months the patient was rehabilitated with fi xed prostheses screwed.results: Flap debridement exposing all the donor and recipient sites allowed repositioning of normal tissues, so the volume of the bone blocks was pre-served by the absence of tension, and since the patient did not use the prosthe-sis during the healing period there was also no pressure on them. The grafted area showed a gain in height (H) and thickness (T) after 6 months, region 34 (H-0.1mm / T-2.6mm), region 35 (H-3.3mm/T-3.5mm), region 36 ( H-4.7mm/T-3.9mm), region 45 (H-6.8mm/T-3.6mm) and region 46 (H-7.4mm/T-5.2mm). The volume obtained permission to install the parallel implants, and centered on the rim and without any complications such as detachment of the block graft, or trepanning exhibition breathes. The bone blocks were well adapted to the original bone with good vascularization and density. In the region of el-ement 44 it was decided not to install the implant, since a bone defect was found that could have jeopardized a successful outcome. Screw-retained metal ceramic fi xed prostheses were fabricated. The right side of the prosthesis re-ceived the cantilever element 44.Conclusions: The surgical technique has enabled the volume of the bone blocks to be maintained due to modifi cation of the incision providing free ac-cess to donor and recipient sites and the repositioning of the fl ap free from tension. Rehabilitation with implants in grafted area is a treatment used in clinical practice, but still more studies are needed in order to assess the sur-vival rate of these implants, as well as the stability of the bone volume around prosthetic implants.

112 i Two year Follow-up Of an autogenousTransplantation Of Maxillary Molar

Ozgun Ozcaka, Kanik Ozgur, Bicakci Tolga, Arikan Fatih

Objectives: Autogenous tooth transplantation has been used as a predictable surgical approach to correct malocclusion and replace edentulous areas. The purpose of this case report is to describe a patient undergoing autotransplan-tation of an impacted maxillary third molar into the socket of the extracted second maxillary molar. Methods: A 54 year old systemically healthy male subject was referred for dental treatment on his right maxillary second molar. Panoramic and periapical radiographs revealed the existence of a periapical lesion and periodontal bone loss. Tooth extraction was therefore indicated. The same clinical and radiographical examinations showed that the unerupted right maxillary third molar was healthy and suitable for tooth autotransplanta-tion. The procedure involved transplantation of the third molar into the ex-traction socket of the non-restorable second molar. Five basic procedural steps were taken: 1) atraumatic extraction, 2) apical contouring of bone at the transplantation site, 3) preparation of a 4-wall bony socket, 4) avoidance of premature occlusal interferences and 5) stabilization of the tooth with placement of a cross suture. The patient was recalled at 1, 3, 6, 12, and 24 months.results: No differences were found in clinical periodontal parameters at 1, 3, 6, 12 and 24 months. At the two year follow-up, no pathological signs were detected clinically or radiographically.

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Conclusions: Autogenous transplantation of the third molar may be consid-ered as an alternative to prosthetic and implant rehabilitation treatment in loss of first and second molars.

113 i The Outcome Of implant rehabilitation in The anterior Maxilla With a papilla-preserving incision Technique and Grafting: a Case report

aysun kaya, Turker Ornekol

Objectives: To prevent the regression and recession of soft tissue and underly-ing hard tissue after the extraction of an infected tooth.Methods: Tooth # 21 extracted due to persistent apical infection and extru-sion. Immediately after extraction, socket was augmented with allograft (Bio-oss,Geistlich Biomaterials) and opening of the socket was covered with a re-sorbable membrane(Bio-Gide,GB). As a temporary, extracted tooth crown was trimmed and bonded to the adjacent teeth to block the opening by pressing over the membrane. Two weeks from the extraction, a 5x10 mm tapered Nobel Replace implant (Nobel Branemark) was placed. A papilla-preserving incision technique was used to elevate the flap, keeping the papillae intact. Guided bone regeneration (GBR) technique was used in conjunction with the implant place-ment. A Maryland bridge was cemented in for the healing period immediately after the surgery. Six weeks after the surgery, a screwable temporary crown was produced to remodel the surrounding soft tissue. Twelve weeks after the surgery, a permanent Procera Zirconia ceramic crown (NB) was cemented on to the procera zirconia abutment (NB).results: On post-operative examinations, a stable state both in the alveolar bone contour and on soft tissue topography was observed. 1 year and 2 year follow-up sessions showed minimal (negligible) tissue loss distobucccal to the crown.Conclusions: GBR is essential to prevent the collapse of surrounding tissues after the extraction. The papilla-preserving incision technique and placement of a provisional prosthesis are also important requirements for achieving suc-cessful functional and aesthetic outcomes in the maxillary anterior region.

114 i Horizontal reconstruction of alveolar ridge using autogenous block bone graft

albert Barroso panella (Spain), Pablo Altuna Fistolera, Albert Calaf Cot

Objectives: The aim of our communication is to expose a case series in which we have used the autogenous block bone graft for the management of the hori-zontal alveolar defect and to evaluate the results and the complications. Methods: A case series are presented and the results are compared to late publications. All of the cases presented moderate-severe horizontal alveolar ridge defects. All of them have been reconstructed with intraoral autogenous block bone graft. A follow up of 6 to 36 months has been done. The results are analyzed depending on: kind of device used for the osteotomy, location of donor site, morbidity of the donor site and possible complications.results: The results have become to be favourable by using these techniques after an average follow up of 16 months. These results are in accordance to actual lit-erature, in which the survival rates and the aesthetic results are very satisfactory.Conclusions: The use of the intraoral autogenous block bone graft for the re-construction of the alveolar ridge seems to be predictable for the rehabilitation with fixed prosthesis of our patients.

115 i Bone regeneration in Extremely Severe atrophic Mandible. a Case report.

radia Hrichi, Joan Pi Anfruns, Joan Pi Urgell

Objectives: The objective of this case report is to present a non-invasive tech-nique for bone regeneration in an extremely atrophic mandible with GBR utiliz-ing a xenograft in combination with a synthetic barrier to allow the placement of dental implants.Methods: A 75 year-old female, edentulous in both maxilla and mandible with extremely severe bone atrophy (type E). The patient’s chief complaint was in-stability of the lower denture with severe functional problems and nerve distur-

bances due to mental nerve compression. Pre-operative CT Scan measurements at the symphysis revealed 4 mm. of residual ridge height and 6 mm. of width. The procedure was performed under conscious sedation and local anaesthesia. A full thickness flap in the anterior area and a partial thickness flap in the posterior area were performed to avoid nerve damage. GBR was performed using a xeno-graft (Bio-Oss) and a titanium-reinforced e-ptfe membrane (Goretex). Mattress sutures provided primary closure. After 6 months of healing time the membrane was removed and three implants were placed (Branemark System) in the inter-foraminal area. Resonance Frequency Analysis (RFA) was used to assess pri-mary stability. A core sample was obtained for histological analysis.results: Post-operative CT scans after 6 months of healing revealed 12 and 6mm of vertical and horizontal bone height gain, respectively. The newly gen-erated bone allowed for the placement of three dental implants to support an implant-assisted overdenture. Primary stability of the implants was achieved and measured by means of RFA. Implant Stability Quotient (ISQ) measure-ments taken at the mesial, distal, buccal and lingual aspects of each implant ranged from 66 to 76. Histological analysis revealed vital and mature bone sur-rounding Bio-Oss particles.Conclusions: Within the limitations of this case report, we can conclude that GBR is a valid technique for bone reconstruction in cases of severe mandibular resorption, avoiding the use of autogenous bone grafts and the consequent donor site morbidity

116 i a Combination Of zygomatic Fixtures, autograft, allograft and prp (platelet-rich plasma) Or prF (platelet-rich Fibrin) allows a Fixed prosthesis rehabilitation Of Extremely resorbed Or accidental Bone loss in Edentulous Maxilla

laurence Evrard, Yassin Bouzelmat, Ramin Atash, Régine Glineur

Objectives: For the maxilla, in the case of post-traumatic loss or of major post-edentation resorption, functional and aesthetic rehabilitation with a fixed prosthesis can be achieved by means of two or four zygomatic fixtures plus two to four conventional implants in the anterior region. In these cases, a reconstruction of the anterior part of the maxilla can be performed, using a bone autograft supplemented by an allograft and platelet concentrates (PRP or PRF), which have been shown to enhance the maturation rate of bone and bone density and to accelerate resorption of some biomaterial particles. Methods: Clinical cases are presented, involving placement of two to four zygomatic fixtures, in conjunction with a cranial or mandibular symphysis autograft, supplemented by use of Freeze Dried Bone Allograft (FDBA) and Platelet-Rich Plasma (PRP) in the form of gel and membranes. Biopsies were taken 4 to 6 months after bone grafting, at the time of implant placement in the region of the anterior maxilla. Histological analysis was performed, in order to evaluate the effects of PRP on bone maturation and bone density, in the case of a bone autograft used in conjunction with an allograft. The four year clinical results are presented.results: Histological sections show the very good degree of maturation of the reconstructed bone (lamellar bone, poor cellularity, absence of inflammatory infiltrate). X-rays show the level of bone around implants.Conclusions: The results presented here show that PRP used in conjunction with allografts and autografts produces very good bone quality and density, allowing implants to be placed. After four years of functional load, all implants are successful.

117 i Minimally invasive removal Of adental implant displaced into The Maxillary Sinus using dental Mini-C-arm Fluoroscope

uilyong lee, Pillhoon Choung, Jongho Lee, Juhyung Yi, Mihyung Kim

Objectives: A dental implant displaced into the maxillary sinus must be re-moved because the implant can cause sinusitis by disturbing mucociliary clearance or causing tissue rejection. Implant migration into the maxillary si-nus has been reported several times. To remove foreign bodies dislodged into the maxillary sinus, three treatment options have hitherto been proposed in the literature: suction from the socket, classical open surgery via the canine fossa and the endoscopic approach.

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We describe a method to retrieve a displaced dental implant from the maxillary sinus using a dental mini-C-arm fl uoroscope. The unit used in this study was a DreamRay®. The DreamRay® fl uoroscope was specifi cally developed for dental implant surgery, endodontic treatments, tooth extractions and preparations for fi llings. The light weight and compact design of the DreamRay® enables it to be moved easily and used in any location and orientation during dental procedures.Methods: We retrieved the dislodged dental implants from the maxillary sinus in two patients through the socket using a mini-C-arm fl uoroscope. The socket was expanded to 6 mm for further instrumentation. In the beginning, we tried to remove the implant using a mosquito by viewing fl uoroscopic images. Real-time fl uoroscopic imaging facilitated delicate control of the mosquito in order to grab the implant. However, controlling the mosquito through the socket proved to be diffi cult. Thus various surgical curettes were used to drag the im-plant toward the socket. Finally, the implant was positioned close to the socket and retrieved using suction.results: The dislodged dental implants were removed successfully. It took only 5 minutes to remove the slipped implant, which had been dislodged into the maxillary sinus. The enlarged socket was then covered with a collagen mem-brane and primary watertight closure was done with 4-0 black silk. The pa-tients returned for follow-up appointments and the wounds healed well.Conclusions: By using a mini-C-arm fl uoroscope to remove the dislodged den-tal implants from the maxillary sinus through the socket in two patients, we confi rmed that the mini-C-arm is an effective and minimally invasive method for retrieving displaced dental implants.

118 i Bone quality Enhancement By platelet Concentration Method

Jung-Bae dan (korea)

Objectives: Weak bone quality is a challenge for successful implantation. Especially in an extraction site in a severely infl amed condition, bone heal-ing is not good. Even after a long period of healing time, bone quality is very poor on that site. The author experienced implant failure after loading . The author concluded the reason for failure was poor bone quality because the ISQ value during healing was so low and didn’t go up well. There have been many implant surfaces to enhance osseointegration. But there are so few bone quality enhancing methods for a osteotomy site with poor bone quality. So the author tried to enhance the bone quality at the osteotomy site with poor bone quality.Methods: The author installed 2 Straumann implants in the maxillary posterior region. One of the implants shows some peri-implant radiolucency and mobil-ity. That implant was removed after some loading period. After removal of the implant, synthetic bone material(Cerasorb) was fi lled.After the healing period, reimplantation was practiced. At installation, the ISQ value was not estimated for very low stability. PRGF (Platelet-Rich-in-Growth Factor) was prepared from venous blood. And the Straumann implant was soaked with PRGF. Excess PRGF fi lled the osteotomy site.results: 3 weeks later, the ISQ was estimated. The ISQ value was 44. 6 weeks later ISQ went up into the seventies.Conclusions: Implant surface and poor bone quality osteotomy site was en-hanced by PRGF. PRGF assisted implant installation was strong for poor bone quality osteotomy site.

119 i Histomorphometric Comparison Of a Macroporous Biphasic Calcium phosphate and inorganic Bovine Bone For Maxillary Sinus augmentation in Human: a pilot Study

Ji-Hyun lee (korea), Ik-Sang Moon

Objectives: The maxillary sinus augmentation technique has been considered as a routine procedure to achieve suffi cient vertical bone height on the maxillary posterior region with severe alveolar bone resorption. As far as bone grafting material for sinus augmentation is concerned, it is still accepted that autog-enous bone graft is the gold standard. However, many researchers have studied other bone substitutes, due to limitations affecting the harvesting of a suffi cient amount of bone and the need for a second surgical site. In particular, macropo-rous biphasic calcium phosphate (MBCP) belongs to alloplast, consisting of 60%

hydroxyapatite and 40% beta-tricalcium phosphate, while inorganic bovine bone matrix (ABBM) is manufactured from bovine bone mineral. This study evaluated the effi cacy of MBCP (MBCP) to ABBM (Bio-Oss®) in the histomorphometrical aspects of new bone formation in maxillary sinus augmentation.Methods: Eight patients were selected after a medical and dental examination. Patients had insuffi cient residual bone height (less than 5 mm) for simulta-neous installation of implant fi xtures on maxillary posterior regions. Residual bone height was measured by a CT scan.They were divided into two groups as determined by randomization and un-derwent maxillary sinus fl oor elevation and bone grafting using MBCP (n=4) or Bio-Oss (n=4). After a healing period (average 6.5 months after surgery), bone cores were harvested for a histomorphometric evaluation and the implant fi xtures were installed. These bone cores were decalcifi ed and 5 um thick sec-tions were cut along the longitudinal plane using a microtome. All sections are stained with Hematoxyline-eosin and evaluated via light microscope coupled to a video camera. The percentage of the different components of the harvested tissue (i.e., new bone, residual bone particles, and soft/marrow tissue) were calculated and recorded.results: Healing process after sinus graft procedure was uneventful, even though small tears (‹ 5 mm) occurred in two sinuses. Bone cores were obtained 22 to 36 weeks post surgery. Histomorphometric analysis of 4 MBCP cores and 4 ABBM cores revealed an average of new bone of 26.94% and 28.94%, respectively. The percentage of residual graft particles was much less in MBCP (11.59% vs. 31.10% for ABBM) with more soft and marrow component (61.47% vs. 39.96% for ABBM). The amount of new bone formed in the sinus does not seem to be related to the length of healing time. The gross histology of the retrieved tissues was similar for the both types of graft material. Histological evaluation revealed that most of the graft particles, both MBCP and ABBM, were surrounded by or embedded in new bone, and in close contact to surrounding new bone. The boundary between particles and new bone was irregular and the contact was close, implying the resorption of particles with the simultaneous apposition of new bone.Conclusions: Since the number of patients and sinuses was limited, the data obtained in this pilot study should not be considered conclusive. How-ever, histological appearance showed that both materials have osteoconduc-tive properties. Both materials are, therefore, appropriate for maxillary sinus augmentation followed by dental implant placement. It is not known whether differences of percentage obtained in histomorphometric analysis have any clinical relevance.

120 i different Technique Of ridge Splitting accordingTo The Thickness Of The Buccal plate: Clinical Cases report

dong Wook Chang (korea)

Objectives: Narrow alveolar ridges are a serious challenge for successful im-plant placement. The ridge split technique seems to be a predictable technique to correct narrow alveolar ridges as compared to onlay bone graft and GBR. Ridge splitting can be applied in both maxilla and mandible. But generally, bone splitting in the maxillary ridges with mostly lower bone density and thin-ner cortical bone plate can more easily be performed than in the mandibular ridges with the denser bone of buccal plate. Occasionally, maxillary ridges with thick buccal plate are present. Therefore, a different method must be ap-plied in the thick and thin buccal plate respectively. In the thin buccal ridges, mostly maxillary ridges, ridge splitting requires crestal and vertical osteotomy. In thick buccal ridges, ridge splitting needs long vertical osteotomies and/or basal horizontal osteotomy to prevent buccal plate fracture additionally.Methods: Case I is ridge splitting with simultaneous implant placement in the maxillary ridge with thick buccal plate. Full thickness fl ap was elevated and mid-crestal osteotomy with a piezoelectric device was performed in the alveolar ridge. Then long vertical osteotomies on the mesial, distal side were performed apically. Ridge expansion was performed with a chisel osteotome. Then the im-plant was inserted into the widened alveolar crest. And then the defect was cov-ered with bone graft material and bioresorbable membrane. The primary closure was achieved. Case II is ridge splitting in the mandibular ridge with thick buccal plate. After fl ap elevation, mid-crestal osteotomy with piezoelectric device was performed in the alveolar ridge. Then the vertical osteotomies on the mesial and distal side and additionally basal horizontal osteotomy was performed. After the expansion, the widened alveolar crest was fi lled with bone graft material and covered with bioresorbable membrane. The primary closure was achieved.

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results: Case I. 4 months after ridge splitting with simultaneous implant placement, 2nd surgery was performed and the implant was surrounded in regenerated bone at the ridge split site without thread exposure. And then 1 month later, implant prosthesis was completed.Case II. 5 months later after ridge splitting, 2nd surgery was performed and the regenerated bone in the ridge split site was sufficient to implant the placement.Conclusions: As regards the thin buccal plate, ridge splitting requires only crestal and vertical osteotomies. On the other hand, as regards thick buccal plate, ridge splitting needs additional osteotomies such as long vertical oste-otomies, basal horizontal osteotomy.This ridge splitting technique according to the thickness of buccal plate is reli-able and enables the buccal plate not to be fractured.

121 i Clinical Evaluation Of Coronally advanced Flap (CaF) + Mucograft® in isolated recession Type defects. Case reports

Marco Clementini (italy), Gianluca Vittorini, Nicola Baldini

Objectives: The primary goals of mucogingival surgery have changed over time from increasing the band of keratinized gingiva to providing predictable root coverage to satisfy patients’ aesthetic demands. Various different surgi-cal techniques have been utilized to augment gingival tissue dimensions. A review comparing the free gingival graft (FGG), the connective tissue graft (CTG) or the coronally advanced flap (CAF) in recession coverage revealed non considerable difference between the individual treatments. In order to improve the predictability of complete root coverage, a new technique has been developed using the CAF in conjunction with CTG. Even if this approach showed improved clinical outcomes, it may be associated with significant pa-tient morbidity due to the wound at the palatal donor site. Instead of using allograft material or autologous transplants, a promising option of avoiding patient morbidity is the use of collagen matrices from animal origin, such as Mucograft® (MG).Methods: The surgical technique utilized to achieve soft tissue coverage is the CAF for single recession. Following administration of local anesthesia, the flap is designed with two vertical releasing incisions and then elevated in a split-full-split fashion, the exposed portion of the root is scaled and then conditioned with EDTA to remove the smear layer, finally thoroughly rinsed with sterile sa-line. The MG is cut to size and placed over the dehiscence defect. The matrix is placed 3 mm apically to the bone dehiscence and 1 mm from the lateral inci-sions (avoid placing MG beneath the sutures) on the prepared mucosal bed and then sutured in place. Subsequently, the root surface and MG will be covered with the CAF: the tissue flap is secured slightly coronally of the CEJ by the use of a sling suture placed at the papilla, using non-irritating sutures. The verti-cal incisions are closed by at least 2–3 sutures. Light pressure will be applied after suturing.results: At 6 months CAF+MG showed very positive outcome measurements in terms of root coverage and KT width in 4 out of 5 patients, according to the sys-tematic review data available in literature about CAF+CTG; these results seem to be stable and associated with a good aesthetic integration and with healthy periodontal conditions; furthermore no signs of inflammation or infection were detected in the period of observation, all the patients reported only a transient, slight pain with a very short FANS medication intake.Conclusions: These preliminary results suggest this new surgical technique (CAF+MG) could be a reliable alternative to the traditional bilaminar technique (CAF+CTG) because of its predictable outcomes in terms of root coverage % in association with a significantly lower patient morbidity avoiding a palatal donor site

122 i Socket augmentation as a useful procedure For replacing a Severely involved anterior Tooth By dental implant

Golamali Golami (iran), Reza Amid

Objectives: Hard tissue deformities are considered to be among the most seri-ous limitations on implant placement in a proper position. Different kinds of materials and methods are available. Despite the success of bone regenerative procedures documented in so many publications, bone regeneration has been a controversial issue. Periodontally involved teeth with severe bone loss have

compromised the restorative-driven approach to implantation. Vertical bone augmentation where horizontal bone loss has occurred is still regarded as a challenging topic.Methods: A fourty-five year old female with a severely deteriorated maxillary lateral incisor requested an implant in order to make a fixed restoration. Se-vere bone resorption circumferentially around the root had lost the neighbour-ing proximal septum and jeopardized the standard procedure. We used guided bone regeneration using a xenograft and barrier membrane for bone replace-ment after tooth extraction. Late implantation was performed and final crown delivered after healing period.results: Uneven healing after bone regeneration, implant placement, and loading occurred. Significant amount of new bone gained in radiographic and clinical findings. Primary stability of implant placed in regenerated bone was demonstrated via high insertion torque. Appropriate bone remodelling and os-seointegration was demonstrated by the high score of implant stability (ISQ). Follow up radiographs taken 8 months after loading showed stable bone level around the fixture neck. Clinically, we could deliver an aesthetic crown without any significant mismatch with neighbouring teeth.Conclusions: Optimal results in single implantation would be a predictable approach even in a compromised situation. Appropriate case selection, flap design, and proper materials are necessary for replacing a tooth with reduced periodontium.

123 i reconstruction Of The Critical Size peri-implant Osseous defects With porous Titanium Granules

Sermet Sahin (Turkey), Metin Sencimen, Hasan Ayberk Altug, Yesim Erkan, Aydin Gulses

Objectives: Pure titanium and titanium alloys (Ti6Al4V) have been used in the manufacture of dental and orthopaedic implants because of their superior me-chanical properties and high corrosion resistance. Porous titanium granules (PTG) have used in many treatments for dental bone regeneration. The most common are sinus lift, regeneration of bone in peri-implantitis defects and post-extraction socket fillings. The aim of this study was to explore the osteo-conductive properties and biological performance of porous titanium granules used in the critical size osseous defects adjacent to titanium implants.Methods: A 27 year old male patient with multiple implants was referred to our clinic for treatment. Three months after dental implant insertion, peri-implan-titis occurred with bone resorption in region around the implants. The following treatment steps involved debridement; full mouth disinfection and accompany-ing antibiotic treatment aiming to reduce any active inflammation. The muco-periosteal flap was removed up to the edge of the infected bone. Removal of all granulation tissue and cleaning of the titanium surface with curette. The decon-tamination of implant and bone was carried out with the tetracycline capsule. At the end of the treatment for regeneration and augmentation, PTG were applied with soft tissue stabilization and renewed pocket formation was prevented.results: The results of the case show that bone can be regenerated using PTG (Porous Titanium Granules), and tissue samples show that new bone grows in and around titanium granules and regenerates the bone tissue around the implant. For the patient and dentist, this means that much time can be saved, unpleasantness can be avoided and costs can be reduced.Conclusions: In the literature, PTG have previously shown that titanium is much more thrombogenic than the other two. Biomaterials are often used in implants, i.e. PVC and steel. Apart from their physical properties, the granules have also shown indications of having good biological properties, such as re-duced inflammation and faster coagulation of the blood.

124 i delayed implant placed into Grafted Extraction Socket Of Molar affected By Chronic periapical lesion in Mandible

Sermet Sahin (Turkey), Hasan Ayberk Altug, Metin Sencimen, Hanand Altug

Objectives: The aim of this case report was to show the clinical outcome of an implant placed into a grafted extraction socket of molar tooth affected by chronic periapical lesion.Methods: A 66-year old partially edentulous male patient with a tooth requir-ing extraction and chronic periapical lesion was referred to our clinic. Tooth

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was extracted, chronic periapical lesion was curetted and that side was treated according to the principles of guided bone regeneration (GBR) by means of deproteinized bovine bone mineral particles in conjunction with a bioresorb-able collagen membrane. Survival and radiographic bone loss of implant were evaluated after two years of function.results: Extraction site displayed suffi cient new bone volume to allow inser-tion of a dental implant. No complication was recorded with implant and pros-thesis was successful.Conclusions: Implant placement into such sites can, therefore, be successfully performed. This procedure can be considered a safe and effective treatment option.

125 i Mandibular reconstruction WithTissue Engineering, a Case report.

Vanessa ruiz Magaz (Spain), Federico Hernández-Alfaro, Manuel Ribera, Pablo Altuna, Eduard Ferrés, Lluís Giner Tarrida

Objectives: Show a new approach to bone regeneration instead of bone trans-plantation in a 32-year old patient who presented an ameloblastoma in her left mandibular angle.Methods: The area affected by the ameloblastoma was resected using an ex-traoral access. At the beginning of the surgery a bone marrow aspirate from the iliac crest was centrifuged in order to concentrate the mesenchymal cell fraction. Using a stereolithographic model of the mandible a titanium mesh was moulded to recreate the angle of the mandible. Two xenograft blocks mixed with recombinant human bone morphogenetic protein-2 and stem cells were used to recreate the resected area on the model. Then the titanium mesh and this com-bination of biomaterials were adapted to the mandible of the patient to recreate the original anatomy. After 6 months three endosseous dental implants were placed in the regenerated bone to restore the masticatory function of the pa-tient. At the time of the implant placement bone samples were collected using a trephine bur and were subjected to histomorphometrical analysis.results: The fundamental of tissue engineering is the regeneration of tissue and restoration of function through implantation of cells/tissue grown outside the body or stimulating cells to grow into an implanted matrix. It is an alterna-tive to conventional reconstruction methods. The three main components of tissue engineering are scaffolds, cells and signalling molecules. Bone mor-phogenetic proteins (BMPs) are multifunction proteins with a wide range of biological activities involving a variety of cell types. BMPs comprise the os-teoinductive component of several tissue engineering products. In late-stage development they are used as replacements for autogenous bone graft. Stem cells are unspecialized cells which are characterized by two properties: their high self-renewal activity and their multilineage differentiation potential. The xenograft blocks stabilized by the titanium mesh act as a scaffold for these tissue engineering materials that promotes the integration of the graft and the new bone formation.Conclusions: In this case the histomorphometric analysis revealed new bone formation around particles of xenograft material. This kind of approach made it possible to restore the aesthetics and the functions for the patient with a limited morbidity and treatment time.

126 i Subepithelial Connective Tissue Graft as a Biological Barrier Membrane in The Treatment Of peri-implant Crestal Bonedefi ciency resulting From Spontaneous Early implant Exposure

avital kozlovsky (israel), Shimshon Slutzkey, Zvi Artzi

Objectives: Premature exposure of submerged implants predispose to peri-implant bone loss which when encountered has to be approached using inter-ceptive treatment aimed to restore the bone. Therefore, therapeutic modality based on the principle of guided bone regeneration (GBR) should be applied. The use of resorbable or non- resorbable membrane is questionable due to the risk of exposure and early resorption of the former and contamination of the latter resulting in impaired bone regeneration. Reclosing the implants to protect the membrane is complicated due to the presented perforation of the mucosa covering the implants and is a disadvantage due to the need for a sec-ond surgical intervention. An innovative technique is suggested to overcome

the complexity of peri-implant guided bone regeneration of bone loss owing to spontaneous implant exposure. During the uncovered phase, a subepithelial connective tissue graft was applied as a biological barrier and for soft tissue closure.Methods: At 4 months post implant placement using the traditional 2-stage approach, a spontaneous exposure of the implant cover screw was observed. Surgery included a mid crestal incision and full thickness fl ap elevation and debridement. Crestal bone resorption exposing 3 mm of 2 implants in the cer-vical surface was detected. The exposed implant surfaces were cleaned and irrigated. Free subepithelial connective tissue graft (SCTG) was harvested from the inner side of the palatal fl ap. The SCTG was perforated in 2 locations and threaded through the neck of the implants with the periosteal side of the connective tissue facing the bone/implants. Healing abutments were placed securing the SCTG in place. Bovine bone mineral, as the fi ller material, was applied beneath the membrane on the exposed implant surface. The SCTG was inserted under the palatal and the perforated vestibular mucosa. Flaps were sutured close to the healing abutments leaving the SCTG exposed in the area between the abutments.results: The healing period was uneventful. Gradual epithelisation of the ex-posed graft surface from the surrounding tissue was achieved and at 2 weeks nearly all exposed portions of the SCTG were re-epithelialised. At 4 weeks post operation, a normal appearance was restored without evidence of in-fl ammation. The area of the facial keratinized tissue surrounding the implant increased signifi cantly presenting a thick type B masticatory mucosa morpho-type. The donor site in the area of the palatal fl ap presented no signs of mor-bidity due to the precise excision of the SCTG, without fl ap perforation, which could result in secondary wound healing. At the end of 3-month follow-up, the area was asymptomatic, and the implant sites showed no signs of infection or bleeding when probed. The radiographic examination revealed bone gain in the area of previously exposed implant threads. The implants were restored with provisional crowns designed to enhance soft tissue contouring and maturing.Conclusions: Soft and hard tissue management following spontaneous expo-sure of implant cover screws, using SCTG, can lead to satisfactory peri-im-plant healing and enhancement of peri-implant bone level. The wound closure over partially exposed SCTG prevents the displacement of the mucogingival junction and increases the width and thickness of the peri-implant keratin-ized mucosa.

127 i resorbable Collagen Membrane Vs. No Membranein The Sinus lift procedure. a Split Mouth Case report.

Basilio Matamoros (Spain), German Solis, Marc Quevedo, Antoni Castellón, Pablo Altuna

Objectives: To compare the clinical and radiographic changes in a bilateral si-nus lift procedure using a resorbable membrane on one side and no membrane on the other side.Methods: A 45-year-old male patient came to our dental school clinic seeking a fi xed rehabilitation in the upper jaw. A fi xed implant-supported denture was planned. Both right and left maxillary sinus were pneumatized and a bilateral sinus lift was needed to place implants in the posterior regions. Right sinus was grafted with a bovine xenograft (Bio-Oss®) and covered with a resorbable collagen membrane (Bio-Gide®). The same graft was used to fi ll the left si-nus but no membrane was used to cover the lateral window due to operating complications. After the healing and graft consolidation, eight conical shaped internal hex Nanotite® implants were placed in the maxilla. After the osseoin-tegration they were rehabilitated with a metal-ceramic fi xed denture.results: After 7 months of sinus graft healing, a new CT scan was performed to measure the new height of both posterior maxillary regions. Different bone density was observed between both sinuses. On the right side the radiographic aspect of the graft was dense and well delimited. In the left sinus the graft was dispersed and invaded by less dense tissue.Conclusions: Using a resorbable collagen membrane in the lateral window af-ter the sinus lift improved the graft preservation, isolation and maintenance of the dimensions. Combining a particulated xenograft and resorbable collagen membrane for the sinus lift with the lateral approach is a predictable and well documented technique. Absence of a barrier between the graft and the peri-ostium may produce a migration of the graft particles and an invasion of the connective tissue infi ltrating the graft material.

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128 i The use Of a New Collagen Matrix (Mucograft®)in Soft Tissue improvement around implants

Georg Gassmann (Germany), Adrian Lucaciu, Philip Keeve

Objectives: Up to now free gingival (fGTG) or connective tissue grafts (fCTG) have successfully been used in achieving attached soft tissue around dental implants. Recently a new collagen matrix (Geistlich Mucograft®) has been suggested as a substitute for the autogenous transplants. It is the aim of this presentation to clinically show stages of healing up to twelve months after in-sertion in three cases.Methods: Materials and Methods: In three female patients (mean age 59.4) the collagen matrix was used to enhance peri-implant attached mucosa around six implants (2 in the upper posterior / 4 in the lower posterior jaw). Patients gave informed consent. The matrix was sutured to the neighbouring soft tissue and the periosteum after peri-implant buccal mucosa split-flap preparation. Heal-ing was documented by taking clinical photographs after one, three, eight and fourteen days and after three, six and up to twelve months. According to the McGuire/Scheyer study (2010) Doxycycline 100, Ibuprofen 600 and CHX mouth-wash 0.12% (Paroex®) were administered postoperatively.results: Results: Healing was uneventful in all cases. No pain was reported by two of the three patients so that they refused to take the pain control medi-cation. One patient needed pain control. After 14 days sutures were removed and complete matrix integration was seen in all cases. A range of 3-9 mm enhanced peri-implant attached mucosa without keratinisation was attained in the peri-implant cases within the observation period of up to twelve months.Conclusions: Conclusion: The porcine collagen matrix may be used as an au-togenous graft substitute in establishing attached peri-implant mucosa. Ac-cording to conflicting protocols concerning postoperative medication the need for postoperatively administered antibiotics seems questionable.

129 i use Of Cortical lamina For Simultaneous Closure Of Oronasal Fistula, reconstruction Of alveolar defects. a Case report.

atef ismail (Egypt), Khaled Barakat

Objectives: Oronasal defects represent a challenging problem for reconstruc-tion as there is a need for cortical cover, good adaptability and an easy fixing technique. Although the autogenous bone is the gold standard for augmen-tation, it lacks adaptability and there is donor side morbidity and difficulty of fixation and stability.Contouring and reshaping of the ridge with cortical contoured bone is considered a real challenge because of the absence of semi-flexible bone. Use of cortical lamina can provide semi-flexible degrees customized to the exact defect shape.Methods: A 35 year old male was suffering from nasal fluid discharge during drinking following a history of surgical removal of the upper left central incisor. Clinical examination showed loss of contour of alveolar buccal bone with slight depression at the vestibular site with slight spearing fistula. CBCT revealed loss of apical bone forming a fistula connected to the nasal cavity. Defect analy-sis revealed a fistula measuring 3 mm x 5 mm and buccal bone defect measur-ing 7 mm wide x 12 mm long. The flap was totally elevated; granulation tissue in the bed was excised.The fistula was curetted to a healthy bone margin. The nasal floor was elevated and sutured in place. Lamina was dipped in saline for 7 minutes then a piece was cut such as to close the fistula, cortices up towards the nose. The defect was filled with collagenized corticocancellous bone chips. The lamina was fixed in place using 3.0 vicryl sutures to surround periosteumresults: Lamina was tolerated to a convex shape restoring the contour accord-ing to the pre CBTC. The flap was scored on its undersurface to allow stretch and complete coverage of lamina. No major complication developed postop-eratively. Minor complications like oedema and lip swelling developed post-operatively increasing after 72 hours and then regressing totally after 7 days. Slight dehiscence appeared at the crestal palatal interface which was treated with careful cleaning and irrigation and was completely resorbed after 10 days. No nasal discharge was reported by the patient whereas buccal contour was totally appreciated by the patient. CBCT after 6 months reveals closure of the defect and valuable bone formation.Conclusions: Versatility and adaptability of cortical lamina and an easy fixa-tion method provide a good solution in such a case without secondary surgery

for bone augmentation with high morbidity of the donor side. This case report demonstrates the possibility of using cortical lamina in small sized alveolar bone defects.

