Cephalometric and digital model analysis of dentoskeletal effects of infrazygomatic miniscrew vs. Essix- anchored Carriere Motion appliance for distalization of maxillary buccal segment: a randomized clinical trial.

TRIAL DESIGN: Parallel. OBJECTIVE: To compare skeletally anchored Carriere Motion appliance (CMA) for distalization of the maxillary buccal segment vs. Essix anchored CMA. METHODS: Thirty-two class II malocclusion patients were randomly allocated into two equal groups. One group was treated with infrazygomatic (IZC) miniscrew- anchored CMA (IZCG) and the other group treated with Essix retainer- anchored CMA (EXG). Two lateral cephalograms and two digital models for upper and lower arches were taken for each patient: immediately before intervention and after distalization had been completed. RESULTS: Distalization period was not significantly different between the two groups. In contrast to EXG, IZCG showed insignificant difference in ANB, lower incisor proclination, and mesial movement of the lower first molar. There was significant rotation with distal movement of maxillary canine and first molar in both groups. CONCLUSION: IZC anchored CMA could eliminate the side effects of class II elastics regarding lower incisor proclination, mesial movement lower molars with a more significant amount of distalization of the maxillary buccal segment but with significant molar rotation. TRIAL REGISTRATION: The ClinicalTrials.gov Protocol Registration and Results System (PRS) has this RCT registered as (NCT05499221) on 12/08/2022.

Evaluation of the antibacterial effect of titanium dioxide nanoparticles combined with acrylic laminates for functional orthodontic appliances: a randomized controlled clinical trial.

BACKGROUND: The objective of this study was to evaluate the antibacterial effect of titanium dioxide nanoparticles incorporated into the acrylic baseplates of the maxillary part of twin block appliances in orthodontic patients during the treatment period. MATERIALS AND METHODS: Twenty-six patients were selected randomly and divided into two groups(n = 13). Test group patients used orthodontic functional appliances containing 1% titanium dioxide nanoparticles in acrylic baseplates. Control group patients used orthodontic functional appliances without titanium dioxide nanoparticles in acrylic baseplates. Swap samples were taken from the palatal gingiva facing the fitting surface of the acrylic component of the maxillary part of a twin block appliance for each patient at five-time intervals (baseline sample, after one, two, four, and six months) and then cultured in blood agar plates to calculate bacterial colony count. The Mann‒Whitney U test and the Friedman test were used to compare data. Bonferroni correction (p value ≤ 0.05) was applied to detect significant differences. THE RESULTS: showed a decrease in the bacterial colony count in the test group compared to the control group. Pairwise comparisons revealed a statistically significant difference in samples after four- and six-month groups (p values = 0.002 and 0.011, respectively) vs. the one-month test group. A higher statistically significant difference was observed in the six-month group (p-value = 0.037) vs. the baseline group in the control group. CONCLUSION: The addition of 1% titanium dioxide nanoparticles to acrylic baseplates of orthodontic functional appliances significantly reduced the bacterial colony count under the base plate after at least four months of application.

Static friction, surface roughness, and antibacterial activity of orthodontic brackets coated with silver and silver chitosan nanoparticles.

BACKGROUND: To determine the effect of silver and silver chitosan nanocoatings on monocrystalline ceramic, polycrystalline ceramic, and metallic brackets regarding friction, roughness, and antibacterial effect against Streptococcus mutans. METHODS: A total of 99 upper right premolar brackets with a 0.022 × 0.025 -inch slot were divided into three groups, each 33 according to coating material; the non-coated group, silver nanoparticles (AgNPs), and silver chitosan nanoparticles (Ag-CsNPs) groups. Each group was equally subdivided into the following three subgroups regarding bracket materials: monocrystalline ceramic, polycrystalline ceramic, and metallic brackets. A universal testing machine determined static friction on a custom-made acrylic jig. Then a profilometer machine was used to collect roughness data, and finally, the anti-cariogenic effect was measured with the disc diffusion technique's "minimum zone of inhibition" against Streptococcus mutans. Two-way ANOVA was used to compare data between groups and subgroups, followed by the Bonferroni test for multiple pair-wise comparisons. RESULTS: The nanocoating effect on ceramic brackets' static friction was non-significant. The AgNPs and Ag-CsNPs coated metallic group revealed a significant increase in static friction-a significant effect of the nanocoating in the surface roughness of monocrystalline and polycrystalline ceramic brackets. A significant favorable effect of AgNPs and Ag-CsNPs against Streptococcus mutans was observed. CONCLUSIONS: AgNPs and Ag-CsNPs coats are unsuitable for decreasing friction in metallic brackets or improving roughness in polycrystalline ceramic brackets. Nano coating can improve roughness in monocrystalline ceramic brackets. Coating brackets with AgNPs and Ag-CsNPs has a tremendous antibacterial effect on Streptococcus mutans, a substantial factor in the incidence of dental caries.

