Effects of Chlorhexidine and Povidone-Iodine Mouth Rinses on the Bond Strength of an Orthodontic Composite

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1 Originl Article Effects of Chlorhexidine nd Povidone-Iodine Mouth Rinses on the Bond Strength of n Orthodontic Composite Abdullh Demir ; Siddik Mlkoc b ; Abdulkdir Sengun c ; Alp Erdin Koyuturk d ; Ygmur Sener e Abstrct: The purpose of this study ws to determine whether the ppliction of two ntibcteril mouth rinses to etched nd unetched enmel ffects the sher bond strength (SBS) of n orthodontic composite resin. Eighty-five lower humn incisors were divided into five groups, ie, group 1: control group, no mouth rinse ws used; groups 2 nd 3: mouth rinses were pplied to the intct enmel surfce before etching; groups 4 nd 5: mouth rinses were pplied to the etched enmel. A bonding gent nd composite resin were pplied to the teeth surfce. For sher bond testing, the specimens were mounted in universl testing mchine, nd n pprtus ttched to compression lod cell ws pplied to ech specimen until filure occurred. The dt were nlyzed using nlysis of vrince nd Tukey honestly significnce tests. Frcture modes were nlyzed by Mnn-Whitney U-test. There ws no sttisticlly significnt difference between the SBS vlues of group 1 ( MP) nd group 4five experimentl pplictions (P.05). However, the SBS vlue of group 3 ( MP) ws significntly lrger thn those of group 4 ( MP) nd group 5 ( MP). In ddition, no significnt differences were observed between group 1 nd groups 2 ( MP) nd 3 ( MP) (P.05). Becuse the ppliction of chlorhexidine nd povidone-iodine before cid etching did not cuse ny decrese in bond strength, it is dvisble for use under the orthodontic resin composite to obtin n ntibcteril effect or to prevent the risk of bcteremi. (Angle Orthod 2005;75: ) Key Words: Chlorhexidine; Povidone-iodine; Sher bond strength INTRODUCTION Trnsient bcteremi fter orthodontic procedures hs been shown in clinicl investigtions. In study on 10 ptients, Degling 1 showed no bcteremi fter the plcement nd removl of orthodontic bnds. On the other hnd, McLughlin et l 2 reported round 10% prevlence of bcteremi fter bnding procedures. Erverdi et l 3 5 found bcteremi prevlences of 7.5% nd 6.6% fter bnding nd debnding procedures, respectively. Antiseptic mouthwshes pplied immeditely before dentl procedures my reduce the incidence nd severity of bcteremi Assistnt Professor, Deprtment of Orthodontics, Fculty of Dentistry, Selcuk University, Kony, Turkey. b Reserch Fellow, Deprtment of Orthodontics, Fculty of Dentistry, Selcuk University, Kony, Turkey. c Associte Professor, Deprtment of Conservtive Dentistry, Fculty of Dentistry, Selcuk University, Kony, Turkey. d Assistnt Professor, Peditric Dentistry, Ondokuz Myis University, Smsun, Turkey. e Assistnt Professor, Peditric Dentistry, Fculty of Dentistry, Selcuk University, Kony, Turkey. Corresponding uthor: Siddik Mlkoc, DDS, PhD, Deprtment of Orthodontics, Selcuk University, Kmpus, Kony 42075, Turkey (e-mil: siddikmlkoc@yhoo.com). Accepted: My Submitted: My by The EH Angle Eduction nd Reserch Foundtion, Inc. Chlorhexidine hs been used s n effective djunct tretment for periodontl disese, both s mouth rinse nd s one of the ingredients in toothpste. 11 Chlorhexidine mouthwsh is commercilly vilble in 0.12% nd 0.2% concentrtions. The mechnism of ction of chlorhexidine mouthwsh seems to be n immedite nd probbly shortlived bctericidl effect, followed by prolonged bcteriosttic ction tht is dependent on ntiseptic bsorbed by the pellicle coting tooth surfce. Considering the drwbcks of ntibiotic use, the use of chlorhexidine lone cn be justifible when performing procedures with low incidence nd low grde of bcteremi in low-risk ptients. 4 Povidone-iodine is wter-soluble combintion of moleculr iodine nd the solubilizing gent polyvinyl-pyrrolidone. This iodophor hs bctericidl effect similr to tht of pure iodine; is effective ginst most of the bcteri, including puttive periodontl pthogens, fungi, mycobcteri, viruses, nd protozo; fils to initite sensitivity rections or llow the development of bcteril resistnce; nd llows for slow relese of iodine, which ensures the estblishment of n optiml, nontoxic concentrtion t bctericidl level. 12 The usul procedure is orl rinsing with chlorhexidine or povidone-iodine for one to two minutes before the dentl procedure