130 i Horizontal and Vertical ridge augmentation in aesthetic zone: a Case report

aliye akcali (Turkey), Muhittin Toman, Nejat Nizam

Objectives: The loss of vital soft and hard tissues after tooth removal can re-sult in alveolar ridge defects which lead to aesthetic and functional problems especially in the anterior maxilla. In such defects, soft and hard tissue grafts are often the treatment of choice. In this case report we aimed to demonstrate horizontal and vertical ridge augmentation using bone graft material, titanium membrane, and subepithelial connective tissue graft.Methods: A 66 year old male patient presenting Seibert class III ridge defect in the right maxillary central and lateral incisor area and Seibert class I ridge de-fect in the left lateral incisor area was referred to the clinic. The Seibert class III defect was reconstructed using bone graft material and titanium membrane and the Seibert class I defect was treated only with connective tissue graft in consecutive appointments. At the right site, the papilla preservation flap was reflected, the defect was filled with cancellous particulate allograft, covered with titanium membrane and flap was closed primarily. At the left site, a pouch was formed in the vestibular area and filled only with connective tissue graft. The titanium membrane was removed at 6th month. Before 6 and 12 months after the augmentation procedures, clinical periodontal parameters were re-corded, the impressions were taken and casts were optically scanned in order to obtain the digital images and make the soft tissue analyses.results: During the healing period, neither soft tissue dehiscence nor mem-brane exposure were noted. Healing was uneventful at both augmented sites. No differences were found in clinical periodontal parameters during the follow up period of the case. The alveolar ridge defect was decreased both in verti-cal and horizontal dimensions. Soft tissue width was increased at 1st and 2nd

months compared to the baseline.Conclusions: Soft and hard tissue grafts for ridge augmentation in anterior maxillary area could be effective treatment choices in development of function and aesthetics.

131 i periodontal Bone regeneration With Nd: yaG laser and laNap protocol

raymond yukna (uSa)

Objectives: The purpose of this presentation is to illustrate the radiographic and histological bone regeneration seen following the Laser-Assisted New At-tachment Procedure (LANAP) surgery using the Nd:YAG laser in humans.Methods: Pre-treatment and post-treatment dental radiographs of patients treated for chronic periodontitis or peri-implantitis with the Laser-Assisted New Attachment Procedure (LANAP) surgery using the Nd:YAG laser will be presented. Cone beam images of some of the patients will be shown. Human histology sections will also be presented.results: Consistent increase in bone support for both natural teeth (infrabony defects and furcations) and dental implants has been seen with the LANAP surgical protocol. The cases shown will illustrate various examples of peri-odontal and peri-implant bone regeneration. Human histology reinforces the radiographic findings.Conclusions: The Laser-Assisted New Attachment Procedure (LANAP) surgery protocol using the Nd:YAG laser demonstrates appreciable potential for peri-odontal and peri-implant bone regeneration.

132 i rotated pedicle palatal Connective Tissue Flap For Soft Tissue Management after Electrocautery injury

ilker keskiner (Turkey), Hanifi Ipek

Objectives: The incorrect usage of electrocautery in dentistry may cause in-juries in gingiva and bone. A surgical procedure, based on a rotated pedicle

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palatal connective tissue fl ap containing periosteum to achieve primary soft tissue closure and to preserve the alveolar bone in the interproximal area after necrotic bone removal, is presented.Methods: A 24-year-old male presented with an electrocautery injury on ac-count of the excision of gingival tissue extending into carious lesion between the maxillary right fi rst molar and second premolar. The lost interdental pa-pilla area showed ulcerations, exposed bone and gingival recession with se-vere pain. A mucoperiosteal fl ap was elevated and necrotic bone was removed. The pedicle palatal connective tissue fl ap was planned to achieve soft tissue closure. It is initiated by making a horizontal incision 2 mm from the gingival margin of the teeth on the mesial side of the defect. After a vertical incision in the canine area, a mucoperiosteal fl ap was elevated. The pedicle connective tissue containing periosteum was harvested, elevated, and rotated to cover the bone in the interproximal area. The superfi cial layer of palatal fl ap was then repositioned and sutured.results: The healing was uneventful with no connective tissue necrosis. One year follow-up showed approximately 1 mm creeping attachment on the root surface and increase in papilla height in comparison with appearance in the third week.Conclusions: The described surgical approach is advantageous since blood supply is provided from the pedicle, which differs from free connective tissue and gingival grafts. The technique, using a rotated pedicle palatal connective tissue fl ap, seems to be a viable treatment approach to achieve primary soft tissue closure in the maxillary interproximal areas.

133 i using xenografts in 3d Bone reconstruction Surgery.a Case report.

Octavi Ortiz puigpelat (Spain), Marin Lissette Meriño

Objectives: Autogenous bone grafts have been for many years the gold stan-dard in bone regeneration surgery. The use of biomaterials as an alternative it is still controversial especially in critical defects such as vertical-horizontal alveolar defects. In such situations Khoury developed 3D bone reconstruction some years ago , where the autogenous cortical blocks serve as buccal and palatal walls and the space between them is fi lled with cortical and/or cancel-lous autogenous bone particles. This technique has been shown to be a predict-able technique for vertical bone augmentation with a low rate of complications. However, the use of this technique sometimes requires a large amount of bone particles to fi ll such a space. The aim of this paper is to show, through a clinical case, the use and the histological evaluation of a xenograft as an alternative for fi lling the space between the blocks during 3D bone reconstruction surgery.Methods: A 35 year old healthy woman was treated in our private offi ce in order to reconstruct a vertical defect of 6 mm in her upper posterior maxillary area. A 3D bone reconstruction technique was performed using a mandibular block harvested from the mandibular ramus area. The space left was fi lled with xe-nograft cancellous bone particles (0.25–1 mm). Once the particles were well packed, a collagen resorbable membrane of 0.3 mm in thickness was placed over the particles to prevent soft tissue migration. A 5 month healing period was left to accomplish bone regeneration. Then, three bone biopsies were taken from the xenograft area using a 2 mm internal diameter trephine. This trephine served as a drill to prepare the implant site. 3.7 by 10 mm implants were in-serted in each biopsy. Then, the biopsies were sent for histological evaluation.results: High number of vital osteocytes was found in the biopsies as well as large amounts of mineralized bone surrounding the xenograft particles. Simi-lar observations were in accordance with those found by Khoury in biopsies obtained in areas where autogenous bone particles were used.Conclusions: Within the limits of this case report we can conclude that the use of xenograft particles can be a good option when the space between cortical blocks is large and large amounts of autogenous particles cannot be obtained during the 3D bone reconstruction. More controlled and prospective studies are needed to determine the effectiveness of such material compared to the autogenous bone particles.

134 i Block allograft technique vs. standard guidedbone regeneration: clinical and radiographical results of asplit mouth guided surgery case report

leonardo amorfi ni (italy), Stefano Storelli, Eugenio Romeo

Objectives: The purpose of this case report is to evaluate the clinical and ra-diographical comes out of an emerging surgical technique by comparing in the same patient and for the same type of bone defect two guided bone regenera-tion techniques.Methods: A 52-years-old patient presented with bilateral edentulous areas in the mandible. Cone beam tomography (CBT), showed a major resorption and the necessity of a bone augmentation. Using CBT-based software it has been possible to obtain a surgical guide and a precise 3-dimensional model of the patient’s jaw using a sterilizable material. Split mouth rehabilitation was per-formed. Four ITI Bone Level Straumann implants were placed using a teeth-supported guide in position 3.4, 4.4 (postextractive), 3.6 and 4.6. On the right atrophic crest, bone chips collected with a scraper mixed with Bio-Oss and resorbable membrane have been used. On the left side a corticocancellous allograft block, shaped before surgery on the stereolithographic model of the patient’s jaw, was secured with osteosintesis screws and protected with a re-sorbable membrane. Following a 6-month healing period, a second CBT evalu-ation was carried out. After complete tissues recovery, two CAD-CAM zirconia bridges were screwed as defi nite prosthesis.results: The preoperative and postoperative scans were then aligned pair wise using an iterative closest point algorithm, which allowed for compari-son between planned and actual implant positions. All measurements were performed using Mimics software (Materialise). Four deviation parameters between each virtual and corresponding actual implant were measured: the mean coronal discrepancy was 0.34 ± 0.29 mm; the mean apical difference was 0.28 ± 0.30 mm; the mean angular deviation was 2.29 ± 1.43 degrees; the mean vertical discrepancy was 0.15 ± 0.32mm. The major discrepancy has been given by post-extractive implants. With the same software it has been possible to quantify the regenerated bone status. A bone resorption of 15% from the ini-tial volume inserted has been registered for the allograft; 5% portion for the conventional technique. Both the bone regeneration was successfully stable a 1 year follow-up.Conclusions: The block allograft procedure has shortened surgical time and reduced post-operation morbidity. Further research is needed to determine whether the 3D block technique had survival rates equal to the others graft materials in term of long follow-up time. As with any regenerative technique, however, treatment of soft tissue will play a crucial role, and the surgeon must treat it skilfully to achieve success. The implants position has a good corre-spondence with the presurgical planning.

135 i intraoral soft tissue regeneration with a tissueengineered metabolic active fi broblast layer

Hans-Joachim Gath (Germany), Martin Heel

Objectives: Tissue engineering offers the ability to new ways of wound treat-ment in the oral cavity. Soft tissue defects are often covered with transplants witch leave donor site defects. After covering a defect with a transplant the structure of the tissue is different which often results in functional defects. The method of tissue engineering offers now the ability to grow a dermal like tis-sue consisting of living fi broblast. In closed bio reactors juvenile human living fi broblast are seeded on a three dimensional scaffold of resorbable vicryl. In these settings the cells create a dermal like living tissue which can be frozen at -80 degrees Celsius. This tissue can be shipped world wide in a just in time set-ting and than after thawed at 37 degrees transplanted. Then after a short time the fi broblast get metabolic active. This tissue can be used to cover intra and extraoral defects. The living juvenile fi broblast cells secret a panel of growth factors like VEGF (vascular endothelial growth factor), PDGF (platelet derived growth factor), IGF (insulin like growth factor) and KGF (keratinizing growth factor) all of them substantial in wound healing. As these growth factors are secreted from living cells the concentration is physiological and acting for a prolonged time.Methods: We used the above described living dermal like tissue to cover in-traoral defects resulting from surgical resection of SSC (squamous cell car-cinomas), preprothetic surgery and periodontal surgery. A SSY of the anterior fl oor of the mouth was resected and would have been reconstructed with a radialis fl ap. Because of the multiple risk factors of the patient a short op-erating time was required. Instead of the radialis fl ap we covered the defects with the dermal like tissue which was fi xed with several sutures to allow the intense contact of the fi broblast with the wound bed. After 10 days the covering

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dressing was removed and the defect evaluated. The same protocol was used for intraoral defects resulting from SSC on the buccal side, for preprosthetic surgery (vestibuloplasty) and for periodontal surgery.results: In all cases after 10 days the covering dressing was removed. In all cases we could observe a mucosal lining of the defects without sings of scar in-formation. This was proofed with a biopsy and subsequent histological evaluation which showed a normal mucosal structure. Even the resected frenulum result-ing from a defect from a SSC in the anterior floor of the mouth was formed new.Conclusions: The use of dermal like living tissue to cover intraoral defects has several benefits. With this protocol we can avoid donor site defects which result in a shorter operating time. More important to use seems to be the mechanism in which these defects heal. Instead of tissue transplanted to the defect we could see a regeneration of the tissue. This can be explained with continues secretion of a panal of growth factors in physiological concentration. The intra-oral wet environment seems to be ideal for the metabolic activity of the living cells. The dermal like tissue is integrated during the 10 days of required heal-ing time and during this process the three-dimensional scaffold resorbs. The disadvantage of the method is that it is not possible to regenerate devincencies in volume. The effect on regenerating bone under these protocol should be evaluated.

CliNiCal rESEarCH, CliNiCal STudiES

201 i Histological analysis Of implants Subjected To immediate Functional loading in Single Tooth replacement

Mauro donati (Sweden), Daniele Botticelli, Vincenzo LaScala, Cristiano Tomasi, Tord Berglundh

Objectives: To evaluate the effect on bone healing of immediate load to im-plants using human histology.Methods: Thirteen patients received two single implants each; 1 immediately loaded (test) and 1 control. Biopsies containing the implant and a narrow zone (0.7–0.8 mm) of the surrounding bone were collected using a trephine drill af-ter 1 month in 9 patients and after 3 months in 4 patients. The biopsies were processed for ground sectioning and prepared for histological analysis includ-ing the degree of bone-to-implant contact (BIC %) and the percentage area of the peri-implant tissues occupied by lamellar bone and woven bone. The local human review board approved the study protocol and prior to enrolment all subjects received information regarding the purpose of the study and signed an informed consent form.results: Three implants subjected to immediate load failed to integrate, 2 in the 1-month and 1 in the 3-month healing group. Analysis using a multilevel, multivariate statistical model demonstrated that while no significant differ-ences in BIC % were found between test and control implants, the percent-age area of woven bone was significantly larger around the test implants than the controls at 1 and 3 months of healing. The analysis also revealed a high correlation between compartments (micro and macro-threaded portion) of the implant for both BIC % and bone density and significant variability between subjects regarding BIC %.Conclusions: It is suggested that immediate loading of implants does not in-fluence the osseo-integration process, while the density of newly formed peri-implant bone at such sites appears to be increased in relation to unloaded control implants.

202 i applications Of Cone-Beam Computed Tomography in dental practice: a literature review

Mohammed alshehri (Saudi arabia), Hadi Alamri, Mazen Alshalhoob

Objectives: This article presents a review of the clinical applications of cone-beam computed tomography (CBCT) in different dental disciplines.

Methods: A literature search was conducted via PubMed for studies on dental applications of CBCT published between 1998 and 2010. The search revealed a total of 540 results, of which 130 articles were clinically relevant and were analyzed in detail.results: The results of this systematic review show the different applications of CBCT imaging in dental practice. Thirty-six articles (27.7%) related to applica-tions in oral and maxillofacial surgery (OMFS), 33 articles (25.4%) to endodontic clinical applications, 22 articles (16.9%) to clinical applications in implant den-tistry, 15 articles (11.5%) to orthodontic clinical applications, 10 articles (7.7%) to clinical applications in general dentistry, 8 articles (6.2%) to the temporo-mandibular joint (TMJ), 5 articles (3.8%) to applications in periodontology and 1 article (0.8%) to CBCT applications in forensic dentistry. 36 articles (27.7%) related to applications in oral and maxillofacial surgery (OMFS), 33 articles (25.4%) to endodontic clinical applications, 22 articles (16.9%) to clinical appli-cations in implant dentistry, 15 articles (11.5%) to orthodontic clinical applica-tions, 10 articles (7.7%) to clinical applications in general dentistry, 8 articles (6.2%) to the temporomandibular joint (TMJ), 5 articles (3.8%) to applications in periodontology and 1 article (0.8%) to CBCT applications in forensic dentistry.Conclusions: The majority of CBCT applications in the practice of dentistry are found in the specialties of OMFS, endodontics, implant dentistry and orthodon-tics. Future research should focus on obtaining accurate data regarding the radiation doses of CBCT systems and the clinical use of CBCT applications in forensic dentistry and prosthodontics.

203 i Evaluation Of The Mucograft® Matrix in CoverageOf periodontium recessions – pilot Study

Marzena dominiak (poland), Dorota Mierzwa

Objectives: The aim of successful periodontal recession coverage is to obtain the maximum percentage of average and complete root coverage (ARC and CRC respectively) of the recession and to achieve superior aesthetics. The aim of this study was to evaluate the clinical effectiveness of the Mucograft® matrix (Geistlich Pharma AG Switzerland) in coverage of periodontal recessions after the 6 month follow-up period.Methods: Treatment was performed at the Department of Oral Surgery, Wro-claw Medical University, Poland on 7 patients, aged from 18 to 45 years. In total, 9 teeth, including 8 in the anterior part of the maxilla and the mandible, underwent treatment. All subjects had single or double recession (Miller class I or II). Procedures were performed using coronally repositioned split-thickness trapezoidal flap in conjunction with the application of the Muco-graft® matrix. Recession depth (RD) and width (RW), height of keratinized tis-sue (HKT), distance from cemento-enamel junction to mucogingival junction (CEJ-MGJ), aesthetic index (acc. to Bouchard classification- AE) and average (ARC) and complete (CRC) root coverage were assessed. Post-surgical com-plications, pocket depth (PD) and plaque index (according to Löe & Silness- PI1) were also evaluated. Measurements were performed using a calibrated periodontal probe (1mm resolution) at the baseline and at 1, 3 and 6 months after surgery.results: The ARC and CRC 6 months after surgery were 84.27% and 55.55% respectively. A significant decrease in RD (about 2,35mm), RW, and 60.65% of HKT (about 1,44mm) increase were noted. There was also a significant de-crease in PD and PI1. The CEJ-MGJ distance decreased by only about 1 mm. Between 3 and 6 months post-surgery, creeping attachment of an average value of 0.27 mm was observed. Estimation of the AE revealed improved aes-thetics in 5 cases and unchanged aesthetics in 2 cases compared to the pre-treatment condition. In no cases were gingival hypertrophy, scars or distortions noted. The colour and consistency of the gingiva were identical with the neigh-bouring tissue. The mucogingival line was repositioned to a location similar to that of the neighbouring teeth. No post-surgery pain was observed in any of the cases (VAS1).Conclusions: The use of the Geistlich Mucograft® matrix in coverage of the periodontal recession is effective, highly predictable and results in a significant increase in the keratinized gingival width. However, the guidelines for working with the matrix must be observed and obeyed.

204 i role Of COlia1, CalCr and pTHr1 Gene polymorphisms in The pathogenesis Of aggressive periodontitis.

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Victoria atrushkevich (russia), Alexander Polyakov, Olga Schagina, Anastasiya Zinovyeva, Maria Zyablitskaya

Objectives: The occurrence of aggressive periodontitis (AgP) has increased signifi cantly. The main pathogenetic factor in AgP is rapid resorption of the alveolar bone. At present the effect of the genes’ parathyroid hormone re-ceptor type 1 (PTHR1), calcitonin receptor (CALCR) and collagen type I alpha 1(COLIA1) on the processes of bone tissue renewal in osteoporosis of the axial skeleton has been proved. Though jawbones are an essential part of the hu-man skeleton, we have suggested that the above-mentioned genes could have an effect on the alveolar process remodeling resulting from disturbance of the stereospecifi c binding of a receptor to its ligand (i.e. PTH and/or calcitonin (CT) as well as from disorders of bone tissue structure resulting from changes in the amount of synthesized protein COLIA1. Consequently, they may infl uence AgP etiopathogenesis.Methods: To perform the study, 164 adults aged 22-47 were selected and separated into 3 groups: patients with AgP=48, healthy (H)=64 and random population sampling (RPS)=52. Dental examination was carried out according to hygiene index (HI), papilla bleeding index (PBI), gingival index (GI), clinical attachment loss (CAL) and teeth mobility (TM). The level of PTH, CT, whole calcium (Cawh) and ionized calcium (Ca2+ ) in patients with AgP and in the control group was analysed. Genotyping was performed using PCR (CALCR and COLIA1 – MLPA, PTHR1 – AFLP) for all groups. A search was carried out for associations between AgP and VNTR polymorphism PTHR1 (5/6/9 tetranucleo-tide repeats (rs 10533296) and single-nucleotide polymorphisms CALCRC›T (rs1801197), COLIA1G›T (rs1800012). All the trials were performed with the written informed consent of patients and the approval of the Ethics Committee of Moscow State University of Medicine and Dentistry.results: The study of periodontal tissues in groups AgP and H resulted in the following fi ndings: HI-29.41 vs. 21.72,p=0.002; PBI-1.88 vs.0.81, p=0.001; GI-1.67 vs. 0.53, p=0.01; CAL-5.42 vs. 0.49, p=0.032; TM-1.57 vs. 0.16, p=0.001. The level of PTH was 56.55 vs. 45.63, p=0.008; CT-2.5 vs. 5.10, p=0.001, Cawh -2.39 vs. 2.03, p=0.006; Ca2+ -1.41 vs. 1.08, p=0.008.Genetic analysis revealed signifi cant difference between groups in the occur-rence of alleles (A) and genotypes (G) in the PTHR1 gene between groups: AgP/H/CSP, where the occurrence for A-5 was 78%, 85%, 65%; for A-6 - 22%, 13%, 34%; for A-9 - 0%, 2%.1%, p=0.002, the occurrence for G-5/5 was 57%,70%,3.8%, for G-5/6 - 39%, 23%,52%, for G-6/6 - 4%, 2%, 8%, for G-6/9 - 0%, 5%, 2%, p=0.003; H/CSP differences in occurrence of A/G p=0.007/0.003 respectively.Differences in the CALCR gene between groups AgP/H/CSP: the occurrence for A-C was 29%, 14%, 23%; for T - 71%,86%,77%, p=0.001, the occurrence for G-C/C - 13%, 3%, 2%; G-C/T - 32%, 45%, 22%; G-T/T - 55%, 72%, 56%, p=0.003; the occurrence of AgP/H for A/G p=0.001/0.002 respectively; AgP/CPS for A/G p=0.02/0.001 respectively.Differences in the COLIA1 gene between groups: AgP/H/CSP for A-G-53%, 72%, 77%; for A-T-47%,28%,23%, p=0.001, the occurrence for G-G/G -32%,48%, 58%, p=005; AgP/H occurrence for A/G p=0.004/0.005 respectively; AgP/CPS occurrence for A/G p= 0.004/0.003 respectively; H/CSP occurrence for A/G p=0.38/0.01 respectively.Conclusions: On the basis of the fi ndings, obtained during relative risk (RR) estimation, the risk of AgP development increases if there are genotypes C/C and C/T of the CALCR gene, genotype T/T of the COLIA1 gene and genotypes 5/6, 6/6 of the PTHR1 gene.

205 i disturbance Of Systemic regulation Of Boneremodelling in patients With aggressive periodontitis

Victoria atrushkevich (russia), Ashot Mkrtumyan, Anastasia Zinovyeva, Maria Zyablitskaya

Objectives: Evaluation of the role of hormonal regulation in the functional status of periodontal tissues has been receiving attention from researchers for a long time. Aggressive periodontitis (AP) resulting in early tooth loss in young and middle-aged persons is of particular interest. Detailed study of skeleton mineralisation peculiarities as well as determination of major in-dices of bone formation and bone resorption in patients with AP will make it possible to reveal any pathogenetic association between disturbances of bone

tissue metabolism and changes taking place in jaws during the development of this periodontal pathology. It will also make it possible to increase the ef-fi cacy of the treatment of AP, since it includes preparations for the correc-tion of disturbances of mineral turnover in the complex therapy of generalized periodontitis.Methods: 173 patients of both sexes (91 females and 82 males) with a diagnosis of severe AP were included in the study. The main criterion for including was early onset of disease (18–20 years old). The condition of teeth and periodontal tissues was estimated by clinical indices. Laboratory assessment of the state of mineral turnover included: whole calcium, ionized calcium, parathormone, calcitonin, osteocalcin and resorption marker 946;-CrossLaps. Statistical as-sessment of the data was carried out using descriptive statistical methods (Students criterion for two groups of comparison with normal sample). The critical value of the signifi cant point is taken as p8804; 05. Linear relationship analysis of quantitative traits was carried out with calculation of Pearson coef-fi cient using the Statistica program, version 6.1 (StatSoft, USA).results: In males with AP, periodontal pockets were observed to be deeper and the level of attachment loss was higher than in females with AP. The se-verity of periodontal tissue involvement correlated with early onset of the dis-ease. Statistically signifi cant differences in bone turnover indices in patients with AP compared with the control group were detected: decrease in calcitonin (2.4 ± 0.26 ng/l, p‹0.01) and osteocalcin levels (5.30 ± 0.67 ng/ml, p‹0.05), which indicates inhibition of osteoblastic function and hence disturbances of osteo-genesis. A statistically signifi cant increase in the ionized calcium level in blood in women with AP (1.13 ± 0.02, p‹0.05) versus control indices was observed in the case of increased parathormone levels (PTH 57.9 ± 3.36 ph/ml). A similar change in the level of calcium homeostasis associated with calcium-regulating hormones (calcitonin 3.0 ± 0.37 ng/l p‹0.05, parathormone 57.5 ± 6.52 ph/ml, osteocalcin 5.8 ± 0.93 ng/ml p‹0.05) was observed in males with AP. Correlation analysis of dependence of severe AP clinical presentation on mineral turnover in patients of both sexes with AP revealed an inverse correlation (r=0.8) be-tween the periodontal bleeding index (PBI) and the level of calcitonin. A moder-ate direct correlation was revealed between the depth of periodontal pocket and the level of parathormone (r=0.4).Conclusions: In summary, our study has shown that disturbance of calcium homeostasis characterized by an increase in ionized calcium associated with an imbalance of indices of calcium-regulating hormones (increase in parathor-mone and decrease in calcitonin) is observed in patients with early onset of AP. A statistically signifi cant decrease in the osteocalcin level in blood serum is also noted, which confi rms inhibition of osteoblasic function and the shift of the remodelling process towards osteoclastic resorption.

206 i impact Of The Method Of Surface debridementand decontamination On The Clinical Outcome FollowingCombined Surgical Therapy Of peri-implantitis. a randomized Controlled Clinical Study.

Frank Schwarz (Germany), Narja Sahm, Gerhard Iglhaut, Jürgen Becker

Objectives: The study aimed to investigate the impact of two surface debride-ment/decontamination (DD) methods on the clinical outcomes of combined sur-gical treatment of peri-implantitis.Methods: 32 patients suffering from advanced peri-implantitis (n=38 combined supra and intrabony defects) were treated with fl ap surgery, granulation tis-sue removal and implantoplasty at bucally and supracrestally exposed implant parts. The intrabony aspects were randomly allocated to surface DD using either i) an Er:YAG laser (ERL) device, or ii) plastic curets + cotton pellets + sterile saline (CPS). In both groups, the intrabony component was augmented with a natural bone mineral and covered with a collagen membrane. Clinical and radiographic parameters were recorded at baseline and after 6 months of non-submerged healing.results: Two patients were lost during follow-up. At 6 months, ERL-treated sites failed to show higher reductions in mean BOP (ERL: 47.8±35.5% vs. CPS: 55.0±31.1%) and CAL values (ERL: 1.5±1.4 mm vs. CPS: 2.2±1.4 mm) when compared with the CPS group. Both groups exhibited a comparable radio-graphic bone fi ll at the intrabony defect component.Conclusions: The study failed to demonstrate any signifi cant impact of the method of surface DD on the clinical outcome following combined surgical therapy of advanced peri-implantitis lesions.

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207 i autologous Bone Block Grafts From The retromolar region For localized ridge augmentation in The aesthetic zone

Milan Jurisic (Serbia), Ivan Kosanic, Miroslav Andric, Vladimir Kokovic, Bozidar Brkovic

Objectives: Adequate bone volume is an essential factor in the long-term suc-cess of implant therapy. Localized alveolar ridge deficiency is a common prob-lem related to implant placement and has a particular impact on the aesthetic of implant-supported fixed prostheses. Autologous bone block grafts are con-sidered to be the method of choice and the “gold standard” for localized ridge augmentation in the aesthetic zone. It has also been shown that the quality and quantity of augmented bone obtained are sufficient for predictable implant stability. The purpose of the present study was to examine the integration and volume maintenance of autogenous bone block grafts and the stability of im-plants inserted following augmentation.Methods: Eighteen adult patients, 11 male and 7 female, with 20 alveolar de-fects who required alveolar ridge augmentation prior to implant placement in the anterior maxilla were included in the study. All patients were aged between 19 and 47 years. All surgical procedures were performed under lo-cal anaesthesia. The approaching incision was of midcrestal type with verti-cal labial extensions including the papillae. Bone block grafts were harvested from the retromolar region of the mandible using trephine burrs. The width of the residual ridge was measured by bone caliper at two points 5 and 10 mm from CEJ of neighbouring teeth, prior to grafting and immediately after graft placement. The graft sites were re-opened after 4 months for the purpose of implant placement and fixation screw removal. The previously described mea-surements of the grafted ridge were repeated at the same reference points. Implant stability was recorded by RFA using an Ostell mentor device, at the time of implant placement and 3, 6 and 12 weeks afterwards.results: Twenty alveolar defects were grafted and 20 implants inserted in 18 patients. No complications or failure of bone graft were recorded during the observation time. Measurement of the horizontal dimension of the residual alveolar ridge (RAR) showed a mean value of 3.06 mm (0–6.0 mm) at 5 mm from CEJ and 5.84 mm (3.7–10.2 mm) at 10 mm. At the time of graft place-ment, the horizontal dimensions were 6.10 mm (4.3–9.0 mm) and 8.74 mm (6.0–12.0 mm), at 5 mm and 10 mm respectively. There was no significant difference in the horizontal dimension of RAR between the values at the time of bone grafting and the time of implant placement. Mean values for initial im-plant stability were 71.25 ± 5,77 ISQ. During the osseointegration period, the implant stability obtained (mean ± SD) for the third week was 70.00 ± 4.76 ISQ, for the fourth week 71.30 ± 4.27 ISQ, for the eighth week 72.60 ± 5.55 ISQ and for the twelfth week 75.00 ± 5.29 ISQ. The statistically significant difference was recorded between the value of the initial primary stability and stability at 12 weeks (p‹0.05).Conclusions: In the light of the significant implant stability and adequate vol-ume of alveolar bone obtained 4 months after the augmentation procedure, the use of autogenous bone grafts can be suggested as a safe and predictable method for successful bone augmentation in the aesthetic zone.

208 i augmentation Of The Maxillary Sinus Floor With deproteinized Bovine Bone Bearing a BMp-2-Functionalized Calcium-phosphate Coating: a pilot Clinical Study

yuelian liu (Netherlands), Sanja Umanjec-Korac, Daniel Wismeijer, Gang Wu, Balsam Hassan

Objectives: The purpose of this prospective clinical trial was to ascertain whether BMP-2 that had been co-precipitated with a layer of calcium phos-phate upon granules of the bone-defect-filling material Bio-Oss® (deprot-einized bovine bone) could be safely used to promote bone formation in the context of sinus-floor lifting. The height and volume of the grafted materials were monitored non-invasively by Cone Beam computer tomography (CBCT); the volume density of newly-formed bone was estimated by a histomorpho-metrical analysis of biopsies.Methods: Nineteen healthy patients (mean age: 58 years), destined to receive a total of 55 dental implants, underwent augmentation of the sinus floor using the lateral-window technique. Twenty-nine sinuses were treated according to one of three different protocols: (i) native Bio-Oss® (Geistlich, Wolhusen, Swit-

zerland); (ii) Bio-Oss® bearing a calcium-phosphate coating into which BMP-2 had been incorporated (130µg/g of Bio-Oss®); and (iii) a mixture of native Bio-Oss® and chips of autologous bone. The heights of the grafts and their volumes were estimated by CBCT on 0.3-mm-thick virtual axial sections, prior to and immediately after augmentation. Biopsies were taken after 6 weeks, 4 months and 6 months for histological analysis of the implantation site and for histomorphometric estimation of the volume density of newly-formed bone.results: Clinically, no differences were observed between the three treatment groups in terms of soft-tissue wound healing and complications. Preopera-tively, the mean height of the alveolar ridge was 2.7mm, which was raised to 14.1mm by the augmentation procedure. During the follow-up period, the vol-ume of the graft increased significantly and to a similar degree in each of the three treatment groups. At each of the probing times (6 weeks, 4 months and 6 months), the stiffness of the augmented bone bed was highest in the groups of patients that had been treated either with Bio-Oss® bearing a BMP-2-func-tionalized calcium-phosphate coating or with a mixture of native Bio-Oss® and autologous bone; it was lowest in the group of patients that had been treated with native Bio-Oss® alone. This evaluation was clinically determined by two independent observers. Preliminary histological findings revealed inflamma-tory reactivity at the 6-week juncture to be lowest in the groups of patients that had been treated either with Bio-Oss® bearing a BMP-2-functionalized coating or with a mixture of native Bio-Oss® and autologous bone; it was highest in the group of patients that had received native Bio-Oss® alone. At the same time point, the volume density of newly-formed bone was highest in the group of patients that had been treated with Bio-Oss® bearing a BMP-2-functionalized calcium-phosphate coating.Conclusions: The CBCT findings and the preliminary histological and histo-morphometric data afford strong indications that BMP-2 elicits no adverse re-activity at the site of implantation when it is borne by Bio-Oss® in the form of a functionalized calcium-phosphate coating; on the contrary: it acts truly in its capacity as an osteogenic agent.

209 i Comparison of autologous Full-Thickness Gingiva and Skin Substitutes for Wound Healing

abraham Vriens (Netherlands), T Waaijman, H.M van den Hoogenband, E.M.de Boer, R.J.Scheper, S.Gibbs

Objectives: Ideally tissue engineered products should maintain the character-istics of the original tissue. The aim of this study was to develop an autologous full- thickness gingiva substitute suitable for clinical applications and to com-pare it with our autologous full- thickness skin substitute that is routinely used for healing chronic wounds.Methods: Epithelial sheets and connective tissue fibroblasts are used to con-struct autologous skin and gingiva substitutes. For each 1.5 cm2 of autologous gingiva substitute to be constructed, a single 3mm biopsy was required. For gingiva this biopsy was obtained from the gingiva distopalatinal to the third molar or adjacent to tooth extraction sites. Epithelial sheets were placed with the most differentiated side upwards on the allodermis and cultured air ex-posed in keratinocyte medium. After approximately 7 days of culturing the pri-mary fibroblast culture and epithelial sheet apart, the allodermis containing the epithelial sheet was placed in contact with the fibroblasts in order to allow fibroblast migration into the reticular side of the dermis. The gingiva substitute was further cultured in DMEM/Hams (3:1). Keratinocyte growth factor (4ng/ml) and 1 ng/ml epidermal growth factor were added to the culture medium for the next 7 days. Penicillin / streptomycin was ommited 4 days before applica-tion to the wound. Gingiva substitutes were ready for application 3 weeks after removal of the gingiva biopsies from the patient.results: For gingiva substitute, three patients requiring multiple tooth extrac-tions were included. The gingiva substitute was applied and held into place by sutures at one extraction site whereas a second extraction site was allowed to heal by conventional second intention healing. Time to 100% healing was defined by full reepithelialization of the wound and no drainage from the site. In all three patients, no rejection of the gingiva substitute occurred. The gingival substitute was incorporated into the surrounding gingiva to such an extent that it could no longer be distinguished from surrounding gingiva after 2 weeks. No inflammation was observed and the gingiva substitute was well tolerated. The full thickness gingiva substitute maintained many of the histological charac-teristics of the tissue from which they were derived. However the number of

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living cell layers and proliferating cells in the gingiva substitute was clearly less in vitro than in vivo. In the gingiva substitute, fi broblasts populated the en-tire dermal matrix, although at a somewhat lower frequency to that observed in vivo(vimentin staining)Conclusions: The gingiva substitute could be applied to a wound in a single, one-step surgical procedure. In the wounds an accelerated and improved heal-ing was observed. Our previous fi ndings indicate that the presence of fi bro-blasts in the dermis in addition to an epithelium will stimulate angiogenesis, and therefore wound healing, more than a construct containing only a epithe-lium. Even though the number of patients involved in the application is very small (n=3) our results represent a large step forward in the area of clinical applications in oral tissue engineering.