Antioxidant effect on shear bond strength of orthodontic brackets after tooth bleaching: A scoping review of in vitro studies.

INTRODUCTION: Tooth bleaching was reported to decrease bond strength of orthodontic brackets. The antioxidant application was investigated to reverse the bleaching effect for immediate bracket bonding. This scoping review of in vitro studies is to assess systematically the effect of antioxidant application on shear bond strength (SBS) before orthodontic bracket bonding after tooth bleaching. MATERIALS AND METHODS: This review was provided according to the Preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews (PRISMA-ScR) guidelines. An electronic literature search was performed for full-text articles in English via Scopus, Web of Science, MEDLINE/PubMed, and Google Scholar databases from 2012 to May 9, 2023. RESULTS: A total of 549 records were retrieved from the electronic search, and 361 after discarding duplicates. According to eligibility criteria, 23 records were included in this study. CONCLUSION: Included studies revealed that antioxidants could increase the SBS of brackets after bleaching. However, there was controversiality whether SBS was just improved or restored to the unbleached level according to various factors, including the antioxidant type, concentration, application time, and form. Most studies reported that 10% sodium ascorbate (SA), ascorbic acid, green tea (GT), and tocopherol solutions restored SBS of metal brackets but not ceramic brackets. The result of 10% SA and GT gel was controversial. Lower concentrations than 10% was effective with pink bark, grape seed, quercetin flavonoid, and chamomile to restore SBS. The included studies revealed that retinol acetate, gooseberry, and dimethyl sulfoxide did not restore SBS.

Shear bond strength of orthodontic brackets bonded to a new version of zirconium all ceramic restoration: An in vitro comparative study.

Objectives: Esthetic restorations such as monolithic zirconia crowns are highly requested for adults nowadays. Bonding orthodontic braces on this type of material became a challenge for orthodontists, because of the special surface treatment needed. This study aims to assess the shear bond strength (SBS) of metal, and ceramic brackets bonded on two types of zirconia ceramics, surface roughness (SR) after different surface treatments for their surfaces, and adhesive remnant index (ARI). Materials and methods: Brackets' base surface area (BSA) was scanned by an extra-oral scanner, then measured. The doubled labial surface of monolithic zirconia crowns (n = 30) and monolithic high translucent zirconia crowns (n = 30) were prepared and each was divided into three groups (n = 10) depending on surface treatment (hydrofluoric acid etching, no treatment, and rocatec airborne abrasion). Extracted lower central incisors (n = 20) were prepared. Each of them was divided into two subgroups depending on the type of bracket bonded on their surfaces (metal and ceramic). The SR, SBS, and ARI were assessed. Statistical analysis used: Tests used are independent-samples t-test, Fisher's exact test, One-Way ANOVA, and Kruskal-Wallis test. Results: The highest SBS and SR were observed in Enamel/Metal and Zirconia/Metal/Rocatec subgroups, respectively. Conclusion: Adequate bond strength could be obtained with the high translucent zirconia group if bonded with ceramic or metal brackets even if no treatment was used. Clinical significance: A proportion of simulation was done like practicing inside the dental clinic to reach the best results regarding the adhesion strength of orthodontic brackets.

Can antioxidant treatment replace delay in bracket bonding? An in vitro study.

