Análise físico-química de balas duras e mastigáveis e o seu efeito desmineralizante em esmalte bovino / Physico-chemical analysis of hard and soft candies and their demineralizing effect in bovine enamel

Objetivo: avaliar o potencial cariogênico de balas duras e mastigáveis e seu potencial desmineralizante em esmalte bovino. Métodos: foram selecionadas 30 balas de diferentes marcas, divididas em balas duras (n=11), Tic Tac®, Halls® e IceKiss®, e balas mastigáveis (n=19), Lílith®, Azedinha®, Mentos Rainbow® e Dori Gomets®. As balas foram dissolvidas em água destilada (1:10) e foram avaliados pH, acidez titulável (ATT) e presença de sólidos solúveis totais (SST/°Brix). Na ciclagem erosiva, 40 espécimes de esmalte bovino foram divididos em quatro grupos (n=10): GCN ­ saliva artificial; GCP ­ ácido clorídrico; GT1 ­ solução da bala Lílith® maçã verde; GT2 ­ solução da bala IceKiss® extraforte. O desafio erosivo foi realizado por 2 minutos, 4x/dia, segui-do de 2 horas de imersão em saliva artificial durante cinco dias. Resultados: os valores de pH para as balas duras e mastigáveis variaram de 2,88 a 5,53 e de 2,73 a 4,16, respectivamente. ATT em pH 5,5 variou de 0,07 mL a 39,40 mL de NaOH 0,1 N, para as balas duras, e de 1,53 mL a 35,83 mL, para balas mastigáveis. ATT em pH 7,0 variou de 0,2 mL a 49,13 mL de NaOH, para balas duras, e de 2,37 mL a 49,97 mL, para as mastigáveis. O conteúdo de SST de todas as balas duras foi superior a 8,5°Brix, já entre as mastigáveis variou de 5,3 a 8,83°Brix. O GCP apresentou maior desmineralização que GCN e GT2 (p<0,05). Conclusão: a maioria das balas duras e mastigáveis dissolvidas em água destilada mostraram-se potencialmente erosivas e cariogênicas.(AU)

Objective: evaluate the cariogenic potential of hard and soft candies and their demineralizing potential in bovine enamel. Methods: 30 candies of different brands were selected, divided into hard candies (n=11): Tic Tac®, Halls® and IceKiss® and soft candies (n=19): Lílith®, Azedinha®, Mentos Rainbow® and Dori Gomets®. The candies were dissolved in distilled water (1:10) and pH, titratable acidity (TT) and presence of total soluble solids (SST/°Brix) were evaluated. In erosive cycling, 40 specimens of bovine enamel were divided into four groups (n=10): GCN - artificial saliva; GCP - hydrochloric acid; GT1 - Lilith® apple green candy solution; GT2 - IceKiss® Extra Strong candy Solution. The erosive challenge was performed for 2 minutes, 4X/day, followed by 2 hours of immersion in artificial saliva for five days. Results: pH values for hard and soft candies ranged from 2.88 to 5.53 and 2.73 to 4, respectively. ATT at pH 5.5 varied from 0.07 mL to 39.40 mL of 0.1 N NaOH for hard candies and 1.53 mL to 35.83 mL for soft candies. ATT at pH 7,0 varied from 0.2 mL to 49.13 mL of 0.1 N NaOH for hard candies and from 2.37 mL to 49.97 mL for soft candies. The content of SST of all hard candies was higher than 8.5 °Brix and for soft candies, varied between 5.3 to 8.83 °Brix. The GCP group showed greater demineralization than GCN and GT2 (p<0.05). Conclusion: most hard and soft candies dissolved in distilled water were potentially erosive and cariogenic.(AU)

Effects of in-office bleaching agent combined with different desensitizing agents on enamel

Abstract Objective: To analyze color change, microhardness and chemical composition of enamel bleached with in-office bleaching agent with different desensitizing application protocols. Materials and Methods: One hundred and seventeen polished anterior human enamel surfaces were obtained and randomly divided into nine groups (n = 13). After recording initial color, microhardness and chemical composition, the bleaching treatments were performed as G1: Signal Professional White Now POWDER&LIQUID FAST 38% Hydrogen peroxide(S); G2: S+Flor Opal/0.5% fluoride ion(F); G3: S+GC Tooth Mousse/Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) paste(TM); G4: S+UltraEZ/3% potassium nitrate&0.11% fluoride(U); G5: S+Signal Professional SENSITIVE PHASE 1/30% Nano-Hydroxyapatite (n-HAP) suspension(SP); G6: S-F mixture; G7: S-TM mixture; G8: S-U mixture; G9: S-SP mixture. Color, microhardness and chemical composition measurements were repeated after 1 and 14 days. The percentage of microhardness loss (PML) was calculated 1 and 14 days after bleaching. Data were analyzed with ANOVA, Welch ANOVA, Tukey and Dunnett T3 tests (p<0.05). Results: Color change was observed in all groups. The highest ΔE was observed at G7 after 1 day, and ΔE at G8 was the highest after 14 days (p<0.05). A decrease in microhardness was observed in all groups except G6 and G7 after 1 day. The microhardness of all groups increased after 14 days in comparison with 1 day after bleaching (p>0.05). PML was observed in all groups except G6 and G7 after bleaching and none of the groups showed PML after 14 days. No significant changes were observed after bleaching at Ca and P levels and Ca/P ratios at 1 or 14 days after bleaching (p>0.05). F mass increased only in G2 and G6, 1 day after bleaching (p<0.05). Conclusions: The use of desensitizing agents containing fluoride, CPP-ACP, potassium nitrate or n-HAP after in-office bleaching or mixed in bleaching agent did not inhibit the bleaching effect. However, they all recovered microhardness of enamel 14 days after in-office bleaching.