210 i long-term results after lateral ridge augmentationusing Two different Techniques

pablo Hess (Germany), Bergen Pak, Georg-Hubertus Nentwig

Objectives: The aim of this retrospective clinical study, performed at the University of Frankfurt, was to investigate the long-term stability of the peri-implant bone and soft tissue after lateral ridge augmentation around Ankylos implants (Dentsply-Friadent, Germany). This study shows the differences be-tween simultaneous and delayed augmentation techniques. It compares the long-term stability of corticocancelleous bone blocks and pure bovine bone substitute (Geistlich, Switzerland). The results are based on data acquired from a standardized examination sheet, performed at annual checks.Methods: All the patients who received a lateral ridge augmentation between 2001 and 2008 were included. 182 implants were inserted and the clinical and radiographic examination was performed on the day of the fi nal prosthetic treatment and annually thereafter until January 2008. The stability of the peri-implant bone and the soft tissue was documented and investigated.results: 113 patients, 71 women and 42 men, with an average age of 47 years (18–73 years) were investigated. In total, 182 Implants were inserted, 107 in the maxilla and 75 in the mandible. The survival rate of the implants was 100%. The success rate for all implants, as defi ned by Albrektsson and Zarb1, was 93%. The average time of the implants in situ was 40.99 months (range 7.8–82.1 months), the average mean loading time was 31.42 months (range 2.9–71 months).At the fi nal recall, 109 (60%) of the implants showed no vertical and horizontal bone resorption, only 1 implant showed a maximum vertical resorption of 4.5 mm, and 1 implant showed a resorption of 5 mm. 157 (86.2%) of the implants showed no gingival recessions.Conclusions: The peri-implant bone and soft tissue showed constant long-term stability in both groups. Due to the high success rate of lateral ridge augmentations with the augmentation methods examined, in combination with the Ankylos-Implant system, we can describe both methods as predictable and safe. Each technique has individual indications, depending on anatomical con-ditions and the surgeon’s experience.

211 i periimplant Bone and Soft Tissue Stability after lateral ridge augmentation using Bovine Bone Substitute – retrospective Clinical Study

Bergen pak (Germany), Pablo Hess, Georg-Hubertus Nentwig

Objectives: The aim of this retrospective clinical study was to evaluate the long term stability of the peri-implant bone and soft tissue around dental implants. To increase the signifi cance of the results, the study was performed with only one implant system and one bone substitute.Methods: The results are based on data acquired from a standardised ex-amination sheet, performed at annual checks. All the patients who received a lateral ridge augmentation with bovine bone substitute (BioOss, Geistlich, Switzerland) and simultaneous implantation (Ankylos, Dentsply-Friadent, Germany) between 2001 and 2008 were examined. The follow up period was seven years (2001 to 2008). 76 patients, 54 women and 22 men with an aver-age age of 51 years (range 18 to 73) were included in this study. 127 implants were inserted. The clinical and radiographic examination was performed on the day of the fi nal prosthetic treatment and annually thereafter until Janu-ary 2008.

results: The average time of the implants in situ was 39.74 months (5.13–82.13) and the average mean loading time was 29.81 months (2.89–70.58). Af-ter the last check, 58 % showed no horizontal and vertical bone resorption. 41 % showed bone loss of up to three millimetres and only one implant showed severe resorption of 75 % of the implant length. Gingival stability was propor-tional to bone stability with a rate of 85 %. None of the controlled implants was lost. Therefore the survival rate was 100% and the success rate was 88.2%.Conclusions: Due to the long-term stability of the hard and soft tissue after lateral ridge augmentation with BioOss / BioGide in combination with the An-kylos-Implant system, we can describe this method as predictable and safe.

212 i Treatment Of Gingival recession defects using Coronally advanced Flap With a porcine Collagen Matrix Compared ToConnective Tissue Graft: a randomized Controlled Clinical Trial

daniele Cardaropoli (italy), Lorenzo Tamagnone, Alessandro Roffredo, Lorena Gaveglio

Objectives: Treatment of gingival recessions is usually performed surgically according to the principles of mucogingival therapy. The use of coronally ad-vanced fl ap (CAF) together with connective tissue graft (CTG) can produce pre-dictable outcomes in terms of recession coverage, gain of keratinized tissue and improvement of gingival thickness. However, the graft harvest may be characterised by high morbidity as a result of the need for a second surgical site, patient discomfort, post-surgical bleeding and a limited supply of donor tissue. In the last years, alternative procedures to CTG have been evaluated to limit invasivity and pain. Recently, a porcine collagen matrix (Mucograft, Geistlich [MG]) has been proposed as a soft tissue graft substitute. The aim of the present study is to evaluate the use of CAF+CTG (control sites) and CAF+MG (test sites) for the treatment of Miller’s class I single gingival recessions, in a prospective randomized controlled clinical trial.Methods: A total of 18 adult non-smoker patients (9 males and 9 females, aged 21 to 59 years [mean age 41.39±10.02 years]) were included in this study. The patients, all systemically healthy without contraindication to periodontal sur-gery, presented 22 single gingival recession defects, classifi ed as Miller’s class I. The defects were randomly assigned by coin toss to the control or test sites, until eleven defects were selected for one of the two groups. The test group received CAF+MG, while the control group received CAF+CTG.Clinical measurements were recorded using a calibrated UNC 15-mm periodon-tal probe and were rounded to the nearest 0.5 mm. At baseline and 12 months post-surgically, the recession depth (REC), probing pocket depth (PPD), clinical attachment level (CAL) and width of keratinized tissue (KG) were recorded. In addition, the gingival thickness (GT) was measured at a buccal location 1 mm apical to the bottom of the sulcus using a no. 15 reamer endodontic instrument.results: All the clinical parameters were statistically evaluated at baseline and after 12 months, using the t-test for both the intra-group and inter-group analy-ses (statistical signifi cance with p‹0.01). At baseline, REC depth was on average 3.09 mm for the test sites and 3.05 mm for the control sites. At 12 months, mean REC was 0.23 mm for the test sites and 0.09 mm for the control sites. At 1 year, the percentage of root coverage was 92.55% in the test group and 97.04% in the control group. The REC reduction was statistically signifi cant for both groups. No difference was found between the sites treated with CAF+MG and those treated with CAF+CTG. No differences were found in PPD among or between the groups. CAL gain was statistically signifi cant for the intra-group analysis, without any difference between the groups. At baseline, KG mean value was 2.23 mm for the test sites and 2.05 mm for the control sites. After 12 months, KG increased in average to 3.45 mm in the test group and to 3.32 mm in the control group. The in-crease in KG from baseline to 12 months was similar for the CAF+MG and for the CAF+CTG group, without any inter-group statistical difference. Both treatment sites experienced a statistically signifi cant increase in GT from baseline to the 1-year evaluation (p‹0.01). At the test sites, GT varied from 0.82 mm to 1.82 mm after 12 months. At the control sites, GT varied from 0.86 mm to 2.09 mm after 12 months. The difference between the groups was not signifi cant.Conclusions: Within the limits of the study, CAF+MG achieved clinical outcomes similar to CAF+CTG in terms of root coverage, CAL gain, KG gain and GT im-provement at the 12-month evaluation. Both procedures offered a predictable means of treatment for gingival recessions in Miller Class I. The collagen ma-trix represents a viable, simple and convenient alternative to connective tissue graft, reducing the morbidity associated with tissue harvesting at the donor site.

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213 i Bio-Oss and Stem Cells From Bone Marrow Obtained From The distal Femur For Sinus Grafting

Juan Carlos ibañez (argentina), Ruben Sambuelli, Maria Agustina Juaneda, Maria Constanza Ibañez, Jose Monqaut

Objectives: Sinus grafting has become a common procedure for obtaining ad-equate height for implant placement in the posterior maxilla. High success or implant survival rates, reduction of healing time and obtaining of a high per-centage of vital bone may be primary objectives when this technique is applied. This investigation was designed to test whether the combination of Bio-Oss grafting material and bone marrow obtained from the distal femur with high concentrations of stem cells is able to be used for sinus grafting in order to obtain high success/survival rates and high percentages of vital bone.Methods: Twelve sinus grafting procedures were performed in seven patients. Residual bone width and height were measured. All the procedures were per-formed using a lateral approach with piezo surgery. Ten to fifteen cc. of bone marrow with stem cells was obtained from the distal femur using an appro-priate trocar and aspirated with a syringe without any anti-coagulants. After eliminating the excess plasma, the bone marrow was mixed with Bio-Oss (large spongious particles) and used to fill the space obtained by elevation of the sinus mucosae. The lateral window was covered with resorbable membranes. After 6 to 9 months of healing, 24 double acid-etched surface implants were placed. RFA analysis was used to measure initial stability. Six implant sites were created with 3.5 mm. trephines in order to obtain vertical biopsies for histological and histomorphometric analyses. After four to six months the implants were loaded.results: All the sinus procedures healed uneventfully. Twenty-two implants were successful and a mean of 42% of vital bone was obtained at the time of implant placement. The mean ISQ obtained at implant placement was 62.3 and 60.8 at implant loading.Conclusions: The results of this preliminary report show that the use of a mix-ture of Bio-Oss with bone marrow obtained from the distal femur seems to be an efficient combination for obtaining an adequate percentage of vital bone when sinus lifting is performed and for obtaining good results when implants with microtextured surface are used.

214 i Teeth Height preservation By Means Of reverse Tooth retention Method

Mykhailo kasiyanchuk (ukraine)

Objectives: Tooth loss due to trauma or periodontal disease is often associated with atrophy of the alveolar ridges. Due to atrophy the final volume of bone tissue and the height of bone ridges are insufficient for dental implant place-ment. The preservation of alveolar ridge dimensions and bone characteristics could be more effective than any augmentation methods. Augmentative bone treatment may result in extensive surgical interventions and increased treat-ment costs. Attempts to reduce alveolar bone resorption include the place-ment of natural roots, root analogues and immediate implantations into the extraction socket, sometimes in combination with membrane or graft tech-niques and other restorative techniques. The aim of this study was to evaluate the effectiveness of reverse tooth retention methods in alveolar bone volume preservation.Methods: Materials and methods: The study included 65 consecutive patients presenting beaked teeth or their roots after trauma or periodontal disease with atrophy beginning. The author’s own method of reverse tooth reten-tion (Ukraine patent U200612) was performed in all cases. According to this method, the treated roots or the remains of the processed dental crown were covered with gum flap sometimes in combination with membrane. The site was treated with red ray laser. The height of the alveolar bone ridges and the height required for insertion of the appropriate implants were calculated in each pa-tient after X-ray or CT evaluation.results: Results. Stable marginal bone conditions can be preserved after 1–8 years following reverse tooth retention. Laser illumination for several days after operation prevents some acute complications. Follow-up observation of patients showed a mean marginal bone loss of 1.2 mm (SD 0.8 mm) dur-ing the period. Vertical resorption in the frontal area was 1.4±0.5 mm in the molar area. Horizontal resorption was absent after 3 years, after 5 years it was 1.7±0.7 mm and after 8 years 1.6±0.9 mm. The absence of any alveolar

ridge atrophy in the retromolar area was observed in 8 patients over 5 years of observation. The degree of atrophy measured by tooth height correlates with intensive smoking habits (r=-0.54, p‹0.05), daily use of alcohol (r=-0.39, p‹0.05) and low calcium diet (r=-0.36, p‹0.05). In 17 cases of root preservation and 45 cases of tooth crown, preparation with reverse retention was carried out and the standard implantation procedure was performed on the basis of sufficient alveolar ridge size (width 6.3±1.7 mm, height 12.0±0.8 mm). In the retromolar area the volume of alveolar plate was insufficient in 3 cases and artificial grafts were used.Conclusions: The results of this study suggest that the reverse tooth reten-tion method can be used successfully before implantation or other prosthetic procedures.

215 i The Effect Of adult MSC On Bone regeneration Following a Sinus augmentation procedure

angelika Wildburger (austria), Michael Payer, Robert Kirmeier, Stefan Tangl, Birgit Lohberger

Objectives: The overall aim of methods of alveolar ridge regeneration is the introduction of efficient, minimally invasive techniques allowing successful im-plant rehabilitation in order to avoid the harvesting of autogenous bone grafts and to reduce donor site morbidity. Mesenchymal stem cells (MSCs) have been considered as promising tools for tissue engineering approaches. Several studies show low postoperative morbidity (Kirmeier et al 2007) and high mes-enchymal stem cell counts in bone marrow aspirate from the proximal tibia (M. Payer et al., EAO Zürich 2006, Krems 2006/ poster presentations).The aim of the present clinical pilot study was to assess whether a non-con-centrated bone marrow aspirate from the proximal tibia showed positive ef-fects when mixed with a xenogenous grafting material (BioOss®).Method: For this pilot study, 6 patients with severely and symmetrically re-sorbed (‹ 3mm) alveolar ridges in the posterior maxilla and requiring implant treatment were included. A bone marrow aspirate (approx. 10ml) from the proximal tibia was harvested during the bilateral sinus augmentation proce-dure. At the randomly selected test site the BMA was added to the bone substi-tute (porous bovine bone mineral, BioOss®). At the control site the augmenta-tion procedure was performed with the bone substitute only.Biopsies were taken from both sites 3 and 6 months after bone augmentation and analysed by means of histomorphometry.results: The histomorphometric analysis did not reveal any significant effect of the bone marrow aspirate. After 3 months of healing there was a mean bone to bone substitute contact (BSC) of 15.06% (SD 12.52) and a mean new bone for-mation in the total volume of the biopsy (NB) of 9.45% (SD 4.15) in the control group, whereas in the test group the mean BSC was 13.67% (SD 17.93) and the mean NB was 10.36% (SD 11.83). After 6 months of healing there was a mean bone to bone substitute contact (BSC) of 17.89% (SD 9,63) and a mean new bone formation in the total volume of the biopsy (NB) of 10.41% (SD 5,25) in the control group, whereas in the test group the mean BSC was 20.26% (SD 11,32) and the mean NB was 11.81% (SD 6.62).Conclusions: There was considerable variability in the results for a small group of patients. No significant effect of bone marrow aspirates could be detected in our study. Larger studies are certainly needed and it would be interesting to see whether a concentrated bone marrow aspirate would produce better results.

216 i Subepithelial Connective Tissue Graft in The Treatment Of adjacent Gingival recessions

Cosmin Cioban (romania), Alexandra Roman, Andrada Soanca, Radu Campian, Daniela Condor

Objectives: Coronally advanced flap (CAF) associated with a subepithelial con-nective tissue graft (SCTG) has been successfully used as a “gold standard” procedure in the treatment of recession-type defects. The aim of this study was to evaluate the clinical outcomes when using a CAF associated with SCTG for root coverage of Miller class 1 adjacent recession defects.Methods: Twelve patients (5 males and 7 females), ages 21 to 44 years (mean age, 30.76±7.29 years), non-smokers, were recruited for the study from the Periodontology Department of the Iuliu Hatieganu University of Medicine and

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Pharmacy in Cluj-Napoca, after giving informed consent. The study protocol was approved by the University’s ethics committee. All patients were suffering from 2 adjacent gingival recessions classifi ed as Miller’s class I and requested surgical root coverage procedures. Clinical measurements were taken by the same periodontal specialist immediately before the surgical treatment and 3, 6 and 12 months after surgery. Measurements included recession height, prob-ing depth, clinical attachment level and width of the keratinized tissue. All sur-gical procedures were performed by the same surgeon, who was not involved with the clinical measurements. Data analysis was performed with SPSS 16 using the Friedman non-parametric overall statistical test.results: Among 12 patients, 24 recessions were evaluated and treated. All surgical procedures were well tolerated by the subjects and no postoperative complications were observed. The results obtained after 3 month showed a coverage rate of 66.67% to 100% (mean 95.14%); in 20 recessions (83.4 %) the coverage yielded 100%. The rates of coverage at 6 and 12 months post-surgery ranged from 75% to 100% (mean 97.9 %); 22 recessions (91.6 %) were covered completely. The width of keratinized tissue (KT) before the surgery ranged from 2 to 4 mm (mean 2.6 mm) and at 6 and 12 months post-surgery ranged from 3 to 5 mm (mean 3.9 mm).Conclusions: Surgical treatment using SCTG in combination with CAF tech-nique resulted in signifi cant root coverage of class I multiple recessions. An increased width of keratinized tissue was observed after the surgery. Acknowl-edgements: This study was supported by the Romanian Ministry of Education and Research, CNCSIS Grant No.1341.

217 i postoperative Complications Following Gingival Grafts:a prospective Cohort Study

daniela Condor (romania), Alexandra Roman, Robert Balazsi, Radu Campian, Cosmin Cioban

Objectives: The aims of this study were 1) to evaluate the postoperative com-plications after free gingival graft (FGG) and connective tissue graft associated with coronal advanced fl ap (CGCAF) used to cover GR and 2) to compare the intensity of these complications between the two techniques.Methods: Seventeen patients were recruited from the Periodontology Depart-ment of Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca. Eleven FGG and ten CGCAF procedures were performed by a single experi-enced practitioner in order to cover GR,. Patients were asked to fi ll out a ques-tionnaire 14 days after the surgery, evaluating postoperative pain, swelling and bleeding. Each symptom was evaluated using a 1 to 10 visual scale, where 1 represented the absence of the symptom and 10 the most intense manifesta-tion. Given the small sample size, the data were analyzed using parametric (in-dependent sample t-test) and non-parametric techniques. We also computed Cohen’s d effect size coeffi cient.results: Every patient experienced at least one minor complication. The pa-tients experienced more pain in the grafted area than in the donor area, for both surgical techniques, with a mean value of 3.09 (1.3 sd) versus 2.27 (1.4 sd) for the CGCAF group and of 3.7 (2.21 sd) versus 2.9 (1.7 sd) for the FGG group. Generally, the effect size for all measured variables reached at least the medium level (d=0.33-0.91); CGCAF generated higher scores on the scale of unpleasantness. The only statistically signifi cant difference between the two techniques was recorded for tumefaction: mean 2.45 (0.93 sd) for FGG and mean 4 (2.21 sd) for CGCAF, t value being 2.12 (p‹0.05).Conclusions: In contrast to existing evidence, our results showed that CGCAF was associated with more severe complications than FGG, even if the differ-ence was signifi cant only for tumefaction. In view of the fact that the proce-dures were all carried out by the same practitioner, the specifi c psychological attributes of the patients may have infl uenced the results. Acknowledgements: This study was supported by the Romanian Ministry of Education and Re-search, CNMP Grant No. 42141 and CNCSIS Grant No. 1341. 218 i large Soft and Hard Tissues Jaw defects.Computer assisted implant Surgery in Microvascular Free Flaps. prospective Clinical Trial.

Silvio Mario Meloni (italy), Giacomo De Riu, Milena Pisano, Olindo Massarelli, Elena Carta

Objectives: The aim of this prospective pilot clinical trial is to evaluate the prosthetic advantages offered by CT-guided implant surgery in patients who have undergone jaw reconstruction with free fl aps, following resection for tu-mours, fi rearms traumas or severe atrophyMethods: 15 patients who had undergone free fl ap maxillary or mandibular reconstruction were selected from among 47 reconstructed patients. At the present date, 7 consecutive patients of both sexes have been treated, with a suffi cient follow-up period (6 months after loading, at least). Prosthetic resto-ration was performed according to a modifi cation of the standard NobelGuide protocol (Procera Software; Nobel Biocare). Computer assisted, dental im-plant placement was based on accurate prosthetic and aesthetic analysis. The standard NobelGuide protocol had to be modifi ed due to the need to adapt the standard technique to these reconstructed patients. A total of 36 fi xtures were installed (Replace Tapered Groovy Nobel Biocare). The implant lengths ranged between 8 and 16 mm; the implant diameters were 3.5, 4.3 or 5 mm. The implants were loaded immediately or after six months, with screw-retained prostheses. Clinical and radiological follow-up was scheduled at 3, 6,12 and 18 months after surgery.results: All seven treated patients were followed up for at least 6 months (range 6–18 months). Two implants were lost during the healing period (CSR 94.5 %). Every patient received a correct provisional prosthetic rehabilitation with a high degree of satisfaction in terms of masticatory function, social func-tioning and overall quality of life. Radiological rough estimation of bone level showed a stable marginal bone level. No other complication, biological or me-chanical, has so far been recorded.Conclusions: Implant-based dental restorations provide many advantages in free fl ap reconstructed jaws. Unfortunately, implant planning can led to many problems in these diffi cult patients. We believe that these complications can be reduced by adopting prosthetic-guided, computer-assisted implant surgery. These preliminary results suggest that the protocol presented here should be adopted in order to achieve the best prosthetic restoration for these diffi cult reconstructions.

219 i Surgical Technology For reconstructionOf Mandibular radionecrosis using Calcium phosphateBioceramics and Total Bone Marrow

Guy daculsi (France), Franck Jegoux, Olivier Malard

Objectives: Treatment of oral carcinomas usually requires surgical removal followed by radiotherapy. Since tumors are frequently bulky, bone is often involved and the surgical procedure requires major resection. Free fl aps still constitute the gold standard in mandibular reconstruction. Complications lead to the need to investigate alternative therapies.Since bone graft and bioceramics alone have failed, adjunction of osteoin-ductive properties has been investigated. Total bone marrow graft use has been investigated in animal and in human clinical applications. We have re-cently proposed the concept of an immediate post-radiation bone marrow graft to provide an osteoinductive potential to the ceramic with good results. According to this data, a pilot study promoted by Nantes and Rennes Hospi-tal ENT department was in progress in humans to determine a bone tissue engineering approach to patients presenting mandible cancer-related bone defects.Methods: Animal experiments were realized in the Nantes National Veterinary School (Oniris) in compliance with European directive number 86/609/CE. The study was conducted in accordance with animal experiment ethics rules. Two cm segmental defects were created in the femoral diaphysis of New Zealand rabbits, and a femoral critical size defect in a canine model.Clinical study: curative technology of radionecrotic mandibular bone defect. Mul-ticentric study, Nantes Hospital promotion (ID RCB: n°2008-A01593-52; Ref BRD 08/10-H). Clinical trial phase 1, non randomized, Bicentrique Nantes-Rennes. This involved ten patients with osteoradionecrosis with surgical ablation, and with the basilar mandibular cortical bone preserved.results: Successful osseous colonization was found suggesting an osteoinduc-tion role of the bone marrow graft in the center of the defect after radiotherapy. According to this data, a pilot study promoted by the Nantes and Rennes Hos-pital ENT department was in progress in humans to determine a bone tissue engineering approach to patients presenting mandible cancer-related bone defects. Clinical follow up revealed no adverse effects and high architectured

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bone regeneration. Some patients showed limited side effect related to insuf-ficient soft tissue reconstruction. In spite of the newly formed bone exposure, the bone regeneration was maintained.Conclusions: This pilot study demonstrated the efficiency of total bone mar-row combined to synthetic bone graft (MBCP+®) for bone regeneration in low trophic areas, particularly for radionecrotic bone defects.Our findings demonstrate that a micro macroporous CaP bioceramics bone graft followed by post-radiation can be revitalized using a total autologous bone marrow graft. This has significant implications for the bone tissue en-gineering approach to patients with cancer-related segmental bone defects.

220 i Vestibuloplasty By Means Of a resorbable Collagen Membrane Versus The autogenous Split Thickness Skin Graft. preliminary results Of a prospective randomized Trial.

Christian Tudor (Germany), Katrin Kiener, Christian Schmitt, Falk Wehrhan, Friedrich Wilhelm Neukam

Objectives: Split thickness skin grafts are considered to be the method of choice in covering large intraoral defects. Donor area morbidity as well as limited differ-entiation to mucosa resulting in an insufficient base for dentures are motivating factors in the development of collagen-based substitutes for intraoral mucogin-gival regeneration. The aim of this in vivo study was to evaluate the suitability of a biodegradable, bovine collagen I/III membrane (Mucograft) as a gingival sub-stitute in surgical vestibuloplastic procedures compared to split-thickness skin autografts. Of particular interest were the formation of keratinized gingiva along the alveolar crest and shrinkage of the area of gained attached gingiva.Methods: To evaluate the outcomes in the use of this membrane as a gingival substitute we carried out a prospective randomized trial.Operative vestibuloplasties have so far been performed in 20 patients using the collagen membrane or split thickness skin grafts, respectively. Evaluation took place after 10, 30 and 90 days.We performed photographic documentation as well as three-dimensional scans intraoperatively and at the end of the follow up time measured the covered ar-eas and the depth of the vestibulum. The formation of keratinized gingiva was shown intravitally by staining with Lugol`s solution and histologically (HE stain-ing) as well as immunohistochemically (Cytokeratin 5/6) in biopsies that were harvested from the area of the covered alveolar crest 90 days after surgery.results: Performance of the surgical procedures was uneventful in both groups. We found no complications such as wound infection or rejection of the transplants or the implants, respectively. Operating time was significantly re-duced by using the collagen membrane (ø 56 min vs. ø 88 min). After 90 days we found comparable shrinkage of the gained area of attached gingiva and the initially gained vestibular depth in both groups. It measured 59% with the use of membranes vs. 62% with the use of skin grafts compared to the initially created neovestibulum. These differences showed no statistical significance. Clinically, we found presence of keratinized epithelium along the alveolar crest in all subjects belonging to both groups. This could be proved by histological and immunohistochemical examination of the harvested biopsies.Conclusions: Taken altogether, we found significant reduction of the operation time and no donor morbidity with the use of the collagen membrane in com-parison to the use of the split thickness skin graft in the described procedure. Both techniques led to the formation of favorable keratinized epithelium along the alveolar crest.

221 i Bone Marrow Concentrate and Bovine Bone Mineral For Bone regeneration in a Clinical Setting

Sebastian Sauerbier (Germany), Daniela Rickert, Felix Koch, Wilfried Wagner, Ralf Gutwald

Objectives: To evaluate the potential of substituting autogenous bone (AB) by bone marrow aspirate concentrate (BMAC). Both AB and BMAC were tested in combination with a bovine bone mineral (BBM) for their ability to cause new bone formation (NBF) in a multicentric, randomized, controlled, clinical and his-tological non-inferiority trial.Methods: 45 severely atrophied maxillary sinuses from 26 patients were evalu-ated in a partial cross-over design. As a test arm, 34 sinuses of 25 patients

were augmented with BBM and BMAC containing mesenchymal stem cells. Eleven control sinuses from 11 patients were augmented with a mixture of 70% BBM and 30% AB. Biopsies were obtained after 3–4 months healing period at the time of implant placement and histomorphometrically analyzed for NBF.results: NBF was 14.3±1.8% for the control and non-significantly lower at 12.6±1.7% for the test (90%-CI-interval -4.6 1.2). Values for BBM of 31.3±2.7% were significantly higher for the test compared to control of 19.3±2.5%(p‹0.0001). Non-mineralized tissue was lower by 3.3% in the test compared to control (57.6%; p=0.137).Conclusions: NBF after 3–4 months is equivalent in sinus, augmented with BMAC and BBM or a mixture of AB and BBM. This technique could be an alter-native to using autografts to stimulate bone formation.

222 i Management Of Severe Maxillofacial Trauma using a Nonvascularized iliac Crest Bone Graft and CadCaM-facilitated Osseointegrated implant prosthodontics

andrew Barber (Great Britain), Paul HR Wilson, Ceri W Hughes

Objectives: This clinical case report describes, illustrates and discusses the maxillofacial and prosthodontic management of a patient who was involved in a severe road traffic accident which resulted in his mandible sustaining commi-nuted fractures. The clinical procedures involved, evidence base for the treat-ment strategy and improvements in quality of life are discussed.Methods: The patient’s chin hit a security barrier while he was travelling at high velocity in a racing car. He was almost decapitated. In hospital, his injuries were imaged. Severe comminution of the left mandibular body necessitated resection and provisional reconstruction with a titanium osteosynthesis plate.Conventional upper and lower complete dentures were poorly tolerated second-ary to facial nerve weakness and left-sided paraesthesia of the trigeminal nerve. The left mandibular body was reconstructed with a nonvascularized iliac crest bone graft. Four months later, five endosseous titanium implants were placed using a submerged protocol.4 months later, the implants were exposed via second stage surgery, and de-finitive abutments placed. The prosthodontic phase of treatment involved the use of a mandibular CAD-CAM titanium overdenture bar (CEKA). An upper con-ventional removable prosthesis and lower overdenture implant were provided to complete the rehabilitation.results: At the end of reconstructive maxillofacial and prosthodontic treat-ment, the patient’s quality of life had improved dramatically in terms of speech, mastication, swallowing and appearance. His quality of life had quantitatively increased as demonstrated by favorable changes to his OHIP EDENT quality of life instrument scores.Conclusions: The maxillofacial-osseointegrated implant prosthodontic recon-struction of a patient with severe maxillofacial high velocity trauma resulting in comminuted fractures to the mandible is described. The clinical procedures, case management, evidence base behind the treatment and quality of life im-plications are described, discussed and illustrated.

223 i Bio-Oss Materials in periodontal regeneration in Organ Transplant patients

peter augustin (Czech republic), Antonin Fassmann, Lydie Izakovicova Holla, Jan Vokurka, Hana Poskerova

Objectives: Organ transplant patients are successfully treated by complex im-munosuppressive therapy. Drug induced gingival overgowth (DIGO) is an unde-sirable side effect of this therapy. Relevant drugs inducing DIGO are Cyclosporin A, Azathioprin, Mycophenolate, Verapamil or Nifedipine. Many other etiological factors are involved in causing it and it is worsened by oral biofilm accumulation. Fibrosis, inflammation and cell accumulation depend on dosage, time and type of drug administration, oral hygiene and the individual reaction of the organism.Methods: I used my own classification for DIGO. I plumbed periodontal pocket depth by using a WHO periodontal probe. I measured each tooth at 4 different places (vestibular, mesial, oral and distal) and determined average values. 0 - no signs of GO, depth of periodontal pocket 0.5 mm1 - GO is localized to interdental papilla, depth of sulcus is 0.5 mm2 - GO to 1/3 of clinical crown, 3 GO to 2/3 of clinical crown,

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4 - GO more than 2/3 of clinical crown or covering whole clinical crown. After supra and subgingival treatment (SRP) we carry out gingivectomy. Six month later, we perform regenerative periodontal therapy by tissue engineering with deproteinized bovine bone matrix (DBBM) and platelet rich plasma (PRP). After activation by thrombin and calcium we make composite gel for implantation into periodontal defects. This gel is covered by resorbable double collagen membrane. Degranulation of thrombocytes and release of growth factors sig-nifi cantly improve quality of periodontal regeneration.results: GHI values on average were 1.4 in men and 1.7 in women. Resorption of alveolar bone was ¼ of dental roots (RTG index was 1.45 in men and 1.14 in women). GO in patients with endosteal dental implants and necessity of pre-prosthetic correction of soft tissue. I examined 3 patients with endosteal dental implants. All of them were surgically treated by gingivectomy. Involvement of interdental papilla in the frontal area of the upper and lower jaw was noted. Daily dosages of the drugs: Sandimmun neoral (Cyclosporin A) 2–15 mg/kg/day, Cellcept (mycophenolate) 2000 mg per day, Immuran (azathioprine) 3 mg/kg/day and Prograf (tacrolimus) 0.1-0.3mg/kg/day.Conclusions: Poster clearly demonstrates utilization of this method in patients after transplantation of the heart and kidney with medication induced peri-odontitis. This therapeutic practice was very acquitted.

224 i Vertical Changes after autogenousOnlay Bone Graft On posterior Maxilla

Sunjong kim (korea), Myung-Rae Kim

Objectives: In spite of the rapid advancement of the implant surgical technique, implant installation on insuffi cient posterior maxillary bone still remains as a signifi cant limitation. Guided bone regeneration, distraction osteogenesis, onlay bone graft and sinus augmentation have been introduced to solve this problem. Onlay bone graft has the advantage of solidity, can be used widely for maintaining bone contour and aiding the stability of the reconstruction site even though it shows reduced capability of osteogenesis and slow revasculiza-tion compared to other bone graft methods.Methods: A consecutive retrospective study was performed on patients who had onlay bone grafts for augmentations of severely atrophied maxilla followed by placement of implants at Ewha Womans University from 2002 to 2009. Study involved the following investigations:1. Analysis of vertical height changes after autogenous block onlay bone graft on maxilla.2. Analysis of peri-implant marginal bone changes of autogenous bone graft on maxilla.Bone graft and implant installation was performed by one operator, and MKIII®, ReplaceSelect® (Nobelbiocare, Sweden),USII®,SSII® (Osstem, Korea)were used for implantation. For statistic evaluation, ANOVA analysis and t-test were used.results: 1. In autogenous onlay block bone graft on maxilla, mean augmentation height was 6.22 mm. Mean resorption of grafted bone was 0.54 mm (8.5%) at 3 months after surgery, 0.99 mm(15.9%) at 6 months after surgery, so r 2. The loss of peri-implant marginal bone grafted from ramus subsequently increased in the premolar area followed by the molar and anterior area, while the iliac bone graft in anterior maxilla resulted in higher resorption than in the molar area.Conclusions: The rate of resorption was greater at 3 months after surgery than that between 3 to 6 months after surgery. And results showed resorption of iliac bone was larger than that of ramal bone with statistical signifi cance. The mar-ginal bone resorption of the iliac graft was signifi cantly larger than that of ramus.

225 i impact Of The Outcome Of Guided Bone regeneration in de-hiscence-Type defects On The long-Term Stability Of peri-implant Health. a prospective randomized Controlled Clinical Study.

Narja Sahm (Germany), Vladimir Golubovic, Frank Schwarz, Jürgen Becker

Objectives: The present clinical study aimed at investigating the impact of re-sidual defect height (RDH) following guided bone regeneration (GBR) in de-hiscence-type defects on the long-term stability of peri-implant health over a period of 4 years.Methods: In a total of n=23 patients, RDH values in dehiscence-type defects at titanium implants were clinically assessed after 4 months of submerged

healing following augmentation using a natural bone mineral (NBM) and ran-domized application of either a cross-linked- (VN) (n=12 patients), or a native collagen membrane (BG) (n=12 patients). RDL values were classifi ed as absent (0 mm, control; n=8), minimal (1 mm, test 1; n=8), or advanced (› 1 mm, test 2; n=7). Clinical parameters (i.e. bleeding on probing - BOP, probing pocket depth - PD, mucosal recession - MR, clinical attachment level - CAL) were recorded (mesio-, mid-, and disto-buccal aspects) at 4 years after prosthesis installation by one blinded and calibrated examiner.results: Mean BOP (43.7±35.6%, 52.1±35.0%, 40.5±34.5%), PD (2.9±0.7 mm, 2.8±0.7 mm, 2.7±0.9 mm), and CAL (3.1±0.9 mm, 3.3±0.8 mm, 3.2±1.3 mm) values at 4 years were comparable in all groups investigated (i.e. control, test 1 and test 2; respectively). Mean MR values tended to be higher in the test 1 and 2 groups (0.5±0.7 mm, 0.5±0.6 mm; respectively), when compared with the control group (0.2±0.4 mm). However, these differences did not reach statistical signifi cance.Conclusions: The present long-term follow up failed to reveal a signifi cant im-pact of RDH on peri-implant health. However, RDH values may be associated with an increase in mucosal recession and therefore compromise the overall esthetic outcome of implant therapy.