BACKGROUND: Deterioration in shear bond strength has been reported after immediate bracket bonding following hydrogen peroxide bleaching. This study compared the effectiveness of three antioxidant agents, namely, alpha-tocopherol, green tea extract, and sodium ascorbate, in reversing the bleaching effect and as possible alternatives to delayed bonding. METHODS: A total of 105 extracted human premolars were arbitrarily assigned to 7 groups (n = 15 each), including group 1 as the unbleached control group and six experimental groups, which were bleached with 40% hydrogen peroxide in three sessions of 15 min each. In experimental group 2, bonding was performed immediately after bleaching, whereas in groups 3 and 4, bonding was delayed for 1 and 2 weeks, respectively; meanwhile, the specimens were immersed in artificial saliva at 37 °C. Groups 5, 6, and 7 were treated immediately after bleaching with 10% of alpha-tocopherol, green tea extract, and sodium ascorbate solutions, respectively, for 15 min. Specimens were processed using 500 thermal cycles between 5 and 55 °C, with a dwell time of 30 s after 24 h of bracket bonding, and then tested for shear bond strength. The adhesive remnant index was examined to evaluate fracture mode. One-way analysis of variance, Kruskal-Wallis H, and post hoc Tukey's honestly significant difference tests were used to compare the data. Significant results were subjected to pairwise comparisons with Bonferroni's correction-adjusted of p values ≤ 0.050. RESULTS: Shear bond strength was significantly lower (p < 0.001) in the immediate bonding and 1-week delay groups than in the control group. However, no significant difference was detected among the 2-week delay, antioxidant-treated, and control groups (p > 0.05). CONCLUSIONS: Application of 10% alpha-tocopherol, green tea extract, or sodium ascorbate for 15 min could restore shear bond strength after 40% hydrogen peroxide bleaching as an alternative to delay in bracket bonding.

Effect of self-assembling peptide and other remineralizing agents on preventing initial enamel lesions around orthodontic brackets: An in vitro comparative study.

OBJECTIVE: To investigate and compare the effect of self-assembling peptide SAP (P11-4), casein phosphopeptide-amorphous calcium phosphate fluoride paste (CPP-ACPF), and fluoride varnish (FV) on preventing enamel demineralization around orthodontic brackets. MATERIAL AND METHODS: Orthodontic brackets were bonded to the buccal surfaces of 80 freshly extracted human maxillary premolars. Teeth were randomly assigned to four groups (n=20) according to the remineralizing agent used as follows: SAP (P11-4) group (Curodont™ Protect/Credentis), CPP-ACPF group (MI Paste Plus®/Recaldent™), fluoride varnish group (Profluoride varnish®/VOCO), and control group. All products were applied according to the manufacturer's instructions. Specimens were cycled in daily refreshed demineralizing and remineralizing solutions for 8h and 16h, respectively, for 28 days. The calcium/phosphorus ratio (Ca/P) and surface microhardness (SMH) were evaluated at baseline and at two and four weeks. Two-way ANOVA (analysis of variance), one-way ANOVA and repeated measures ANOVA were used for statistical analysis. RESULTS: Two-way ANOVA demonstrated significant differences between remineralizing agents and time points. After 4 weeks, the SAP (P11-4) group had had significantly higher Ca/P ratio and SMH (1.68±0.11 and 346.47±55.38) compared to other groups, followed by CPP-ACPF (1.52±0.19 and 283.53±64.75), FV (1.37±0.14 and 262.80±82.98), and the control group (1.31±0.10 and 213.00±41.95). Significantly higher Ca/P ratio and SMH were observed at 2 weeks in the control group (1.44±0.10 and 269.63±57.37) and FV group (1.52±0.09 and 321.17±55.24) compared to 4 weeks. No significant differences were found regarding Ca/P ratio and SMH at 2 weeks in the CPP-ACPF (1.55±0.15 and 295.14±53.88) and SAP P11-4 groups (1.64±0.10 and 320.18±58.04) compared to 4 weeks. CONCLUSION: SAP (P11-4) had the greatest remineralizing efficacy compared to FV and CPP-ACPF. Moreover, extended period of time improved the preventive efficacy of SAP (P11-4) compared to the other regimens.