2 THE EFFECTS OF MOUTH RINSES ON THE BOND STRENGTH Filler et l 13 determined the sher bond strength (SBS) of composite bonded to chlorhexidine-treted nd untreted enmel. They demonstrted tht the differences between SBS for the control nd the experimentl groups were not significnt. Also the results of this study indicte tht the use of ntibcteril rinse would not compromise composite bond strengths, other prmeters such s microlekge my be ffected by interction of chlorhexidine with the enmelbonding surfce. Bishr et l 14 nd Dmon et l 15 determined the effects of chlorhexidine vrnish on the bond strength of orthodontic dhesives on the etched enmel surfce. Bishr et l 11 lso indicted tht SBS is not significntly ffected when chlorhexidine is pplied if the vrnish is premixed with the selnt nd pplied on the etched enmel surfces nd then light cured. In the orthodontic literture, there is little or no informtion bout the use of mouthwsh forms of povidone-iodine. There lso re limited studies on the chlorhexidine mouth rinse on bonding to the enmel before plcing the brcket. Even though pplying chlorhexidine to the enmel surfce could dd n incresed protection round the brcket periphery ginst bcteri, it could lso influence the bond strength dversely, depending on the method of ppliction. Therefore, the purpose of this study ws to determine whether the ppliction of chlorhexidine nd povidone-iodine to the etched nd unetched enmel ffects the SBS of n orthodontic resin composite. MATERIALS AND METHODS Humn mndibulr incisors extrcted becuse of periodontl resons were stored t 4 C in physiologicl sline solution. Teeth with hypoplstic res, crcks, or gross irregulrities of the enmel structure were excluded from this study. The criteri for tooth selection dictted no pretretment with chemicl gent such s lcohol, formlin, hydrogen peroxide etc. The teeth were removed from soft tissue remnnts, clculus, nd clened with fluoride-free pumice nd rubber cup. Eighty-five teeth were selected for this study. The roots of the teeth were cut with wter-cooled dimond disk nd the crowns mounted in 3-cm-dimeter circle mold using chemiclly cured crylic resin. The crowns were mounted so tht their vestibule fces were perpendiculr to the bse of the molds. Before strting bonding procedure, the surfce of the ech tooth ws polished for one minute using the combintion of polishing gent nd brush t low speed (3000 rpm) in contr ngle hndpiece. The teeth were rndomly distributed in four experimentl groups nd one control group, ech contining 17 teeth. The chlorhexidine (0.2% chlorhexidine gluconte, Drogsn Phrmceuticls, Ankr, Turkey) nd povidone-iodine (7.5% povidone-iodine, Knsuk Phrmceuticls, Istnbul, Turkey) were pplied to the teeth under the following conditions. Group 1, control groupno ntibcteril mouthwsh solution ws used. A 37% orthophosphoric cid gel (3M 393 FIGURE 1. Appliction pprtus of orthodontic composite on the enmel surfce. Dentl Products, St Pul, Minn) ws used for 15 seconds for the cid etching of the teeth. The teeth were then rinsed with wter for 15 seconds nd dried with n oil-free ir for 10 seconds. In ll cses tht were etched, the frosty white ppernce of etched enmel ws noticed. Orthodontic composite resin ws then pplied to enmel surfce. Group 2the smples were stored in 0.2% chlorhexidine solution for 60 seconds, rinsed with wter for 10 seconds, nd then etched for 15 seconds. Orthodontic composite resin ws then pplied to enmel surfce using the sme procedure of the control group. Group 3the smples were kept in 7.5% povidone-iodine solution for 60 seconds, rinsed with wter for 10 seconds, enmel surfces were then etched, nd the sme procedures were pplied s with the control group. Group 4the teeth were etched for 15 seconds, rinsed, nd plced in 0.2% chlorhexidine solution for 60 seconds. The solution ws rinsed with wter for 10 seconds, nd orthodontic composite resin ws pplied s with the control group. Group 5fter etching, the teeth were plced in 7.5% povidone-iodine solution for 60 seconds. The