226 i prevalence Of peri-implant diseases associated WithThe TiOblast (TM) dental implant 9 years after insertion

Julia karbach (Germany), Peer Wolfgang Kämmerer, Karl Martin Lehmann, Victor Palarie, Joachim Wegener

Objectives: Peri-implant diseases are compromising implant success and sur-vival. Data on the prevalence of peri-implant diseases are rare. A clinical evalu-ation of the long-term prevalence of peri-implant diseases (mucositis, peri-im-plantitis) of the TiOblast dental implant (Astra Tech, Sweden) was conducted.Methods: A total of 237 implants were inserted in 47 patients (mean age 57 years (17-77; standard deviation (SD: 9.6); male n=25, female n= 22) between 1994 and 2005. In a clinical examination after a mean time of 9.12 years (5-12; SD 1.3) after insertion, implant related peri-implantary parameter (plaque index (PI), sulcus bleeding index (SBI), pocket depth (PD), bone loss (BL) in relation to time of insertion were evaluated. A classifi cation into healthy tissue, mucositis and peri-implantitis was conducted.results: PI, SBI, PD and BL of implants are given in fi gure 2a-c. 211 implants (89%) were seen to be healthy, in 21 implants (8.9%) mucositis and in 5 cases (2.1%, fi gure 3) peri-implantitis was diagnosed. Evaluated risk factors for peri-implant diseases were alcohol abuse, irradiation and female gender (fi gure 4). 79% of patients with healthy tissue, but only 66% of patients with mucositis and 20% of patients with peri-implantitis were making regular control visits.Conclusions: After a mean time of 9.12 years, the TiOblast (TM) dental implant shows a marginal rate of peri-implant diseases. Even with the low number of implants with surrounding mucositis and peri-implantitis, the risk factors alcohol abuse, prior irradiation and female gender could be evaluated. Addi-tionally, the need for regular control visits with supportive follow-up care has shown to be important for success rates of dental implants.

227 i a 2-year prospective Clinical and radiographicStudy Of implants placed after Maxillary Sinus augmentationWith Bovine Hydroxyapatite

Tommaso anello (italy), Alessandro Rossi, Luigi Tagliatesta, Laura Serioli, Matteo Chiapasco

Objectives: The aim of the present study was to evaluate success and survival rates of implants placed in maxillary sinus grafted with bovine hydroxyapatite (Bio-Oss®Geistlich) and resorbable collagen membranes (Bio-Gide®Geistlich) in patients with residual bone height of up to 5 mm, residual bone width of at least 5 mm and with maintenance of an acceptable vertical intermaxillary relationship.Methods: Sixty patients (age 26-70 years) participated in this study. Eight pa-tients required bilateral sinus grafts and 52 patients required monolateral si-nus grafts (total 68 sinuses). Residual bone volumes were measured in the preoperative computer tomography (CT) for each patient; the average bone height was 4.49 mm and the average bone width was 5.84 mm. All patients were treated with the same surgical technique consisting of sinus fl oor augmentation with a lateral approach. Bovine hydroxyapatite was the sole

45

graft material and a resorbable membrane was placed over the lateral window. All implants were placed in a delayed procedure. 120 implants (58 Straumann implants, Straumann®, Basel, Switzerland; 62 Astra, Astra Tech®, Mölndal, Sweden) were scheduled for subsequent surgery 6 months after the graft was performed. Prosthetic load was performed after 5 months from implant place-ment.results: All sinus grafts showed full engraftment. The most frequent intraop-erative complication was perforation of the sinus membrane (18%), but none was such to compromise the completion of the surgical reconstruction. Per-forations were treated either by increasing the elevation of the sinus mucosa, and/or with the aid of resorbable collagen membranes. The mean follow-up from prosthetic loading was 24 months. The marginal bone loss around dental implants was 0.85 mm (ds +/- 0.35 mm); only three implants showed a higher marginal bone loss, which was considered as clinical failure (Albrektson crite-ria). No implants were removed during the follow-up period. The overall sur-vival and success rates of implants were 100% and 97.5% respectively.Conclusions: Despite the limited follow-up, the present study suggested that bovine hydroxyapatite, used alone for maxillary sinus grafting, is a reliable and predictable material for the survival and the success of dental implants placed in patients with residual bone height of up to 5 mm, residual bone width of at least 5 mm and entailing maintenance of an acceptable vertical intermaxillary relationship.

228 i Comparative volumetric and density study of symphysis donor defects: Filled or unfilled with bone substitute

devorah Schwartz-arad (israel), Pablo Altuna Fistolera, Albert Calaf Cot

Objectives: Intra-oral autogenous bone grafts are a convenient source of bone in reconstruction of the residual ridge prior to dental implant placement. The aim of this study is to evaluate bone volume and density of symphysis donor defects filled with bovine bone material compared with unfilled symphysis donor defects.Methods: The study included 24 patients who underwent either alveolar ridge reconstruction or maxillary sinus elevation. Two groups were studied: symphy-seal donor defects filled with bovine bone material, and unfilled symphyseal donor defects. Pre- and post-operative volumetric and bone density variables were determined using CT scans and the software program SimPlant®.results: At 6 months post-operative, the filled donor defects exhibited a sig-nificant increase in bone volume and density (97.7% and 116%, respectively) compared with unfilled donor defects (73.4% and 35.5%, respectively). At 18 months post-operative, volume and density of unfilled donor defects were re-evaluated, yet no significant increase was found in bone volume.Conclusions: Unfilled donor sites generate defects that cannot achieve a "res-titutio ad integrum", while filled donor sites associate with complete bone regeneration as determined by bone volume and density analysis. High bone density of filled donor defects may indicate high bone quality and could enable re-entering of the site.

229 i a New Method Of Closing an Oroantral Communication using a resorbable Membrane

Joris Wes (Netherlands), MF Wes, BJ Wes, JPR van Merkesteyn

Objectives: An oroantral communication (OAC) after extraction of maxillary posterior teeth is treated in most cases by primary surgical closure. This study presents a new, simple and time-reducing method using a Geistlich Bio-Gide membrane® without primary closure.Methods: Twelve patients with an OAC after extraction of a maxillary molar were treated according to the new method. First the alveolus is inspected after extraction and loose fragments are removed. A Geistlich Bio-Gide membrane® is rolled in a cone-shaped manner. Then the tip of the membrane is folded over and placed in the alveolus. The membrane is convex towards the maxillary sinus and concave towards the oral cavity. When the nose-blowing test is nega-tive, a cross mattress suture is placed for fixation of the membrane. Peripac® was used in most patients as an intra-oral bandage. Patients had check-ups two and six weeks postoperatively.results: After two weeks all OAC’s were closed. In one patient with pre-op sinusitis symptoms, treatment with rinsing the sinus and antibiotics resolved

symptoms. In one patient with a light sinusitis post-op, treatment with antibi-otics resolved symptoms. After 6 weeks all patients showed adequate wound healing. The average operating time was 10 minutes.Conclusions: This study shows the possibility of treating patients with an oro-antral communication directly after extraction using a biodegradable mem-brane without primary surgical closure of the wound. More research is needed to confirm the results and the indications of the new method.

230 i Five years Clinical Follow up Bone regeneration With Cap Bioceramics

Guy daculsi (France), Clemencia Rodriguez, Sylvia Mitja

Objectives: Among all the materials used for pre-implant bone reconstruc-tion, autologous bone is the gold-standard. A second site surgery is, however, required, making the surgery more complicated. To overcome the autograft limits, many biomaterials were proposed. Human or animal origin materials have disadvantages: limited supply and risk of contamination. Consequently, synthetic products were developed, like MicroMacroporous Biphasic Calcium Phosphate (MBCP), a mix of hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP). MBCP offers a great potential for bone regeneration as its chemi-cal composition is close to biological bone apatites. MBCP already proved its efficiency in different human clinical applications, but there was only a little clinical data on maxillofacial surgery.The aim was to report 5 years of clinical follow-up on bone regeneration after socket preservation using MBCP with 2 HA/TCP ratios, for evaluation of re-sorption and bone ingrowth at the expense of the bioceramic.Methods: MBCP® (ratio 60/40) and MBCP+®(ratio 20/80) were used. MBCP® and MBCP+® are biphasic CaP intimate mixture of HA/TCP 60/40 and 20/80, with interconnected macroporosity and microporosity (70% total porosity with 75% of macropores of 300 to 600µm and 25% of micropores).Forty cases have been distributed in three groups for alveolar pocket filling. Seven cases without filling are controls, as the two others are filled with MBCP 60/40 or MBCP 20/80. X-Ray at 0, 3, 6, 12 months and a 5 years follow-up for some patients were performed. Bone biopsies were realized before dental im-plantations. Light microscopy, SEM and µCT were performed.results: In all the 40 cases, radio-opacity of the implantation site decreases over time, indicating resorption and bone ingrowths at the expense of the two bioceramics. No difference in the resorption kinetics appeared on X-Ray. After 1 year, the implantation site looks like the physiological bone and is maintained iover time. The newly formed bone is preserved after 5 years, unlike the control cases (without filling), where we observed a decrease of 2 to 5 mm.In light microscopy, bone ingrowth is observed in all the biopsies. Bone tra-beculae appeared in the samples, without statistical differences and a large osteoconduction is noticed in close contact to the granules. More resorption over time is measured for MBCP 20/80, when time of implantation and residual granules are compared.Conclusions: The immediate filling of the alveolar socket after tooth extrac-tion is a preventive method to bone resorption. In the long term, resorption and bone growth were demonstrated for both MBCP® with two HA/TCP ratios (40%/60% and 20% 80%). This data confirms the resorbability of MBCP® and the high osteoconduction and regeneration.

231 i injectable Bone Substitute (MBCp Gel®):Clinical results in Human Maxillo-Facial Surgery

Guy daculsi (France), Pierre Weiss, Léon Philippe Clergeau, Bénédicte Henckel, Bernard Giumelli

Objectives: Calcium phosphate bioceramics, which are often used for bone regeneration because of their close resemblance to the bone mineral phase, display biocompatibility, bioactivity and excellent osteoconductive properties.In odontology, the size and accessibility of the various sites (endodontic, ex-traction?) required the development of injectable forms. These new therapeu-tic approaches and improvements in bioceramics mixed with hydrogel have led to the development of injectable bone grafts for bone regeneration.Methods: MBCP® Gel is a CaP aqueous suspension obtained by associating BCP ceramic (60% HA and 40% beta-tricalcium phosphate; MBCP®, mineral

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46

phase granules 80 to 200 µm in diameter) with a 3% aqueous solution of hy-drogel. A clinical trial (Nantes Hospital) was performed in 11 human sockets after extraction (36 or 46). We have checked the clinical reaction by question-ing patients about pain. Radiography was performed before implantation, 15 days, 3 and 6 month afterwards. For some patients we have radiography after 3 years and some biopsies to control bioactivity have been performed as part of the clinical trial.Scanning Electron Microscopy SEM Micro Computerized Tomography and light microscopy were performed.results: See photos and analysis. It was an explorative study and the results showed no pain due to the biomaterial implantation, no infection, no infl amma-tion and perfect biocompatibility. The safety and the bioactivity of this concept of biomaterial were confi rmed in human implantation, after several animal pre-clinical studies.Conclusions: Human clinical trial with MBCP Gel® confi rm the biocompatibil-ity in human, but the kinetics of resorption and bone substitution seem to be different from the animal studies. The radiological study shows no osteolysis in contact of the biomaterial, an increase of the density and a decrease of the volume of the injected biomaterial.

232 i Comparative review Of Sinus augmentation Techniques

Orsolya rásonyi-kovács (Hungary), Árpád Joób-Fancsaly

Objectives: Vertical resorption of the alveolar process and pneumatisation of the maxillary sinus lead to a reduced distance between the sinus and the alveolar process. Sinus augmentation surgery is widely used to augment the upper molar region before implant placement. Tatum described the open technique in 1986 and it has been developed further by several innovations since that time. Sum-mers reported the closed technique in 1994. It is less traumatic, but allows a limited extent of augmentation. The aim of the present poster is to compare the advantages and disadvantages of the various sinus augmentation techniques via literature review, and to present the success rates we found in our cases.Methods: The success rates of various sinus lift techniques were examined clinically and radiologically in accordance with internationally accepted criteria in patients treated during the past ten years in our clinic.results: The present study proved that the most successful technique is open sinus augmentation, and that the other techniques and innovations (closed, balloon etc.) have fewer indications, but can be successful when they are used properly. Sinus grafting /sinus elevation/ is trustworthy, has good results and is an effective method for sinus augmentation. The success rate of augmenta-tion cases in the present study was 97.2%, comparable to results published in international literature.Conclusions: The present poster reviewed and compared various techniques via a retrospective study and literature review. An attempt is made at providing a guideline to the indications and usage of the various techniques.

233 i angled implants as an alternative ToBone augmentation in Severely resorbed Maxilla

Tamás ruszin (Hungary), Béla Czinkóczky, Sándor Bogdán

Objectives: The possibilities of implant restoration in the severely resorbed maxilla (Fallschüssel class 5) were reviewed. These include implant placement in combination with bone augmentation, angled implants, or "zygoma implants. Furthermore, the purpose of the study was to do a long-term follow-up of bone loss around angled implants in the severely resorbed edentulous or partially dentate maxilla.Methods: During eight years (average 4.3 years) of follow-up, 24 patients with 28 angled implants were examined, where the implant angulation was more than 15 degrees (the smallest angulation was 34 degrees and the highest 56 degrees). In every case the implant length was minimum 13 mm. All implant supported restorations were screwed or cemented bridge works. All patients were recalled every six months; the implants were examined clinically and radiologically.results: Out of 28 implants one had to be removed in the 5th month, around one implant a 2.5 mm bone loss was found during the 1st year after implant loading. Around the rest of the implants no signifi cant bone loss was noted after the initial bone loss.

Conclusions: The results of the present long-term follow-up study correlated with results found in literature. According to those, with appropriate indica-tions, angled implants can be a successful therapeutic method in severely re-sorbed maxillary bone, and as such, they could be an alternative to extensive bone augmentation procedures.

234 i The infl uence Of periodontal TreatmentOn Serum lipid and Systemic Marker levels in patientsWith destructive periodontal disease

Wisam kamil (Malaysia), Rola Habashnah, Lina Abbood

Objectives: Data on whether periodontal therapy affects serum lipid levels is inconclusive. The purpose of this study is to investigate the effect of non-surgical periodontal therapy on the cholesterol levels and hs-CRP of medically healthy individuals suffering from advanced periodontitis.Methods: Following protocol review and approval by the Institutional Re-view Board of Jordan University of Science and Technology a total of fi fty fi ve periodontitis patients randomly distributed into either a treatment group (37 patients) who received non-surgical periodontal therapy with intensive oral hygiene instructions and a repeated course of therapy for residual bleeding in periodontal pockets or a control group (18 patients) who received delayed periodontal treatment after completion of the clinical trial evaluation. Medical history, demographic data and clinical periodontal parameters, total choles-terol, LDL, HDL, triglyceride, and C-reactive protein were collected at baseline and three months at reassessment appointments.results: The results showed statistically signifi cant improvements for all peri-odontal clinical parameters and the non-surgical periodontal therapy had no effect on the lipid parameters (P-Value=0.322, 0.540, 0.451, and 0.154 for LDL, HDL, Total Cholesterol, and Triglycerides respectively) in contrast to the signifi -cant decrease in the infl ammatory marker CRP (P-Value=0.003).Conclusions: In this study population, serum lipid levels were not associated with any improvement in periodontal heath while the destructive periodontal disease associated with increased circulating concentrations of his-CRP and the periodontal therapy reduces CRP levels.

235 i Guided Bone regeneration in Sinus lift procedures

ramón Gómez Meda (Spain), Maria Varela Cruz, M. Isabel Prada Lopez, Sonia Liste Grela

Objectives: The aim of this study is to establish the effi ciency of the sinus lift procedure with a lateral window approach in the implant-supported rehabilita-tion of very atrophic edentulous posterior maxillae (no more than 1-4 mm of alveolar bone height).Methods: This study retrospectively evaluated the results of 39 sinus lift graft augmentations performed to place 75 implants in the posterior maxilla. Grafts were accomplished with Bio-Oss® combined with autogenous bone removed from within the mouth. The donor site was the external wall of the sinus and the zygomatic arch. A safescraper was used. Therefore no second location site was used. Sand-blasted screw-type implants (Xive® implants, by Dentsply) were placed simultaneously to the surgery. A membrane (Bio-Gide®) was used to cov-er the graft in all cases. Implants were exposed 3 to 6 months later. After waiting one month for the soft tissue to heal, the implants were prosthetically restored. The osseointegration was evaluated during a follow-up period of 6 to 36 months. Implant survival rate and peri-implant conditions, such as marginal bone re-sorption (mm.), pocket depth (mm.), plaque and bleeding indices were evaluated.results: The most frequent intraoperative complication of the technique was tearing of the sinus membrane in 6 cases (15%). There were no clinical com-plaints of maxillary sinusitis. Ten core biopsy specimens were taken at the time of the second surgery and evaluated. Histological evaluation of cores revealed good bone formation around the Bio-Oss particles after 6 months.The use of long implants provided for a favourable implant-crown ratio (›1.09) and produced an overall clinical survival rate of 100% over the observation period.Conclusions: On the basis of this retrospective study, we conclude that excel-lent osseointegration and peri-implant parameters may be anticipated for im-plant-supported restorations placed after sinus lift procedures in combination with Bio-Oss and Bio-Gide.

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236 i Computed Tomography analysis Of Schneiderian Membrane after lateral Sinus augmentation procedure

Guillaume anduze-acher (France), Benoit Brochery, Philippe Bouchard

Objectives: Bone substitute grafting is nowadays a well-established proce-dure for maxillary sinus floor augmentation before implant placement. So far, the impact of these procedures on the sinus membrane has not been explored. Therefore, it is of interest to evaluate the modifications of the Sch-neiderian membrane following grafting procedures.The aim of this study was to measure, with computed tomography, changes to the Schneiderian membrane following lateral sinus augmentation pro-cedure with a bovine bone xenograft (Bio-Oss®) and a collagen resorbable membrane (Bio-Gide®).Methods: Thirty lateral sinus augmentation procedures were performed on 26 healthy patients (22 females) with a mean age of 51.2 +/- 8.33 years. Bo-vine xenograft (Bio Oss®) was used as bone substitute and the lateral win-dow was closed with a resorbable membrane (Bio-Gide®). Post operative computed tomographies (CT scan) were analyzed with an image analysis system (ImageJ®). The thickness of the sinus membrane, the alveolar bone height, and the sinus filling were measured pre and postoperatively. Sta-tistical analysis (p=0.05) and intra-class correlation were performed. Cor-relation between the Schneiderian membrane height pre and post opera-tion were defined by linear regression. Finally, robust multiple regression analysis tested the association between dependant variable (Schneiderian membrane height) and independent variables (tobacco, periodontal ante-cedents, time between CT scans, complications, bone substitute, aggressive or chronic periodontitis).results: Ten months post operation (+/-5.64 months), a significant decrease of the mean sinus membrane thickness was observed (p=0.017), from 2.28 (+/- 2.14) mm to 2.07 (+/- 1.88) mm. Non-significant resorption of crestal crest was found (p=0.64), from 3.69 (+/- 1.19) mm to 3.63 (+/- 1.22) mm. The bone fill into the sinus was 13.19 +/- 3.11 mm, with an available total bone height of 16.94 +/- 3.33 mm. The correlation between pre and post membrane thickness was low (r=0.15). Multivariate analysis highlighted the influence of post operative healing time and chronic periodontitis (p=0.05).Conclusions: The Schneiderian membrane may be subjected to modification following sinus augmentation procedures. This modification may be inter-preted as an adaptation of the membrane over time. In healthy sinuses, the preoperative thickness of the membrane is not a prognosis factor for the postoperative thickness of the membrane following lateral augmentation.

237 i Maxillary Sinus Floor augmentation For implant placement: Clinical, Histological and Histomorphometric Study in 150 patients

dimitrios zabaras (Greece), Ioannis Gisakis, Spyros Bouboulis, Athanasios Spanos, Vasilios Petsinis

Objectives: The reconstruction of edentulous patients with adequate bone vol-ume by using dental implants has become a viable treatment option with high predictability. However, initial stabilization is difficult to achieve in the poste-rior maxillary regions where cortical bone is thin or absent due to severely resorbed alveolar ridges. Maxillary sinus lift procedures applied with various grafting materials enable clinicians to place implant-supported prostheses even in cases with increased pneumatization of the maxillary sinus. The ob-jective of this study was to histologically and histomorphometrically evaluate new bone formation after maxillary sinus floor augmentation (SFA) using au-tologous bone (AB), demineralised freeze-dried bone allograft (DFDBA) and platelet-rich plasma (PRP).Methods: 150 patients (80 women, 70 men, mean age 62 yrs) with bony height under the sinus ‹3 mm, in need of bilateral SFA using lateral window approach, before implant placement, were recruited. A 2-stage protocol was conducted. Patients were randomly divided in 3 groups of 50 patients each. In each group the right sinus was grafted with AB (in total 150 sinuses, control group, CG), while the left sinus (experimental group, EG) was treated with: 1st group: DFD-BA, 2nd group: DFDBA+AB, in the ratio 50/50, 3rd group: AB+PRP. In all cases lateral osteotomies were closed with resorbable collagen membranes. After a healing period of 6 months, bone cores biopsies were collected, by trephine bur, at implant placement. Five-micron thick sections, stained with haematoxylin-

eosin and Masson's trichrome, were used. 300 biopsies were processed for his-tomorphometric evaluation of the mean percentage of bone, residual graft and connective tissue by area. A total of 746 implants were placed into grafted sites.results: All patients had uneventful postoperative healing. Adequate bone vol-ume was clinically observed in all cases. All implants were restored functional-ly. Histological analysis revealed the presence of newly formed bone in all biop-sies. Bone showed a lamellar well-organized structure, in direct contact with residual graft (RG) particles. There was no evidence of acute inflammatory in-filtrate. Histomorphometric evaluation revealed an overall mean bone volume (MBV) of 51.6±17.1%, 32.7±13.5% of connective tissue (CT), and 15.7±10.3% of RG. The MBV was higher in cases where a combination of AB + DFDBA was used (54.2%) (p‹0.05). The addition of PRP in AB did not significantly increase MBV (p›0.05). In detail, analysis of the samples showed an average of: a) 1st group: 51.6% MBV, 19.1% RG particles, and 29.3% CT, b) 2nd group: 54.2% MBV, 17.6% RG particles, and 28.2% CT, c) 3rd group: 51.9% MBV, 12.7% RG particles, and 35.4% CT, d) Control group: 48.6% MBV, 13.3% RG particles, and 38.1% CT.Conclusions: The use of DFDBA + AB 50/50 mixture appears to promote, in the severe atrophic maxilla, a satisfactory bone formation. DFDBA is biocompat-ible and osteoconductive when used in SFA procedures and it may be used safely without interfering with the normal reparative bone process. The ad-dition of PRP did not appear to significantly enhance bone formation. No in-vestigated biomaterial was completely resorbed, but all the residual particles demonstrated close bone integration to form a hybrid tissue.

238 i Guided Bone regeneration For Extraction Socket augmentation: Clinical, Histologic and Histomorphometric Study in Humans

ioannis Gisakis (Greece), Demos Kalyvas, Konstantinos Tosios, Vasilios Petsinis, Konstantinos Alexandridis

Objectives: The preservation of bone volume immediately after tooth removal might be necessary to optimize the success of implant placement in terms of aesthetics and function. The objectives of this 3-months randomized, con-trolled, clinical study were: 1) to compare the bone dimensional changes fol-lowing tooth extraction alone versus extraction plus ridge preservation using allograft or xenograft and a collagen membrane; and 2) to analyze and com-pare histological and histomorphometric aspects of the extraction-alone sites to the grafted sites.Methods: 24 adult patients (19 male, 5 female, mean age 36.3 yrs) requiring an extraction and delayed implant placement were randomly selected to receive either extraction alone (EXT, control group, 8 cases) or ridge preservation (RP) using: demineralised freeze-dried bone allograft (DFDBA, 8 cases) or deprot-einized bovine bone mineral (BBM, 8 cases) and a collagen membrane. 12 ex-traction sites were located in maxilla and 12 in mandible. 8 sites (33.3%) were located in anterior areas, 7 in premolar regions (29.2%) and 9 in molar areas (37.5%). Following extraction and at the time of implant placement (IP), hori-zontal and vertical ridge dimensions were measured. After a healing period of 3 months, bone core biopsies were collected, by a trephine bur, at IP. Five-micron thick sections, stained with haematoxylin-eosin and Masson's trichrome, were used. A total of 24 biopsies were processed for histomorphometric evaluation of the mean percentage of bone, residual graft and connective tissue by area.results: The width of the RP group decreased from 9.2±1.2 mm to 8.0±1.4 mm (p›0.05), while the width of the EXT group decreased from 9.1±1.0 mm to 6.4±2.2 mm (p‹0.05). The vertical change at the buccal side for the RP group was a gain of 1.3±2.0 mm versus a loss of 0.9±1.6 mm for the EXT group (p‹0.05). The biopsies harvested from the grafted sites revealed formation and remodelling of trabecular bone, which was highly mineralized and well structured. New bone formation and connective tissues (CT) on and around DFDBA and BBM particles were widespread. No inflammation was observed. Histomorphomet-ric analysis revealed more bone in the EXT group, 70.1% versus 68.2% in the RP group (p›0.05).The RP group included both vital bone (58.9%) and non-vital (9.3%) graft fragments. In detail, analysis of the samples showed an average of: a) DFDBA group: 58.7% vital bone (VB), 5.9% residual graft particles (RGP), and 35.4% CT, b) BBM group: 59.1% VB, 12.6% RGP, and 28.3% CT, c) Control group: 70.1% VB and 29.9% CT.Conclusions: Ridge preservation using DFDBA or BBM and a collagen mem-brane improved ridge height and width dimensions when compared to extrac-tion alone. The quantity of bone observed on histological analysis was slightly lower in preservation sites, although these sites included both vital and non-vi-

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tal bone. Overall, no serious complication was seen during the healing period. In most patients marginal mucosa and bone levels remained stable following restoration. Implant success and survival rates were 100%.

239 i lingual Foramina and Their Bony Canalsin The Median region Of The Mandible: a CBCT Study

iuliana Babiuc (romania), Mihaela Pauna

Objectives: To investigate the presence of the lingual foramina and their bony canals in the midline of the mandible by means of cone beam computed to-mography and to describe their anatomical features.Methods: 36 subjects underwent CBCT examination of the mandible for im-plant therapy. The sagittal and axial cross sections through the anterior man-dible were carefully examined in order to detect the lingual vascular canals. Their presence, number, position, diameter and trajectory were established.results: Lingual foramina in the midline of the mandible were observed in all 36 subjects. An average of 1.5 foramina/subject was identifi ed. In 31% of the cases more than one foramen and canal could be observed. The average diam-eter of the canals was 0.84 mm. The average distance from the foramina to the base of the mandible was of 11.2 mm. 62.0% of the canals had a descending trajectory, 17.3% were solely anterior and 20.7% had an ascending trajectory.Conclusions: CBCT examination can reveal multiple anatomic features of the mandible that must be taken into account when planning an implant treatment. It can demonstrate the presence, position, size and morphology of the lingual vascular canals in the median region of the mandible. Clinicians should be aware of these anatomical structures and their possible implications.

240 i Clinical Evaluation Of a Novel Bone Graft Materialas a Composite in Sinus lifting applications: a pilot Study

alper Gultekin (Turkey), Safak Ahmet, Z.Cuneyt Karabuda

Objectives: Insuffi cient bone volume is a common problem in the rehabilitation of the edentulous maxilla with an implant supported prosthesis. In the posteri-or maxilla, the presence of the maxillary sinuses often limits the available bone height for dental implant placement. Maxillary sinus fl oor augmentation has been shown to be a predictable approach to correct this defi ciency. Since the technique of sinus elevation was introduced, various bone replacement materi-als have been used successfully. Biphasic calcium sulphate (BondBone, MIS-Israel) is a synthetic osteoconductive, bioresorbable novel bone grafting mate-rial that has been recently introduced for clinical use in sinus lift procedures.Methods: This study is the fi rst to use dental volumetric tomography (DVT) to histologically and radiographically evaluate and compare two different graft ma-terials; inorganic bovine bone matrix (ABBM) BioOss (Geistlich, Switzerland) and HA/ß-TCP – 4Bone (MIS, Israel) mixed with biphasic calcium sulphate (BCS) as a composite. A total of 11 patients with insuffi cient bone height in the maxillary posterior area were selected. Following the sinus lifting procedure with a lateral approach, one composite graft material (ABBM + BCS) was placed in one side and the other composite (HA/ß-TCP + BCS) was placed in the other side. Five months after, a trephine core was taken for bone biopsy core samples and sent for histological analysis. Also DVT were taken three times as before the sinus lift operation, right after the procedure and lastly fi ve months after healing for radiographic evaluation of available bone volume during the healing phase.results: No complications were observed during the surgical procedures. No signs or symptoms of maxillary sinus disease were observed during the fi ve months after sinus lift procedure. High resorption rate in early healing phase in DVT measurements were measured for both composite graft materials. New bone formation was also detected in histological samples.Conclusions: Future studies are needed to confi rm the ability of this novel bone replacement material with different mixture ratios as a composite and for lon-ger healing periods.

241 i Evaluation Of Straumann® Bone Ceramic in The TreatmentOf Exposed implants Threads, prospective Clinical Study

atef ismail (Egypt)

Objectives: In implant placement post extraction we are faced with different challenges; a major challenge is to gain the primary stability of the inserted implants. The most important challenge is the coronal gap between the im-plant and surrounding bone with exposed implant threads. We are faced with both vertical and horizontal bone defects besides fenestration in some cases. Different augmentation material and techniques can be utilized to solve this challenge. One of the most important criteria of augmentation material selec-tion is its osteoconductive properties, providing good volume stability and ex-ceptional handling properties. Straumann® Bone Ceramic fully synthetic bone substitute with optimized morphology leads the way to new vital bone, with excellent wetting properties and good handling.Purpose of this prospective study was to evaluate the possibility of augmenting the exposed implant threads with Straumann® Bone Ceramic.Methods: 12 patients indicated for extraction and immediate placement in the anterior and premolar area and removal of the defective tooth. Curettage of the socket and removal of all granulation tissue. Insertion of the selected im-plant according to the manufacturer’s protocol. 7 sites with marginal defects, 5 sites have fenestration defects with exposed threads (4~12 showed implants threads). All the exposed threads in both marginal and fenestration defects were registered clinically and photographically before augmentation. All cases received a fi rst layer of thin autogenous bone harvested by bone scrapers. All sites augmented with Straumann® Bone Ceramic.All cases were covered with collagen membrane. After 6 months in secondary surgery both marginal and fenestration defects were evaluated by measur-ing the exposed implant threads registered clinically and photographically. All cases received defi nitive restoration after 6 months. All cases were evaluated radiographically for 18 months.results: In this prospective clinical study 12 patients (7 females, 5 males) were selected with special inclusion criteria indicating single tooth extraction and immediate placement in the anterior and premolar regions. All patients re-ceived root form implants with length (13 mm ~16 mm), diameter (3.5 mm ~ 4.4 mm). In this prospective study 7 implant sites have marginal defects and 5 sites have fenestration with exposed implants threads (4 ~ 12) was recorded. After 6 months of augmentation with Straumann® Bone Ceramic, we gained complete coverage of exposed implant threads, which was seen in 11 of 12 implant sites. Complete coverage of 5 sites with fenestration defects. Complete coverage of 6 of the 7 sites with marginal defects. 1 site showed 1 to 2 remaining exposed implant threads of the marginal defect sites. Radiographic evaluation extended to 18 months showed stability of marginal bone around implants.Conclusions: In implant placement post extraction, different augmentation materials and techniques can be utilized to overcome the vertical and hori-zontal bone defects. In this prospective study Straumann® Bone Ceramic fully synthetic bone with optimized morphology can be used to obtain marginal bone with excellent wetting properties and good handling. Straumann® Bone Ceramic can be used successfully to augment exposed implants threads.

242 i The use Of Frozen Homologous Bone in patientsaffected By Serious upper Maxillary atrophy

paolo piacentini (italy), Gianmaria Agnelli, Massimo Bellia, Umberto Zanetti

Objectives: The authors present a series of 12 patients affected by serious up-per maxillary atrophy (degree 5–6 according to Cawood and Howell) in which fi xed implant rehabilitation, after grafting frozen homologous bone, has been realized, with follow up at 48 months.The aim of the study is to demonstrate that the use of frozen homologous bone can be an alternative to the autogenous bone in the rehabilitation of serious maxillary atrophies, guaranteeing the same clinical results in terms of stabil-ity of tissues and integration of positioned implants. In this work, an analysis was made of the histological implication of frozen homologous bone integrated on the native bone. The histological aspects were compared with the normal evolution of bone guarizon. So 12 pz was examined. At time points T0, T1, T2.Methods: 12 patients with serious maxillary atrophy were included in the study. They underwent the usual surgical procedure: inlay and onlay reconstruction using frozen bank bone in association with PRP. After 6 months means of syn-thesis, they were then removed and contemporary implants were inserted fol-lowing the usual technique. In 4 patients, as adequate stability was achieved, we were able to proceed with an immediate load; while in other cases, in which an adequate torque insertion was not achieved, a differed implant load was

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preferred (8 patients). After 4–5 months the surgical sites were re-opened and we proceeded with implant rehabilitation using either a provisional screwed implant, or a definitive screwed implant (in the immediate load cases).results: The evaluation consisted in a histological control at T0, T1 (implant insertion) and T2 (follow up or during secondary intervention. A good integra-tion of the frozen homologous bone with the native bone was achieved. Subse-quently 76 superior maxillary implants (diameter 4 and 13-11.5 mm of length respectively) were evaluated: the loss of 2 implants out of 76 (2.63%) with a success rate of 97.5 was demonstrated.Conclusions: The rehabilitation of serious maxillary atrophies using fresh ho-mologous bone seems to be a viable alternative to the autogenous bone treat-ment technique. The histological aspect of T1 bone shows that there was less osteoblast and osteocitis than in normal bone. This characteristic seems to correlate with a correct cortical relationship and engaged midollare that con-firms a different pattern of integration with bony material of the host.