The effects of micro-osteoperforation on upper first molar root resorption and bone density after distalization by miniscrew-supported Fast Back appliance in adults: A CBCT randomized controlled trial.

OBJECTIVE: To evaluate, primary the effects of Micro-osteoperforation (MOP) on orthodontically induced inflammatory root resorption (OIIRR) of maxillary first molars, and secondary, the density of surrounding alveolar bone during distalization phase with Fast Back distalizer. MATERIALS AND METHODS: Female patients between 16-20 years of age (University of Mansoura), meeting the criteria, were included between March to September 2019. They were randomly, and equally allocated into control and MOP groups. Both of them underwent distalization with Fast Back distalizer. 3MOPs were applied in the intervention group, distal to the first molars using a 3D printed guide. CBCT images were obtained before and after distalization. Apical root resorption maxillary first molars' roots, and alveolar bone density surrounding them were evaluated using independent-samples t-test. Time of distalization phase was assessed using Mann-Whitney U test. Correlation and partial correlation tests were done between resorption of roots, bone density, and time. RESULTS: Screening of 50 patients, and exclusion for 30 of them were done. Only 20 subjects underwent the trial to the end. In MOP group, OIIRR of mesiobuccal roots significantly increased (MD=-0.2 (-0.34 to -0.01), P<0.05), and significantly decreased for disto-buccal roots (MD=0.6 (0.45 to 0.72), P<0.001). The second and third layers of bone density decreased significantly in MOP group (MD=116.7 (50.8 to 182.5), MD=560.4 (327.9 to 792.7) respectively, P<0.001). Time for distalization phase was significantly reduced in MOP group (P<0.001). CONCLUSIONS: MOP decreased OIIRR for nearby distobuccal roots by reduction in surrounding density of bone, and increased OIIRR for the far mesiobuccal roots.

A 3-dimensional finite element analysis to evaluate the impact of force direction, insertion angle, and cortical bone thickness on mini-screw and its surrounding bone.

Background. The present study aimed to assess the stress and strain distribution on mini-screws and the surrounding bone in cases of different cortical bone thicknesses (CBTs), mini-screw insertion angles, and force directions using finite element analysis (FEA). Methods. Inventor professional version 8 software was used to construct 24 three-dimensional assemblies of mini-screws inserted with different insertion angles (30º, 60º, and 90º) in alveolar bone blocks with different CBTs (0.5, 1, 1.5, and 2 mm). The models simulated mini-screws inserted in bones with different CBTs and different insertion angles. A 2-N load was applied in two directions to mini-screw heads. The resultant stresses of the applied load were collected from the output of the ANSYS program. Results. The results indicated that force direction affected bone strains as the horizontal force generated more strains on cortical bone than the oblique one. Force applied to 60º inserted mini-screws generated much more strains on cortical bone than 90º and 30º inserted mini-screws. In a 60º inserted mini-screw, the horizontal force generated about 45% more strains on cortical bone than the oblique one. The exerted microstrain on bone decreased as CBT increased. Conclusion. It can be concluded that inserting mini-screws at 60º to the bone surface should be avoided as it generates much more strains on cortical bone than 90º and 30º, especially when a force parallel to the bone surface is applied.

Evaluation of zinc-oxide nanocoating on the characteristics and antibacterial behavior of nickel-titanium alloy.

OBJECTIVE: To investigate the effect of ZnO nanocoating on mechanical properties of NiTi orthodontic wires and antibacterial activity. METHODS: 0.016 x 0.022-in NiTi orthodontic wires were coated with ZnO nanoparticles using an electrochemical deposition method with three electrodes system in 0.1M Zn(NO3)2. Mechanical properties and frictional resistance of the coated wires were investigated using an universal testing machine. Antibacterial effect of ZnO coating was also investigated. RESULTS: A stable adhered ZnO nanocoating on NiTi wires was obtained. The coated wires have a significant antibacterial activity against S. aureus, S. pyogens and E. coli, and a reduction of frictional forces by 34%. CONCLUSION: ZnO nanocoating may improve the antibacterial effects of NiTi wires and reduce the frictional resistance. Coating may be implanted in orthodontic practice for faster and safer treatment.