smples were rinsed with wter for 10 seconds, nd composite resin ws pplied s with the control group. An orthodontic bonding gent (Trnsbond XT, 3M Unitek, Monrovi, Clif) ws used nd light cured in ll groups. An orthodontic composite resin ws dded to the surfce by pcking the mteril into the cylindricl plstic mtrices with 2.34-mm internl dimeter nd three-mm height (Ultrdent, South Jordn, Uth) (Figure 1). Excess composite ws crefully removed from the periphery of the mtrices with dentl explorer. Bonding gents nd composites were cured with HILUX (Benlioğlu Dentl, Ankr, Turkey) curing light for 40 seconds. The intensity of the light ws t lest 400 mw/cm 2. The specimens (Figure 2) were then stored in distilled wter

3 394 DEMIR, MALKOC, SENGUN, KOYUTURK, SENER TABLE 1. Men SD (MP) Sher Bond Strength Vlues nd Sttisticl Comprison of Groups (n 17) Group 1 Group 2 Group 3 Group 4 Group 5 Groups Men SD A B B A A According to Tukey honestly difference tests, mens hving sme letter re not sttisticlly different from ech other (P.05). FIGURE 2. Orthodontic composite block over enmel. TABLE 2. Group 1 Group 2 Group 3 Group 4 Group 5 Modes of Filure After Sher Bond Test Adhesive (%) Cohesive (%) Mixed (%) 16 (94.1) 13 (76.5) 13 (76.5) 14 (82.4) 15 (88.2) 1 (5.9) 1 (5.9) 3 (17.6) 2 (11.8) According to Mnn-Whitney U-tests P (23.5) 3 (17.6) Frcture nlysis Frcture nlyses were performed using n opticl stereomicroscope (Olympus SZ4045 TRPT, Osk, Jpn). Filures were clssified s cohesive if more thn 80% of resin ws found remining on the tooth surfce, dhesive if less thn 20% of the resin remined on the tooth surfces, or mixed if certin res exhibited cohesive frcture, wheres other res exhibited dhesive frcture. Sttisticl nlysis Descriptive sttistics including the men nd stndrd devition were clculted for ech of the five groups. Comprisons of mens were mde using nlysis of vrince (ANOVA) nd Tukey honestly significnce tests. Frcture modes were nlyzed by Mnn-Whitney U-test. RESULTS FIGURE 3. Appliction of force on composite block by the stubshped pprtus. t 37 C for 24 hours before bond strength testing. For sher bond testing, the specimens were mounted in universl testing mchine (Model 500, Testometric, Lncshire, UK) (Figure 3). A notch-shped pprtus (Ultrdent) ttched to compression lod cell t crosshed speed of one mm/min ws pplied to ech specimen t the interfce between tooth nd composite until filure occurred. The mximum lod (N) ws divided by the cross-sectionl re of the bonded composite posts to determine SBS (in MP). The descriptive sttistics, including the men nd stndrd devition, nd sttisticl comprisons for ech group re shown in Tble 1. The results of ANOVA reveled sttisticlly significnt differences in bond strengths mong the groups (P.05). When povidone-iodine nd chlorhexidine were pplied before etching the enmel surfce, it ws shown tht the SBS of the orthodontic composite resin ws higher thn tht of control (P.05). However, the ppliction of test solution on the etched surfce did not ffect the SBS of orthodontic composite resin when compred with control vlues (P.05). The frcture ptterns of the specimens re given in Tble 2. Mnn-Whitney U-test ws used to compre filures mong themselves in ll groups. In generl, greter per-

4 THE EFFECTS OF MOUTH RINSES ON THE BOND STRENGTH centge of the frctures were dhesive filures t the toothcomposite junction (P.05). DISCUSSION This study ws undertken to test the effects of different mouth rinse pplictions on the SBS. The results of this study indicte tht the ppliction of 0.2% chlorhexidine nd 7.5% povidone-iodine on the enmel surfce, either before or fter etching, did not dversely ffect the bond strength of the dhesive. The effects of 0.2% chlorhexidine nd 7.5% povidoneiodine fter cid etching my be importnt when direct restortions re intended, 13 but in dily orthodontic prctice, orthodontists do not cid etch the teeth nd, before bonding the brckets, sk the ptient to mouth rinse. In this cse, not only will the mouth rinse solution bth the etched enmel, but mixture of the mouth rinse nd the ptients sliv, nd this could ffect the qulity of bonding. However, 0.2% chlorhexidine or 7.5% povidone-iodine solution cn be