243 i Fares Wedge Technique: a New Simple Method For 3d ridge augmentation

Fares kablan (israel)

Objectives: Recently, there has been an increase in the number of patients with different degrees of atrophic jaw ridges who contact oral surgeons to seek rehabilitation with dental implants. Many of them have had removable appli-ances, so the need for bone augmentation is increasing. Several bone graft-ing techniques and materials are used, but consistent results are difficult to achieve especially in the case of mandible and vertical defects.Space maintenance capacity of the graft materials used is an important fac-tor among several factors affecting success of bone augmentation procedures.In this report I present a new and simple method “Fares Wedge technique" for 3-dimensional ridge bone augmentation.Methods:41 patients (58 sites), 11 at maxilla, 47 at mandible were treated by this technique during the last years(Sept 2008- Dec 2010). Retromolar/Ramus are the gold standard as donor sites. In one case we used the palatal torus and in another case bone block from the osteotomy site of maxillary correction in the same operation. After preparation of the graft block and recipient site, our technique used slices of the former (creating thin bone wedges) and grooves of the latter. We created multiple compartments which were filled with allog-enous bone, and covered with biodegradable membrane, suturing the flap ten-sion free. In some cases we used soft tissue free graft. We waited 3–4 months until implants were inserted. During this period we recalled the patients sev-eral times to observe the healing process.results: The recovery time, morbidity, costs and complications were all favour-able in all of our patients. The success rate was 97%, in two patients the graft was partially exposed and treated with saving and rounding the exposed wedges and oral hygiene maintenance, but the augmentations were saved. In one additional case, we lost the majority of the graft volume. At 40 sites implant insertion was successful (115 implants), at 2 sites the follow up failed and 15 sites are still in the recall period, and have favourable healing. The bone gain was 3–8 mm vertically and 4–10 mm horizontally. No complications were observed at the donor site.Conclusions: Wedge technique utilizes Auto/Allogenous bone grafts. The goal of autogenous graft slices was space maintenance, and that of the allogenous material was to fill the compartments produced between the autogenous bone wedges. The donor site is appropriate with favourable morbidity and costs. The bone volume achieved was satisfactory, especially since the majority of our augmented areas had 3-dimensional posterior mandibular defects. The bone volume with lateral augmentations was more satisfactory.

244 i reconstruction Of Orbital Floor Fractures With Collagen Membrane (Bio-Gide)

Massimo Marasco (italy)

Objectives: Orbital floor fractures, often combined with zygomatic fractures, are common fractures of the midface. Surgery of orbital fractures is done to free incarcerated or prolapsed orbital tissue and to restore the anatomical skeletal size of the orbit and to prevent soft tissues fibrosis. Different materials have been tested over the years to achieve this purpose. Traditionally, autog-

enous grafts have been used as the material of choice; in recent years allo-plastic materials have gained popularity because of their availability and ease of use. Lyodura was a standard for the reconstruction of the orbital floor until cases of Creutzfeldt-Jakob disease were reported, so that polydioxanone (PDS) is widely used today. However, infections around the implant are reported.Methods: This report presents the results obtained by the application of col-lagen membrane (Bio-Gide) which was treated surgically because of blow-out fractures from 2008 and 2010 at the Department of Maxillo-Facial Surgery of the Istituto Ortopedico I. Galatioto Villa Salus Augusta (SR).In this clinical study on 14 patients with orbital floor defects, we evaluated the use of a collagen membrane (Bio-Gide). Computed tomography controls and ophthalmologic examinations were performed after 6 months.results: No intra-operative complications occurred. Peri-operatively and post-operatively, no complications such as infections were observed.In instances of orbital rim fractures, the collagen membrane could additionally cover these defects. After 6 months, computed tomography controls revealed a complete reposition of orbital tissue and, very important, even bone regenera-tion. Diplopia and hypoaesthesia were completely reversed after half a year. Smaller defects (up to 1 cm) of the orbital floor can be restored with a collagen membrane. However, for larger defects, stability may not be sufficient.Conclusions: There was a reduction in operative time with the use of Bio-Gide membrane implants compared with the use of bone, no infections occurred so Bio-Gide collagen membrane is a safe and very useful material for orbital floor fracture reconstructions.

245 i analgesic Consumption Following Sinus lifting Surgery

Shirali Shiraliyev (Turkey), Volkan Arisan, Alper Gultekin, Cuneyt Karabuda

Objectives: The aim of this study was to investigate the rate of analgesic con-sumption following open sinus lifting surgery.Methods: The study group consisted of 26 patients consisting of 10 male and 16 females who applied to the Istanbul University Faculty of Dentistry, Department of Oral Implantology for treatment for maxillary edentulism. Due to insufficient vertical bone height in the posterior maxilla, sinus lifting surgery was performed using the lateral window technique. The elevated sinus space was filled with in-organic bovine bone matrix (Bio-oss/Geistlich, Switzerland) and closed by a re-sorbable collagen membrane (Bio-Gide/Geistlich, Switzerland). The number of analgesic+ anti-inflammatory naproxen sodium tablets (550 mg, Apranax forte/Abdi Ibrahim, Turkey) consumed in the postoperative week was recorded by all patients. Results were analyzed using the Mann Whitney U test (p‹0.05).results: Mean age of the patient group was 55.4 (SD 7.75) years. All surgical operations were completed without any complications. The mean total num-ber of consumed analgesics was 6.12 (SD 1.89) tablets throughout the week after surgery. Mean number of analgesics consumed by men (6.1 (SD 1.24) and women (6.22 (SD 1.13) was statistically not significant (p=0.12).Conclusions: Within the limits of this study it can be concluded that sinus lift-ing surgery using the lateral window technique involving deproteinized bovine bone and a resorbable collagen membrane leads to a moderate level of anal-gesic consumption (6.12 tablets) in the following week.

246 i a New Surgical Technique Of Sinus Floor Elevation

Tatiana kolesnikova (russia), Ziad Raad

Objectives: Grafting of the maxillary sinus in both one- and two-stage proto-cols has become a highly predictable surgical technique for site development and for the placement of implants to support dentures. All of the surgical tech-niques to elevate the maxillary sinus present the possibility of perforating the Schneiderian membrane. Thus, complications can occur during the osteotomy, which is performed with burs, or during the elevation of the membrane using manual elevators.The purpose is to present a new surgical technique that radically simplifies maxillary sinus surgery, thus avoiding perforating the membrane.Methods: The method includes “transposition of the maxillary sinus floor by interlaminar osteotomy of the alveolar ridges”. The aim of the method is to enhance the osseointegration of the implant by forming a subantral space for placement of the implant. The risk of damaging the mucous membranes of

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the maxillary sinus in this case is lower because all the walls are made of bone tissue. A very important condition should be considered when applying this method and it is the height of the subantral alveolar ridge, which should not be less than 5 mm.The core of the new surgical technique is interlaminar osteotomy of the sub-antral parts of the alveolar ridges in a horizontal plane. The lower part of the fragment, which includes the mucous membrane and the compact bone layer, forming the fl oor of the maxillary sinus, will be shifted upwards, thus creat-ing the subantral space. The subantral space was fi lled with bone substitution material coupled with autogenous bone.results: The sample consisted of 221 patients and 657 posterior maxillary im-plants. The mean duration of follow-up was 22.50+19.06 months. The 5-year survival rates for implants in the ungrafted and grafted posterior maxilla were 88.00% and 87.8%, respectively (P=0.8).Endoscopic analysis after 6 months didn’t show any signs of pathological changes in the sinus area. This method received a patent - 2260391 in 20.09.05; more than 200 patients have been op-erated on using this method since 2005.Conclusions: The suggested modifi cation helps to decrease the risk of damaging the mucous membrane of the maxillary sinus; it creates optimal conditions for performing reparative osteogenesis and implant osseointegration procedures.

247 i Strategy For Management Of infectious Tooth ExtractionSite in aesthetic implant Therapy: Combined usage Of Bio-Oss Collagen and platelet-rich Fibrin

Hui Wu (China), Lin-xin Qiu

Objectives: The outcome of implant therapy is no longer measured by the im-plant survival rate alone, but also by long-term aesthetic and functional suc-cess. However, loss of an infected tooth in the aesthetic area usually causes hard and soft tissue defects which can lead to an unsatisfactory restoration result. So the question of how to prevent ridge resorption and gingival reces-sion has become a universal concern. Various graft materials have been used in attempts to preserve the alveolar ridge following tooth extraction. Among these materials, bovine bone mineral displays osteoconductive properties forming an effective bone/graft matrix for implant placement. But little was known about it in infected tooth extraction sites in aesthetic implant therapy. Thus the purpose of this study was to evaluate the clinical result of combined usage of Bio-Oss collagen and PRF in infected tooth extraction sites, and to in-vestigate the indication, surgical technique, and the implant time of this socket preservation method.Methods: From Jul 2006 to Jan 2010, 21 patients were enrolled in this study, 13 male and 8 female, average age 36. 23 infected teeth in the aesthetic area were extracted and socket was preserved immediately with Bio-Oss collagen and PRF, including 15 central incisors, 4 lateral incisors, 2 canines and 2 premo-lars. Panoramic radiograph and periapical fi lms were taken to observe bone healing and osseointegration. At the time of implant, a core biopsy was taken from the centre of the extraction site with a trephine bur (D 2 mm) and then histomorphometrically observed. The bone healing time, implant type, initial stability and graft surgery were recorded with statistics.results: 23 teeth were extracted and bone graft healing took place uneventful-ly. All sites were clearly different from the original alveolar crest, allowing the retrieval of samples from the socket centre. The average diameter and length of 23 implants was 3.8±0.3 mm and 13.2±1.7 mm. The thickness of 7 implants labial lamina was less than 1 mm, then GBR surgery was undertaken (30.4%). Others were thicker than 1 mm(69.6%). 6 of them were given connective tissue transplantation because labial fullness was poorer than on the contralateral side(26.1%). 10 were given only implant surgery(43.5%). 3 of them had early placement with soft tissue healing (type 2, typically 4 to 8 wk of healing), 16 teeth positions had early placement with partial bone healing (type 3, typically 12 to 16 wk of healing), 4 implants had placement after more than 4 months be-cause of orthodontic treatment. In all implants initial stability was higher than 30 Ncm, 7 of which were higher than 40 Ncm and had immediate restoration.Conclusions: As infected tooth with bone defect in the aesthetic area, preser-vation of fresh socket immediately by the combined use of Bio-Oss collagen and PRF could preserve the contour of the ridge effectively and provide good bone volume and quality for aesthetic implant therapy. It could make clinical manipulation easy, reduce expense, shorten the treatment period and reduce patient trauma, so it will have a wide clinical application.

248 i Treatment Of Miller Class i and ii Multiple Gingival recessions With a Bioresorbable Collagen Matrix (Mucograft®): a prospective, randomized, Controlled Split-Mouth Clinical Trial

Balint Molnar (Hungary), Sofi a Aroca, Tibor Keglevich, Peter Windisch, Giovanni E. Salvi, Anton Sculean

Objectives: The aim of this prospective, randomized, controlled split-mouth clinical trial was to compare the treatment of Miller Class I and II multiple gingival recessions using the modifi ed coronally advanced tunnel (MCAT) tech-nique by means of either a bioresorbable collagen matrix or a connective tissue graft (CTG).Methods: Seventeen subjects in good general health exhibiting multiple Miller Class I and II gingival recessions (i.e. at least 3 recessions per site) were includ-ed and treated. According to a computer-generated randomization schedule, recession sites were treated using the MCAT technique by means of either a bio-resorbable collagen matrix (Mucograft®, Geistlich, Wolhusen, Switzerland) (test) or a CTG harvested from the palate (control). The following clinical parameters were assessed at baseline and at 1, 3, and 6 months postoperatively: recession depth and width, width and thickness of keratinized tissue, distance from the tip of the papilla to the contact point, papilla width, probing pocket depth.results: No allergic reactions, soft tissue irritations or matrix exfoliations occurred at test sites. Mean root coverage amounted to 1.2 ± 0.4 mm at test sites vs. 1.5 ± 0.6 mm at control sites. The mean increase in keratinized tissue width amounted to 0.2 ± 0.4 mm at test sites vs. 0.5 ± 0.6 mm at control sites. Complete root coverage was found in 52% of test sites vs. 72% of control sites. Duration of surgery and patient morbidity were statistically signifi cantly lower in the test compared to the control group, respectively.Conclusions: hese outcomes indicate that: i) treatment of Miller Class I and II multiple gingival recessions using the MCAT technique combined with either Mucograft® or CTG may result in substantial mean root coverage, but lower complete root coverage with Mucograft® and ii) Mucograft® may represent a valuable alternative to the palatal connective tissue graft, resulting in lower patient morbidity and duration of surgery. The present study was supported by a grant from Geistlich, Wolhusen, Switzerland.

249 i The Comparison Of Effi cacy and Stability Of VerticalBone augmentation after ddBM+hrpdGF, Bone Ceramic+EMd, and allogenous Bone+ Natix around The implants

andrej Wojtowitz (poland), Jan Perek, Kaminski Artur

Objectives: A bone regeneration process was described recently by Urist and Huggins. The key factors are: cells, growth factors (BMPs) and blood stream. The advanced bioengineering methodology: stem cells, human recombinant factors, invented scaffolds were used for bone augmentation in jaw bone de-fect treatment. Five advanced “hybrid” techniques, based on tissue engineer-ing, using scaffold with or without growth factors were present and compared with the effects of stimulation of osteogenesis/resorption = remodelling of alveolar bone by transplants: 1. DDBM with hrPDGF (Bio-Oss+/-Gem21S) 2.DDBM without GEM21 S, 3. Bone Ceramic with Emdogain, 4. Bone Ceramic without EMD, 5. Tigran+allogenous cortical bone granules, processed in tis-sue bank (Central Tissue Bank, Warsaw Medical University, Ethics committee agreement).Methods: The “hybrid” transplants were installed together with implants dur-ing one-step surgery and consisting of bone transplant around 5–7 implants each in fi ve groups of the male patients (age 40-65) for measurements. Trans-plants were applied in the maxilla aesthetic area, where all implant sites were covered up to the bone level approx 1- 1.5 mm of the anterior site of the im-plant, the posterior site was covered by jaw bone.The correlation of bone profi le (Straumann Bone Profi le Device) and ISQ-Ostell in time-intervals: 1/2, 3, 6, 12, 24 months were measured and evaluated. The implant’s survival rate and implant’s success rate as well as recession rate were evaluated clinically. The Ostell-ISQ provides objective and non-invasive measurements of the implant stability at the placement as well as during the healing and bone maturation period.results: Two implants were lost. The implant success rate was 96%. The high-est decrease in bone profi le was found where bone ceramic was applied. There were no signifi cant differences when bone ceramic was enriched by EMD. The

51

annual loss of bone profile around the implant was approximately 20 % of the volume. In this group the smallest implant success rate were found, as well as highest bone-gingival recession around the implants.The best implant success rate was found when tigran and allogenous-cortical bone were used. Similar results were reached for DBBM + hrPDGF, significantly better when enriched by hrPDGF added into the transplant. Newly formed bone augmented under influence of Tigran and cortical allogenous bone shows the most stable results and closest similarity to the Bio-Oss with GEM 21 S. Tigran is not a carrier, it is a unique stable x-ray marker for bone augmentation. The process between bone and titanium interface is very well known and described.Conclusions: It seems that application of growth factors (GF) is more effective than guided bone regeneration (GBR) of jaw bone, especially in the vertical plane. It is very probable that EMD as a non-recombinant, but isolated factor is rapidly released from the scaffold environment and has a lower or incidental biological activity in comparison with potent recombinant hrPDGF. The adhe-sion of GF to titanium is not known, but the highest affinity of GF to the surface of natural mineral is well described.

250 i Treatment Of Bisphosphonate-associated Osteonecrosis Of The Jaw With Mesenchymal Stem Cells

pit Jacob Voss (Germany), Rainer Schmelzeisen, Egle Veigel, Eva Jablonka, Marc Metzger, Sebastian Sauerbier

Objectives: Bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) is a clinical problem with well described morbidity, especially when given intra-venously. Surgical management with necrotomy is often required where con-servative management has failed, but is not without the risk of relapse. The role of marrow derived mesenchymal stem cell (MSC) grafting in promoting wound healing is well described. The aim of this study was to assess the role of MSC in the management of BP-ONJ.Methods: In a pilot study, 8 patients with refractory BP-ONJ were managed with surgical resection of necrotic bone followed by MSC grafting. Marrow de-rived cells were aspirated from the iliac crest and concentrated using a chair-side bone marrow concentration procedure to obtain MSC. MSC were then grafted into the defect with autologous thrombin and a Bio-Gide membrane. In all cases bony edges were rounded and the wound was closed using a three layer technique.results: At 12-15 months follow up, all patients showed satisfactory healing with no signs of wound-infection, dehiscence or recurrence of BP-ONJ. Only one patient developed significant complications, i.e. sepsis of unknown origin, two months postoperatively.Conclusions: This pilot study into the surgical management of refractory BP-ONJ with mesenchymal stem cell grafting seems to be a promising treatment modality. Our results suggest that further prospective investigation is warranted.

251 i a pilot Study To Evaluate Safety and Effectiveness Of Natural Bone Block Mineral For Bone augmentation Of One-Tooth-Gaps

Simone Heuberer (austria), Ela Balic, Stefan Tangl, Georg Watzek

Objectives: The aim of the pilot study was to use natural bone block mineral for horizontal ridge augmentation of single tooth gaps. Two patients of the Bernhard Gottlieb School of Dentistry, Vienna, Austria, were involved in this pilot study.Methods: Patients with an insufficient ridge width of a single tooth gap and of a good general health were included. Augmentation was achieved with a hy-droxyapatite- and collagen- containing natural bone block mineral, which was fixed onto the decorticalized vestibular bone wall and covered by a collagen membrane. Clinical and radiographic examinations were performed; bone core biopsies were histologically analyzed.results: The primary parameter was implant placement after 16 weeks of heal-ing and the outcome was positive. No material-related adverse effects were en-countered.Conclusions: Discussion: After 16 weeks of healing the bone within the defects was not yet corticalized and narrow implants were used. Conclusion: Manage-ment of demanding defects such as ridge augmentation with a volume stable natural bone block mineral has to be further investigated and optimized for the clinical use.

252 i The role Of pericranium in The prevention Of Wound Complication and implant Survival Following reconstruction Of Severely deficient Edentulous ridges

alberto Coggiola (italy), Matteo Chiapasco, Elena Corsi

Objectives: To evaluate the influence of pericranium used for the coverage of autogenous bone grafts for the reconstruction of severely atrophic jaws on: a) the incidence of wound dehiscences; b) the survival rate of implants placed; c) peri-implant bone resorption; and d) the incidence of peri-implantitis.Methods: 34 patients presenting with severely atrophied edentulous ridges were reconstructed with autogenous bone blocks. In 16 patients (control group) the grafts were covered with a collagen membrane, while in 18 patients (test group) a layer of pericranium was placed over the collagen membranes covering the bone blocks. Four to 5 months later, 178 implants were placed in the reconstructed areas and prosthetic rehabilitation was started 3 to 4 months afterwards. The mean follow-up of patients after the start of prosthetic loading was 31 months.results: The incidence of dehiscences was 5% in the test group and 12% in the control group, while peri-implantitis occurred in 5% and 25% in the test and control groups, respectively. Peri-implant bone resorption and implant survival rates did not show statistically significant differences between the two groups.Conclusions: The use of pericranium may reduce the incidence of dehiscence after reconstruction of atrophic ridges as well as the occurrence of peri-im-plantitis, while it seems to have no effect on peri-implant bone resorption and survival rate of implants placed in the reconstructed areas.

253 i long-Term results Of Hard Tissue reconstruction using alloplastic and autologous Grafts – What did We learn in The last 15 years?

yorck zebuhr (austria), Dusan Kosarevic, Gert Santler

Objectives: Hard tissue regeneration and reconstruction came into focus as dental implantology developed to a standard method of rehabilitation. The aim was to use implant rehabilitation methods in the osseous compromised situ-ation as well. Originating from autologous procedures, xenogenous materials had the effect of reducing donor site morbidity.Methods: Retrospective analysis of consecutive alveolar augmentation proce-dures from a maxillofacial unit in the years 1995–2000 regarding primary out-comes and long-term results focusing on stability of the primary osseous and prosthodontic/implant reconstruction.results: The majority of osseous and prosthodontic reconstructions have good primary and long term outcomes. Problematic cases were re-evaluated and investigated for risk factors.Conclusions: Hard tissue grafting is a safe procedure and results are stable even in the long term.

254 i Maxillary Sinus Grafting With (NanoBone®) Hydroxyapatite Embedded in a porous Silica Gel Matrix in Humans: Histological, Histochemical, and Histomorphometric results

dieter Bosshardt (Switzerland), Jean-Pierre Carrel, Michael Bornstein, Daniel Buser, Jean-Pierre Bernard

Objectives: To evaluate the amount of new bone after sinus floor elevation with a synthetic bone substitute material consisting of hydroxyapatite embedded in a porous silica gel matrix (NanoBone®/NB), since information is scarce in humans when new biomaterials are used.Methods: The lateral bone window approach was applied in eight patients re-quiring a sinus floor elevation procedure to install dental implants. After eleva-tion of the Schneiderian membrane, the cavities were filled with 0.6 mm gran-ules of NB mixed with the patients’ blood and a collagen membrane (Bio-Gide®; group 1) or a platelet-rich fibrin (PRF) membrane (group 2) was placed over the bony window. After 7–11 months of healing (in one case after 24 months), 16 biopsies were harvested during implant bed preparation. After aldehyde fixa-tion, the samples were decalcified in EDTA and embedded in LR White resin. Sections were stained with basic fuchsin and toluidine blue. The percentage of new bone, residual filler material, and soft tissue was determined histo-

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morphometrically. In addition, sections were histochemically treated to detect tartrate-resistant acid phosphatase (TRAP) enzyme activity, normally being as-sociated with osteoclast-like cells.results: Four biopsies had to be excluded from the analyses, since only old bone from the residual ridge was contained in the trephine due to incomplete tissue retrieval. In the augmented region of the remaining 12 biopsies, new bone formed a dense network of evenly distributed bone trabeculae interconnect-ing with neighbouring NB particles, which were structurally non-homogeneous and appeared porous. Numerous TRAP-positive multinucleated cells were mainly observed at the soft tissue-NB interface. For group 1, the amount of new bone, residual fi ller material, and soft tissue was 28.7%±5.4, 25.5%±7.6, and 45.8%±3.2, respectively. For group 2, the corresponding values were 28.6%±6.9, 25.7%±8.8, and 45.7%±9.3. All differences between groups 1 and 2 were not sta-tistically signifi cant. The lowest and highest values of new bone were 21.2% and 34.1% for group 1 and 17.4% and 37.8% for group 2, respectively.Conclusions: The amount of new bone after the use of NB for sinus fl oor eleva-tion in humans is comparable to the highest values found in the literature for other synthetic or xenogeneic bone substitute materials such as Straumann BoneCeramic® or Bio-Oss®. Concerning the amount of new bone, there was no additional benefi cial effect of the PRF membrane over the Bio-Gide® mem-brane. TRAP-positive osteoclast-like cells appear to be involved in the degra-dation of the synthetic biomaterial.

255 i radiographic Evaluation Of Marginal Bone levelsFollowing immediate implant placement into Extraction Sockets

Nobuyoshi Sugioka (Japan)

Objectives: The aim of this prospective study was to evaluate the amount of buccal/palatal bone loss that occurred over 1 year of healing following their installation into extraction sockets using cone-beam computed tomography.Methods: In 26 subjects, single-tooth implants were placed immediately into extraction sockets in the maxilla (tooth locations 15/25). After implant instal-lation, a series of measurements were made to determine the dimension of the ridge using cone-beam computed tomography and the void between the implant and the extraction socket. These measurements were repeated in the re-entry procedure over 1 year.results: The implant survival rate was 100% for all 26 implants. The study dem-onstrated that the removal of single teeth and the immediate placement of an implant resulted in marked alterations of the dimension of the buccal ridge and the horizontal as well as the vertical gap between the implant and the bone walls.Conclusions: Implant placement into extraction sockets will result in signifi cant bone reduction of the alveolar ridge.

256 i retrospective Study Of 101 implantsinserted in augmented Maxillary Sinus

Joao antonio dosualdo (Brazil)

Objectives: The aim of the present study was to evaluate bone formation fol-lowing maxillary sinus augmentation using bovine bone substitute material Bio-Oss® and to determine the rates of long-term success and current radio-graphic images of the implants installed after the sinus lifting procedure and to analyze the modifi cation/alteration of the grafting images in a case of maxillary sinus augmentation, recording and comparing radiographic images at 1 week, 2 months, 8 months, 1, 2, 5 and 10 years after surgery.This long-term evaluation has been performed comparing radiographic im-ages at different times and involved a total of 58 sinus fl oor elevation pro-cedures, carried out on 36 patients (average age of 49.6 years) according to the technique described by Tatum (1986) and a total of 101 dental implants inserted.Methods: Between July 2000 and December 2010, a total of 101 implants were installed in 36 patients (12 men / 24 women), who were aged between 45 and 83 years (average: 60.2 years), in which the surgical procedure of the sinus lifting technique were consecutively enrolled on edentulous ridge bone (less than 4 mm). Straumann SLA® implants were placed after 8 months of graft healing. After another 3 months, the occlusion was restored with fi xed prostheses and followed at least for 5 years of functional loading. All the patients were followed

through visits that were scheduled for 1 and 12-month intervals during the fi rst postoperative year and annually or bi-annually thereafter. At each recall, clinical and radiographic examinations of the sinuses and implants, including computerized tomography (CT), were performed.results: Ten of 101 implants were lost, giving a cumulative survival rate (CSR) of 91.1%. All lost implants were substituted and all followed patients had fi xed prostheses functioning after 5 years of loading.Conclusions: This study suggests that the installation of implants after the sinus lifting procedure combined with deproteinized bovine bone (Bio-Oss®) grafting in cases with pneumatization of the posterior maxilla have great predictability and high survival rates. Therefore, these procedures represent a reliable option for the treatment of patients and enable clinicians to place implant-supported prostheses even in cases with increased pneumatization of the maxillary sinus with atrophic alveolar bone.

257 i augmentation Of alveolar ridge afterComminuting Fractures With distraction Osteogenesis

Miha kocar (Slovenia), Andrejka Eberlinc, Andrej Kansky, Vojko Didanovic

Objectives: Distraction osteogenesis (DO) is an established method to gain al-veolar bone in the alveolar ridge. Comminution of the alveolar ridge is often associated with fractures of the upper and lower jaw. The aim of the study is to fi nd out if DO is an appropriate surgical procedure to gain bone for reconstruc-tion with dental implants.Methods: Reconstruction with DO was performed on four patients (2 male, 2 female), average age was 25 (18–34). Comminution of the alveolar ridge (3 mandibles, 1 maxilla) with loss of teeth (4–6) was present in all. After the heal-ing period and due to jaw fractures, clinical and x-ray examination was carried out. It was found out that 8 to 14 mm of bone needed rehabilitation. Temporary partial dentures were delivered preoperatively. Under general anaesthesia, osteotomy and fi xation of distractors (Medartis) were performed. Bi-or mono-directional (2/2) distractors were used depending on the clinical need. Distrac-tion started 10 days later, 0.5 to 0.75 mm per day. In 2 cases, buccal angulation of the distracted segment was added at the end. According to the protocol, panoramic radiographs were performed. The consolidation period lasted 16 weeks, distractors were removed and 12 dental implants (Ankylos, Dentsply-Friadent) were inserted. Implants were uncovered 4 months later and fi xed prosthetics were delivered.results: With DO 9 to 15 mm of bone defi ciencies was gained and gave us conditions for rehabilitation with dental implants. Bi-directional distractors gave us the opportunity to correct distracted segments in a better position. In any case, no extra augmentation procedures were needed. Implantations were performed immediately after the consolidation period, 8/4 implants of 17 mm/14 mm in length. All of them were osteointegrated.Conclusions: All 4 cases with DO vertical defi ciencies of the alveolar ridge were anatomically corrected. Use of bi-directional distractors made the correction of the buccal-lingual vector possible. The established height of the alveolar ridge made the insertion of dental implants possible. Partial dentures were used for additional stabilization of the osteotomized segment.

258 i Hard and soft tissues protection in immediateVS delayed implant placement

Wang ying (China), Ye Lin, Bo Chen, Linxin Qiu, Yu Zhang, Hui Wu

Objectives: Immediate placement of implants has been found to have a high rate of success. It was shown that major changes in an extraction site occur in the fi rst 3 months after tooth extraction. While many researchers believe that delayed implant placement for anterior teeth is more predictable for the esthetic result. This study is to observe the clinical result of immediate implant and delayed implant.Methods: Group 1: Immediate implant9 Patients presented untreatable anterior upper teeth. Cone Beam CT were took before surgeries. Teeth were extracted without fl ap refl ection, and im-plants (Nobel Biocare Replace/Ankylos) were inserted simultaneously. Bio-Oss granules and Bio-Gide membrane were used to fi ll the gap between the implant and the bone wall. Mattress suture was adopt on both sides of the

53

healing abutment to achieve the primary wound closure. Cone beam CT was took after 6 months from the day of implants placement.Group 2: Delayed implant5 patients presented two untreatable anterior upper teeth. We follow the de-layed implant protocol. Teeth were extracted with bone (Bio-Oss/Bio-Oss Col-lagen)graft. Implants (Nobel Biocare Replace/Ankylos) were placed following two stage protocol with guided bone regeneration (Bio-Oss granule and Bio-Gide membrane) after 3 months. 6 months after the implant placement, heal-ing abutments were placed. Cone bean CT was took after 6 months from the day of implants placement.results: Through the comparison of the 3D-CT pre-op and post-op, the alveo-lar bone was preserved very well on both groups. The gingival margin level and the papilla are quite favorable on both groups. On the second group, during the early months after teeth extraction, the papilla showed different level absorp-tion, while recovered spontaneously after delivered provisional crowns.Conclusions: Both two cases got optimize esthetics means both two protocols can achieve optimized esthetics. Immediate implant shows more time-saving, while delayed implant shows more time-consuming, and complicated. We rec-ommend Bone grafts combine with membrane technique for both immediate implant and delayed placement. Long-term prospective studies on tissue sta-bility and esthetic outcomes are needed in the future.

259 i implant location and related primary and secondary stability

Volker Clar (austria), Alexander Heschl, Susanne Platzer, Michael Payer, Martin Lorenzoni, W.A.Wegscheider

Objectives: The objectives of our study were to evaluate the different mean insertion torque and Periotest values for the jaws, to show correlations to dif-ferent indications and to determine the accuracy to document implant stability and to show possible predicting capacity for early implant failures.Methods: The present study was conducted as a retrospective non-controlled single centre trial. 475 males and 706 females (3123 Xive and Frialit II implants) underwent implant rehabilitation and their collected data was used for our study. All implants were inserted as late implants more than 3 months after healing. The implants were placed with an increasing counter-torque (Torque-Controler, Nobel-Biocare, Gothenburg, Sweden). The Periotest was used according to the manufacturer´s instructions during second stage surgery. The insertion torque and Periotest values were documented and the mean values were evaluated. results: Early failures were found for 7 Xive® implants (0.3 % of 2299 implants) and for 31 Frialit II® implants (3.8 % of 824 implants). For Frialit II implants it was evaluated that the group with lower insertion torque than 45 Ncm the failure rate was higher (p‹0.011). Xive implants didn´t show a difference, but the failure rate was very low for calculations. Mean insertion torque values for Frialit II® implants were the lowest in the maxilla followed by the mandible. For Xive® implants the same finding could be assessed. Sinus procedures were evaluated to have a negative effect on the primary stability (p‹0.001). Length and diameter didn´t show a statistical significant influence on neither insertion torque nor Periotest value (r=0.092; r=0.055). Periotest was statistical signifi-cant higher for the failure group (p‹0.001). Implants inserted in the mandible (anterior›posterior) showed higher mean Periotest® values than the implants placed in the maxilla (anterior‹posterior) (p‹0.001).Conclusions: The present clinical study illustrates that insertion torque and Periotest value are both useful noninvasive systems to measure implant sta-bility. Early implant failure can be predicted, but the sensitivity of both instru-ments is too weak to rely just on their measurement.

260 i a clinical study of bovine hydroxyapatite in maxillary sinus floor elevation – results after a maximum observation period of 15 years

Volker Clar (austria), Alexander Heschl, Susanne Platzer, Michael Payer, Martin Lorenzoni, W.A.Wegscheider

Objectives: The objective of our study was to investigate the effect of a de-proteinized bovine bone mineral on long term survival and implant stability of Frialit and Xive implants placed in combination with a sinus lift.Methods: 1462 implants (683 Frialit II and 779 Xive implants) were placed in combination with a maxillary sinus augmentation. A sinus bone graft was al-

ways performed when the bone height was less than 9.5mm, using the modi-fied lateral window technique by Kent and Block in combination with resorbable membranes. Bovine hydroxyapatite (Bio-Oss® Geistlich and Sons, Wolhusen, Switzerland) was used to augment the sinus. A two-stage procedure was used in patients with a preoperative bone height of less than 5mm. A bone graft had a healing period of 8 to 9 months before implant insertion. One-stage proce-dure was used when bone height exceeded 5mm and the bone was sufficient for implant insertion. The first visit included medical, dental status, a complete oral exploration and radiographic examination. All implants were inserted as late implants more than 3 months after healing. results: 34 Frialit II implants were failures. 4.9 % of 683 Frialit II implants were lost and show an overall survival rate of 95.0 %. 4 Xive implants (0.5%) failed and the survival rate for Xive implants was evaluated with 99.7%. Sinus procedures were evaluated to have a negative effect on primary stability measured with Torque-Controler®. For both types of implants a statistical significance was as-sessed (p‹0.001). Frialit II® implants which were inserted after a delayed healing period of the sinus augmentation showed a lower mean insertion torque than Frialit II® implants which were inserted simultaneously with a sinus augmenta-tion (p‹0.002). Xive® implants didn´t show a statistical significant effect for these two different situations (p‹0.108). At second stage surgery mean PTV value of Frialit II implants was -3.8 and showed a statistical significant difference to Xive implants with a mean PTV value of -5.43 (p‹0.001).Conclusions: Promising long-term outcomes were observed for implants with sinus floor elevation with bovine hydroxyapatite. Even if sinus procedures have a negative effect on primary stability, survival rates of Frialit II and Xive im-plants placed in combination with sinus augmentation are comparable to sur-vival rate of implants placed without a maxillary sinus floor elevation.

