Antibacterial and Smear Layer Removal Efficacy of Er:YAG Laser Irradiation by Photon-Induced Photoacoustic Streaming in Primary Molar Root Canals: A Preliminary Study.

OBJECTIVE: The objective of this study was to compare antibacterial and smear layer removal efficacy of the erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation by photon-induced photoacoustic streaming (PIPS), neodymium:yttrium-aluminium-garnet (Nd:YAG), and diode lasers and conventional irrigation agent in primary molar root canals. BACKGROUND: The selection, application, and activation of the irrigant are important factors affecting the success of the endodontic treatment. MATERIALS AND METHODS: Distal root canals of human primary mandibular molar teeth used for antimicrobial efficacy evaluation were first inoculated with Enterococcus faecalis (n = 25). Smear layer removal efficacy was evaluated on the noninoculated specimens (n = 20). The root canals in the first treatment groups were irrigated with a conventional technique using 5% sodium hypochlorite (NaOCl). In the laser groups, the root canals were irradiated with either Nd:YAG (1064 nm) or diode lasers (940 nm) followed by NaOCl irrigation agent. In the fourth groups, the NaOCl irrigation agent was activated with an Er:YAG laser (2940 nm) by PIPS tip using nonablative settings. Antibacterial efficacy was determined by viable counts of E. faecalis after treatments. The treated root canals were examined by scanning electron microscopy to determine the smear layer removal efficacy of treatments. RESULTS: Statistically significant (p < 0.05) reductions in the number of E. faecalis were achieved in Nd:YAG and diode laser groups and Er:YAG laser by PIPS-activated irrigation groups compared to the NaOCl group. Er:YAG laser by PIPS-activated irrigation resulted in more cleaning of the root canal walls and a higher quantity of open tubules. CONCLUSIONS: These findings suggest that Er:YAG laser by PIPS-activated irrigation can be considered as an effective irrigant agitation technique in pediatric endodontics.

Biofilm formation by Staphylococcus aureus isolates from a dental clinic in Konya, Turkey.

The ability of Staphylococcus aureus to form biofilm is considered to be a major virulence factor influencing its survival and persistence in both the environment and the host. Biofilm formation in S. aureus is most frequently associated with production of polysaccharide intercellular adhesion by ica operon-encoded enzymes. The present work aimed at evaluating the in vitro biofilm production and presence of the icaA and icaD genes in S. aureus isolates from a dental clinic in Konya, Turkey. The surfaces of inanimate objects were sampled over a period of six months. S. aureus isolates were subjected to Congo Red Agar (CRA) and crystal violet (CV) staining assays to evaluate their ability of biofilm production, while the presence of the icaA and icaD genes was determined by polymerase chain reaction. S. aureus contamination was detected in 13.2% of the environmental samples. All the 32 isolates were observed to be positive for both the icaA and icaD genes. Phenotypic evaluations revealed that CV staining assay is a more reliable alternative to CRA assay to determine biofilm formation ability. A high percentage of agreement (91%) was observed between the results from CV staining and ica genes' detection assays. Phenotypic and genotypic evaluations should be combined to detect biofilm formation in S. aureus. Our findings indicate that dental clinic environments should be considered as potential reservoir for biofilm-producing S. aureus and thus cross contamination.

In Vivo and In Vitro performance of Conventional Methods, DIAGNOdent, and an Electronic Caries Monitor for Occlusal Caries Detection in Primary Teeth.

PURPOSE: The purpose of this study was to evaluate and compare the clinical and laboratory performances of an electronic caries monitor (ECM-IV) and the DIAGNOdent device with that of conventional methods, including visual (VE) and radiographic examinations (RE), for the detection of occlusal caries in primary teeth. METHODS: Three different observers examined 200 primary molars before extraction (in vivo), immediately after extraction (in vitro 1), and 14 days after extraction (in vitro 2). Examinations were performed visually, radiographically using the DIAGNOdent and ECM-IV devices. RESULTS: Among all the methods, the ECM-IV yielded the highest sensitivity and Az (Area under the ROC curve) values at the enamel (D1) threshold and visual examination for dentin (D3) threshold. For reproducibility, the ECM-IV presented the highest Kappa values at the D1 threshold, and the DIAGNOdent presented the highest Kappa values at the D3 threshold. Both devices presented high intraclass correlation coefficient values, although DIAGNOdent showed higher values than ECM-IV in all stages of the study and for all observers. CONCLUSION: Considering the importance of early identification of caries in primary teeth, the use of the ECM and DIAGNOdent devices, together with conventional examination methods, will increase the rate of identification of occlusal caries during routine clinic visits.