Evaluation of zinc-oxide nanocoating on the characteristics and antibacterial behavior of nickel-titanium alloy

ABSTRACT Objective: To investigate the effect of ZnO nanocoating on mechanical properties of NiTi orthodontic wires and antibacterial activity. Methods: 0.016 x 0.022-in NiTi orthodontic wires were coated with ZnO nanoparticles using an electrochemical deposition method with three electrodes system in 0.1M Zn(NO3)2. Mechanical properties and frictional resistance of the coated wires were investigated using an universal testing machine. Antibacterial effect of ZnO coating was also investigated. Results: A stable adhered ZnO nanocoating on NiTi wires was obtained. The coated wires have a significant antibacterial activity against S. aureus, S. pyogens and E. coli, and a reduction of frictional forces by 34%. Conclusion: ZnO nanocoating may improve the antibacterial effects of NiTi wires and reduce the frictional resistance. Coating may be implanted in orthodontic practice for faster and safer treatment.

RESUMO Objetivos: Avaliar o efeito do nanorrevestimento de óxido de zinco (ZnO) sobre as propriedades mecânicas e propriedades antibacterianas de fios ortodônticos de NiTi. Métodos: Fios 0,016" x 0,022" de NiTi foram revestidos com nanopartículas de ZnO por meio de um método de deposição eletroquímica com um sistema de três eletrodos a 0,1M Zn(NO3)2. Uma máquina universal de testes foi utilizada para avaliar as propriedades mecânicas e a resistência friccional dos fios revestidos. Além disso, também foram analisadas as propriedades antibacterianas do revestimento de ZnO. Resultados: Obteve-se uma aderência estável das nanopartículas de ZnO sobre os fios NiTi. Os fios revestidos apresentaram atividade antibacteriana significativa contra S. aureus, S. pyogens e E. coli, e apresentaram uma redução de 34% na força de atrito. Conclusão: O revestimento com nanopartículas de óxido de zinco pode melhorar as propriedades antibacterianas e reduzir a resistência friccional dos fios de NiTi. Assim, o revestimento dos fios pode ser utilizado na Ortodontia visando tratamentos mais rápidos e seguros.

Enamel around orthodontic brackets coated with flash-free and conventional adhesives.

OBJECTIVE: To evaluate enamel roughness and color after debonding flash-free adhesive precoated brackets and brackets coated with conventional orthodontic adhesives using nonbonded enamel as control. MATERIALS AND METHODS: A total of 80 extracted human premolars were divided into the following four groups: group I: APCTM Flash-Free adhesive precoated brackets; group II: APCTM PLUS adhesive precoated brackets; group III: noncoated brackets, which were coated manually at the time of bonding (all three brackets were ClarityTM Advanced ceramic brackets [3M Unitek, Monrovia, CA, USA]); group IV: nonbonded enamel (control). Bonded premolars were subjected to demineralization, and then brackets were debonded. Each group was then divided into two subgroups to assess enamel around the debonded brackets, and also enamel in the control group, using an atomic force microscope and spectrophotometer. In addition, 12 samples were used to assess the bracket/adhesive/enamel junction with a scanning electron microscope. RESULTS: Mean values of root mean square roughness (Rq) and maximum profile valley depth (Rv) for APCTM Flash-Free, APCTM PLUS, and ClarityTM Advanced groups were 140 nm and 482 nm, 210 nm and 727 nm, and 447 nm and 1243 nm, respectively. All three groups showed higher roughness and depth values than the control enamel. Spectrophotometer results yielded ∆E* of 3.7 ± 0.6, 5.1 ± 0.4, and 7.1 ± 0.6 for APC™ Flash-Free, APC™ PLUS, and ClarityTM Advanced groups respectively. Color coordinates showed progressively higher L* and b* values and progressively lower a* values from group I to group III. CONCLUSIONS: Under the same demineralization conditions, enamel around debonded APC™ Flash-Free adhesive precoated brackets showed less roughness and color changes compared to the other two groups.