Effect of two erosive protocols using acidic beverages on the shear bond strength of orthodontic brackets to bovine enamel

Abstract Objective: To assess the short-term effect of two in vitro erosive challenge protocols on the bond strength of metal orthodontic brackets on bovine enamel. Methods: Sixty bovine incisors were selected and randomly divided into six groups: AS7 (artificial saliva - 7 days, Control Group); CC7 (Coca-Cola™ - 7 days); LJ7 (lime juice - 7 days); AS30 (artificial saliva - 30 days, Control Group); CC30 (Coca-Cola™ - 30 days); LJ30 (lime juice - 30 days). Microhardness testing was performed prior to the erosive challenge to verify the standardization of samples. Immersion was performed 4x/day for five minutes, for either 7 or 30 days. After immersions were concluded, the brackets were bonded and shear bond strength was assessed after 48 hours. The Adhesive Remnant Index (ARI) was also assessed. Data were analyzed by two-way ANOVA, followed by Tukey's post-hoc and Student's t test for paired samples, and the Kruskal-Wallis non-parametric test (α = 5%). Results: The mean and standard deviation of microhardness testing of total samples were 281.89 ± 44.51 KHN. There was no statistically significant difference in shear bond strength for the time factor (7 or 30 days; F5.54= 0.105; p = 0.901). However, there was a statistically significant difference for the solution factor (F5.54= 6.671; p = 0.003). These differences occurred among solutions of Saliva x Coca-Cola™ (p = 0.003) and Coca-Cola™ x Lime Juice (p= 0.029). The assessment of the Adhesive Remnant Index showed no significant difference between groups. Conclusions: The immersion time used in the erosion protocols did not affect the bond strength of brackets to teeth. Coca-Cola™ induced significantly higher shear bond strength values than lime juice and artificial saliva. However, the short term effects of 7/30 days in this in vitro study may not be extrapolated for in vivo ones. Clinical studies should be conducted, substantiating the laboratory results.

Resumo Objetivo: avaliar o efeito de curto prazo de dois protocolos de desafio erosivo, in vitro, na resistência adesiva de braquetes ortodônticos metálicos em esmalte bovino. Métodos: Sessenta incisivos bovinos foram selecionados e divididos aleatoriamente em seis grupos: SA7 (saliva artificial - 7 dias, Grupo Controle); CC7 (Coca-Cola® - 7 dias); SL7 (suco de limão - 7 dias); SA30 (saliva artificial - 30 dias, Grupo Controle); CC30 (Coca-Cola® - 30 dias); SL30 (suco de limão - 30 dias). Foi realizado o teste de microdureza antes do desafio erosivo, para verificar a padronização das amostras. A imersão foi realizada quatro vezes ao dia, por cinco minutos, durante 7 ou 30 dias. Finalizadas as imersões, os braquetes foram colados e, após 48 horas, foi avaliada a resistência ao cisalhamento. O Índice de Adesivo Remanescente (IAR) também foi avaliado. Para análise dos dados, foram utilizados os testes ANOVA dois fatores, seguido do post-hoc de Tukey e teste t de Student para amostras pareadas, e o teste não-paramétrico de Kruskal-Wallis (α?#8197;= 5%). Resultados: a média e o desvio-padrão do teste de microdureza das amostras totais foi igual a 281,89 ± 44,51 KHN. Não houve diferença estatisticamente significativa na resistência ao cisalhamento para o fator tempo (7 ou 30 dias; F5,54= 0,105; p= 0,901). Contudo, houve diferença estatisticamente significativa para o fator solução (F5,54=6,671; p= 0,003). Essas diferenças ocorreram entre as soluções de Saliva x Coca-Cola® (p= 0,003) e Coca-Cola® x suco de limão (p= 0,029). Ao avaliar o Índice de Adesivo Remanescente, não foi possível verificar diferença significativa entre os grupos. Conclusões: o tempo de imersão utilizado nos protocolos de erosão não afetou a resistência de união dos braquetes aos dentes. A Coca-Cola® induziu valores de resistência ao cisalhamento significativamente mais altos do que o suco de limão e a saliva artificial. No entanto, os efeitos em curto prazo de 7 e 30 dias, nesse estudo in vitro, não podem ser extrapolados para os estudos in vivo. Estudos clínicos devem ser conduzidos, fundamentando os resultados laboratoriais.