Periostitis ossificans managed with endodontic treatment.

Periostitis ossificans (PO) is a specific type of chronic osteomyelitis. Radiographically, it is characterized by the presence of lamellae of newly formed periosteal bone outside the cortex, giving the characteristic appearance of "onion skin." The most common cause of PO is periapical infection of the mandibular permanent first molar, which occurs primarily in children and young adults. Treatment in these cases is directed toward eliminating the source of the infection, either by extraction of the offending tooth or endodontic therapy. The purpose of this paper is to present a case of PO involving a permanent mandibular first molar managed with endodontic treatment.

Antimicrobial effect of ozonated water, sodium hypochlorite and chlorhexidine gluconate in primary molar root canals.

OBJECTIVE: The aim was to determine the antimicrobial effect of ozonated water, ozonated water with ultrasonication, sodium hypochloride and chlorhexidine (CHX) in human primary root canals contaminated by Enterococcus faecalis (E. faecalis). MATERIALS AND METHODS: Fifty-eight extracted human primary molar teeth were used. Crowns were cut off using a diamond saw under water-cooling. One hundred roots were obtained and mechanically prepared. The roots were then sterilized by autoclaving in water for 15 min at 121°C. All samples were contaminated with E. faecalis for 24 h and the root canals were randomly divided into five groups (n = 20). Group I: 25 mg/L of Ozonated water (O3aq), Group II: 25 mg/L of O3aq with ultrasonication, Group III: 2.5% Sodium hypochloride (NaOCl), Group IV: 2% CHX and Group V: Positive control. The canal of each specimen was irrigated for 4 min and positive control was untreated. All root canals were agitated with sterile saline solution. The saline solution was collected from canals with sterile paper points. For each specimen, the paper points were transposed to eppendorf vials containing 2 ml of brain heart infusion. According to bacterial proliferation, the mean values of optical density were achieved by ELISA (Biotek EL ×800, Absorbance Microplate Reader, ABD) and the data were analyzed. RESULTS: NaOCI, CHX and two types of O3aq were found statistically different than positive control group. NaOCI irrigation was found significantly most effective. CONCLUSIONS: NaOCl, CHX and O3aq applications provide antibacterial effect in vitro conditions in primary root canals.

Effect of different surface treatments on the shear and microtensile bond strength of resin-modified glass ionomer cement to dentin.

OBJECTIVE: The aim of this study was to evaluate the effect of different surface treatments on the microtensile bond strength (µTBS) and shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) to dentin. MATERIALS AND METHODS: Fifty-two extracted human molars were flattened to obtain dentin surfaces. For SBS assessment 40 teeth were divided into four groups according to their surface treatments (acid etching, Er:YAG laser QSP mode, Er:YAG laser MSP mode and control-SiC) (n = 10). A plastic cylinder was placed over the differently treated dentin surfaces and RMGIC was placed into the rings and polymerized. Twelve teeth were used for the µTBS test. The treated dentin surfaces described above were restored with 4 mm high RMGIC and light cured; then, the specimens were sectioned into serial sticks (n = 15) and µTBS and SBS were tested for failure in a testing machine with a 1 mm/min crosshead speed. The data were analyzed by one-way ANOVA and Tukey HSD tests (α = 0.05). RESULTS: Acid etching showed significantly higher SBS than the other groups (p < 0.05). Er:YAG QSP and MSP-treated groups showed higher SBS values than the control group, but the difference was not statistically significant (p > 0.05). Er:YAG MSP showed the highest µTBS value followed by acid etching, whereas the control group exhibited the lowest value (p < 0.05) and the differences between the control group and Er:YAG QSP were not significant (p > 0.05). CONCLUSIONS: The application of Er:YAG MSP mode and acid etching to dentin can be used for improving the bond strength of RMGIC.

Reattachment of fractured maxillary incisors using fiber-reinforced post: Two case reports.

OBJECTIVE: The reattachment of the crown fragment to a fractured tooth is a conservative treatment that should be considered for young patients with crown-root fractures to the maxillary incisors if the subgingival fracture can be exposed to provide isolation. Gingivectomy, the surgical or orthodontic extrusion of the apical fragment is necessary to expose the subgingival fracture. This report demonstrates the treatment of two cases with the combination of gingivectomy or resective osseous surgery, reattachment of coronal fracture and fiber-reinforced polymer posts and shows three years long term follow-up. Subgingivally extended crown-root fractures of maxillary incisors were restored with a combination of chemically cured resin material, light cured resin material and polyethylene fiber. CONCLUSION: Within the limitations of this case report, it was demonstrated that reattachment of tooth fragments can successfully benefit periodontal health, aesthetic needs and normal functioning after three years.