Colour change of ceramic brackets with the use of coloured beverages in adolescent patients: A randomized clinical trial.

OBJECTIVE: To clinically evaluate colour change of ceramic orthodontic brackets with the use of coloured beverages as ceramic brackets' resistance to discoloration has become a major concern. MATERIAL AND METHODS: A prospective two parallel groups-split mouth randomized trial with a 1:1 allocation ratio. Two equal groups including 40 adolescent patients from the orthodontic department (Faculty of Dentistry, Mansoura University, Egypt), scheduled for maxillary premolar extractions were bonded with 2 types of mono-crystalline ceramic brackets: Type 1 (Inspire ICETM) and Type 2 (Radiance PlusTM). Participants in each group were asked to rinse with either black tea or Cola. After extraction, the colour of the 80 debonded brackets was compared to that of 20 control brackets from each type by spectrophotometer according to the international standard CIELAB colour space (CIE L*a*b*). The latter consists of three coordinates: L* (lightness value), a* and b* (the colour channels). The total colour difference ΔE* is the distance between two colours in this three-dimensional colour space. The colour change was also assessed by digital image analysis according to the RGB model. RESULTS: Type 1 brackets showed mean ΔE* values of 2.24±0.25 in black tea and 1.76±0.1 in Cola groups (P<0.001), while Type 2 brackets showed means of 1.99±0.15 in black tea and 1.56±0.1 in Cola groups (P<0.001). The mean RGB values were 174.3±12.02 in black tea and 185.6±6.9 in the Cola groups of type 1 brackets (P<0.001), while were 166.5±17.8 in black tea and 190.8±8.9 in Cola groups of type 2 brackets (P<0.001). CONCLUSION: Black tea showed more significant effect than Cola on the two bracket types. Bracket type affected the colour change in each beverage group.

In vitro testing of shear bond strength of orthodontic brackets bonded to different novel CAD/CAM ceramics.

Background. The present study aimed to evaluate the bond strength of metal bracket (MB) and ceramic bracket (CB) bonded to different CAD/CAM ceramic substrates etched with hydrofluoric acid (HFA) vs. phosphoric acid (PA). Methods. A total of 120 CAD/CAM ceramic blocks in 12 groups were fabricated from three different CAD/CAM ceramic materials: VITABLOCS Mark II, VITAENAMIC, and IPS e.max CAD. Each ceramic material group was divided into two etching groups: one treated with 9.5% HFA and the other treated with 37%. Sixty metal and CBs of the upper right central incisor were bonded to the HFA-treated blocks. Another 60 metal and CBs were bonded to the PA treated blocks. All the bonded specimens were thermocycled before shear bond strength (SBS) testing. Then the bond failure mode was recorded Results. There were no significant differences in SBS values between the three CAD/CAM ceramic materials. The HFA-treated specimens exhibited significantly higher SBS values than the PA-treated specimens. Also, the SBS values of CBs were significantly higher than the metal brackets (MBs). The adhesive remnant index (ARI) score was 4 for most of the groups, indicating that almost no adhesive remained on the porcelain surface. Conclusion. The CAD/CAM ceramic type did not influence SBS; however, HFA exhibited significantly higher SBS compared to PA.

Characteristics of adhesive bonding with enamel deproteinization.

OBJECTIVE: To evaluate the effect of using sodium hypochlorite (NaOCl) on the bond characteristics of orthodontic metal brackets bonded to enamel surface using three adhesive systems. METHODS: One hundred twenty premolars were selected and randomly divided into two equal groups of 60 teeth/ each (Groups I and II). The teeth of Group I were left untreated while those of Group II were exposed to 5.25% NaOCl for 1 minute. The teeth in either group were randomly subdivided into three equal subgroups of 20 teeth/ each (A, B and C), according to the type of adhesive system used to bond the brackets. In Subgroup A, phosphoric acid + Transbond XT primer and adhesive were used. In subgroup B, Transbond Plus self-etching primer (SEP) + Transbond XT adhesive were utilized. In subgroup C, phosphoric acid + SmartBond LC adhesive were used. The shear bond strength (SBS) and the degree of adhesive penetration to enamel surface were assessed. Data analyses were performed using ANOVA, post-hoc (LSD), t and chi-square test. RESULTS: Transbond XT had significantly higher SBS than SmartBond LC (p< 0.05). Phosphoric acid provided significantly higher SBS and degree of adhesive penetration than SEP (p< 0.05). NaOCl significantly increased SBS and degree of adhesive penetration in Subgroups B and C (p< 0.05). CONCLUSION: Adhesion quality of Transbond XT adhesive is better than SmartBond LC. Phosphoric acid is more effective than SEP. NaOCl enhances the bond characteristics.