pplied over the etched enmel surfce nd then rinse the teeth with wter. Then, orthodontic composite resin cn be pplied over the etched enmel surfce. Filler et l 13 determined the SBS of composite bonded to chlorhexidine-treted nd untreted enmel. In their study, the experimentl group ws immersed in 0.12% chlorhexidine gluconte for one minute, four times in dy, for seven dys. The present study ws in ccordnce with the study of Filler et l 13 showing tht the SBSs of Prism APH composite for the control nd the experimentl groups were not significntly different. The uthors consider tht the result my be ttributed either to lck of effects of chlorhexidine or to the cid etch tht dissolves the ffected superficil enmel, leving n unffected substrte for bonding. The ccelerted regimen of exposure should hve provided higher concentrtions of chlorhexidine or povidone-iodine thn normlly encountered in vivo. Three possible explntions could ccount for the lck of effects of chlorhexidine or povidone-iodine on the bond strength of the resin composite to enmel. First, if the enmel substrte ws ltered by chlorhexidine or povidone-iodine, then ny significnt chnges my hve been negted by the cid etch before bonding. Legler et l 16 determined the depth of etch in ground enmel cused by vrious concentrtions nd times of exposure of phosphoric cid by clculting the mount of clcium dissolved by cid etching nd by using surfce profilometry. They reported tht 37% phosphoric cid solution fter 30-second exposure resulted in n pproximtely 16- m depth of etch. If chlorhexidine or povidone-iodine penetrted enmel to this extent or less, it my hve been removed by the etching, negting ny effect it might hve hd on the composite to enmel bond strength. Second, lthough one might expect chlorhexidine or povidone-iodine to ffect surfce enmel bsed on diffusion nd dsorption studies of other substnce, eg, fluoride, moleculr size my influence the effects of substnce on enmel. For exmple, the fluoride ion is smll enough to replce hydroxyl groups in the hydroxyptite crystl. This reduces the crystllite size, which decreses solubility in the presence of cid. However, the chlorhexidine nd povidone-iodine molecules re significntly lrger thn the fluoride ion, nd hydroxyptite crystls in the superficil enmel my be less ffected by chlorhexidine nd povidone-iodine becuse of moleculr sptil reltionship. Finlly, chlorhexidine or povidone-iodine my hve been bsorbed by the enmel but were then relesed into the distilled wter during storge between rinses. 13 In our study, SBS vlues were t very high level when compred with the previous bonding studies. In the current study, different protocol ws used for sher testing compred with previous studies to eliminte some criticl spects of the testing protocols ffecting the outcome. For instnce, the brcket bse design my contribute to the mislignment of lod ppliction during testing, mking the bonding system prone to filure, introducing vritions tht depend on the stress grdients generted. It hs lso been found tht vribility exists mong the mnufcturers with respect to the design or dimensions of the brckets in nominlly identicl prescriptions. 18 This vribility poses significnt problem in studies evluting brcket bond strength. 19 Becuse the thickness of the dhesive lyer is smll, the tips of the bldes could not be ccurtely plced on it once the force ws pplied. The tips of bldes my devite towrd the joint between the dhesive nd the brcket bse or between the dhesive nd the enmel, which my significntly ffect the results. Blunting of bldes during use, prticulrly the pointed ones, would hve incresed the force level pplied on lter specimens. For these resons, we used only orthodontic composite blocks without bonding brcket for sher bond test. Most of the orthodontic bonding studies hve shown mixed- or cohesive-type filure After SBS testing, prt of the composite resin hs remined on either the enmel surfce or on the brcket bse. Therefore, the SBS vlues obtined re cohesive filure of orthodontic composite rther thn dhesive filure between enmel nd composite resin. Becuse brckets were not used in the present study, dhesive filures were obtined between enmel nd the orthodontic composite. Therefore, rel SBS vlues between enmel nd composite were mesured rther thn cohesive filure in composite. Thorough plque nd inflmmtion control is very difficult in ptients with fixed orthodontic pplinces, nd the use of chemicl gents in the form of mouth rinses or orl sprys hs been shown to be useful djuncts. Mouth rinses could be helpful in orthodontic ptients for suppressing orl mutns or other microbe levels when the rinses re used before the plcement of fixed orthodontic pplinces. 23 Jentsch et l 24 performed trnsmission electron microscopic study to verify the influences of mouth rinses on