Effect of light curing units and storage time on the degree of conversion of fissure sealants / Efeito das unidades fotopolimerizadoras e do tempo de armazenamento no grau de conversão dos selantes de fissuras

OBJECTIVE: To investigate the effect of light curing units and storage time on the degree of conversion of fissure sealants. MATERIAL AND METHOD: Three different fissure sealants were used: a resin-based pit and fissure sealant (Clinpro SealantTM), a polyacid modified resin composite (Dyract SealTM), and a resin modified glass ionomer cement (VitremerTM). Each fissure sealant was polymerized with a halogen, high intensity quartz tungsten halogen, LED. Half of the specimens were tested to assess the degree of conversion immediately after polymerization and the others after one month’s storage in artificial saliva. The degree of conversion was measured by FTIR. The data were analyzed using two way ANOVA. RESULTS: Statistical analysis of Dyract SealTM showed significant differences between the DC values of samples tested immediately and again after one month’s storage (p < 0.05). The DC values of ClinproTM increased after the storage period (p < 0.05). The DC of VitremerTM showed no change after storage (p > 0.05). Results of the curing units testing showed no significant differences among the DC of samples polymerized with LED, HQTH, OTH tested immediately and again after one month for Dyract SealTM, VitremerTM and Clinpro SealantTM (p > 0.05). CONCLUSION: Light curing units had no effect on the degree of conversion of the fissure sealants. But storage after initial light activation and polymerization for one month in artificial saliva can affects on DC of fissure sealants.

OBJETIVO: Investigar o efeito de unidades de polimerização por luz no grau de conversão dos selantes de fissuras. MATERIAL E MÉTODO: Três diferentes selantes foram utilizados: um selante resinoso de fissuras (Clinpro SealantTM, uma resina composta poliácida modificada (DyractSealTM) cimento de ionômero de vidro modificado (VitremerTM). Cada selante de fissura foi polimerizado por LED halógeno de quartzo/tungstênio. Metade dos espécimes foi testada para assegurar o grau de conversão imediatamente após polimerização e outros após um mês de armazenamento em saliva artificial. O grau de conversão foi medido por FTIR. Os resultados foram analisados por meio do ANOVA. RESULTADOS: A análise estatística do Dyract SealTMdemonstrou diferenças estatisticamente significantes entre os valores DC dos espécimes testados imediatamente e novamente após um mês de armazenamento (p < 0,05). Os valores do ClimproTM aumentaram após o período de armazenamento (p < 0.05). O DC do VitremerTM não demonstraram alterações após o armazenamento (p > 0.05). Os resultados das unidades de fotopolimerização não mostraram diferenças significantes ente DC de amostras polimerizadas com LED, HQTH, O TH testados imediatamente e novamente após um mês para o Diract SealTM, VitremerTM e Climpro SealantTM. CONCLUSÃO: Unidades de fotopolimerização não tiveram efeito no grau de conversão dos selantes de fissuras. Porém, armazenamento após ativação inicial e polimerização por um mês em saliva artificial pode afetar o DC dos selantes de fissuras.

Temperature rise under normal and caries-affected primary tooth dentin disks during polymerization of adhesives and resin-containing dental materials.

The purpose of this study was to compare the temperature rise under normal and caries-affected primary tooth dentin during photopolymerization of two adhesives and resin-containing restorative materials. Caries-affected and normal dentin disks were prepared from extracted primary molars with only mesial or distal approximal caries (4 mm in diameter, 1 mm in height). Temperature rise during photopolymerization of adhesive materials was measured with a J-type thermocouple wire that was connected to a data logger. Data were analyzed with two-way ANOVA and independent samples t-test. Temperature rise under caries-affected primary tooth dentin disks was higher than that of normal primary tooth dentin disks during polymerization of both adhesive systems and resin-containing dental materials (p < 0.05). It was found that adhesive systems induced a higher temperature rise during polymerization as compared to the resin-containing restorative materials (p < 0.05). In particular, temperature rise during polymerization of adhesive materials exceeded 5.5 degrees C under caries-affected primary tooth dentin.

Conventional and high intensity halogen light effects on water sorption and microhardness of orthodontic adhesives.