Characteristics of adhesive bonding with enamel deproteinization

ABSTRACT Objective: To evaluate the effect of using sodium hypochlorite (NaOCl) on the bond characteristics of orthodontic metal brackets bonded to enamel surface using three adhesive systems. Methods: One hundred twenty premolars were selected and randomly divided into two equal groups of 60 teeth/ each (Groups I and II). The teeth of Group I were left untreated while those of Group II were exposed to 5.25% NaOCl for 1 minute. The teeth in either group were randomly subdivided into three equal subgroups of 20 teeth/ each (A, B and C), according to the type of adhesive system used to bond the brackets. In Subgroup A, phosphoric acid + Transbond XT primer and adhesive were used. In subgroup B, Transbond Plus self-etching primer (SEP) + Transbond XT adhesive were utilized. In subgroup C, phosphoric acid + SmartBond LC adhesive were used. The shear bond strength (SBS) and the degree of adhesive penetration to enamel surface were assessed. Data analyses were performed using ANOVA, post-hoc (LSD), t and chi-square test. Results: Transbond XT had significantly higher SBS than SmartBond LC (p< 0.05). Phosphoric acid provided significantly higher SBS and degree of adhesive penetration than SEP (p< 0.05). NaOCl significantly increased SBS and degree of adhesive penetration in Subgroups B and C (p< 0.05). Conclusion: Adhesion quality of Transbond XT adhesive is better than SmartBond LC. Phosphoric acid is more effective than SEP. NaOCl enhances the bond characteristics.

RESUMO Objetivo: avaliar os efeitos do uso de hipoclorito de sódio (NaOCl) sobre as características de colagem de braquetes ortodônticos metálicos na superfície do esmalte, utilizando três sistemas adesivos. Métodos: cento e vinte pré-molares foram selecionados e divididos aleatoriamente em dois grupos iguais, cada um com 60 dentes (Grupos I e II). Os dentes do Grupo I não foram tratados, enquanto os do Grupo II foram expostos ao NaOCl a 5,25% por 1 minuto. Os dentes de ambos os grupos foram subdivididos, aleatoriamente, em três subgrupos iguais, cada um com 20 dentes (A, B e C), de acordo com o tipo de sistema adesivo utilizado para colar os braquetes. No Subgrupo A, foi utilizada a combinação ácido fosfórico + Transbond XT (primer e adesivo). No Subgrupo B, foi utilizada a combinação Transbond Plus autocondicionante (SEP) + Transbond XT (adesivo). No Subgrupo C, foi utilizada a combinação ácido fosfórico + SmartBond LC (adesivo). Foram avaliados a resistência ao cisalhamento e o grau de penetração do adesivo na superfície do esmalte. A análise dos dados foi realizada utilizando-se os testes ANOVA, post-hoc (LSD), t e qui-quadrado. Resultados: o Transbond XT teve uma força de adesão significativamente maior do que o SmartBond LC (p< 0,05). O ácido fosfórico propiciou força de adesão e grau de penetração do adesivo significativamente maiores do que o SEP (p< 0,05). O NaOCl aumentou significativamente a força de adesão e o grau de penetração do adesivo nos Subgrupos B e C (p< 0,05). Conclusão: a qualidade da adesão do adesivo Transbond XT é melhor que a do SmartBond LC. O ácido fosfórico é mais eficiente do que o SEP. O NaOCl melhora as características da colagem.