5 396 DEMIR, MALKOC, SENGUN, KOYUTURK, SENER dentl plque. Their study showed tht rinsing with chlorhexidine digluconte without ny dditionl orl hygiene procedure resulted in continuous significnt decrese in plque thickness. The uthors suggested tht the ppliction of chlorhexidine digluconte solutions is beneficil for the plque control in the orl cvity. The mechnism of ction of chlorhexidine mouthwsh seems to be n immedite nd probbly short-lived bctericidl effect, followed by prolonged bcteriosttic ction tht is dependent on ntiseptic bsorbed by the pellicle coting tooth surfce. 25 Appliction of ntiseptic mouthwshes before orthodontic bnding-bonding my reduce the incidence nd severity of bcteremi 26,27 s well s my reduce enmel deminerliztion round the orthodontic bnd or brcket bses. 28 The orthodontist hs concerns bout bcteremi nd dentl cries development during fixed orthodontic tretment. The ppliction of ntibcteril mouth rinses tkes smll mount of clinicl chir time nd cn be ccomplished by stff personnel, without ny significnt decrese in bond strength of the orthodontic composite resin to enmel surfce. CONCLUSIONS Treting enmel with both 0.2% chlorhexidine nd 7.5% povidone-iodine significntly incresed SBS. However, the pplictions of 0.2% chlorhexidine nd 7.5% povidone-iodine do not significntly ffect the bond strength to the etched enmel surfce. As result, the use of 0.2% chlorhexidine nd 7.5% povidone-iodine mouth rinses to clen the teeth before cid etching cn be recommended s prt of the bonding protocol. Further clinicl studies hve to be plnned to test whether these mouth rinses cn prevent white spot lesions or dentl cries. REFERENCES 1. Degling TE. Orthodontics, bcteremi nd the hert dmged ptient. Angle Orthod. 1972;42: McLughlin JO, Coulter WA, Coffey A, Burden DJ. The incidence of bcteremi fter orthodontic bnding. 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Chicgo, Ill: Quintessence Publishing Co; 1989: Büyükyilmz T, Øgrd B, Dhm S. The effect on the tensile bond strength of orthodontic brckets of titnium tetrfluoride (TiF4) ppliction fter cid etching. Am J Orthod Dentofcil Orthop. 1995;108: Kotn TR. A comprison of stresses developed in tension, sher peel, nd torsion strength testing of direct bonded orthodontic brckets. Am J Orthod Dentofcil Orthop. 1997;112: Årtun J, Berglnd S. Clinicl trils with crystl growth conditioning s n lterntive to cid-etch enmel pretretment. Am J Orthod. 1984;85: Oliver RG. The effect of different methods of brcket removl on the mount of residul dhesive. Am J Orthod Dentofcil Orthop. 1988;93: Usumez S, Orhn M, Usumez A. Lser etching of enmel for direct bonding with n Er,Cr:YSGG hydrokinetic lser system. Am J Orthod Dentofcil Orthop. 2002;122: Zchrisson BU. Cuse nd prevention of injuries to teeth nd supporting structures during orthodontic tretment. Am J Orthod. 1976;69: Jentsch H, Hombch A, Beetke E, Jons L. Quntittive trnsmission electron microscopic study of dentl plquen in vivo study with different mouth rinses. Ultrstruct Pthol. 2002;26: Jenkins S, Addy M, Wde W. The mechnism of ction of chlorhexidine. A study of plque growth on enmel inserts in vivo. J Clin Periodontol. 1988;15: McFrlne TW, Ferguson MM, Mulgrew CJ. Postextrction bcteremi: role of ntiseptics nd ntibiotics. Br Dent J. 1984;156: Tzukert AA, Leviner E, Sel M. Prevention of infective endocrditis: not by ntibiotics lone. Orl Surg Orl Med Orl Pthol. 1986;62: Twetmn S, Hllgren A, Petersson LG. Effect of ntibcteril vrnish on mutns streptococci in plque from enmel djcent to orthodontic pplinces. Cries Res. 1995;29: