research article shear bond strength of orthodontic...

Research ArticleShear Bond Strength of Orthodontic Brackets Fixed withRemineralizing Adhesive Systems after Simulating One Year ofOrthodontic Treatment

Gisele Lima Bezerra1 Carlos Rocha Gomes Torres2

Mateus Rodrigues Tonetto3 Alvaro Henrique Borges3 Milton Carlos Kuga4

Matheus Coelho Bandeca1 and Leily Macedo Firoozmand5

1CEUMA University Josue Montello 01 Renascenca II 65075-120 Sao Luıs MA Brazil2Sao Paulo State University Avenida Engenheiro Francisco Jose Longo 777 12245-000 Sao Jose dos Campos SP Brazil3University of Cuiaba Beira Rio 3100 Jardim Europa 78065-900 Cuiaba MT Brazil4Sao Paulo State University Rua Humaita 1680 14803-901 Araraquara SP Brazil5Federal University of Maranhao Avenida dos Portugueses 1966 65080-805 Sao Luis MA Brazil

Correspondence should be addressed to Matheus Coelho Bandeca mbandecagmailcom

Received 13 April 2015 Accepted 5 August 2015

Academic Editor Grant McIntyre

Copyright copy 2015 Gisele Lima Bezerra et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The objective of this study is to assess in vitro the shear bond strength of orthodontic brackets fixed with remineralizing adhesivesystems submitted to thermomechanical cycling simulating one year of orthodontic treatment Sixty-four bovine incisor teethwere randomly divided into 4 experimental groups (119899 = 16) XT Transbond XT QC Quick Cure OL Ortholite Color and SEPTransbond Plus Self-Etching PrimerThe samples were submitted to thermomechanical cycling simulating one year of orthodontictreatment Shear bond strength tests were carried out using a universal testingmachine with a load cell of 50KgF at 05mmminuteThe samples were examined with a stereomicroscope and a scanning electronmicroscope (SEM) in order to analyze enamel surfaceand Adhesive Remnant Index (ARI) Kruskal-Wallis and Mann-Whitney (with Bonferroni correction) tests showed a significantdifference between the studied groups (119901 lt 005) Groups XT QC and SEP presented the highest values of adhesive resistance andno statistical differences were found between them The highest frequency of failures between enamel and adhesive was observedin groups XT QC and OL Quick Cure (QC) remineralizing adhesive system presented average adhesive resistance values similarto conventional (XT) and self-etching (SEP) adhesives while remineralizing system (OL) provided the lowest values of adhesiveresistance

1 Introduction

Orthodontic practice is in constant improvement enablingthe use of new techniques and materials benefiting bothpatient and professional Thus attempts to inhibit the devel-opment of carious lesions in patients under orthodontic treat-ment have been focused on the control of bacterial biofilmsaround the orthodontic accessories [1 2]

Orthodontic braces physically alter the microbiologicalenvironment leading to an increase in the formation ofbacterial biofilm due to the formation of a higher number ofbiofilm retention sites [3] An increase in the incidence of

initial carious lesions and inflammation of the gum tissue isverified in patients submitted to orthodontic treatment withfixed braces [4]

Some studies [5 6] have been investigating materialsthat can be used as an alternative to adhesive systems andcomposite resins aiming to prevent enamel demineralizationaround the orthodontic brackets

In Orthodontics the adhesive system maintains theorthodontic accessories in accurate places during the entiretreatment helping in the reestablishment of an ideal occlu-sion The orthodontic treatment must correct the occlusionin a satisfying way however it must not alter the preexisting

Hindawi Publishing Corporatione Scientific World JournalVolume 2015 Article ID 903451 7 pageshttpdxdoiorg1011552015903451

2 The Scientific World Journal

Table 1 Experimental groups

Groups Adhesive systemscomposition Commercial brandlotexpiration date

XT

Transbond XT light cure adhesiveAdhesive triethylene glycoldimethacrylate (TEGDMA) and BISGMAResin silica BISGMA N-dimethylbenzocaine and hexafluorophosphate

3M Unitek Orthodontics ProductsSouth Peck Road Monrovia USAL 1308100970Exp 0615

QC

Quick Cure fluorideAdhesive bisphenol dimethacrylate hydroxyethyl methacrylate andacetoneResin silica BISGMA triethylene-glycol-dimethacrylate(TEGDMA) and sodium fluoride

Reliance Orthodontic products IncItasca Illinois USAL 123643Exp 0514

OLOrtholite Cure color changeAdhesive phosphate acrylic monomer ethanol acetone and amineResin triethylene glycol dimethacrylate (TEGDMA) BISGMAamine and fluoride compounds

OrthoSource USASherman way Hollywood USAL CUKAExp 0414

SEPTransbond Plus Self-Etching PrimerAdhesive mono- and di-HEMA phosphates distilled water andfluorine compounds

3M Unitek Orthodontics ProductsSouth Peck Road Monrovia USAL 488941cExp 0314

health of teeth and supporting tissues otherwise the treat-ment benefits might be questioned

The current tendency is the improvement of adhesivesystems with simplified application protocol altogether withpromoting satisfying adhesive resistance reducing procedureerrors and minimizing damage to tooth structure [7] Self-etching systems that have acidic components reduce theinconveniences of excessive demineralization of the structureof the tooth and provide a decrease in the number ofsurgical procedures [8 9] Adhesive systems that allegedlyhave remineralizing properties are displayed in themarket [56] however the longevity of the treatment was not confirmedin the literature

Thus the biomechanical behavior of these new systemshas to be investigated so that they can be effectively appliedduring the entire orthodontic treatment As a major part ofthe studies evaluates the adhesive resistance of orthodonticbrackets just right after their installation [6 8 10 11] a longtime treatment evaluation is an important factor

Considering these questions regarding different adhesivesystems and the lack of studies assessing the adhesive resis-tance of remineralizing adhesives the present study aimsto perform the shear bond strength of orthodontic bracketsfixedwith remineralizing adhesive systems submitted to ther-momechanical cycling simulating one year of orthodontictreatment The null hypothesis tested is that there is nostatistical difference in the resistance values when conven-tional remineralizing and self-etching systems are applied

2 Materials and Methods

The present experiment used 64 bovine incisors justextracted cleaned and stored in distilled waterThis researchproject was approved by Animal Experimentation EthicsCommittee (protocol number 0732013) The criteria ofinclusion for tooth selectionwere the following tooth enamel

with no fissures and no previous application of chemicalagents such as hydrogen peroxide alcohol and formalinThesample size was calculated considering 120572 equal to 5 powerof Kruskal-Wallis test 75The result was a size (119899) of 16 teethin each group (PASS 11 NCSS LLC Kaysville Utah USA)

The bovine teeth were sectioned in the cervical line andthe roots which are disposedThe dental pulp was extirpatedwith the aid of a dentin curette (Duflex Lucas number 86SSWhite Rio de Janeiro RJ Brazil) and the pulp chamber wasirrigated with distilled water air-dried and obliterated withutility wax

The teeth were positioned in 25mm times 20mm PVC cylin-drical tubes (Tigre Joinville SC Brazil) keeping the buccalsurface positioned at the bottomof the base and embedded inacrylic resin (VIPI Sao Paulo SP Brazil) In order to obtainplain buccal surfaces parallel to the block base these weresubmitted to plaining and polishing with sandpaper (gran-ulations 200 400 600 and 1200) (3M Sumare SP Brazil)with the aid of a polishing machine (Panambra Tecnica ImpExp Ltda Sao Paulo SP Brazil) with irrigation and constantuniform pressure

The adhesive systems presented in Table 1 were applied inthe making of the experimental groups

21 Fixation of the Brackets Sixty-four stainless steel ortho-dontic brackets were used for upper central incisors with15mm high and 40mm wide mesh bases (Roth 002210158401015840times 003010158401015840 KIRIUM Abzil Ind amp com Ltda Sao Josedo Rio Preto SP Brazil) The buccal surface of the teethenamels underwent prophylaxis with fluoride-less pumicestone (SSWhite Rio de Janeiro RJ Brazil) and water for tenseconds