OBJECTIVE: To test the null hypothesis that when the equivalent total light energy is irradiated to three orthodontic adhesive resins, there is no difference between the microhardness and water sorption values regardless of the curing light sources. MATERIALS AND METHODS: Samples were divided into six groups according to the combination of three orthodontic adhesives (Kurasper F, Light-Bond, Transbond XT) and two light intensities (quartz tungsten halogen [QTH] and high intensity quartz tungsten halogen [HQTH]). One half of each of the 40 samples of three adhesive pastes was polymerized for 20 seconds by a QTH light source, and the other half was polymerized for 10 seconds by a HQTH light source. Water sorption was determined and Vickers hardness was established with three measurements per sample at the top, center, and bottom. Statistical analysis was performed using two-way analysis of variance (ANOVA) with multiple comparisons (Tukey-HSD). RESULTS: Statistically significant differences were found among all adhesives for water sorption and hardness values cured with QTH and HQTH. The HQTH curing unit resulted in higher values than did the QTH. The highest water sorption values were observed for Kurasper F cured with HQTH and the lowest value was observed for Transbond XT cured with QTH. For microhardness Light-Bond cured with HQTH produced the highest values, and Transbond XT cured with QTH produced the lowest. CONCLUSIONS: When the equivalent total light energy is irradiated to three orthodontic adhesive resins, there are significant differences between the microhardness and water sorption values cured with the QTH and HQTH light source. The null hypothesis is rejected.

Bond strength of two total-etching bonding systems on caries-affected and sound primary teeth dentin.

AIM: As bond strength of currently available adhesive systems in caries-affected teeth dentin on primary tooth dentin was not well known, the bond strength of two bonding systems (PQI and OptiBond Solo Plus) was evaluated on caries-affected and sound primary molar tooth dentin and observed the micromorphology of the adhesive-dentin interfaces. METHODS: By grinding both the sound (n = 30) and caries-affected (n = 30) approximal surfaces of teeth, flat dentin surfaces were obtained. The prepared surfaces were bonded with one of the each adhesive systems and a composite resin. After storing the bonded specimens in water at 37 degrees C for 24 h, the samples were sectioned and the bond strength of the adhesive systems was tested by the microshear test method. The data were statistically analysed. RESULTS: Microshear bond strengths of PQI group for caries-affected and sound primary tooth dentin were 9.43 +/- 2.44 (MPa) and 9.32 +/- 2.95 (MPa) (P > 0.05), respectively, and the bond strengths of OptiBond Solo Plus group for caries-affected and sound primary tooth dentin were 15.33 +/- 3.59 (MPa) and 11.96 +/- 2.30 (MPa) (P < 0.05), respectively. Micromorphological features between sound and caries-affected dentin were similar in both PQI and OptiBond Solo Plus groups. CONCLUSION: Both the adhesives showed significantly different bond strengths in caries-affected dentin but showed similar bond strengths in sound dentin.

Microtensile and microshear bond strength of an antibacterial self-etching system to primary tooth dentin.

OBJECTIVES: The aim of this study was to test the hypothesis that the bonding ability of antibacterial bonding system to primary dentin was not different from the parental material which did not contain any antibacterial component. METHODS: Extracted human non-carious primary molars were ground to expose the coronal dentin, and then randomly divided into two experimental groups: treatment with Clearfil Protect Bond or with Clearfil SE Bond (Kuraray Medical Inc.). Composite-dentin sticks with a cross-sectional area of approximately 0.90 mm(2) were prepared and subsequently subjected to microtensile bond strength (muTBS) and microshear bond strength (muSBS) tests. For the muTBS tests, specimens were attached to an Instron testing machine with a cyanoacrylate adhesive. For muSBS testing, the sticks were mechanically fixed to the muSBS testing apparatus. The bonds were stressed in shear or tension at a crosshead speed of 1mm/min until failure occurred. Resin-dentin interfaces produced by each system were examined using SEM. The data were analyzed with Mann-Whitney's U test. RESULTS: The muTBS and muSBS of Clearfil Protect Bond were 30.69+/-9.71 and 9.94+/-3.78 MPa, respectively. Clearfil SE Bond showed significantly greater values of 37.31+/-9.57 and 12.83+/-3.15 MPa, respectively. SEM analysis demonstrated similar micro-morphological features including the thickness of the hybrid layer for both materials. CONCLUSIONS: It was showed that antibacterial self-etching system Clearfil Protect Bond showed lower bond strength values compared to primary dentin than that of to Clearfil SE Bond on primary dentin. (Eur J Dent 2008;2:11-17).