261 i an Operator error: a risk factor for implant loss

Mehnaz kamali (united arab Emirates)

Objectives: To investigate the reasons for immediate implant loss. To investigate the reasons for implant loss during healing period. To investigate the risks fac-tors associated with implant loss at 3 stages (Immediate loss, implant loss during healing and implant loss following healing). To investigate clinical errors leading to forced explanation in cases with good primary stability at time of placement. To investigate common surgical errors causing lack of primary stability. To inves-tigate patient related factors causing lack of primary stability. To investigate im-plant design faults that can cause immediate loss despite good primary stability.Methods: Retrospective observational study of 63 lost and failed implants dur-ing 2009 at Dubai Health Authority. Approval to conduct the study was obtained internally from the Dental Centre at Dubai Health Authority.Sample population: All implants which were lost following surgical placement during 2009 were included in the study. Time of implant loss was categorized as immediate loss, loss during healing period and loss following healing pe-riod. The implant systems used at DHA were 3 different types of Friadent Im-plants: Xive, Ankylose and Frialet. Data collection was completed from com-puter based clinical records and from digital x-rays as well as implant surgical and failure forms. Clinical Errors were categorized into: Implant planning and selection errors and surgical skill related errors. Additional patient related factors and implant design factors were also investigated for comparison. All clinical procedures followed during the surgical placement were investigated and recorded and their association with the different stages of implant loss was calculated in the form of percentages. Data were entered in excel sheet and percentages were calculated and presented in tables and charts.results: The total number of 547 implants was placed by 10 different opera-tors. The total number of 61 was lost implants. 62% of implants were lost due to poor primary stability while 36% of those lost were had good primary stabil-ity and were lost due to different factors. Factors that resulted in poor primary stability included surgical skill related errors such as incorrect stage of im-plant placement (Immediate and early placement) and implant selection errors including incorrect implant size selection, incorrect implant length selection, and incorrect placement techniques and implant placement with initial high torque. 60% the implants were lost immediately at the time of placement. The frequency of loss reduced as the healing period progressed. 70% of those lost immediately were due to lack of primary stability. Those which were not lost due to poor primary stability were lost due to implant design faults and due to operator related surgical skills in implant placement such as implant posi-

clinical reSearch, clinical StudieS

54

tioning and angulations errors. 36% of the total lost implants were explanted during the healing period and only 23% of the latter were due to poor primary stability. Factors that lead to implant loss during healing period were due to patient related factors. 95% of all lost implants were prior to functional loading and the additional 5 % were explanted on re-entry (second stage)Conclusions: Operator errors such as poor surgical handling, positioning er-rors and incorrect implant size/length selection may lead to immediate im-plant loss and replacement during surgical procedures. Theses factors are less frequent in cases were implant were lost during healing period. In the latter additional factors related to implant design as well as patient related factors becomes more important. The fact that 95% of the implants were lost prior to functional loading confi rms that surgical related factors have a signifi cant ef-fect on the outcome of implant surgery. As a result operator skills in implant type selection and surgical placement skills greatly infl uence the successful placement of implants. Implants are costly operations and all steps must be carefully planned to avoid costly errors. Patients with high risk factors must be assessed and strict protocols must be implemented to ensure long term success.

BaSiC rESEarCH, iN ViTrO STudiES

301 i recombinant Human Bone Morphogenetic protein-2(rhBMp-2) delays The differentiation Of Osteoblast-like Cells Grown On Titanium Surfaces

adriane yaeko Togashi (Brazil), Fabiano Cirano, Marcia Marques, Francisco Pustiglioni, Luiz Antonio Lima

Objectives: The aim of this study was to assess the infl uence of the chemical characteristic and roughness of titanium surfaces on osteoblast-like prolif-eration and differentiation cultured in medium added to bone morphogenetic protein-2 (BMP-2).Methods: Osteo-1 cells were grown on titanium discs with the following sur-faces: 1) machined surface, 2) coarse grit-blasted and acid-etched (SLA) and 3) modifi ed SLA (SLAactive) in the absence or presence of rhBMP-2 20ng/ml in culture medium. Osteo-1 proliferation was evaluated at 24 hours. Cell differentiation was evaluated by total protein content (PT), collagen content and ALPase activity assays at 7, 14 and 21 days and mineralized matrix for-mation at 21 days. Data were compared by analysis of variance (ANOVA) and Tukey test.results: Cell proliferation (p=0.0936) and mineralized matrix formation (p=0.0456) were not affected by different surfaces or by the addition of rhBMP-2 to the medium. Osteo-1 cells cultured on SLA surface showed a signifi cant increase in total protein content at 21 days. Collagen content was not affected by different surfaces or by the addition of rhBMP-2 to the medium at 14 and 21 days. ALPase/PT ratio (p=0.0000) was affected by treatment and time.Conclusions: he results suggest that the addition of rhBMP-2 to the culture medium did not have any effect on osteoblast proliferation and delays the dif-ferentiation of Osteo-1 cells grown on surfaces of different degrees of rough-ness at each point in time. All tested surfaces of titanium allowed an expres-sion of osteoblast phenotype-like matrix mineralization by Osteo-1 cells.

302 i Thermal Changes in Bovine Bone duringimplant Site preparation. a Comparative in Vitro Study:Twisted Stainless Steel and Ceramic drills

Natália Oliveira (Spain), Fernando Alaejos-Algarra, Javier Mareque, Eduardo Ferrés-Padró, Frederico Hernandez-Alfaro

Objectives: The purpose was to assess thermal changes in bovine bone tissue with the use of twisted stainless steel and zirconia-based drills during implant site preparation, more specifi cally to:

1. determine local temperature changes in bovine rib bone during 50 implant site preparations using a twisted stainless steel drill and a ceramic drill, at depths of 8 and 10 mm;2. evaluate drill wear after 50 implant site preparations by means of scanning electron microscopy (SEM).Methods: Twelve bovine bones were cleared of all soft tissue and frozen in sa-line solution at -10° C. Prior to use, the bone were sectioned in blocks . Fifty implant site preparations were performed on these bone blocks using a sur-gical unit linked to a testing device in order to standardize/simulate implant drilling procedures. Constant irrigation at 50ml/min. (21°±2°C) and a drilling torque of 800 rpm were used. During each implant site preparation the fol-lowing data were recorded: room temperature, bone baseline temperature, maximum bone temperature recorded at 8 mm and 10 mm, maximum load applied during drilling up to 8 and 10 mm and total preparation time. Bone temperature variation was calculated at both depths in each perforation and relative to each previous recorded bone baseline temperature.Scanning electron microscopy was performed prior to and after drilling.results: The mean temperature increase for the stainless steel drill was 0.8°C and 2.2°C, and for the ceramic drill 0.7°C and 1.8°C at depths of 8mm and 10mm respectively. Signifi cantly higher bone temperatures were obtained with both drills at depths of 10mm (P _< 0.05). The temperature increase was cor-related with the number of perforations (P _< 0.05).There was no signifi cant difference in temperature rise when comparing both drills, and no association between temperature and the drilling force applied. Signifi cantly higher forces were used when drilling with the stainless steel drill at both depths. No severe signs of wear or deformation were detected after 50 uses.Conclusions: Both drills can be used up to 50 times without producing harm-ful temperatures to bone tissue or severe signs of wear and deformation. Drill material and design appear to infl uence cutting effi ciency, but do not produce signifi cant temperature variations with the drilling protocol applied. Drilling depth was a predominant factor in bone temperature variations during implant site preparations.

303 i a Single-Species Biofi lm ModelTo Evaluate implant Cleaning Strategies

Haiyan lin (China), Dongmei Deng, Yuelian Liu, Daniel Wismeijer, Wim Crielaard

Objectives: Implant cleaning is a crucial step in successful bone regeneration in patients with perimplantitis. For the development of effi cient implant cleaning strategies, a reproducible, high throughput, in vitro biofi lm model is urgently need-ed. The aims of this study are to establish a single-species biofi lm model and test its reproducibility in biofi lm growth and in response to antimicrobial treatments.Methods: Streptococcus mutans biofi lms were formed on the surfaces of tita-nium discs with different degrees of roughness in 24-well microtiter plates. The biofi lm medium was refreshed every 8h and 16h. One day and three day old bio-fi lms were treated with sterile water or 0.2% chlorhexidine for 10 min. Biofi lm viability was evaluated by colony forming unit (CFU) counts. Each experiment was repeated 3–4 times and in each experiment, 3–4 replicate samples were included.results: Up to 48 independent biofi lms could be formed on the titanium discs in one experiment. Good reproducibility in CFU counts was observed; the coef-fi cients of variance (CV) were within 2% irrespective of the age of the biofi lms and the roughness of the substrate. Ten minutes of chlorhexidine treatment signifi cantly reduced biofi lm viability. However, reproducibility was decreased, being 70% for 1-day old biofi lms and 8% for 3-day old biofi lms. It was noticed that the CFU counts of 1-day old biofi lm after chlorhexidine treatment was close to the detection limit (100 CFU/disc).Conclusions: This S. mutans biofi lm model is a high throughput model. It shows good reproducibility in growth but lower reproducibility in response to treatments. Increasing numbers of replicate samples should be considered in implant cleaning evaluation for this type of biofi lm model.

304 i Tissue Engineering Strategies For The in Vitroreconstruction Of dental pulp-like Tissue:The role Of dental pulp Stem Cells and Growth Factors

Stefano Sivolella (italy), Eriberto Bressan, Gian Antonio Favero, Mario Berengo, Letizia Ferroni, Barbara Zavan

55

Objectives: The most important function of dental pulp is to maintain tooth vitality by supplying minerals and organic materials. Injured pulp tissue may undergo necrosis, prompting the need for endodontic and reconstructive treat-ment or the extraction of the tooth involved. Several mechanical strategies have been developed to preserve a healthy pulp in prosthetic and restoration procedures, but until now no 3D in vitro biological approaches have been at-tempted. The aim of the present work was the in vitro reconstruction of a den-tal pulp-like tissue by combining tissue engineering strategies with dental pulp stem cell biology as predictive tool for use in cytotoxicity testing.Methods: Human-derived dental pulp stem cells (DPSCs) were seeded on to a hyaluronan-based scaffold and cultured for up to 21 days in differentiation medium enriched with neuronal and endothelial growth factors. Histological and molecular analyses were performed 3, 7, 14 and 21 days after differentia-tion in order to investigate the organization of the extracellular matrix and the neuronal and endothelial commitment of the cells.results: Morphological analyses showed that DPSCs were distributed both on the surface and within the three-dimensional construct. In particular, DPSCs grew well inside the scaffolds, filling all the spaces between the fibres. Immunohisto-logical staining and gene expression for the principal neuronal, endothelial, and extracellular matrix components confirmed the correct commitment of the cells.Conclusions: Tissue engineering strategies can be used for the successful in vitro reconstruction of a dental pulp-like tissue with biological characteristics closely resembling those of natural pulp tissue. Such strategies may represent an innovative approach to the in vitro study of how the dental architecture de-velops and a useful tool for use in screening for cytotoxicity.

305 i Comparison Of Clinical and Histomorphometric Bone Gains in Three dimensions Obtained From Bovine Cortical Bone Screws and autogenous Onlay Grafts in dogs Beagles

Guliherme piragine (Brazil), Marco Pontual, Hedilberto Sousa, Danielle Lima, Ricardo Magini, Leonardo Bez

Objectives: To compare newly formed bone after bovine cortical bone screw placement and onlay autogenous bone graft procedure.Methods: Eighteen female Beagle dog tibias received 4 bovine cortical bone screws and an onlay autogenous bone graft. Both augmentation techniques resulted in newly formed bone. Fluorchromatic bone markers were injected into the dogs at different time intervals. Sections of the samples were analyzed by fluorescence microscopy 2, 4, and 6 months post-operatively. The fluoro-chrome markers were alizarin, calceíne and tetracycline.results: Newly formed bone was observed in sections made of samples col-lected from both procedures. The bovine cortical bone screw was partially present in the samples and seemed to reduce in quantity as time intervals ex-tended. Additionally, the bone was contiguous to the receptor site. This could be attributed to the bone neoformation. The autogenous onlay bone graft was gradationally substituted after being integrated into the receptor site faster than the newly formed bone, suggesting an osseoinduction and osseoconduc-tion characteristic. The newly formed bone was highly cellular, showing the presence of osteocytes and osteoclasts. Two months postoperatively, the corti-cal bovine bone screw technique showed statistically significant bone forma-tion compared to the onlay bone graft. This finding was confirmed after analy-ses at intervals of 4 and 6 months.Conclusions: The bovine cortical bone screw was shown to be highly osteoin-ductive. The authors suggest its use compares with that of onlay autogenous grafts for bone graft augmentation procedures. The bovine cortical screw used for bone augmentation proved to be a better long-term solution than the on-lay autogenous bone graft procedure, due to the higher bone resorption at the onlay graft surgical site.

306 i Comparative Study Of Nano Vitamin C application and Generic Vitamin-c application in Gingival Fibroblast

dongju Choi (korea), JunWoo Park

Objectives: Current nanotechnology has developed for many different kinds of materials. Examination of their physical and biological activities reveals significant difference in the material characteristics of nano-sized materials.

However, most studies have focused on metallic compounds and there have been few studies of organic materials. Our aim here was to examine the effects of nano vitamin C applied to the gingival fibroblast and to compare it to applica-tion of generic vitamin C.Methods: To compare the size difference and physical characteristics of nano vi-tamin C and generic vitamin C, we use nano vitamin C made by Nanocuretech (Daejeon, Korea) and generic vitamin C made by Sigma-Aldrich (Chicago, IL, USA).Cell culture was carried out to examine the effect of vitamin C on fibroblast. Fibroblast was taken from healthy gingiva and Dulbeccos modified Eagle’s medium-high glucose was used for the culture medium.MTT assay was performed to find the safety concentration of vitamin C, which was prepared from 0.01 µg/ml to 50 µg/ml and observed for 24 to 48 hours.Collagen assay and real-time RT-PCR were also checked in order to observe the effect of nano vitamin C.results: Scanning electron microscopy showed that generic vitamin C was 50 times bigger than nano vitamin C and twice as large in solution.There was no difference in MTT assay between the two particles. However, col-lagen synthesis was significantly increased by nano vitamin C in lower concen-tration compared to generic vitamin C. In particular, type I and type IV collagen synthesis were significantly increased by nano vitamin C (P 0.001).Conclusions: Both nano vitamin C and generic vitamin C are effective in type I and type IV collagen synthesis. Nano vitamin C is more effective in lower concen-trations than generic vitamin C.

307 i apical Bud Cell-Secreted Factors promote Odontoblast differentiation in Vitro and accelerate Mineralized Tissue Formation in Human dental pulp Stem Cells in Vivo

park Joo-Cheol (korea), Jihyun Lee, Won Jun Shon

Objectives: Epithelial-mesenchymal interaction is essential for odontoblast differentiation. However, the epithelial factors that control odontoblast dif-ferentiation are unclear. The aim of this study was to evaluate the effect of ameloblast on human dental pulp stem cells (hDPSCs) differentiation in vitro and in vivo.Methods: We isolated hDPSCs from human third molar and apical bud cells (ABCs) from mouse incisors. After odontoblast co-culture with ABCs, we in-vestigated the effect of ABCs-SF on hDPSCs in vitro. Co-cultured odontoblast and hDPSCs with ABCs were analyzed by real time PCR and western blot. Alizarin red S staining was carried out to observe calcified nodule formation in odontoblast treated with ABCs-SF. To identify the effect of ABCs-SF on DSPP promoter, luciferase activity was measured. hDPSCs treated with ABCs-SF were transplanted to the subcutaneous skin of immune-compromised mice to confirm the effect of ABCs-SF on mineralized tissue formation in vivo. We also analyzed ABCs-SF using LC-MS/MS to find which factor affects odontoblast differentiation and mineralized tissue formation in hDPSCs.results: Co-cultured hDPSCs with ABCs increased expression of dentin sia-lophosphoprotein (DSPP), but decreased bone sialoprotein (BSP). ABCs-SF treatment resulted in upregulation of DSPP promoter activity but downregu-lation of BSP promoter activity in odontoblasts. Oral epithelial cell (KB-SF) had no influence on DSPP promoter activity. Interestingly, transplantation of hDPSCs treated with ABCs-SF produced more mineralized tissue than the con-trol hDPSCs. Furthermore, the area of mineralized tissue formed in hDPSCs treated with ABCs-SF was similar to that formed with BMP2 treatment as used for positive control. BMP-related factors were not contained in ABCs-SF. The results of the ABCs-SF analysis showed the existence of various proteins with extremely diverse locations and functions. In particular, copine 7, a molecule detected in the ABCs-SF analysis, increased odontogenic/osteogenic gene ex-pression in MDPC-23.Conclusions: These results suggest that ABCs-SF could promote the differen-tiation and mineralization of hDPSCs in vitro and bone formation in vivo. Taken together, concentrated ABCs-SF would be applicable to regeneration of min-eralized tissue. In addition, copine 7, a newly identified molecule in ABCs-SF, could be a new candidate factor in the modulation of odontoblast differentiation.

308 i promotion Of Early implant Healing Via Chemical and Biomimetical Titanium Surface Modifications – platelet activation and Cytokine release in Vitro

baSic reSearch, in Vitro StudieS

56

peer kämmerer (Germany), Matthias Gabriel, Thomas Scholz, Carl-Maximilian Kirchmaier, Marcus Oliver Klein, Bilal Al-Nawas

Objectives: Platelet releasate has been shown to promote osteogenetic cell proliferation and differentiation. The chemistry of biomaterials has a high im-pact on platelet activation. More specifi cally, the bioactive cell adhesive peptide sequence Arg-Gly-Asp (RGD) triggers platelet activation mediated by the IIb3 integrin receptor. Accordingly, chemical and biomimetical (immobilized RGD peptide) modifi cations of titanium (Ti) surfaces may enhance early platelet ac-tivation and bony healing of implants. Therefore, the aim of the study was to evaluate platelet activation with subsequent platelet derived cytokine release by accordingly modifi ed Ti surfaces.Methods: Materials and methods: Acid-etched (A, Ra=0.83 µm, CA=106°) and large grit sandblasted, acid-etched (SLA, Ra=3.2 µm, CA=109°) titanium surfac-es were investigated. Additionally, RGD peptides were chemically immobilized on A and SLA surfaces (A-RGD (CA=0°), SLA-RGD (CA=0°)). The different Ti sur-faces were incubated with platelet concentrate from three healthy volunteers at room temperature for 15 and 30 minutes. High thrombogenous collagen served as a control group. Using the supernatant, platelet consumption was assessed via platelet count (PC). Cytokine release was quantifi ed via the level of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF).results: After 15 min, the rough SLA surface in particular showed a strong de-crease in PC and a strong increase in VEGF and PDGF levels. After 30 min, high platelet consumption as well as high levels of VEGF and PDGF were measured for A-RGD surfaces, indicating a delayed effect of the surface modifi cations on platelet activation.Conclusions: Modifi cations of surface roughness modifi cations seem to infl u-ence early platelet activation and cytokine release after 15 min whereas sur-face modifi cations via RGD peptide on plainer surfaces lead to a further, more specifi c promotion of platelet activation and degranulation after 30 min. The observed effect could be valuable for critical clinical situations such as com-promised bone sites.

309 i Biomimetic Calcium phosphate Bone FillerWith Coordinated delivery Of Multiple-drugs

Tie liu (Netherlands), Yuanna Zheng, Gang Wu, Daniel Wismeijer, Yuelian Liu

Objectives: The aim of this study is to develop a novel bone fi lling material that would be not only biodegradable and biocompatible, but also capable of coordinate-ly delivering multiple bioactive agents as a goal to heal voluminous bone defects.Methods: Biomimetic Calcium Phosphate (BioCP), a novel bone-fi lling mate-rial, was made from 5-fold supersaturated calcium phosphate solution (CPS) at 37°C and pH 7.4 using biomimetic principles. Fluorescein-isothiocyanate labelled bovine serum albumin (FITC-BSA) was incorporated into BioCP during the preparation as a model protein. BioCP was characterized using scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The in-vitro degradation rate of BioCP was monitored by measuring released calcium ions using atomic adsorption spectrometry. The rate and pattern as well as the in-vitro release kinetics of BioCP and incorporated proteins were monitored. BioCP material was tested by mouse osteoblasts, compared to de-proteinized bovine bone, using ALP activity and DNA assay.results: BioCP showed an amorphous morphology and a ratio of calcium and phosphorus at 1.48. The size of BioCP granules can be 0.3-2.0 mm. The BSA was successfully incorporated into BioCP with an incorporation rate of 89.1±1.9% when the BSA concentration was 10 mg/L in the 5×CPS. The deg-radation rate of BioCP was correlated with the protein release, and the later showed a slower release kinetic. The BioCP material improved the ALP expres-sion/DNA more than deproteinized bovine bone (P ‹ 0.05), when mouse osteo-blasts were cultured on them separately after 7 days’ culture.Conclusions: Biodegradable BioCP bone fi lling materials are not only useful for bone repair, but also can act as a drug delivery system. The fl exibility of BioCP in structure and its capacity of coordinately delivering bioactive agents conferred on the novel bone fi lling material a promising application potential in healing voluminous bone defects with different etiologies.

310 i The use Of BMp in Maxillary Sinus lifting andin Human Extraction Sockets: a Systematic review

rodrigo Guerra de Oliveira (Brazil), Bianca Oliveira, Andre Dias, Plinio Ramos, Leonardo Picinini

Objectives: Analyze through a systematic review of current knowledge the use of BMPs in surgery of maxillary sinus lifting and in human extraction sockets.Methods: Systematic review based on the MEDLINE (National Library of Medi-cine) databases, without linguistic restrictions, using the following keywords: Bone morphogenetic protein, rhBMP-2, maxillary sinus lift and in human extraction sockets. Only randomized controlled trials that used rhBMP-2 for reconstruction of alveoli after tooth extraction and/or lifting of the maxillary sinus, published in the last ten years, were included.results: We identifi ed seven studies, of which only six were part of the scope of this review. The studies involved 362 patients, and were quite different in terms of site, sample size, protein concentration, used vehicle, and registration of clinical and radiographic data. Therefore, it was not possible to perform a meta-analysis of data obtained.Conclusions: From the data obtained in this systematic review it can be con-cluded that the reviewed studies recommend the use of rhBMP-2 for recon-structive treatment after dental extraction or vertical increase of maxillary si-nus. The subject still needs further randomized controlled trials, as the paucity of scientifi c evidence was evident.

311 i Establishment Of Gingival EpithelialWound Healing Models and Measurement Of The infl uenceOf different ECM-Molecules On Wound Closure

Thomas imhof (Switzerland), Stephanie Mathes, Ursula Graf-Hausner

Objectives: Oral soft tissue regeneration has become a main issue in the de-velopment of substitute materials. But systems enabling the evaluation of bio-materials in a simulated soft tissue wound are still rare. We present gingival models, which serve as appropriate tools for wound closure characterization.Methods: For the evaluation of cell migration the bottoms of well plates were coated with ECM molecules (Elastin, collagen I, fi bronectin and collagen IV). Immortalized human gingival keratinocytes were grown in a growth factor supplemented culture medium. The keratinocytes were seeded on the coated surface and they formed a cell monolayer. This monolayer was then wounded by scratching and the wound closure was monitored by the use of an auto-mated microscope.For the full evaluation of full thickness epithelial wound healing, gingival fi bro-blasts were expanded in a DMEM/F12 medium and were incorporated in collagen I gels, which were placed underneath a PET membrane of cell culture inserts. This membrane was coated before with different ECM molecules. Elastin, fi bro-nectin and collagen I were used. On the surface of the membrane a multilayered epithelium with gingival keratinocytes was grown. The already well developed epithelium was then wounded and the wound closure was monitored daily.results: In the scratch wound assay the speed of the keratinocyte migration was investigated. It was shown that protein coatings of a surface have a signifi -cant impact on migration speed. On a collagen I coated surface, for example, the keratinocytes migrated faster compared to an uncoated surface.In the 3D organotypic epithelial model wounds were created after 7 days of incubation at the air-liquid phase using a pipette tip. The photographic moni-toring of the wounded epithelium that was grown on uncoated PET membranes showed that the wounds were partly closed after 5 days.The histological characterization of the grown epithelia using HE-staining of paraffi n sections showed that they were well stratifi ed and keratinized. For the immune histological characterization keratin 1/10, involucrin and the prolif-eration marker Ki67 were used as marker proteins. The keratin 1/10 was ex-pressed in the stratum spinosum and granulosum. Involucrin was expressed from the stratum spinosum to the stratum corneum.Conclusions: The wound assays presented here provide biological relevant data supporting the assumption of a promising test system to evaluate bioma-terials and chemical compounds and their effect on gingival epithelial wound healing. The test models can be analysed frequently and so the progress of wound healing can be well monitored and documented.

312 i Evaluation Of Nanoporous and Macroporous polymer Hydro-gels as a potential Barrier For Guided Bone regeneration (GBr)

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david lescano (argentina), Edith I. Yslas, Maria A. Molina, Claudia Rivarola, Cesar Barbero, Viviana Rivarola

Objectives: 1. Synthesis of (poly(n-isopropylacrylamide-co-(2-acrylamido-2-methylpropane sulfonic acid)) (PNIPAm-co-2%AMPS).2. Characterization of PNIPAm-co-2%AMPS using a scanning electron micros-copy (SEM).3. Determination of permeability properties of PNIPAm-co-2%AMPS nano and macroporous hydrogels.4. Evaluation of biocompatibility of PNIPAm-co-2%AMPS nano and macropo-rous hydrogels using LM2 cell lines.5. Analysis of cell adhesion on membrane surfaces of PNIPAm-co-2%AMPS nano and macroporous hydrogels.Methods: In order to prepare the nanoporous polymer, the hydrogel was dried by heating the PNIPAm-co-2%AMPS and a polymer network without voids in its structure was obtained. Further swelling of this material in water increased the network chain space in the polymer matrix by ~36 nm.To obtain the macropores, the polymer was prepared below the bulk freezing tem-perature of the reaction system (-18o C). During this process ice crystals acted as a template for the formation of the macro pores. To characterize the structure of these materials, SEM studies were carried out at low vacuum and low field using a LEO 1450VP SEM. The permeability of these hydrogels was determined by pas-sive diffusion of toluidine blue and Höechst dye. Biocompatibility of these materi-als was checked by following morphology and adhesion of LM2 cells cultured over the hydrogels. These experiments were performed using fluorescent microscopy. Toluidine blue and Höechst dyes were used as probes for labelling the cells.results: SEM studies show clear macroporous structure. The distribution of macropore size is very narrow with a mean value of about ~64 nm. The shape and size of the macropores change after the gel is subjected to drying and rehy-dration. During drying the pores collapse and are then rehydrated into a differ-ent shape. After the initial rearrangement, the pore morphology remains stable during drying/wetting cycles. To calculate the size of the pores in nanoporous hydrogels we used the theory of equilibrium swelling obtaining an average of 36 nm. The adhesion of cells to hydrogels was studied observing cell interactions with these substrates. Microscopic examination revealed that the cells adhered to and grew onto the surface of material as well as inside its pores, showing regular cell morphology. Fluorescence microscopy analysis showed that the cells adhered and normally grew onto the surface of material as well as inside its pores. This result shows that the hydrogels were non-cytotoxic.Conclusions: We have evaluated both nano and macroporous hydrogels as a membrane barrier for GBR. We showed that both micro and macroporos-ity allow exchange of water and small molecules. In addition the material is biocompatible for lm2 cells. These studies demonstrated that the pnipamm-co-2%amps nano and macro porous hydrogels have a high potential as a bar-rier membrane for GBR. Future experiments are necessary to evaluate the behavior of hydrogels in vivo.

313 i The Enhancement Of Osteogenesis in 3d By using a Sub-Mesenchymal Stem Cell population From The dental pulp

Jordi Caballe (Spain), Carlos Gil, Marc Fabregat, Dani Garcia, Luis Giner, Maher Alatari

Objectives: Large bone defects are a major clinical problem, because in up to 40% of patients autologous bone grafts are not available. Bone bioengineering would be a good solution to this common problem. To improve the regenerative capacity of osteoblasts in 3D, we used a sub-mesenchymal stem cell popula-tion from the dental pulp DPPSC as a candidate for bone tissue engineering.Methods: In the present study, we evaluated the osteogenic capacity between DPPSC and DPMSC isolated from the same donor (n=5) y cultivated in the same osteogenic medium in a 3D cell carrier glass scaffold. The differentiation was evaluated by SEM analysis, the expression of bone markers like ALPH, osteo-calcin, Coll I and osteonectin by q-RT-PCR. We also compared calcium deposi-tion, the Alizarin staining test and ALP activity.results: Bone was formed by DPPSC in perfect continuity with the trabecular host bone structure and demonstrated the high interconnectivity of the re-stored bone network. A significant difference was observed in the expression of bone markers, Calcium deposition and ALP activity during the osteogenic differentiation used DPPSC more than DPMSC.

Conclusions: This study showed the possibility of DPPSC as a potentially inter-esting candidate for bone tissue engineering.

314 i Osteoblastic and Osteoclastic differentiation On Sla and Hydrophilic Modified Sla Titanium Surfaces

yong-dae kwon (korea), Sung-Moon Bang, Ji-Yeon Yoo, Young-Joo Kim, Ho-Jin Moon, Ji-Yong Kim

Objectives: In terms of bone remodelling, osteoclastic activity is also worth investigating besides that of osteoblasts on a titanium surface. This study was to evaluate the activities of both of osteoblastic and osteoclastic differentiation on SLA and hydrophilic modified SLA surfaces.Methods: Osteoblastic assays: Titanium (Ti) discs were obtained from Insti-tute Straumann, representing the following surfaces: smooth pre-treatment (PT; as control), sandblasted/acid etched (SLA), and hydrophilic SLA (modSLA). MC3T3-E1 cells were cultivated on the respective substrates for osteoblastic differentiation. To evaluate the osteoblastic differentiation, ALP assay was per-formed and the Alizarin red S test was performed for the mineralization test after 1 week, 2 weeks and 3 weeks. For the molecular biological study, the RT-PCR test was performed to investigate the expression of Runx2, osteopontin (OPN) and osteocalcin (OCN).Osteoclastic assays: Mouse derived bone marrow monocytes were cultivated on the respective substrates for 7 days for differentiation of osteoclasts. For the osteoclastic differentiation, M-CSF and RANKL were included in the culture medium. We confirmed the constitution of osteoclast differentiation using the confocal laser microscope, TRAP activity and RT-PCR.results: In osteoblastic experiments, the SLA and modSLA surfaces signifi-cantly increased the expression of Runx2, OPN and OCN mRNA compared with that of the control. The expression of Runx2 and OPN as early markers was up-regulated the most in 2 weeks, but that of OCN as a late marker was up-regulated the most in 3 weeks. The promotion of osteogenic differentiation is demonstrated by increased Alizarin red S and ALP assay. In osteoclastic ex-periments, the SLA and modSLA surfaces showed decreased attachment and differentiation of monocytes. Based on the findings of the confocal microscope, monocytes were sparse and osteoclastic differentiation was rarely seen. The results of TRAP activity and RT-PCR supported these results.Conclusions: The SLA and modSLA surface enhanced osteogenic differentiation of MC3T3-E1 cells more than the PT surface did. But the monocytes did not ad-here to the SLA and modSLA surfaces and their differentiation was disturbed. This result may imply that differentiation of monocytes is prevented on these surfaces.It may be concluded that the modSLA surface will promote the osteogenic ef-fect and prevent the bone resorption by avoiding osteoclastic differentiation around the surface of an implant.

315 i Osteoclastic differentiation Of Mouse derived Monocytes On Magnesium-incorporated Submicro-porous Titanium Oxide Surface

yong-dae kwon (korea), Sung-Moon Bang, Young-Joo Kim, Ji-Yong Kim, Ji-Yeon Yoo, Ho-Jin Moon

Objectives: The objective of this study is to demonstrate the effects of an Mg-incorporated submicro-porous Ti oxide surface on the osteoclastic differentia-tion of mouse-derived monocytes.Methods: A titanium oxide surface incorporating magnesium ions (Mg) was compared with an untreated titanium surface (PT) and tissue culture polysty-rene (TCP) served as a control substitute. For the osteoclastic differentiation, M-CSF and RANKL were added to the culture medium. Mouse derived bone marrow monocytes were cultivated on respective substrates and differentiated for 7 days. We confirmed the constitution of osteoclasts by the confocal laser scanning microscope, TRAP activity tests and RT-PCR.results: Confocal laser microscope investigation showed the increased osteo-clastic differentiation capacity of Mg-incorporated surfaces compared to that of PT and TCP. Both PT and Mg-incorporated Ti oxide surfaces showed typical actin rings of osteoclastic differentiation. It was further demonstrated by gene expression data and increased TRAP activity assay. The mRNA synthesis of various osteoclast specific genes (TRAP, c-fos, NMP9, OSCAR) was measured by means of reverse transcription polymerase chain reaction (RT-PCR).

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Conclusions: These results support the contention that Mg-incorporated sub-micro-porous Ti oxide surface may improve the differentiation of osteoclasts.

316 i Osteoporosis in The Maxillofacial area – a Study in Sheep

pit Jacob Voss (Germany), Egle Veigel, Rainer Schmelzeisen

Objectives: Osteoporosis (OP) is characterized by low bone mass and microar-chitectural deterioration of bone tissue. The presence of this disease in the cra-niomaxillofacial (CMF) area remains unclear. The available small animal mod-els show defi ciencies. The aim of the present study was to assess bone changes occurring in the mandible in a sheep model of generalized osteoporosis.Methods: Bone loss was induced in ten Merino sheep by ovariectomy (OVX), weekly intramuscular administration of glucocorticoids (GC) for 6 months and a calcium-reduced diet. The intervention group was divided in two subgroups: 5 animals were killed after 3 months and 5 animals after 6 months. The objec-tive of this approach was to assess bone recovery for a longer period of time after steroid suspension, with a view to allowing implantation in this animal model without the negative side-effects of steroid medication. Five untreated animals served as controls. Bone mineral density (BMD) was assessed by dual-energy X-ray absorptiometry at the lumbar spine at baseline and after 1, 3, 6, 9, and 12 months. Lumbar and mandibular bone biopsies were obtained and analyzed with micro-CT. The studied variables were the bone volume to tissue volume ratio (BV/TV), trabecular thickness (Tb. Th.), trabecular number (Tb. N.) and trabecular separation (Tb. Sp.). The cortical thickness was also measured.results: Lumbar BMD decreased progressively in the intervention group and was most signifi cantly low after 6 months (p ‹ 0.001). Lumbar trabecular bone showed a signifi cant decrease in BV/TV (p ‹ 0.05) in the inducted group. Signifi -cant changes were also found in the mandibles for BV/TV (p ‹ 0.05). Regional variations were found for other parameters in the mandible. The cortical width was substantially reduced in the intervention group (p ‹ 0.001).Conclusions: The OVX rat has become the standard small animal model for OP. The lack of cortical remodelling in rodents and their reduced body mass are major limitations while testing implants. A big animal model for OP is neces-sary in such cases. Bone loss can be induced on sheep by various methods. We showed that bone loss is achievable in a short period of time and that the changes have a generalized nature. This sheep model meets the criteria for further investigation in the CMF area.