Groups XTQCOL and SEPwere submitted to the appli-cation of the adhesive systems according to the specificationsin Table 2 Maximum pressure was applied in the bracketbonding or the standardization of the strength exercised and

The Scientific World Journal 3

Table 2 Application methods of the adhesives systems used in this study

Groups Application method

XT QC and OL

(i) Etching phosphoric acid 37 30 s on the enamel(ii) Washing for 30 s and air jet drying(iii) Active application of 2 layers of the adhesive (5 s)(iv) Using a brief air jet to evaporate the solvent and make sure there is a thin uniform layer(v) Photopolymerization for 20 s(vi) Resin application and photopolymerization for 10 s each surface (mesial distal cervical and incisal)

SEP(i) Active application of 2 layers of the adhesive (5 s)(ii) Use of a brief air jet(iii) Photopolymerization for 20 s(iv) Resin application and photopolymerization for 10 s in each surface (mesial distal cervical and incisal)

the thickness of the resin layerThe excesswas removed beforepolymerization with a dental explorer (Duflex number 5 SaoPaulo SP Brazil) A properly trained and calibrated operatorperformed all procedures

The adhesive system and resin underwent photopolymer-ization with the device fast-curing cordless LED light (3MESPE dental Landsberg am Lech Germany) with a radiome-ter-checked (Gnatus Ribeirao Preto SP Brazil) light intensityof 800mWcm2

22 Thermomechanical Cycling All the testing groups weresubmitted to thermomechanical variation cycles using adental wear simulator (ER 11000 ERIOS Sao Paulo SPBrazil) The specimens underwent thermal cycles between 5and 55∘C with a dwell time of 30 s During this procedure aforce of 50Nwas delivered at 1Hz In order to simulate a one-year clinical treatment according to Gale and Darvell [12]100000mechanical cycles and 500 thermal cycles (ISO 11405)were performed

23 Shear Bond Strength Test A universal testing machine(EMIC Sao Jose dos Pinhais PR Brazil) with a load cell of50Kgwas used to perform the shear bonds strength test con-currently applied to the buccal surface of the enamel in theincisal-cervical direction close to the enameladhesive junc-tion at 05mmmin until it fractured The strength requiredto remove the accessories was measured in Newton (N) andthe shear bond strength in megapascal (MPa) The resultswere obtained with the aid of the computer software (TESC)connected to the universal testing machine EMIC

24 Evaluation under Stereomicroscope and Scanning ElectronMicroscope (SEM) After shear testing the samples were ana-lyzed in a stereoscopicmagnifier (KozoOptical and Electron-ical Instrumental Nanjing-Jiangsu China) with 20xmagnifi-cation to determine the Adhesive Remnant Index (ARI)Thismeasurement was performed in accordance with the scoresvarying from 0 to 3 Score 0 = no amount of adhesivematerialadhered to the tooth 1 = less than half of the adhesivematerialadhered to the tooth 2 = more than half of the adhesivematerial adhered to the tooth and 3 = all adhesive materialadhered to the tooth including bracket mesh impression

For SEM the samples were dehydrated during 5 h inincreasing concentrations of alcohol (70 90 and 99)

and they were placed on metal stubs labeled and sputter-coated with 120-A thick gold palladium (MED 020 BAL-TEC Balzers Liechtenstein) They were then analyzed undera scanning electron microscope (SEM) operating at 15 KVin order to visualize the adhesive remnant andor enamelcondition after the removal of the brackets The capture ofthe images was performed with software coupled to theMEV(Inspect 550 Fei) allowing the obtainment of photomicro-graphs

25 Statistical Analysis Thedatawere analyzedwithKruskal-Wallis and Mann-Whitney with Bonferroni correction teststo verify the difference the difference between the studiedgroups as the data distribution was considered abnormalaccording to Kolmogorov-Smirnov tests The significancelevel of 119901 lt 005 was applied

TheAdhesiveRemnant Index data presented as an ordinalqualitative variable were analyzed with Kruskal-Wallis andDunn tests

The analyses were performed using the statistics softwareSPSS Statistics version 200 (IBM Armonk NY USA)

3 Results

31 Shear Bond Strength Test Descriptive and inferentialstatistics of the adhesive resistance in the studied groups arerepresented in Table 3

Shear bond strength tests after one-year period simu-lation demonstrated that the groups XT SEP and QC didnot present statistical differences between them and providedthe highest shear bond strength values when compared withgroup OL (Figure 1)

32 Stereomicroscope ARI Evaluation ARI frequency distri-bution is represented in Table 4 where it was possible toobserve that the score ldquo0rdquo was predominant in the groups XTQC and OL which represents adhesive failure

The condition of highest adherence ARI = 3 (all adhe-sive material adhered to the tooth including bracket meshimpression) was observed in the groups SEP and OL

33 Scanning ElectronMicroscope (SEM) Analysis The groupbonded with the antibacterial adhesive Quick Cure (QC)presented cracks and depression on the enamel surface after


Table 3 Shear bond strength (MPa) analysis of orthodontic adhesives

Groups Adhesive systems 119873 Mean (standard deviation) Median (MPa) 25ndash75XT Transbond XT 16 108 (18)A 104 92ndash126QC Quick Cure 16 104 (12)A 103 98ndash105OL Ortholight Cure 16 88 (07)B 86 82ndash94SEP Transbond Self-Etching Primer 16 103 (11)A 103 92ndash107lowastDifferent letters indicate statistically significant differences according to post hoc tests with Bonferroni correction (119901 lt 0005)

Table 4 Adhesive remnant scores (ARI) of the four groups [119899 ()] average score median and statistical difference found

Group (119899 = 16) ARI score Average score (median) Dunn0 1 2 3

XT 10 (625) 2 (125) 3 (188) 1 (63) 069 (0) AQC 7 (438) 2 (125) 4 (25) 3 (188) 119 (1) ABCOL 7 (438) 0 (0) 3 (188) 6 (375) 150 (2) ABSEP 2 (125) 3 (188) 5 (313) 6 (375) 194 (2) BlowastDifferent letters indicate statistically significant differences (119901 lt 005)

lowast

lowast

1600

1400

1200

1000

800

600

1 2 3 4

37

40

45

(1) XT(2) SEP

(3) QC(4) OL

Figure 1 Box-plot median and standard deviation of the valuesof shear bond strength (MPa) in the different adhesive systems andstudied groups

removing the brackets presenting damage to the toothstructure (Figure 2)

In the other groups XT SEP andOL there was no damageto the enamel surface that could be visualized at the SEM(Figure 3)

4 Discussion

White spot lesions are usually observed in orthodonticpatients due to cleaning difficulties [13 14] and long periodsinvolving the treatment Therefore the increasing searchfor the development of materials and techniques aimingto reduce the damaging effects caused by the use of fixedorthodontic braces is observed After the treatment simula-tion the remineralizing adhesive systems presented various

results according to the compositionbrand of the materialsThus the null hypothesis was rejected

The bonding resistance of orthodontic brackets is usuallyverified 24 hours after installation [6 8 10 11] Howeverboth primary stability and longevity of the brackets areextremely important as the brackets are susceptible to avariety of forces inside the oral cavityThe adhesive resistanceis influenced by many factors such as bracket surface areaadhesion technique type of adhesive applied bracket basedesign and adhesion protocol [15 16] Ideally an orthodonticbracketmust reproduce a good orthodontic strength supportmasticatory loads and be easily removable at the end ofthe treatment without causing injuries to the tooth surfaceNevertheless a substantial part of in vitro studies [10 11] doesnot use any type of artificial fatigue prior to the assessment ofadhesive resistance but thermomechanical cycling is recom-mended [17] in order to consider its real adhesive longevity

The assessed adhesiveresin systems presented adhesiveresistance values in accordance with the parameters found inthe literature [11 16] with group OL being the only one topresent lower values However the average values obtainedby the adhesive system (OL) were higher to those indi-cated by Reynolds [18] showing that the bonding resistancemust reach a value over 60Kgfcm2 (588MPa)80Kgfcm2(784MPa) to be properly applied for clinical needs

After the one-year simulation the shear bond strengthof the self-etching system Transbond Self-Etching (103MPa)and remineralizing system Quick Cure (104MPa) werestatistically similar when compared with the conventionalsystem Transbond XT (108MPa) as verified in previousstudies [19]On the other hand the groupOrtholite (88MPa)presented the lowest adhesive resistance average values indi-cating that these results seem to be material-dependent theremineralizing system Quick Cure presented the same shearbond strength as the standard system (Transbond XT) andthe remineralizing system (Ortholite) presented lower adhe-sive resistance confirming previous studies [20] The chem-ical formulation of the Ortholite adhesive presents fluoride


E R

lowast

(a) (b)

(c)

Figure 2 (a) Images of group QC (a) Magnification of 500x showing injuries in the enamel with the bracket debonding (b) Images instereomicroscope of the tooth buccal and (c) bracket base

compounds but manufacturers do not specify the compo-nents used or their amountThus as seen in the literature [6]some different results are obtained depending on the formu-lations handled by each manufacturer

According to the information given by the manufacturer(Table 1) adhesive systems have fluorine in their composi-tion in the form of sodium fluoride hexafluorophosphatefluoridric complex and fluoride composites for Quick CureTransbond XT Transbond Self Etching and Ortholite CurerespectivelyTherefore even if remineralizing composites areadded to the material it is necessary to verify its influence onthe bonding resistance

Evaluating concentrations of calcium phosphorus sili-con and carbon Chow et al (2011) [5] verified that therewas no significant statistical difference between the adhesivesTransbond XT and Quick Cure However regarding anticar-iogenic potential Quick Cure presented significantly loweradherence of S mutans and a decrease of 236 of the lesiondepth area in relation to the control group whereas Trans-bond XT presented an increase of 32 of the lesion deptharea in relation to the control Considering the toxicity of thematerials Malkoc et al (2010) [21] indicate that the adhesivesystem Transbond XT demonstrated a decrease in the num-ber of vital fibroblasts when compared to the adhesive systemQuick Cure and the control group

Studies have been carried out intending to develop mate-rials that prevent demineralization andor promote reminer-alization of tooth enamel adjacent to the orthodontic brackets[5 6] ACP (amorphous calcium phosphate) is also suggestedas a cooperator or independently used as a prevention agentNevertheless some studies [22 23] demonstrate that systemscontaining ACP can reduce the bonding strength of bondedbrackets in relation to conventional adhesives

The analysis of the adhesive interface after shear bondstrength test indicated a higher frequency of faults in theinterface adhesive-enamel which was also observed in stud-ies in vivo [24] The exception was the group Transbond Self-Etching that according to the literature can offer potentialbenefits when compared with systems that promote total acidetch due to its smaller reversible alterations on the toothenamel surface [25] Through the visualization using SEMit was verified that the antibacterial adhesive Quick Curewhich presented adhesive resistance values higher than thoseof Ortholight Cure and similar to conventional adhesive (XT)and self-etching adhesive (SEP) presented severe damage tothe buccal surface with fractures in the enamel resulting fromthe debonding of the bracketsThe other groups presented nosignificant permanent damage to the tooth enamel Based onthis information further studies are required to elucidate theinfluence of these materials on the adhesion to the toothenamel


E R

(a)

E R

(b)

E R

(c)

Figure 3 (a) Microimages of group XT Magnification of 500x (b) Microimages of group SEP Magnification of 500x (c) Microimages ofgroup OL Magnification of 500x

5 Conclusions

Considering the limitations of this study after the one-yearorthodontic treatment simulation through thermomechani-cal cycling it was possible to observe that

(1) Quick Cure (QC) adhesive remineralizing systempresented average adhesive resistance values such asconventional (XT) and self-etching (SEP) systems

(2) Ortholite Cure (OL) remineralizing system presentedlower adhesive resistance values

(3) except the group treated with self-etching adhesive(SEP) most of the faults occurred in the interfaceenamel-adhesive

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The authors would like to thank FAPEMA (Brazil) forfinancial support

References

[1] S-J Ahn S-J Lee B-S Lim and D-S Nahm ldquoQuantita-tive determination of adhesion patterns of cariogenic strep-tococci to various orthodontic bracketsrdquo American Journal ofOrthodontics and Dentofacial Orthopedics vol 132 no 6 pp815ndash821 2007

[2] M Amasyali S Enhos T Uysal I Saygun A Kilic and OBedir ldquoEffect of a self-etching adhesive containing an antibac-terial monomer on clinical periodontal parameters and sub-gingival microbiologic composition in orthodontic patientsrdquoAmerican Journal of Orthodontics and Dentofacial Orthopedicsvol 140 no 4 pp e147ndashe153 2011

[3] A Demling W Heuer C Elter et al ldquoAnalysis of supra-and subgingival long-term biofilm formation on orthodonticbandsrdquo European Journal of Orthodontics vol 31 no 2 pp 202ndash206 2009

[4] N E Atack J R Sandy andMAddy ldquoPeriodontal andmicrobi-ological changes associated with the placement of orthodonticappliances A reviewrdquo Journal of Periodontology vol 67 no 2pp 78ndash85 1996

[5] C K W Chow C D Wu and C A Evans ldquoIn vitro propertiesof orthodontic adhesives with fluoride or amorphous calciumphosphaterdquo International Journal of Dentistry vol 2011 ArticleID 583521 8 pages 2011


[6] G T Minick L J Oesterle S M Newman andW C ShellhartldquoBracket bond strengths of new adhesive systemsrdquo The Amer-ican Journal of Orthodontics and Dentofacial Orthopedics vol135 no 6 pp 771ndash776 2009

[7] T Buyukyilmaz S Usumez and A I Karaman ldquoEffect of self-etching primers on bond strengthmdashare they reliablerdquo AngleOrthodontist vol 73 no 1 pp 64ndash70 2003

[8] F L Romano S W Tavares D F Nouer S Consani and M BBz de AraujoMagnani ldquoShear bond strength of metallic ortho-dontic brackets bonded to enamel prepared with self-etchingprimerrdquo The Angle Orthodontist vol 75 no 5 pp 849ndash8532005

[9] R Yamada T Hayakawa and K Kasai ldquoEffect of using self-etching primer for bonding orthodontic bracketsrdquo The AngleOrthodontist vol 72 no 6 pp 558ndash564 2002

[10] C A Reicheneder T Gedrange A Lange U Baumert and PProff ldquoShear and tensile bond strength comparison of variouscontemporary orthodontic adhesive systems an in-vitro studyrdquoAmerican Journal of Orthodontics amp Dentofacial Orthopedicsvol 135 no 4 pp 422e1ndash422e6 2009

[11] R J Scougall Vilchis S Yamamoto N Kitai and K YamamotoldquoShear bond strength of orthodontic brackets bonded withdifferent self-etching adhesivesrdquoTheAmerican Journal ofOrtho-dontics andDentofacial Orthopedics vol 136 no 3 pp 425ndash4302009

[12] M S Gale and B W Darvell ldquoThermal cycling procedures forlaboratory testing of dental restorationsrdquo Journal of Dentistryvol 27 no 2 pp 89ndash99 1999

[13] S E Bishara C Oonsombat M M A Soliman and J WarrenldquoEffects of using a new protective sealant on the bond strengthof orthodontic bracketsrdquo Angle Orthodontist vol 75 no 2 pp243ndash246 2005

[14] D Gray and G McIntyre ldquoDoes oral health promotion influ-ence the oral hygiene and gingival health of patients undergoingfixed appliance orthodontic treatment A systematic literaturereviewrdquo Journal of Orthodontics vol 35 no 4 pp 262ndash2692008

[15] P Cozza LMartucci L De Toffol and S I Pencoc ldquoShear bondstrength of metal brackets on enamelrdquo The Angle Orthodontistvol 76 no 5 pp 851ndash856 2006

[16] A R Davari S Yassaei A R Daneshkazemi and M H YosefildquoEffect of different types of enamel conditioners on the bondstrength of orthodontic bracketsrdquoThe Journal of ContemporaryDental Practice vol 8 no 1 pp 36ndash43 2007

[17] S Schaneveldt and T F Foley ldquoBond strength comparison ofmoisture-insensitive primersrdquo American Journal of Orthodon-tics and Dentofacial Orthopedics vol 122 no 3 pp 267ndash2732002

[18] I R Reynolds ldquoA review of direct orthodontic bondingrdquo BritishJournal of Orthodontics vol 2 pp 171ndash178 1975

[19] V Cacciafesta M F Sfondrini E Barina A Scribante FGarino and C Klersy ldquoEffect of different light sources andguides on shear bond strength of brackets bonded with 2 adhe-sive systemsrdquoAmerican Journal of Orthodontics and DentofacialOrthopedics vol 128 no 1 pp 99ndash102 2005

[20] A D S G Stumpf C Bergmann J R Prietsch and J VicenzildquoShear bond strength of metallic and ceramic brackets usingcolor change adhesivesrdquo Dental Press Journal of Orthodonticsvol 18 no 2 pp 76ndash80 2013

[21] S Malkoc B Corekci H E Ulker M Yalcin and A SengunldquoCytotoxic effects of orthodontic compositesrdquoThe Angle ortho-dontist vol 80 no 4 pp 571ndash576 2010

[22] W J Dunn ldquoShear bond strength of an amorphous calcium-phosphate-containing orthodontic resin cementrdquo AmericanJournal ofOrthodontics andDentofacial Orthopedics vol 131 no2 pp 243ndash247 2007

[23] T Uysal A Ustdal M Nur and B Catalbas ldquoBond strength ofceramic brackets bonded to enamel with amorphous calciumphosphate-containing orthodontic compositerdquo European Jour-nal of Orthodontics vol 32 no 3 pp 281ndash284 2010

[24] T Sessa J Civovic T Pajevic et al ldquoScanning electron micro-scopic examination of enamel surface after fixed orthodontictreatment in-vivo studyrdquo Srpski arhiv za celokupno lekarstvovol 140 no 1-2 pp 22ndash28 2012

[25] M Fjeld and B Oslashgaard ldquoScanning electron microscopic eval-uation of enamel surfaces exposed to 3 orthodontic bondingsystemsrdquo American Journal of Orthodontics and DentofacialOrthopedics vol 130 no 5 pp 575ndash581 2006

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Table 1 Experimental groups

Groups Adhesive systemscomposition Commercial brandlotexpiration date

XT

Transbond XT light cure adhesiveAdhesive triethylene glycoldimethacrylate (TEGDMA) and BISGMAResin silica BISGMA N-dimethylbenzocaine and hexafluorophosphate

3M Unitek Orthodontics ProductsSouth Peck Road Monrovia USAL 1308100970Exp 0615

QC

Quick Cure fluorideAdhesive bisphenol dimethacrylate hydroxyethyl methacrylate andacetoneResin silica BISGMA triethylene-glycol-dimethacrylate(TEGDMA) and sodium fluoride

Reliance Orthodontic products IncItasca Illinois USAL 123643Exp 0514

OLOrtholite Cure color changeAdhesive phosphate acrylic monomer ethanol acetone and amineResin triethylene glycol dimethacrylate (TEGDMA) BISGMAamine and fluoride compounds

OrthoSource USASherman way Hollywood USAL CUKAExp 0414

SEPTransbond Plus Self-Etching PrimerAdhesive mono- and di-HEMA phosphates distilled water andfluorine compounds

3M Unitek Orthodontics ProductsSouth Peck Road Monrovia USAL 488941cExp 0314

health of teeth and supporting tissues otherwise the treat-ment benefits might be questioned

The current tendency is the improvement of adhesivesystems with simplified application protocol altogether withpromoting satisfying adhesive resistance reducing procedureerrors and minimizing damage to tooth structure [7] Self-etching systems that have acidic components reduce theinconveniences of excessive demineralization of the structureof the tooth and provide a decrease in the number ofsurgical procedures [8 9] Adhesive systems that allegedlyhave remineralizing properties are displayed in themarket [56] however the longevity of the treatment was not confirmedin the literature

Thus the biomechanical behavior of these new systemshas to be investigated so that they can be effectively appliedduring the entire orthodontic treatment As a major part ofthe studies evaluates the adhesive resistance of orthodonticbrackets just right after their installation [6 8 10 11] a longtime treatment evaluation is an important factor

Considering these questions regarding different adhesivesystems and the lack of studies assessing the adhesive resis-tance of remineralizing adhesives the present study aimsto perform the shear bond strength of orthodontic bracketsfixedwith remineralizing adhesive systems submitted to ther-momechanical cycling simulating one year of orthodontictreatment The null hypothesis tested is that there is nostatistical difference in the resistance values when conven-tional remineralizing and self-etching systems are applied

2 Materials and Methods

The present experiment used 64 bovine incisors justextracted cleaned and stored in distilled waterThis researchproject was approved by Animal Experimentation EthicsCommittee (protocol number 0732013) The criteria ofinclusion for tooth selectionwere the following tooth enamel

with no fissures and no previous application of chemicalagents such as hydrogen peroxide alcohol and formalinThesample size was calculated considering 120572 equal to 5 powerof Kruskal-Wallis test 75The result was a size (119899) of 16 teethin each group (PASS 11 NCSS LLC Kaysville Utah USA)

The bovine teeth were sectioned in the cervical line andthe roots which are disposedThe dental pulp was extirpatedwith the aid of a dentin curette (Duflex Lucas number 86SSWhite Rio de Janeiro RJ Brazil) and the pulp chamber wasirrigated with distilled water air-dried and obliterated withutility wax

The teeth were positioned in 25mm times 20mm PVC cylin-drical tubes (Tigre Joinville SC Brazil) keeping the buccalsurface positioned at the bottomof the base and embedded inacrylic resin (VIPI Sao Paulo SP Brazil) In order to obtainplain buccal surfaces parallel to the block base these weresubmitted to plaining and polishing with sandpaper (gran-ulations 200 400 600 and 1200) (3M Sumare SP Brazil)with the aid of a polishing machine (Panambra Tecnica ImpExp Ltda Sao Paulo SP Brazil) with irrigation and constantuniform pressure

The adhesive systems presented in Table 1 were applied inthe making of the experimental groups

21 Fixation of the Brackets Sixty-four stainless steel ortho-dontic brackets were used for upper central incisors with15mm high and 40mm wide mesh bases (Roth 002210158401015840times 003010158401015840 KIRIUM Abzil Ind amp com Ltda Sao Josedo Rio Preto SP Brazil) The buccal surface of the teethenamels underwent prophylaxis with fluoride-less pumicestone (SSWhite Rio de Janeiro RJ Brazil) and water for tenseconds

Groups XTQCOL and SEPwere submitted to the appli-cation of the adhesive systems according to the specificationsin Table 2 Maximum pressure was applied in the bracketbonding or the standardization of the strength exercised and




XT QC and OL













3 Results












lowast

lowast

1600

1400

1200

1000

800

600

1 2 3 4

37

40

45

(1) XT(2) SEP

(3) QC(4) OL




4 Discussion







E R

lowast

(a) (b)

(c)








E R

(a)

E R

(b)

E R

(c)


5 Conclusions







Acknowledgment


References


































Biomaterials












Journal of






















XT QC and OL













3 Results












lowast

lowast

1600

1400

1200

1000

800

600

1 2 3 4

37

40

45

(1) XT(2) SEP

(3) QC(4) OL




4 Discussion







E R

lowast

(a) (b)

(c)








E R

(a)

E R

(b)

E R

(c)


5 Conclusions







Acknowledgment


References


































Biomaterials












Journal of

























lowast

lowast

1600

1400

1200

1000

800

600

1 2 3 4

37

40

45

(1) XT(2) SEP

(3) QC(4) OL




4 Discussion







E R

lowast

(a) (b)

(c)








E R

(a)

E R

(b)

E R

(c)


5 Conclusions







Acknowledgment


References


































Biomaterials












Journal of




















E R

lowast

(a) (b)

(c)








E R

(a)

E R

(b)

E R

(c)


5 Conclusions







Acknowledgment


References


































Biomaterials












Journal of




















E R

(a)

E R

(b)

E R

(c)


5 Conclusions







Acknowledgment


References


































Biomaterials












Journal of















































Biomaterials












Journal of



















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