Effect of storage duration/solution on microshear bond strength of composite to enamel.

The aim of this study was to determine the effect of three storage solutions and two storage durations on microshear bond strength (microSBS) of a resin composite. Sixty non-carious human permanent molars were stored in three storage solutions (0.1% thymol, 10% formalin, and distilled water). Each tooth was separated mesio-distally into two parts. Specimens of the first part were stored for 24 hours, while specimens of the second part were stored for two months in the solutions. After each storage period, the enamel surface was covered with a composite resin in combination with an etch-rinse adhesive system. Specimens were then serially sectioned into sticks of 1 mm' bond area and subjected to microSBS test. There were no statistically significant differences between the two storage periods for each solution (p>0.05). The thymol solution group showed lower microSBS values than those of distilled water for both storage periods (p<0.05). As for the formalin group, its microSBS values were not statistically different from those of distilled water and thymol groups at each storage period (p>0.05). In conclusion, the thymol solution caused the microSBS of the resin composite to decrease when compared to both formalin and distilled water after 24 hours and two months. However, the microSBS of the resin composite was not affected by storage duration.

Fluoride levels of human plasma and breast milk.

OBJECTIVES: The aim of this study was to determine the fluoride levels in breast milk and plasma of lactating mothers who regularly consumed drinking water with low levels of fluoride. METHODS: One hundred twenty five healthy mothers aged between 20-30 years old who had given birth within 5-7 days were included in the study. Besides being otherwise healthy, the primary selection criteria stipulated the absence of fluoride supplement consumption one month before delivery. Approximately 5 ml breast milk and 5 ml blood samples were obtained from each participating mother at a hospital setting, where the mothers were scheduled for a regular hospital diet. The blood samples were centrifuged in fluoride-free heparinized polyethylene tubes and stored at -18 degrees C until measurements were made. Breast milk samples were directly refrigerated as with blood samples until measurements. The fluoride concentrations of milk and blood samples were assessed using an ion-selective fluoride electrode combined with an ion analyzer. RESULTS: The fluoride levels of the plasma and breast milk samples were measured as 0.017+/-0.011 ppm and 0.006+/-0.002 ppm, respectively. The fluoride concentration of plasma was significantly higher than that of breast milk (P<.01). Correlation analysis revealed a significant relation between the groups (P<.01). CONCLUSION: A limited level of fluoride transmission from plasma to breast milk was detected. Nevertheless, a significant correlation between the fluoride concentrations of breast milk and plasma was evident.

An unusual association of odontomas with primary teeth.

Odontomas generally appear as small, solitary or multiple radio-opaque lesions found on routine radiographic examinations. Traditionally, odontomas have been classified as benign odontogenic tumors and are subdivided into complex or compound odontomas morphologically. Compound odontomas commonly occur in the incisor-canine region of the maxilla and complex odontomas are frequently located in the premolar and molar region of both jaws. Occasionally, odontoma may cause disturbances in the eruption of teeth such as impaction, delay eruption or retention of primary teeth. In general, odontomas occur more often in the permanent dentition and are very rarely associated with the primary teeth. In this report; two cases of compound odontoma associated with primary teeth is presented. (Eur J Dent 2007;1:45-49).

Conventional and high-intensity halogen light effects on polymerization shrinkage of orthodontic adhesives.

The objectives of this study were to compare the polymerization shrinkage of three orthodontic adhesives. In addition we wanted to determine the effectiveness of the high-intensity quartz tungsten halogen (HQTH) in curing orthodontic adhesives on polymerization shrinkage with that of the quartz tungsten halogen (QTH). A total of 120 glass ring molds were prepared using a low-speed saw. The internal surface of the glass rings were roughened and etched. Adhesive pastes were placed into the glass molds, which were sandwiched between two glass slides. Samples were divided into six groups according to the combination of three orthodontic adhesives (Kurasper F, Light Bond, and Transbond XT) and two light intensities. One half of each 40 samples of three adhesive pastes was polymerized for 20 seconds by a QTH (Hilux 350), and the other half was polymerized for 10 seconds by a HQTH (Optilux 501). The volumetric polymerization shrinkage for each system was measured through the specific density method modified by Puckett and Smith. Statistical analysis was performed using two-way analysis of variance for intergroup comparisons. The HQTH-curing unit resulted in a more polymerization shrinkage than did the QTH for all investigated adhesives. However, no statistically significant differences were found. The highest shrinkage was observed for Light Bond cured with HQTH (1.59 +/- 0.82%), and the lowest value was observed for Transbond XT cured with QTH (1.23 +/- 0.60%). There are no significant differences in polymerization shrinkage of the three investigated orthodontic adhesives when polymerized with a QTH or a HQTH.