317 i a New 3d-Construct For Bone augmentation in implantology

ralf Smeets (Germany), Jörg Handschel, Daniel Rothamel, Marco Blessmann, Max Heiland, Andreas Kolk

Objectives: Compromised bony conditions or bone volume defi ciency are com-monly encountered problems in dental implantology. The objective of this study was the basic research for the development of a three dimensional osteoregen-erative scaffold, analogous to bone, consisting of a textile component combined with a bone substitute material (BSM) for midfacial surgery. The infl uence of this bone regenerative construct was analyzed with respect to the proliferation and osteogenic differentiation of mesenchymal stromal cells (MSC).Methods: MSCs were cultivated for 21 days in three dimensional constructs, made with a number of commercially available BSMs (Cerasorb® M, Ostim®, Fortoss VitalTM, Tricos®, Nanobone®, BioOss®, OsteoBiol®mp3), in combination with a fi brin glue and a textile component of poly-L-lactic acid( PLLA). Prolifera-tion, cytotoxicity, alkaline phosphatase (ALP) activity and gene expression were tested for each material composition over the whole period of the study. Fur-thermore, osteogenic marker proteins were immunohistochemically analyzed.results: Via determination of ALP, gene expression analysis and immunhis-tochemical staining, a delay of differentiation was established within all of the three dimensional construct compositions. Furthermore, the results indicated that the choice of BSM had no bearing on the osteogenesis of the MSC. BioOss induced an osteogenic differentiation. Using the BSMs Ostim, Cerasorb M and Fortoss VitalTM, osteogenic differentiation was detected within two of three assays. The highest ALP-concentration was detected in three dimensional con-struct containing Ostim, but no genes of bone markers could be detected by RT-PCR. A similar outcome was found with the ß-tricalcium phosphate compo-

sition (Cerasorb M) and the hydroxyapatite composition. However, in the con-struct with the Fortoss VitalTM component, the osteogenic differentiation was established via determination of the ALP-concentration and analysis of gene expression, but not via immunohistochemical staining analysis.Conclusions: The study results demonstrate that mesenchymal stromal cells did not lose potential for osteoblastic differentiation within the three dimen-sional constructs. However the osteogenesis occurs after a time lag of seven days. In the three dimensional constructs analyzed, results indicated that when considering the choice of mineral component of the composition, equivalent effi cacy was found with hydroxyapatite and ß-tricalcium phosphate as a source of calcium.

318 i Modifi ed Silk Membranes:an innovative Scaffol in Guided-Tissue regeneration

ralf Smeets (Germany), Daniel Rothamel, Jörg Handschel, Marco Blessmann, Max Heiland, Andreas Kolk

Objectives: Guided tissue regeneration (GTR) is well established for different types of barrier membranes. Here we report a novel ST-silk membrane which offers advantages compared to established animal derived collagen mem-branes. ST-silk membranes can be surface functionalised, are free from any potentially infective pathogens and have excellent mechanical properties. In this study we achieved functionalisation of the ST-silk membranes with hy-droxyapatite (HA) and the proliferative effects of the membranes were evaluat-ed on osteoprogenitor cells e.g. rat mesenchymal stromal cells (MSC) in vitro.Methods: First, native ST-silk membranes were tested regarding their effects on proliferation rates of L929 fi broblasts and dysplastic oral keratinocytes (DOK cell line). Possible cytotoxic effects were analysed by monitoring LDH ac-tivity. Thereafter, HA-functionalized ST-silk membranes were seeded with rat MSCs and the effects on osteogenic differentiation were evaluated for 7 days. Additionally the membranes were scanned via different imaging modalities: Refl ection electron microscopy (REM), µ-CT and digital microscopy VHX-600.results: ST-silk membranes demonstrated good biocompatibility without neg-ative effect in terms of vitality/proliferation of L929 and DOK cells over 22 days. The membranes showed osteoinductive effects (increase in alkaline phospha-tase activity) on rat MSCs after 7 days. Biomechanical tests of the membranes result in elongation values of up to 170% with collagen compared to 440% with silk and tear-off of 8.5MPa using collagen compared to 11.6 MPa for silk.Conclusions: Functionalisation of ST-silk membranes with hydroxyapatite seems to have an osteoinductive effect on MSCs in vitro with biocompatibility and mechanical stability superior to membranes based on collagen. These innovative devices open promising avenues for any application in guided tissue regenera-tion and as scaffold material in tissue engineering for dental applications.

BaSiC rESEarCH, prECliNiCal STudiES

401 i Effect Of platelet-rich plasma On Bone regeneration in Combination With Beta-Tricalcium phosphate in Calvarial defects in Ovariectomized rabbits.

Jae-Jun ryu (korea), Il-Yeon Kim

Objectives: The aim of this study was to assess the effectiveness of Platelet-Rich Plasma (PRP) on bone regeneration in combination with beta-tricalcium phosphate (TCP) alloplast in calvarial defects in ovariectomized rabbits.Methods: Fourteen Zealand white rabbits were ovariectomized to induce ex-perimental osteoporosis. After 6 weeks, 2 bilateral defects measuring 10mm in diameter were created in the parietal bones. In the experimental group, one defect was fi lled with beta-TCP combined with PRP and the other was fi lled with bovine bone mineral combined with PRP (PRP group). In the control group, each defect was fi lled with beta-TCP and bovine bone mineral only (Non-PRP

59

group). Dual energy X-ray absorptiometry was obtained at baseline and 6 weeks after ovariectomy. After 4 weeks, the animals were sacrificed and cal-varial sections were prepared. Bone mass (BV/TV) was measured by micro-CT. Histological and histomorphometic analyses were carried out on samples. The gathered data were statistically analysed (ANOVA, t-test, p ‹ 0.05).results: Bone mineral density (BMD) decreased significantly at 6 weeks after ovariectomy (p ‹ 0.05). The quantitative micro-CT analysis demonstrated a sta-tistically significant difference in new bone formation between the PRP and non-PRP group. BV/TV was higher in the PRP group (P ‹ 0.05). The histological ex-amination showed new bone formation around the bone substitute particles in all groups. In the histomorphometric analysis, the PRP group showed a greater area of new bone formation than the non-PRP group (p ‹ 0.05). beta-TCP par-ticles were more rapidly resorbed than bovine bone particles. Therefore areas of remaining particles were lower in the groups grafted with beta-TCP particles.Conclusions: The osteoconductivity of the beta-TCP alloplast was similar to that of bovine bone mineral in ovariectomized rabbits. The PRP group showed higher values than the non-PRP group in micro-CT and histomorphometrc analysis in terms of new bone formation. The PRP may have beneficial effects on bone regeneration when added to osteoconductive materials in osteoporotic hosts.

402 i Histological Evaluation Of autologous periodontal ligament Cells With Enamel Matrix derivatives in artificial Class Furcation defects. an Experimental Study in Monkeys

Weidong zhu (China), Jianxia Hou, Kaining Liu, Huanxin Meng, Xiaolin Tang

Objectives: To evaluate whether autologous periodontal ligament cells (PDLCs) combined with or without enamel matrix derivatives (EMD) can pro-mote periodontal tissue regeneration (including alveolar bone, cementum and periodontal ligament) in artificial class furcation involvement (FI) in monkeys.Methods: The autogenous PDLCs obtained from the extracted first pre-molar were cultured in vitro with Bio-oss Collagen. Eighteen chronically infected class FI defects were surgically created at the mandibular molars and second premolars of three adult male Macaca fascicularis monkeys. Six furcation de-fects with different therapies in each monkey were included: PDLCs/Bio-oss Collagen + EMD (PBE), Bio-oss Collagen + EMD (BE), PDLCs/ Bio-oss Colla-gen (PB) and Bio-oss Collagen (B) at first and second molars, EMD and the blank at second pre-molars, respectively. All of the furcation defects (including buccal and lingual sides) were covered with collagen membranes before flap close. The monkeys were euthanized 6 months after implantation. Healing of the periodontal defects was evaluated histomorphometrically with hematoxylin and eosin stain and the regenerated periodontal tissues were expressed as percentages.results: The dimension of defect between two roots and the buccal-lingual distance in the second premolar were smaller than that in the molars. The new alveolar bone, new periodontal ligament and new cementum regenerated in the defects of the second premolars (78%–84%, 69%–82% and 86%–89%, respectively) were significantly greater than those in the defects of the mo-lar groups (42%–51%, 40%–45% and 46%–73%, respectively). The new tissues in the defects of molars were approximately the same, except that there was much more new cementum in the PBE (73%) group than in the other groups (46%–50%). There was less regeneration in the defects where gingival reces-sion occurred and did not cover the entrance of defects; epithelial proliferation and connective tissue infiltrated by inflammatory cells instead of new tissue regeneration were observed in such defects.Conclusions: Class FI could not predictably be resolved even with the combina-tion of PDLCs and EMD. The sizes of FI (including depth height, buccal-lingual and mesial-distal dimension), coverage of gingival flap and local inflammation would influence the treatment outcome.

403 i Histological and Histomorphometrical Study Of Extraction Socket Grafted With deproteinized Bovine Bone Mineral and Calcium phosphate Materials

Seungbeom kye (korea), Seungyoon Shin, Seungmin Yang, Sangik Park

Objectives: The purpose of this study was to evaluate the histological result of bone substituting materials on extraction sockets.

Methods: We compared the histological findings of control (no graft), Bio Oss, MBCP (HA 60%, beta-TCP 40%), Polybone (polyphosphate containing calcium phosphate) in the extraction sockets. The mandibular premolar teeth of 4 bea-gle dogs were extracted for bone grafting. All alveolar extraction sockets were thoroughly debrided with a surgical curette to remove the periodontal liga-ment. The graft materials were filled into the extraction sockets. The animals were sacrificed 90 days after implantation. Both treated and control mandibu-lar sites were histologically evaluated with light microscopy.results: Histological observation at 90 days revealed that the control and ex-perimental sites had healed uneventfully without any adverse tissue reaction. Regenerated new bone formation ratio was 34.5% for control, 22.1% for Bio Oss, 28.4% for MBCP and 23.8% for Polybone. There was no statistical differ-ence between graft materials.Conclusions: These results suggest that Bio Oss, MBCP and Polybone are promising bone substituting materials to promote normal tissue healing and new bone formation.

404 i adipose-derived Stem Cells (adSc) as a Tool For The in Vitro reconstruction Of Safety Vascularized Bone Grafts

Barbara zavan (italy), Eriberto Bressan, Stefano Sivolella, Gian Antonio Favero, Vittorio Favero

Objectives: In the field of tissue engineering and regenerative medicine, adult stem cells are increasingly recognized as an important tool for in vitro re-constructed tissue-engineered grafts. In the world of cell therapies, mesen-chymal stem cells from bone marrow or adipose tissue are undoubtedly the most promising progenitors for tissue engineering applications. In this setting, adipose-derived stem cells (ADSCs) are generally similar to those derived from bone marrow and are most conveniently extracted from tissue removed during an elective cosmetic liposuction procedure showing moreover a great potential in term of endothelisation. The aim of the present work was to investigate the use of ADSCs as tools for improving the in vitro and in vivo reconstruction of a safety vascularized bone graft.Methods: The aim of the present study was to investigate the use of ADSCs as tools for improving the in vitro and in vivo reconstruction of a safety vascu-larized bone graft. Human ADSCs obtained from abdominoplastic procedures were first grown in monolayer culture, and after 14 days, were loaded into a bovine-derived hydroxyapatite clinical-grade scaffold and tested for prolifera-tion, cellular distribution and for osteogenic and vasculogenic gene expression. The safety of the cultures was investigated using the CGH array for 3D cultures. ADSC adhesion, distribution, proliferation and gene expression demonstrated not only full commitment on to osteogenic and vasculogenic lineage but also that the endothelisation significantly improves osteo-commitment. In the end, for in vitro cultures, genetic analyses confirmed the safety of the long-term culture of ADSCs in 3D scaffolds. For in vivo calvarial defect regeneration, HA bone grafts embedded with ADSCs were implanted for 3 weeks.results: The histological and gene expression results demonstrated in this case also that the presence of ADSCs shows the highest expression of osteogenic and vasculogenic markers, compared with the samples with no stem cells.Conclusions: This study demonstrated that the presence of endothelial cells signficantly improves the osteo-commitment of adult stem cells in vivo and in vitro.

405 i deproteinized bovine bone mineral in marginal defects at implants installed immediately into extraction sockets – an experimental study in dogs

Marco Caneva (italy), Daniele Botticelli, Gabriele Baffone, Idelmo Rangel, Niklaus P. Lang

Objectives: The aim of the present experiment was to evaluate the influence of DBBM and collagen membrane on alveolar ridge preservation and on the os-seointegration of implants placed into alveolar sockets immediately after tooth extraction in a dog model.Methods: In the mandibular premolar region, implants were installed immedi-ately into the extraction sockets of 6 Labrador dogs. DBBM and collagen mem-branes were placed at test sites, while the control sites received no augmenta-

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60

tion materials. The implants were intended to heal in a transmucosal mode. After 4 months of healing, the animals were sacrifi ced and ground sections were obtained for histomorphometric evaluation.results: After 4 months of healing, all the implants were integrated (n=6). Both at the test and the control sites, bone resorption occurred. The greatest coro-nal bone-to-implant contact was at the buccal aspect 2.8 ± 1.3 mm and 2.0 ± 1.1 mm, at the control and test sites respectively. This distance was statistically signifi cant (p ‹ 0.05).Conclusions: The present study demonstrated that the use of deproteinized bovine bone mineral (DBBM) and a collagen membrane at implants placed into sockets immediately after tooth extraction generate a higher level of bone-to-implant contact compared to the control site. The use of DBBM and a collagen membrane, however, did not prevent the resorption of the buccal bone crest.

406 i Bone regeneration at implants placed into ExtractionSockets Of Maxillary incisors in dogs

de Santis Enzo (italy), Daniele Botticelli, Fabio Pantani, Priscilla Pereira Flavia, Marco Beolchini, Niklaus P. Lang

Objectives: To compare the infl uence of autologous or deproteinized bovine bone mineral as grafting material on the healing of buccal dehiscence defects at implants installed immediately into the maxillary second incisor extraction socket in dogs.Methods: In the maxillary second incisor sockets of 12 Labrador dogs, im-plants were installed immediately following tooth extraction. A standardized buccal defect was created and autologous bone particles or deproteinized bovine bone mineral were used to fi ll the defects. A collagen membrane was placed to cover the graft material, and the fl aps were sutured to fully submerge the experimental areas. Six animals were sacrifi ced after 2 months and 6 after 4 months of healing. Ground sections were obtained for histological evaluation.results: After 2 months of healing, all implants were osseointegrated. All buc-cal dehiscence defects were completely fi lled after 2 months irrespective of the augmentation material (autologous bone or BioOss®) applied. Bone-to-implant contact on the denuded implant surfaces was within a normal range of 30-40%. However, the newly formed tissue at 2 months was partially resorbed (› 50% of the area measurements) after 4 months.Conclusions: Applying either autologous bone or deproteinized bovine bone mineral to dehiscences at implants installed immediately into extraction sock-ets resulted in a high degree of regeneration of the defects with satisfactory bone-to-implant contact on the denuded implant surface.

407 i Wnt11 Signalling May Control Bone remodelling

riina rytivaara (Finland), Irina Nagy, Jorma Määttä, Hanna Kokkonen, Seppo Vainio, Juha Tuukkanen

Objectives: Wnt11 is one of the 19 Wnt signalling proteins that are involved in cell differentiation, apoptosis and migration during development and in adulthood. Wnt proteins are transported along canonical and non-canonical pathways. Canonical signalling stabilises beta-catenin and has been proven to increase bone mass and osteoblast differentiation (Day et al. Dev Cell 2005). There has been disagreement as to whether Wnt11 activates or deactivates canonical signalling (Tao et al. Cell 2005, Railo et al. Exp Cell Research 2008). Some research into the effects of Wnt proteins on bone has been done. Fried-man et al. overexpressed Wnt11 in MC3T3E1 pre-osteoblasts. They noticed that beta-catenin accumulation and bone morphogenetic protein (BMP) induced ex-pression of alkaline phosphatase and mineralization was promoted because of overexpression of Wnt11 (Friedman et al. J Biol Chem 2008). Wnt11 also in-creased expression of other osteoblast-associated genes. Thus Wnt11 seems to be an infl uential factor in osteoblast maturation.Methods: C57B16 Wnt11 knockout mice and wild types aged between 2 months to 10 months were used. In all, 13 wild type male mice and 9 knockouts were compared and with females comparison was made between 15 wild type mice and 12 knockouts. Primary osteoblast cultures of 14 days in the presence of Na-ß-glycerophosphate and vitamin C were prepared from the bone marrow mesenchymal stem cells of WT and KO mice. RT-PCR indicated that Wnt11 is expressed in osteoblasts. Total RNA was isolated on day 3, 7, 9 and 14 from

the osteoblast cultures. The right femurs and tibias of the mice were prepared for histological samples. The samples were stained with hematoxylin-eosin to analyse endosteum and periosteum and with tartrate resistant acid phos-phatase (TRACP) staining to analyse osteoclasts. Microcomputed tomography (µCT) was used to analyse long bone morphology. Results were analysed with SPSS software with univariate analysis of variance taking into account the dif-ferent ages of the mice.results: Wnt11 was expressed in osteoblasts on culture days 3, 7, 9 and 14. The osteoblast differentiation and mineralization assay revealed that the Wnt11 defi ciency retarded osteoblast maturation. As indicated by the preliminary re-sults, the cancellous bone volume was different in mice at different age but did not differ between knockouts and wild types. This non-signifi cance may also be affected by the small number of mice.Conclusions: Wnt11 defi ciency seems to delay osteoblast differentiation and mineralization but the extent of this inhibitory effect requires further investiga-tion. Growth factors regulate bone metabolism by complex routes and Wnt11 may be one piece in that puzzle. Wnt11 enhances osteoblast maturation to-gether with BMP2 and R-spondin 2 (Friedman et al. 2009). The infl uence of this pathway may still be offset to some extent by all the other factors involved in the bone forming process.

408 i Clinical and Histological assessments Of EquimatrixFor purifi ed recombinant Human platelet-derived GrowthFactor-BB in a periodontal defect

david kim (uSa), Soo-Woo Kim, Peter Schupbach, Marc Nevins

Objectives: Growth factors are natural biological molecules that mediate and regulate key cellular events such as cell proliferation, chemotaxis, differentia-tion and matrix synthesis by binding to specifi c cell-surface receptors. Purifi ed recombinant human PDGF-BB (rhPDGF-BB) along with various matrices un-derwent a series of rigorous and extensive preclinical and clinical investigations to test their safety and effi cacy in periodontal regeneration. Despite the advanc-es in periodontal regeneration brought about by the rhPDGF-BB, the quest for alternative matrices is rationalized since the clinical effectiveness of rhPDGF-BB is dependent upon the delivery system’s ability to bind and release a thera-peutic dose of rhPDGF-BB at the strategic time. The objective of our study was to evaluate the safety and effi cacy of a new matrix (Equine particulate graft, Equimatrix) in combination with rhPDGF-BB for periodontal regeneration.Methods: Two-walled box type intrabony defects were surgically created on the proximal and buccal side of the mandibular 2nd premolars and 1st molars in 6 healthy female hounds fi ve weeks after the extraction of their mandibular 3rd and 4th premolars. A reference notch was made on the exposed roots with an inverted cone burr at the base of the defects. Prior to grafting, Equimatrix was thoroughly saturated with 0.3mg/mL rhPDGF-BB for a minimum of 10 minutes to allow for absorption of the PDGF molecule to the surface of the graft matrix. The defects were then fi lled to the level of the alveolar crest, and the fl aps were coapted for a tension-free primary wound closure. The negative control group did not receive any type of grafting. All animals were sacrifi ced 10 weeks after the periodon-tal regeneration procedures. Both histological and histomorphometric analyses were performed to investigate the quantity of new bone and cementum formation.results: During the postoperative period, healing was uneventful for all ani-mals. Light microscopic analysis for the negative control group noted that the alveolar bone defects were mainly fi lled with fi brous tissues with minimal amount of new bone formation compared to the bone substitute group. For the Equimatrix + rhPDGF-BB group, a remarkable evidence of newly formed bone which surrounded the bone substitute materials was evident. The mean new bone formation was 42.0 ± 13.3 % for the Equimatrix + rhPDGF-BB group while it was 19.8 ± 11.7 % for the negative control group. This difference was statistically signifi cant (P ‹ 0.01). The periodontal ligament was maintained along the root surface with no evidence of root resorption or ankylosis. In addition, a statistically signifi cant amount of new cementum formation was evident for the Equimatrix + rhPDGF-BB group (P = 0.001). The mean new cementum length and % for the Equimatrix and rhPDGF-BB were 4.8 ± 1.3 mm and 80.2 ± 19.1 %, while they were 1.7 ± 1.9 mm and 35.8 ± 27.4 % for the negative control group.Conclusions: Equimatrix and rhPDGF-BB demonstrated a statistically signifi -cant amount of new cementum length and a greater amount of new bone area compared to the control group. The potent wound-healing effects of rhPDGF-

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BB in combination with Equimatrix provided an innovative method for local de-livery of highly potent growth modulators to maximize regenerative potential.

409 i dental Trauma Management awareness among primary Schools Teachers in ajman, united arab Emirates.

raghad Hashim (united arab Emirates)

Objectives: To assess, by means of a self-administered structured question-naire, the level of knowledge of primary schools teachers in Ajman with re-gards to the immediate emergency management of dental trauma.Methods: The questionnaire was sent to teachers in randomly selected pri-mary schools in Ajman. A total of 161 teachers responded (response rate 84.4%). The questionnaire surveyed teachers’ background and knowledge and management of tooth fracture and avulsion, and also investigated teachers’ attitudes and self-assessed knowledge.results: Ninety-one percent of the teachers were females, 51.6% in their thir-ties; 61.5% had university qualifications. Fifty teachers had received formal first aid training, only thirteen of them recalled that they had received training in the management of dental trauma. Concerning the management of tooth frac-ture, 138 respondents (85.8%) gave the appropriate management for fractured tooth. Over 121 (75%) of the respondents indicated that professional assistance should be urgently sought if a permanent tooth had been avulsed, but they had little knowledge of the correct media for transporting the avulsed tooth. Most teachers were unsatisfied with their level of knowledge of dental trauma and the majority were interested in having further education on the topic.Conclusions: The findings revealed that the level of knowledge of management of dental trauma (especially tooth avulsion) among school teachers in Ajman is inadequate and education campaigns are necessary to improve their emer-gency management of dental injuries.

410 i The impact Of Osteoporosis and diabetes On Graft Consolidation in rat Calvaria

alexander Fügl (austria), Stefan Tangl, Claudia Keibl, Georg Watzek, Heinz Redl, Reinhard Gruber

Objectives: Implant placement frequently depends on bone augmentation. However, the impact of systemic metabolic diseases on the consolidation of bone substitutes remains poorly understood. Our goal is to study the impact of osteoporosis and diabetes on graft consolidation in rat calvaria.Methods: We determined a rat model in which methacrylate hemispheres filled with deproteinized bovine bone mineral were fixed on the calvaria. One group received streptozotocin (STZ) to induce diabetes mellitus and rats treated with an equivalent solution served as controls. Another group of animals underwent ovariectomy (OVX), causing osteoporosis. The control animals remained un-treated. Specimens were assessed by histomorphometry and µCT.results: Graft consolidation was similar between the two groups. The rate of new bone formation after 4 weeks was 0.61±0.53% in the STZ group and 0.69±0.91% in the control group. After 8 weeks, the rates of new bone formation were 4.98±3.16% in the OVX group and 2.35±1.30% in the control group. The vol-ume occupied by the bone substitute was not affected by STZ or OVX treatment. The low amount of newly formed bone could not be quantified by µCT.Conclusions: We conclude that neither STZ nor OVX altered the early phase of graft consolidation. Our findings are limited by the weak osteogenic potential of the rat calvaria in this augmentation model.

411 i Histological Evaluation Of The quantite Of Bone Formation

Sergio Gehrke (Brazil)

Objectives: The aim of the present study was to assess the influence of a nano-crystalline hydroxyapatite in titanium hemispheres in the skull of rabbits. The bone growth was assessed by analyzing histological sections taken 30 days after surgery. The proposition was to evaluate the potential of bone stimulation and promotion of the nanocrystaline Hydroxiapatite NanoBone® in titanium hemispheres in contact only with blood from the bone tissue.

Methods: Five adult New Zealand rabbits (Oryctolagus cuniculus) were used in this study. Three were sacrificed after 30 days. Each animal provided 2 sites on its skull. The sites for stabilization of the hemispheres were made with a trephine 9 mm in diameter and 1 mm in length. 10 perforations were made in the circles thus formed with a 699 conical burr in order to stimulate bleeding. The hemispheres were filled with nanocrystalline Hydroxiapatite NanoBone® (Artoss GmbH, Germany). After sacrifice, sections were obtained and stained using the Hematoxilin/Eosin (HE) and Masson’s trichrome (MT) methods.results: Intense cell proliferation along with extensive formation of collagen and bone matrix could be observed in the samples after 30 days. This large number of cells was still present after 30 days. This demonstrates the excel-lent osteoconductive properties of the material. The sections showing good results in terms of bone quality and quantity, amount of new bone and number of cells involved in the bone neoformation process.Conclusions:The results of this material at 30 days indicate that grafting with NanoBone® promotes new bone formation, providing the grafted area with a greater amount of cellular activity. This would theoretically allow successful installation of implants in an adequate bone bed. Additional studies would be necessary to confirm this statement.

412 i Combined Surgical Therapy Of advanced ligature-induced peri-implantitis defects. part i. Cone-beam Computed Tomographic analysis.

Mihatovic ilja (Germany), Narja Sahm, Vladimir Golubovic, Jürgen Becker, Frank Schwarz

Objectives: To evaluate the impact of rhBMP-2 on the radiographic bone gain (RBG) (i.e. cone-beam computed tomography, 90 kV, 3.1 mA, voxel size 0.2 mm) after surgical therapy of ligature-induced peri-implantitis in dogs employing a particulated bone filler (NBM) (intrabony - i) combined with either an equine bone block (EB) or implantoplasty (P) (supracrestal - s).Methods: Defect sites were randomly allocated in a split-mouth design to the following groups: (1) NBM (i)/ EB (s) (i.e. EB and EB+rhBMP-2), or (2) NBM (i)/ P (s) (i.e. P and P+rhBMP-2). The sites were left to heal in a submerged posi-tion for 12 weeks.results: Mean RBG values were significantly lowest in the P group (1.0±1.0 mm), when compared either with the EB (1.7±0.7 mm), EB+rhBMP-2 (1.8±1.6 mm), or P+rhBMP-2 (2.0±0.8 mm) groups. The differences between the EB, EB+rhBMP-2, and P+rhBMP-2 groups were statistically non-significant. Mean RBG values were equally distributed between mesial/distal and vestibular/oral aspects in all groups.Conclusions: It was concluded that i) rhBMP-2 soak-loaded NBM may have the potential to improve RBG at i-components, and ii) EB with or without rh-BMP-2 did not seem to be associated with a complete radiographic bone fill at s-components.

413 i Transforming Growth Factor-ß1 accelerates resorption Of a Calcium Carbonate Biomaterial in periodontal defects

ki-Tae koo (korea), Ulf Wikesjo, Young Ku, Yong-Moo Lee, Yang-Jo Seol,In-Chul Rhyu

Objectives: It has been suggested that several growth or differentiation factors accelerate the degradation of biomaterials used as carriers. The objective of this study was to evaluate the possible action of rhTGF-ß1 on the biodegrada-tion of the calcium carbonate carrier and its effect on periodontal regeneration with a special focus on bone.Methods: The rhTGF-ß1 in a putty-formulated particulate calcium carbonate carrier was implanted into critical-size, supra-alveolar periodontal defects under conditions for GTR in five beagle dogs. Using a split-mouth design, con-tralateral, supra-alveolar periodontal defects were implanted with rhTGF-ß1in a carrier or with carrier alone (control). The animals were euthanized at week 4 post-surgery and block biopsies of the defect sites were collected for histo-logical and histometric analysis. The following parameters were recorded for buccal and lingual tooth surfaces for each section: defect height, defect area, regenerated bone height, regenerated bone area, residual carrier area and re-sidual carrier density. Measurements at tooth level and generalized estimat-

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ing equations were used to assess the impact of different factors on carrier resorption. Wald tests were used for multiple comparisons, and the level of signifi cance was set at 5%.results: The rhTGF-ß1 and control groups did not differ signifi cantly with re-gard to defect characteristics (defect height, device height, and wound area). There were also no statistically signifi cant differences in bone formation (height and area) among the treatments. On the other hand, total residual carrier was signifi cantly smaller in sites that received rhTGF-ß1 compared to that in the control (P = 0.04). Similarly, carrier density was considerably smaller in the rhTGF-ß1 group; this difference did not reach statistical signifi cance (P = 0.06). This observation may indicate that rhTGF-ß1 increased the resorption rate of the putty-formulated particulate calcium carbonate carrier, but this effect did not infl uence bone formation or regeneration of the periodontal attachment. A stratifi ed analysis for wound area showed that carrier density and residual car-rier area were signifi cantly smaller for the rhTGF-ß 1 group in smaller wound areas (P ‹ 0.05). No signifi cant differences were observed for these parameters in larger wound areas (p › 0.05). No signifi cant differences were observed be-tween experimental groups regarding new bone height and area irrespective of wound area (P › 0.05). In the multivariable model, residual carrier area was signifi cantly smaller for the rhTGF-ß1 group, and this difference remained sig-nifi cant even after adjusting for wound and bone area.Conclusions: Within the limitations of the study, it may be concluded that rhT-GF-ß1 accelerates biodegradation of a particulate calcium carbonate biomate-rial, indicating a biological activity of the rhTGF-b1 formulation apparently not encompassing enhanced or accelerated periodontal regeneration.

414 i in Vivo Comparison Of Carbonated HydroxyapatiteSynthetic and xenogenic Scaffolds For Bone Tissue Engineering

alex Gurin (russia), Vladimir Komlev, Inna Fadeeva

Objectives: Synthetic calcium phosphate biomaterials have been widely used in bone tissue applications and are of considerable interest as scaffold materials due to properties of osteoconduction, resorbability and in some cases osteoin-duction. This study is devoted to in vivo evaluation of carbonated hydroxyapatite synthetic scaffolds (CHA) for potential use in bone tissue engineering in compar-ison with bovine bone derived (xenogenic) carbonated hydroxyapatite (Bio-Oss).Methods: Synthetic scaffolds with carbonate content of about 6 wt.% were synthesized by solid-state reaction and divided into 2 groups: 1st group sur-face micropores ‹ 10 µm and inner cavities about 400 µm, 2nd group surface macropores about 150 µm and inner cavities 300 µm. For comparison Bio-Oss spongiosa small granules (Geistlich, Switzerland) were used.X-ray diffraction, Fourier transform infrared spectroscopy (FTIR-4200, Shi-madzu Co Ltd), evaluation of solubility in isotonic solution of 0.9% NaCl for 3 weeks, scanning electron microscopy (Hitachi S4800), histology evaluation (15 days) in hole bone defect on Wistar rats, statistical morphometric analysis of bone matrix formation was performed by one-way analysis of variance (ANOVA) with the MicrocalTM OriginTM Version 5.0 software package.results: X-ray diffraction results demonstrated that the broadening peaks of the CHA scaffolds are similar to the pattern of natural human bone, X-ray microanal-ysis demonstrated the presence of nitrogen in Bio-Oss granules. FTIR showed that the broad duplet bands at 1420, 1455 cm-1 and the band at 875 cm-1, which were characteristics of carbonate, were clearly observed in the CHA and Bio-Oss. The resorption rate in 0.9% NaOH was higher in CHA group 2. SEM showed dif-ferences in the structure of sintered CHA: scaffolds in the 1st group had surface micropores ‹10 µm, on the cross section we observed inner cavities of about 200 µm in diameter; scaffolds in the 2nd group had surface macropores of about 150 µm and inner cavities of about 300 µm. Bio-Oss granules had surface micropores of about 4–10 µm and large inner holes of about 500-800 µm. Histological evalua-tion showed active bone formation on synthetic CHA scaffolds in 2nd group.Conclusions: It is reasonable to use CHA scaffolds with surface macropores of about 150 µm as a bone substitute for fi lling bone defects. Porous scaffolds with micropores ‹10 µm have large inner cavities which could be used as a delivery carrier for stem cells and antibiotics.

415 i peripheral Blood as a Monitor Of Bone HealingEvents in The rabbit Mandible after augmentationWith and Without Collagen Membrane

Victor palarie (Moldova), Peer W. Kämmerer, Olga Tagadiuc, Viorel Nacu, Bilal Al Nawas

Objectives: This experimental project was designed to evaluate differences in the sequential biochemical bone healing events that occur during the initial stages of guided bone regeneration (GBR) of chronic lateral ridge defects in rabbits with deproteinized bovine bone (Bio Oss®, GeistlichPharma AG), cov-ered and non-covered with collagen membrane (Bio-Gides®, GeistlichPharma AG). The outcomes of bone regeneration were measured by the activities of total and bone acid phosphatase and alkaline phosphatase in peripheral blood.Methods: Eight weeks after formation of a defect in the right lateral mandible of six rabbits, the bone grafting procedure was carried out. In three animals (group +), GBR with Bio Oss® particles and collagen membrane was applied. In three animals, only the bone substitute was used (group -). The peripheral blood was collected before surgery, 1, 24 and 72 hours, 7 days, 2 weeks and 3 weeks after surgery. Total acid phosphatase (TAcPh), bone acid phosphatase (BAcPH), total alkaline phosphatase (TAlPh) and bone alkaline phosphatase (BAlPh) activities were determined in the peripheral blood, using standard kits (Elitech, France).results: Before surgery, no differences were detected between the two groups. One hour after surgery, all parameterswere signifi cantly higher in group + (TAcPh p=0.001, BAcPh p=0.003, TAlPh p=0.021, BAlPh p=0.006). 24 hours after surgery, only TAlPh activity was signifi -cantly higher in group + (p=0.035). After 72 hours, all parameters were seen to be signifi cantly higher in group + (TAcPh p ‹ 0.001, BAcPhp ‹ 0.001, TAlPh p=0.013, BAlPh p=0.024), whereas after 7 days no differences could be seen. After two weeks, TAcPh (p=0.003), BAcPh (p=0.003) and BAlPh (p=0.007) were higher in group -. A signifi cant difference in favour of group - could also be detected after 3 weeks (TAcPH p=0.002, BAcPH p=0.001, TAlPH p=0.001, BAlPh p=0.008).Conclusions: Higher levels of enzyme activity indicate more intense bone re-modelling. GBR with bone substitute particles and collagen membrane showed a desirable earlier remodelling activity.

416 i The infl uence Of alendronate On OsseointegrationOf Nanotreated dental implants in New zealand rabbits

Efstathia Tsetsenekou (Greece), Demos Kalyvas, Triantafi llos Papadopoulos, Nikos Papaioannou, Georg Watzek, Stefan Tangl

Objectives: Growing clinical demands for stronger and faster bone bonding to the implant have motivated the development of methods for enhancing osseo-integration. The application of bisphosphonates in order to optimise bone heal-ing has recently attracted great interest. N-containing bisphosphonates, such as alendronate, are the more potent drugs in this class. The aim of this study was to determine the effect of alendronate on the osseointegration of a well-documented nanotreated implant system in a rabbit femoral condyle model.Methods: Thirty-two adult female New Zealand White rabbits received one implant (3,25mm in diameter and 10mm long) in their left femoral condyle, a week after they were ovariectomized. Half of them were saline-treated (con-trol, group A) and the other half were alendronate treated (group B). Rabbits from both groups were euthanized after 6 and 12 weeks respectively.results: The specimens were evaluated histologically and histomorphometri-cally. Upon histological evaluation, no obvious differences between the control and treatment group were found. Implants showed good integration into the bone tissue surrounding them. There were also no statistically signifi cant dif-ferences in bone to implant contact (BIC) and the amount of bone tissue (BV/TV) in the immediate neighbourhood of the implant at both healing periods.Conclusions: The systemic administration of alendronate was not found to af-fect the histological osseointegration of implants in animals with a hormonal status resembling that of healthy post-menopausal women. Further research will be needed to investigate this approach.

417 i Histological Evaluation Of Bone regenerationin Surgically Created defects in rabbit Maxilla usingHydroxyapatite Bone Graft-prp Combination

Caner atalay (Turkey), Vakur Olgaç, Elif Ergül, Ibrahim Akyazi, Duygu Yaman, Korkud Demirel

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Objectives: New bone formation promoted by regenerative treatment methods is still one of the important aims of periodontology and implantology. Guided bone regeneration is known as a predictable technique for bone augmentation. Allo-plastic graft materials have good osteoconductive properties, have no limitations on availability and have no risk for disease transmission. Their composition closely resembles the inorganic phase of bone. The degranulating granules of thrombo-cytes release growth factors that affect wound healing. The aim of this study was to assess bone regeneration in surgically created defects in rabbit maxilla using al-loplastic bone substitute (hydroxyapatite)-platelet rich plasma (PRP) combination.Methods: 30 New Zealand White rabbits were divided into 2 groups of 15 animals each. Bilateral 10mm ×5mm×3mm bone defects were created in the maxilla of each animal. Group 1 had one defect filled only with HA-bone graft and covered with resorbable collagen membrane, while the other defect was left empty and served as control. Group 2 had one defect filled with HA-bone graft and PRP, which was prepared from 10 ml autogeneous blood drawn from the auricular artery and covered with resorbable collagen membrane, while the other defect was left empty. Five animals in each group were sacrificed at day 15, 30 and 60. Bone sections were fixed in formalin, decalcified in sodium citrate and formic acid and placed in paraffin. Sections 5–7µm thick were pre-pared, stained with haematoxylin and eosin and analyzed under light micro-scope by an experienced observer. Histological analysis was used to quantify the amount of new bone within the defects.results: The animals were maintained without adverse events. Bone fill was assessed on a scale from 1 to 4: 1–30% (1), 31–60% (2), more than 60% (3), complete (4). At day 15, 30 and 60 bone fill in Group 1 and 2 was greater than in the control group, but there were no remarkable differences in bone fill be-tween Group 1 and Group 2. Remnants of bone graft were observed at day 15, 30 and 60 in defects filled with HA bone graft or HA-bone graft-PRP combina-tion. Kruskal Wallis, Wilcoxon sign-rank tests were used for statistical analysis.Conclusions: Wound healing within normal limits was observed in all groups. No difference was observed between Group 1 and Group 2. Compared to HA, treatment with a combination of PRP with HA did not lead to significantly greater bone regeneration in surgically created bone defects. Adding PRP to alloplastic bone grafts did not create any histological difference. However, PRP facilitates handling of the bone graft. The study was supported by Istanbul Uni-versity Department of Scientific Research Projects.

418 i Sinus lift in Sheep With Mesenchymal Stem Cells

Sebastian Sauerbier (Germany), Michele Maglione, Toshiyuki Oshima, Samuel Porfirio Xavier, Rainer Schmelzeisen, Ralf Gutwald

Objectives: New reconstructive and less invasive methods have been searched in order to optimize bone formation and osseointegration of dental implants in maxillary sinus augmentation. The aim of the presented ovine split-mouth study was to compare autogenous bone, bovine bone mineral (BBM) alone and in combination with mesenchymal stem cells (MSCs) regarding their potential in sinus augmentation.Methods: Bilateral sinus floor augmentations were performed in 12 adult sheep. BBM and MSCs were placed into the test side and only BBM in the contra-lateral control side of 6 sheep. In the other 6 sheep BBM and MSCs were mixed and placed into one side and autogenous bone in the other side. 3 animals of each group were sacrificed after 8 and 16 weeks. Augmentation sites were analysed by computed tomography, histology and histomorphom-etry. Statistically analyses were performed according to the mixed model by Pinero and Bates (function lme in package nlme under R).results: The differentiation assay revealed that multipotential mesenchymal stem cells had been transplanted. The initial volumes of both sides were similar and did not change significantly with time. A tight connection between the particles of BBM and the new bone was observed histologically. Bone formation was significantly (p=0.027) faster by 49 % in the test sides and comparable to autogenous bone.Conclusions: The combination of BBM and MSCs accelerated new bone for-mation in this model of maxillary sinus augmentation. This could allow early placement of implants.

419 i Effectiveness Of autograft and Bovine derived Hydroxy apatite Grafted Simultaneously With implant placement in Maxillary Sinus in Space Maintenance and New Bone Formation

young-Sung kim (korea), Su-Hwan Kim, Won-Kyung Kim, Young-Kyoo Lee, Yong-Moo Lee

Objectives: Since Boyne & James and Tatum, sinus augmentation has been used widely and showed clinically satisfactory result. However, regenerated bone in maxillary sinus was usually evaluated indirectly by X-ray images es-pecially in instances of simultaneous sinus augmentation and implant place-ment. In this study, sinus augmentation with simultaneous implant placement in rabbit maxillary sinus was performed.The purpose of this study was to evaluate the effectiveness of autogenous graft and bovine derived hydroxyapatite grafted simultaneously with implant place-ment in maxillary sinus in space maintenance and new bone formation histo-logically and histometrically.Methods: 12 New Zealand white rabbits (aged 3 months, weight 3–3.5 Kg) were used for the this study. There were three experimental groups: control group (BC), in which sinus membrane was elevated and the sinus space filled with blood clot, autograft group (AB), in which the sinus space was filled with autog-enous bone harvested from calvarium, and xenograft group (BHA), in which the sinus space was filled with bovine derived hydroxyapatite. The grouping was the result of randomisation. A 1.4-mm in diameter, 6-mm long titanium bone screw was used as an implant analogue. Half of the rabbits were sacrificed 4 weeks after surgery, and the others were sacrificed 8 weeks after surgery.Histological observation of prepared undecalcified sections was performed under a light microscope. For histometric analysis, the vertical height of most apical bone contact (VH), the amount of newly formed bone in the area of inter-est (NFB), the bone-to-implant contact (BIC) were measured using an image analysis software.results: BC group showed collapse of sinus membrane and small amount of new bone formation limited around original sinus floor (OSF). In AB group, si-nus membrane was found above screw apex. Major new bone formation was observed at 4 weeks, while remodeling of newly formed bone and adipose cell rich central region was observed at 8 weeks. BHA group showed retention of sinus membrane above screw apex. New bone formation was limited between graft particles and the amount of new bone formation increased from 4 weeks to 8 weeks. Bone-to-implant contact was observed in all groups.The vertical height of most apical bone contact (VH) was greatest in BHA group followed by AB group and BC group (p=0.002). However, there were no sta-tistical significances in the amount of newly formed bone (NFB) and bone-to-implant contact (BIC) (p › 0.01). In comparisons of intra-group differences between 4 weeks and 8 weeks, there were no statistically significant pairs in all groups (p › 0.01).Conclusions: From the results of this study, we can conclude as follows. Im-plant placement without augmenting the elevated sinus space is not appropri-ate in bone-deficient maxillary posterior region. Xenograft as well as autograft can maintain the augmented sinus space. Autograft is superior to xenograft in the amount of new bone formation and maturation of newly formed bone. However, the clinical significance of the formation speed and maturation of new bone should be investigated.

420 i The Effect Of Micro-Macroporous Biphasic Calcium phosphate and deproteinized Bovine Bone Mineral On Exophytic Bone Formation in rabbit Calvaria

Sung Guen kim (korea), Jin-cheol Kim, Yeek Herr, Jong-Hyuk Chung, Seung-Il Shin, Young-Hyuk Kwon

Objectives: The purpose of the present study was to evaluate the osteocon-ductive effect of micro-macroporous biphasic calcium phosphate (MBCPTM, MBCP) and deproteinized bovine bone mineral (Bio-Oss®, DBB) on exophytic vertical bone formation in guided bone regeneration using titanium reinforced e-PTFE membrane (TR).Methods: Membrane was contoured in a rectangular parallelepiped shape (8 mm length, 5 mm width and 4 mm inner height). MBCP and DBB were used as fillers in the space under the membrane. In addition, graft material was incorporated with 8% inorganic polyphosphate (polyP). Twenty adult male New Zealand white rabbits were used in this study and 4 rabbits were al-lotted to each group randomly. Decortication was performed on calvaria to promote blood supply in the wound area and the membrane was fixed with 4 fixation pins at each surgical site. The test groups were divided as

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following: TR+MBCP (Test I), TR+MBCP+polyP (Test II), TR+DBB (Test III), TR+DBB+polyP (Test IV), and TR without any fi ller served as a control. The experimental animals were sacrifi ced at 8 and 16 weeks after the surgery as scheduled. Non-decalcifi ed preparation was processed for histological and histomorphometric analysis.results: Control group and test group I showed the highest new bone forma-tion at 16 weeks. There was no signifi cant difference in the new bone formation between test groups I and II at 16 weeks. All groups showed a greater amount of new bone formation at 16 weeks compared to 8 weeks and only test group III showed a statistically signifi cant difference. Extent of new bone formation in test group I was greater than any other groups at 8 and 16 weeks, but there was no statistically signifi cant difference. New bone formation in Test group IV was prominent in upper half of exophytic space at 8 and 16 weeks.Conclusions: Within the limitations of our experiment, it could be concluded that more favorable new exophytic bone formation was obtained when using DBB rather than MBCP. PolyP incorporation in both MBCP and DBB showed no signifi cant infl uence in the new bone formation.

421 i The Effect Of Composite Graft With deproteinized Bovine Bone Mineral and Mineralized Solvent-dehydrated Bone allograft On Exophytic Bone Formation in rabbit Calvaria

park Seyong (korea), Hwa-Suk Seok, Young-Hyuk Kwon, Yeek Herr, Jong-Hyuk Chung, Seung-Il Shin

Objectives: The purpose of the present study was to evaluate the osteoconduc-tive effect of composite graft on exophytic vertical bone formation in guided bone regeneration with titanium reinforced e-PTFE membrane (TR). Deproteinized bo-vine bone mineral (Bio-Oss®, DBBM) and mineralized solvent-dehydrated bone allograft (Puros®, SDA) were used as fi ller materials in the space created by TR.Methods: TR was contoured in rectangular parallelepiped shape (8 mm length, 5 mm width and 4 mm inner height) and sterilized with ethylene oxide before surgery. Twenty New Zealand adult white male rabbits (mean weight 2 kg) were used in this study and 4 rabbits were allotted to each group randomly. Decor-tication was performed on calvaria to promote blood supply in wound areas and TRs were fi xed with 4 fi xation pins at each surgical site. The test animals were divided into 5 groups as following: TR+DBBM (group 1), TR+SDA (group 2), TR+Mix (group 3, DBBM:SDA=1:1 in volume), TR+Layer (group 4, upper 2 ? area with DBBM, lower 2 ? area with SDA), and TR (control group, without any fi ller). The experimental animals were sacrifi ced 8 and 16 weeks after the surgery as scheduled. Non-decalcifi ed preparation was processed for histological and histomorphometric analysis.results: New bone formation in the test group using DBBM was greater than the group using SDA. However, much more residual graft material was found in DBBM groups. At 16 weeks, TR+DBBM (group 1) showed a signifi cantly higher rate of residual graft (p ‹ 0.05). TR+SDA (group 2) showed prominent cellular degradation and bone remodeling. TR+Mix (group 3) presented favor-able conditions for new bone formation and graft resorption at 8 and 16 weeks. TR+Layer (group 4) showed a distinct histological difference between the up-per and lower areas. New bone formation was slightly decreased at 16 weeks compared with at 8 weeks in group 4.Conclusions: It can be concluded that more favorable new exophytic bone formation could be obtained by means of composite graft of DBBM and SDA. Sandwich bone augmentation, such as layer by layer grafting technique, was also effective in new bone formation and remodeling.

422 i Tissue reaction To a Novel Bilayered Collagen-Based Matrix For Guided Bone and Guided Tissue regeneration, Histological analysis Of animal and Human Tissue

Shahram Ghanaati (Germany), Markus Schlee, Christoph Goerlach, James Kirkpatrick, Robert Sader

Objectives: A fast connective tissue ingrowth within a bone defect, which was augmented with bone substitute materials, negatively infl uences the desired bone regeneration outcome. Biomaterial research is therefore eager to pro-duce biocompatible membranes and matrices, which serve as barrier-like elements at the interface between bone and the surrounding soft tissue. The

infl ammatory response, which is related with its degradation is often a limiting factor for biomaterial integration within the tissue interface. A fast degradation may lead to an insuffi cient barrier function of the membranes. Accordingly, unsatisfactory tissue integration and an undesired connective tissue ingrowth might result. The aim of the present study was to analyze the tissue reaction to a novel bovine sourced collagen I-III based bilayered matrix after implantation in murine and human tissue.Methods: Using the subcutaneous implantation model in CD-1 mice, the tis-sue integration and response to the collagen I-III-based double layered matrix were analyzed for up to 60 days (3, 10, 15 and 60 days). The tissue response to this matrix was assessed by means of general and special histological detec-tion methodologies. The degradation of the two matrix components was fur-thermore measured histomorphometrically. The integration of the matrix in human oral tissue was also assessed by histological analysis of histological biopsies after successful soft tissue reconstruction with this matrix. Silk fi broin as a naturally derived protein was used as a control.results: Throughout the study period, a mild infl ammatory response was observed within the implantation bed of the collagen based matrix. Only few lymphocytes, predominantly macrophages and no multinucleated giant cells were detectable at any study time points. The matrix was detectable within the fi rst 30 days in its bilayered structure. Starting with day 30, however, the breakdown of the matrix was initiated. Correspondingly, its integration within the surrounding connective tissue began. In human tissue, good integration of the matrix was observed which enabled aesthetically desirable soft tissue regeneration. Also in human tissue no unphysiological infl ammatory reaction, i.e. multinucleated giant cells was observed. Silk fi broin served also as a good barrier. It induced, however, the dense infl ux of infl ammatory cells within the implantation bed along with multinucleated giant cells. Accordingly, the con-trol material underwent faster biodegradation.Conclusions: The present in vivo studies in mice and humans reveal that the new collagen based matrix serves as an ideal barrier-like structure. This ma-terial induces no undesired foreign body response in both species and can be used for soft and hard tissue regeneration. No multinucleated giant cells were observed in mice and humans. Ongoing combined in vitro and in vivo studies with human endothelial and mesenchymal cells will assess the suitability of this matrix for complex tissue engineering.

423 i Biomimetic, BMp-2-Functionalisation Of deproteinised Bovine Bone Confers Osteoinductivity and improves Biocompatibility

Gang Wu (Netherlands), Ernst B. Hunziker, Yuanna Zheng, Daniel Wismeijer, Yuelian Liu

Objectives: The repair of critical-sized bony defects remains a challenge in the fi elds of implantology and orthopaedics. Although healing can be aided by the transplantation of autologous bone, the supply of this tissue is limited and its removal is associated with donor-site morbidity. Hence, alternative bone-defect-fi lling materials both natural and synthetic have been sought for commercial production on a large scale. Deproteinised bovine bone (DBB) represents one such material. However, this material is neither osteoinductive nor well toler-ated within the bony compartments. This study was designed to functionalize de-proteinised bovine bone with a BMP-2-bearing calcium-phosphate coating, and to evaluate the osteogenesis and infl ammatory activity of the end product in vivo.Methods: Four groups were established: (i) DBB alone; (ii) DBB bearing a calcium-phosphate coating (no BMP-2); (iii) DBB bearing an adsorbed depot of BMP-2 (no coating); and (iv) DBB bearing a co-precipitated layer of calci-um phosphate and BMP-2. Coatings were prepared using a well-established biomimetic procedure. The release kinetics of a coating-incorporated and a directly-adsorbed fl uorescently-tagged protein depot were monitored in vitro. DBB granules (Geistlich) were implanted at an ectopic (subcutaneous) site in rats (n=6 animals per group), and retrieved 5 weeks later for a histomorpho-metric analysis of the volume densities of the bone, bone marrow, fi brous cap-sule and foreign-body giant cells (a gauge of infl ammatory reactivity and thus of biocompatibility).results: The coating-incorporated protein depot was released more gradually than the adsorbed one (52% depletion after 35 days vs. 100% depletion after 13 days). Five weeks after implantation, the volume densities of the fi brous cap-sular tissue and foreign-body giant cells were signifi cantly lower in the BMP-2-bearing-coating group than in the two non-coated groups. Consistent with

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these findings, the volume densities of bone and bone marrow were higher in this group than in that in which BMP-2 was adsorbed directly onto the DBB granules. In the two non-BMP-2-bearing groups, no bone was deposited.Conclusions: Functionalization of DBB with a co-precipitated layer of calcium phosphate and BMP-2 not only renders the material osteoinductive, but also suppresses the inflammatory reactivity that is associated with the native prod-uct. The attributes that are acquired by coating native DBB with a BMP-2-func-tionalized layer of calcium phosphate greatly enhance the material’s clinical potential in the repair of critical-sized bony defects.

424 i reconstruction Of Critical-Sized Bone defects Grafted With different Biomaterials in Sheep: a Computed Tomographic analysis

Chih-long Chen (Netherlands)

Objectives: To evaluate whether the different biomaterials may affect the heal-ing of large critical-sized bone defects manifested in cone-beam computed tomography (CBCT).Methods: 96 cylindrically drilled holes of 13 mm depth and 8 mm diameter were created respectively within the proximal and distal parts of bilateral hu-merus and femurs of 12 sheep. The defects were assigned to one of the eight groups and filled with different biomaterials: 1) no graft, 2) chips of autologous bone (AB), 3) deproteinized bovine bone mineral (DBBM), 4) DBBM mixed with AB, 5) DBBM upon which bone morphogenetic protein 2 (BMP2) was adsorbed, 6) DBBM with biphasic biomimetic calcium phosphate coating (DBBM-CaP), 7) DBBM-CaP upon which BMP2 was adsorbed, 8) DBBM-CaP into which BMP2 was incorporated during the biomimetic coating procedures. After 4- and 8-week healing periods, the sheep were sacrificed respectively for CBCT evaluation and grey value measurement of the defects by using 3D Accuitimo (Morita, Osaka, Japan) and Amira software (Visage Imaging Inc., San Diego, California). Analysis of variance (ANOVA) is applied to examine the difference among the 8 groups.results: In Group 1, the empty defects, only minor or negligible grey value and well-defined border of the defects could be observed on CBCT images after 4 and 8 weeks after surgery. Among the others, group 2 exhibited significantly the lowest measured grey value at both time points. Group 8 showed the high-est grey value compared with groups 3 to 7 after 8 weeks, but the difference was not statistically significant.Conclusions: Cone-beam computed tomography successfully distinguishes au-tologous bone graft from deproteinized bovine bone mineral used in reconstruc-tion of critical-sized defects in sheep. Histomorphometric analysis is needed to clarify the effectiveness of these biomaterials in promoting regeneration.

425 i impact Of Vitamin d On Osseointegration in The Ovariectomised rat

Gabriella dvorak (austria), Georg Watzek, Reinhard Gruber, Alexander Fügl, Alexandra Meinl, Stefan Tangl

Objectives: Vitamin D, a systemic calcium-regulating hormone, has an ana-bolic effect on bone metabolism. Recent data suggests a positive impact on the fracture healing process and mechanical properties of callus. According to several epidemiologic studies a majority of the elderly population is vitamin D deficient. Whether inadequate vitamin D levels or supplemental administration of vitamin D has an impact on osseointegration remains unknown. Vitamin D administration may enhance osseointegration and thus healing time in elderly patients. The overall objective was to demonstrate the immanent importance of vitamin D supplementation on enhanced bone regeneration in an estrogen deficient population.Methods: Fifty adult female rats were divided randomly into three groups. Vi-tamin depletion group with a vitamin D free diet, control group fed a standard diet and vitamin D depletion-repletion group, fed a vitamin D food after 6 weeks of vitamin D depletion. After a housing period of 8 weeks two titanium implants with a diameter of 1 mm and a length of 3 mm were placed in the tibia. At the time of implant placement and scarification blood samples were collected in order to evaluate serum levels of 25(OH) D and parathyroid hormone (PTH). A double fluorochrome labeling method was used to demonstrate the dynamics of healing and the influence of vitamin D. In order to quantify the percentage

of the implant surface in contact with mineralized bone; referred to as “bone-to-implant contact” (BIC) and “Bone volume per tissue volume” (BV/TV), histo-morphometrical analysis was performed.results: The median of the bone volume in the cortical area (BV/TV) of the de-pletion group (De) was 95.65% and 93.24 % in depletion-repletion group (DeRe) compared to 96.91% in controls (p=0.005). Whereas the bone volume (BV/TV) in the medullary compartment showed a median of 12.39% in the depletion group (De), 11.37% in the depletion-repletion group (DeRe) compared to 12.27% in the control group (p=0.87).Bone to implant contact (BIC) in the cortical area showed a median of 62.73% in the De group, 76.88% in DeRe and 80.95% in Co (p=0.017). In the medullary compartment BIC had a median of 26.91% in De, 22.47% in DeRe and 29.46% in Co (p=0.041). Vitamin D insufficiency could similarly decrease bone remodeling activities around dental implants and potentially prolong the healing time for osseointegration to take place.Conclusions: The combined withdrawal of vitamin D/ calcium in combination with catabolic effects on bone metabolism of aging and estrogen deficiency will lead to delayed osseointegration, reversed by vitamin D administration. Even further we expect a positive dose response effect of vitamin D supplementation on the site-specific bone volume.

426 i immediate and Staged implant placement in Bone defects Grafted With deproteinised Bovine Bone Mineral, Hydroxyapatite/tricalcium phosphate Or autogenous Bone in an Experimental Bone defect Model

luiz a. Salata (Brazil), Antonio A. Antunes, Patricio J. Oliveira-Neto, Carla G. Pessoa, Gustavo A. Grossi-Oliveira, Paulo E.P. Faria

Objectives: Implant installation in fresh extraction sockets requires extra care in order to preserve marginal bone walls from extensive resorption. Several previous reports claim deproteinized bovine bone mineral (DBBM); a combi-nation of hydroxyapatite and β-tricalcium phosphate (HA/TP); and particulate autogenous bone (AB) can render less vertical bone loss when placed imme-diately with the implant. However, there is only incipient data whether a late approach, in which osteoconductive materials could be applied and left to heal bone gaps before implant installation. This study aimed at comparing the influ-ence of the timing (immediate or late approach) upon implant stability, osseo-integration and alveolar crest resorption.Methods: Six dogs underwent extractions of all lower premolars and first mo-lars, bilaterally. Three months later four bone defects (6mm wide and 4mm long) were drilled with trephine at one mandible side and randomly filled with DBBM, HA/TP, AB, and coagulum, respectively. Two months later four defects were created on the other side and biomaterials were used as described above together with an implant (OsseoSpeed™, Astra Tech AB, Sweden) in each site. Four implants were placed contra laterally in healed defects. Animals were euthanized two months later. Implant stability was measured by RFA (Oss-tell Mentor™, Osstell AB, Sweden) at installation and after sacrifice. Biopsy of experimental sites were subjected to ground sections (Exact™, Apparate-beau, Germany) for histology and histometry (BA and BIC); distance of implant shoulder to higher coronal bone contact (IS-B) and alveolar crest point (IS-C). Statistical analysis was performed by ANOVA, Tukey and paired t-Student test.results: The staged procedure resulted in increased implant stability, as compared with the immediate approach (p=0.002). The BA e BIC values in the staged technique showed to be superior (p=0.002). The coagulum group exhib-ited higher BIC as compared with the remaining biomaterials (p=0.004) at the macro thread and total implant body (p=0.007). The DBBM and HA/TP groups revealed similar BA and BIC values compared to AB. The staged technique was found with less crest resorption (p _< 0.005). The use of biomaterials did not af-fect (p › 0.005) the ISC-B and ISC-C measurements. The histological examina-tion revealed DBBM and HA/TP particles either in contact with implant surface or involved by bone. The immediate technique resulted in higher concentration of particles suggesting a time-related resorptive pattern. The defects with bio-materials in the immediate group were occupied by woven bone and scarce lamellar bone. In the staged group mature bone was depicted thoroughly what-ever the filler.Conclusions: Implants placed in healed defects with biomaterials or coagulum resulted in better stability, as a consequence of higher BIC and BA. The coagu-lum rendered better BIC compared to other materials. Late technique should

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be preferable to immediate approach because of alveolar crest maintenance. This latter effect is explained by the so-called contact osteogenesis theory, as the coupling process of coagulum and implant surface was somewhat hindered by physical interposition of biomaterials particles.

427 i repair Of Onlay Calvarial Bone Grafts under Specifi canti-Cox 2 anti-infl ammatory drug infl uence: Study in rabbits

leandro Nunes (Brazil), Claudia Biguetti, Gustavo Caviquioli, Leandro Holgado, Eduardo Moreschi, Mariza Matsumoto

Objectives: A number of molecular mechanisms regulate bone repair. Among them, it is known that cyclooxygenase 2 enzyme (COX-2) is essential for bone tissue formation and maturation. The aim of the present study was to evalu-ate onlay intramembranous (IM) and endochondral (EC) autogenous bone graft incorporation in the calvaria of rabbits under specifi c COX-2 anti-infl ammatory drug action.Methods: Thirty six male adult, New Zealand rabbits were divided into 3 groups: Group 1) Control, treated with saline solution; Group 2) Calvaria graft, treated with Eterocoxib, Group 3) Iliac graft, treated with Eterocoxib, beginning three days before the surgical procedure and continuing throughout all the experimen-tal period. After 7, 14, and 30 days, the animals were sacrifi ced and the grafted areas retrieved for morphological microscopic analysis of the interface area.results: Different patterns of integration were observed between IM and EC grafts with a decreased bone formation in the interface of IM grafts during all periods, and a similar result after 30 days between EC and Control Groups, de-spite the decreased bone formation at the 14th day when compared to IM grafts.Conclusions: From these results, it is suggested that inhibition of COX-2 en-zyme produces a negative effect in bone onlay graft incorporation by means of distinct activities for IM and EC bones.

428 i Tantalum pentoxide as a radiopacifi er in injectableCalcium phosphate Cements For Bone Substitution

Jan Willem Hoekstra (Netherlands), Jeroen JJP Van Den Beucken, Sander CG Leeuwenburgh, Gert J Meijer, John A Jansen

Objectives: The behaviour of calcium phosphate (CaP) cements in animal testing and clinical applications is currently solely based on analysis of two-dimensional (2D) histomorphometric techniques, which is not a proper repre-sentation of the in vivo three-dimensional (3D) situation. The reason for this is that non-invasive 3D imaging techniques (e.g. micro Computed Tomography, µCT) do not allow discrimination between the synthetic materials and bone due to the chemical resemblance of CaP cements and the mineral phase of bone.In view of this, the present study aimed at evaluating the feasibility of using tan-talum pentoxide (Ta2O5) as a biocompatible radiopacifi er in vivo. After physi-cochemical characterization, the radiopacifying capacity and biocompatibility of CaP cement containing Ta2O5 were evaluated in a distal femoral condyle model in rats. µCT and histology were used to assess radiopacifying capacity and biocompatibility of Ta2O5 enriched CaP cement, respectively.Methods: The experimental material was obtained by mixing Ta2O5 powder with CaP powder at a 10/90 wt.% ratio (CaP-T group); plain CaP powder was used as a control (CaP-C group). An aqueous solution of 2% Na2HPO4 was used as the liquid phase, with a liquid-to-powder ratio of 0.39 ml/g.To determine the physiochemical characteristics of the materials, the crystal-line structure of CaP-T, CaP-C and Ta2O5 was evaluated using X-ray diffrac-tion (XRD). Furthermore, rheological properties (initial and fi nal cement setting times) of CaP-T and CaP-C were analyzed using a standardized Gillmore test.In the in vivo experiment, 6 male Wistar rats were used, observing national guidelines for the care and use of laboratory animals. Both material groups (CaP-T and CaP-C) consisted of 6 samples. All animals alternately received CaP-T and CaP-C in the left and right distal femoral condyle (bilateral implan-tation; 2 implant sites per animal; 3 mm diameter and 5 mm depth) with an implantation period of 6 weeks.results: XRD analysis showed that the hybrid material (CaP-T) demonstrated diffraction peaks of Ta2O5 at identical locations while apatitic CaP peaks were slightly moved to the left, indicating a modest increase in unit cell size in the CaP crystal lattice of CaP-T compared to CaP-C.

In the Gillmore test, CaP-T and CaP-C showed similar initial setting times of approximately 140 s. In contrast, the fi nal setting time of CaP-T was signifi -cantly increased to ~5 min compared to CaP-C (~4 min; p‹0.001).The surgical procedure in the in vivo experiment was uneventful for all animals and all animals remained in good health during the entire 6 week implantation period. In contrast to CaP-C, CaP-T allowed unambiguous distinction of CaP cement from native bone tissue and volumetric measurements of the materi-als by means of µCT scanning. Furthermore, CaP-C and CaP-T both showed no adverse tissue responses (e.g. infl ammation or fi brous tissue formation) at the implantation site using light microscopy.Conclusions: The incorporation of Ta2O5 as a radiopacifi er into CaP cements enabled discrimination between bone substitute material and surrounding tis-sue by means of µCT. Compared to plain CaP cement, Ta2O5-enriched CaP cement did not alter the biological response upon implantation in a rat femoral condyle. Consequently, Ta2O5 represents an effective and biocompatible addi-tive for monitoring the overall bone behaviour as well as degradation proper-ties of CaP cements.

429 i Comparison Of The Vertical Bone regeneration Outcomeusing Block and particulate Forms Of Bio-Oss® Bone Graft.a Histological Study Of rabbit Mandible.

Christos koutrogiannis (Greece), Alexandros Veis, Nikolaos Dabarakis, George Romanos, Irodis Barlas, Elina Petsa

Objectives: Xenografts have been employed to increase the insuffi cient bone height vertically. The aim of this study is the histological comparison of the vertical bone regeneration outcome using bovine bone graft (Bio-Oss®) in block and particulate forms in a rabbit mandible experimental model.Methods: The lateral mandible area below the molars of 20 adult New Zea-land rabbits was fl attened and used as the experimental site for vertical bone regeneration using standard surgical techniques. In 10 animals assigned in group A, cubic form block grafts (4x4 mm) were placed and stabilized using shaped orthopaedic plates secured with bone screws. In the remaining 10 ani-mals assigned in group B, the particulate form of the graft was gently packed into the custom made perforated metallic cubes (4x4 mm internally) which were secured over the fl attened lateral mandible area with bone screws. All samples were left to heal for two months. The animals were then sacrifi ced; the samples were retrieved, prepared for non-decalcifi ed ground sections and analyzed histologically. The two most central sections were taken from each sample. Graft Area (GA), New Bone Area (NBA), Bone to Graft Contact (BGC) and the Maximum Vertical Height (MVH) of the new bone were measured and analyzed statistically.results: The healing procedure was uneventful in all experimental animals. A certain degree of new bone regeneration could be seen in all histological samples mostly close to the basal and middle areas. In group A the block form of Bio-Oss® was integrated with the basal bone. New bone trabeculae deriving from the basal native bone penetrated and were developed within the graft in form of seams covering the intra-lumen surfaces of the graft framework. The % GA was 34.54 ±14.46 and the % NBA=10.01±6.88. In group B the particulate form of Bio-Oss® presented signifi cantly lower GA percent-age (16.7±8.04, p=0.0014 ‹ 0.05). The new bone growth was observed deriving from the basal native bone and interconnecting the graft particles. The % NBA was however signifi cantly lower than in group (A =4.83±1.89, p=0.023 ‹ 0.05). No signifi cant differences existed in mean BGC and MVH values: (BGC: grou-pA:38.94±28.49, groupB:38.51±23.94, p=0.96 › 0.05, MVH groupA:72.76±24.48, groupB:62.2±17.43 p=0.36 › 0.05).Conclusions: Both forms of Bio-Oss® bone graft were capable of producing bone regeneration in vertical direction under the limitations of this study. The block form presented higher percentages of both graft and new bone volumes while no difference existed in new bone to graft contact percentage as well as in the maximum height where new bone development was observed. The new bone development patterns were different between groups and no resorption signs in either graft forms were noticed.

430 i Bioactive Nucleic-acid Coatings For implantsas an innovative approach For diffi cult Bone Conditions –an Experimental Study in Minipigs

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andreas kolk (Germany), Florian Probst, Oliver Bissinger, Jochen Weitz, Christian Plank, Ralf Smeets

Objectives: Particularly in compromised bone conditions dental implants are able to expand their indications by osteoinductive coatings. The transfer of nucleic acids makes it possible to strengthen the body´s own cell production of particular or combined cytokines like BMP-2 and TGF-Beta or IGF without the drawbacks of direct applications of recombinant proteins. Until now, the central issue of bioactive surfaces has been stability and release behaviour. This problem could be resolved completely by a special coating procedure with PDLLA.Methods: Pre-test series yielded an abrasion of 5% of the complete coating during the implantation procedure. In an experimental study with 18 Göttingen minipigs 6 coated implants with different concentrations of BMP-2-plasmid were inserted into the maxilla in a split-mouth-design. Controls were made with reporter gene or recombinant protein BMP-2. Evaluation of bone-implant-interface and bone regeneration took place after 14, 28 and 56 days by per-forming µCT, histology, immunhistochemistry and polymerase chain reaction (PCR).results: All coatings with nucleic acid achieved significant higher mineraliza-tion rates after 14 and 28 days (31.4% ± 4.8/64.5%± 5.1) than controls (22.9%± 4.3/47.8%± 8.4) (p ‹ 0,05), so that osseointegration was more advanced in the nucleic acid therapy groups. The most effective combination seems to be BMP-2 with a DNA concentration of 12 µg, because the precedent vascularization enhances the dimension stability of the newly formed bone. Implants coated by recombinant protein BMP-2 osseointegrated fast, but with less stability of dimensions.Conclusions: Results of this study first realized with human, stable coated im-plants with nucleic acids demonstrated a significant positive effect of the plas-mids concerning optimizing bone regeneration and osseointegration. There was only transient integration into the cell genome without organic spread, so that nothing gets in the way of the application to humans in the future.

431 i a Model for periimplantitis induction in Mice

Marc Föge (Germany), Marc Menzebach, Mathias Neuschl, Jörg Wiltfang, Stephan Becker

Objectives: Development and therapy of periimplantitis is a non-resolved emerging problem. The aim of this pilot study was to establish a model for periimplantitis in mice as a base for tests with immune-deficient knockout organisms to improve the knowledge about development and progression of periimplantitis.Methods: In 8 mice titanium implants were inserted in the median of the pal-ate. 4 of these implants had ligatures (periimplantitis group). After two weeks of healing time the animals received a special diet enriched with sugar and flavor. After nine weeks micro-CT examinations to evaluate the periimplant tis-sue and histologies were performed.results: Dental implant insertions within the oral cavity are possible in liv-ing mice. Implants with ligatures showed significantly larger periimplant bone defects than controls. The radiologic findings were confirmed by histology. At the end of the observation period, the portion of implants lost was higher in the ligature group.Conclusions: This is the first publication to describe the insertion of dental implants in living mice. Additionally, it is the first time that periimplant infec-tion could be induced in that species. This model will pave the way to study knockout-mice with reduced or even enhanced resistance to periimplantitis.

baSic reSearch, Preclinical StudieS