Shear bond strengths of self-etching adhesives to caries-affected dentin on the gingival wall.

The purpose of this study was to evaluate the bonding ability of five current self-etching adhesives to caries-affected dentin on the gingival wall. Seventy extracted human molars with approximal dentin caries were employed in this study. In order to obtain caries-affected dentin on the gingival wall, grinding was performed under running water. Following which, specimens mounted in acrylic blocks and composite resins of the bonding systems were bonded to dentin with plastic rings and then debonded by shear bond strength. With Clearfil SE Bond, bonding to caries-affected dentin showed the highest bond strength. With Optibond Solo Plus Self-Etch, bonding to caries-affected dentin showed higher shear bond strength than AQ Bond, Tyrian SPE & One-Step Plus, and Prompt-L-Pop (p<0.05). Further, the bond strengths of Clearfil SE Bond and Optibond Solo Plus Self-Etch to sound dentin were higher than those of Prompt-L-Pop, AQ Bond, and Tyrian SPE & One-Step Plus (p<0.05). In conclusion, besides micromechanical interlocking through hybrid layer formation, bond strength of self-etch adhesives to dentin may be increased from additional chemical interaction between the functional monomer and residual hydroxyapatite. The results of this study confirmed that differences in bond strength among self-etching adhesives to both caries-affected and sound dentin were due to chemical composition rather than acidity.

Effect of desensitizers on the bond strength of a self-etching adhesive system to caries-affected dentin on the gingival wall.

A self-etching dentin adhesive was evaluated for its ability to bond to caries-affected and sound dentin after applying three desensitizers to the gingival walls. Sixty extracted human molars, with approximal dentin caries, were cut horizontally on the long axis of the tooth through caries-affected gingival walls. Carious dentin was removed with SiC paper by means of a caries detector to expose caries-affected dentin. The molars were randomly assigned to four groups: control and three experimental groups-Micro Prime, Glauma Desentizer and Cervitec. Desensitizers were applied to the dentinal surfaces according to manufacturers' instructions. A resin composite was bonded to both the caries-affected and sound dentin of each tooth using a bonding system and plastic rings. The restoration was debonded by shear bond strength. The application of Micro Prime and Gluma Desensitizer to caries-affected dentin did not show any effect on bond strength testing. However, Cervitec caused a decrease in bond strength to caries-affected dentin. The effect of desensitizers on the bond strength of the self-etch bonding agent to caries-affected dentin changed according to the chemical composition of the materials. Desensitizer application on sound dentin is recommended with self-etch bonding systems.

Effects of chlorhexidine and povidone-iodine mouth rinses on the bond strength of an orthodontic composite.

The purpose of this study was to determine whether the application of two antibacterial mouth rinses to etched and unetched enamel affects the shear bond strength (SBS) of an orthodontic composite resin. Eighty-five lower human incisors were divided into five groups, ie, group 1: control group, no mouth rinse was used; groups 2 and 3: mouth rinses were applied to the intact enamel surface before etching; groups 4 and 5: mouth rinses were applied to the etched enamel. A bonding agent and a composite resin were applied to the teeth surface. For shear bond testing, the specimens were mounted in a universal testing machine, and an apparatus attached to a compression load cell was applied to each specimen until failure occurred. The data were analyzed using analysis of variance and Tukey honestly significance tests. Fracture modes were analyzed by Mann-Whitney U-test. There was no statistically significant difference between the SBS values of group 1 (31.64 +/- 3.62 MPa) and group 4-five experimental applications (P > or = .05). However, the SBS value of group 3 (36.56 +/- 5.95 MPa) was significantly larger than those of group 4 (30.00 +/- 4.97 MPa) and group 5 (30.26 +/- 7.30 MPa). In addition, no significant differences were observed between group 1 and groups 2 (34.33 +/- 7.26 MPa) and 3 (36.56 +/- 5.95 MPa) (P > or = .05). Because the application of chlorhexidine and povidone-iodine before acid etching did not cause any decrease in bond strength, it is advisable for use under the orthodontic resin composite to obtain an antibacterial effect or to prevent the risk of bacteremia.