TiF4 varnish protects the retention of brackets to enamel after in vitro mild erosive challenge

Abstract The effect of fluoride agents on the retention of orthodontic brackets to enamel under erosive challenge is little investigated. Objective: The aim of this study was to evaluate the effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) agents on the shear bond strength of brackets to enamel and on the enamel microhardness around brackets under erosive challenge. Methods: Brackets were bonded to bovine incisors. Five groups were formed according to fluoride application (n=10): TiF4 varnish, TiF4 solution, NaF varnish, NaF solution and control (without application). The specimens were submitted to erosive challenge (90 s cola drink/2h artificial saliva, 4x per day for 7 days). Solutions were applied before each erosive cycle and varnishes were applied once. Vickers Microhardness (VHN) was obtained before and after all cycles of erosion and the percentage of microhardness loss was calculated. Shear bond strength, adhesive remnant index and polarized light microscopy were conducted after erosion. The data were analyzed by ANOVA, Tukey, Kruskal-Wallis and Mann-Whitney U tests (α=0.05). Results: The %VHN had no statistically significant differences among the experimental groups. However, considering the comparisons of all groups with the control group, TiF4 varnish showed the highest protection from enamel demineralization (effect size of 2.94, while the effect size for the other groups was >2.4). The TiF4 varnish group had significantly higher shear bond strength compared to other groups. There was no difference among groups for adhesive remnant index. Polarized light microscopy showed higher demineralization depth for the control group. Conclusions: Application of NaF and TiF4 agents during mild erosive challenge minimized the enamel mineral loss around brackets, however only the experimental TiF4 varnish was able to prevent the reduction of shear bond strength of brackets to enamel.

Effect of erosive challenges on deciduous teeth undergoing restorative procedures with different adhesive protocols - an in vitro study

ABSTRACT Objective: To evaluate the effect of erosive challenges on the tooth- restoration interface of deciduous teeth treated with different adhesive protocols. Material and Methods: Deciduous molars were cut mesiodistally, then embedded, abraded and polished (n=80). Samples were randomly divided according to the adhesive system used into: G1 (Adper Single Bond2®, etch-and-rinse), G2 (Universal Single Bond®, self-etching), G3 (OptibondFL®, etch-and-rinse with Fluoride) and G4 (BondForce®, self-etching with Fluoride). After standardized cavity preparation (2 mm diameter x 2 mm depth), adhesive systems were applied and samples were restored (composite resin Z350®). Half of the samples were exposed to erosive/abrasive cycles (n = 10, each adhesive group), and the other half (control group; n = 10) remained immersed in artificial saliva. For microleakage analysis, samples were submersed in methylene blue and analyzed at 40x magnifications. Cross-sectional microhardness (CSMH) was carried out (50 g/5 s) at 25 μm, 50 μm, and 100 μm from the eroded surface and at 25 μm, 75 μm, and 125 μm from the enamel bond interface. Results: Regarding microleakage, 7.5% of the samples showed no dye infiltration, 30% showed dye infiltration only at the enamel interface, and 62.5% showed dye infiltration through the dentin-enamel junction, with no difference between groups (p≥0.05). No significant difference was observed in CSMH at different depths (two-way ANOVA, p≥0.05). Conclusions: We did not observe significant changes in microleakage or CSMH after erosive/abrasive challenges in deciduous teeth treated with different adhesive protocols (etch-and-rinse and self-etching adhesives, with and without fluoride).

One-year aging effects on microtensile bond strengths of composite and repairs with different surface treatments

Abstract The present study aimed to evaluate effects of different surface treatments and aging of composite cylinders on bond strength of composite resin repair. Thirty-two composite cylinders were produced and divided into four groups according to type of surface treatment and storage time of composite cylinder and repair. Cylinder surface of control group (Gcontrol) received no treatment before composite repair. Other groups were sandblasted with aluminum oxide (GAl2O3), followed by silane (GAl2O3sil) or adhesive (GAl2O3ad). Composite cylinders were stored in artificial saliva for either 24 hours or 1 year. Repairs were performed and stored in artificial saliva for 24 hours or 1 year and repair strength was evaluated using microtensile bond strength test. Data were submitted to Student’s t test, two-way ANOVA, and post hoc test for storage time and treatment (α = 0.05). Gcontrol group showed lower values of aging of composite cylinder and storage time of repair (24 hours or 1 year for both) compared with other groups (p < 0.05). GAl2O3ad and GAl2O3sil groups did not exhibit decreased microtensile bond strength with aged repairs (1 year; p > 0.05). Polymer degradation was significant for composite cylinders during the first year of storage in Gcontrol, GAl2O3, and GAl2O3ad groups (p < 0.05). In GAl2O3sil group, storage time of composite cylinders was not significant (p > 0.05). Aging of composite resin influenced bond strength of restoration repair for up to 1 year. Sandblasting with Al2O3, followed by application of silane layer, produced high bond strength after composite or repair aging.

Influence of biofilm formation on the mechanical properties of enamel after treatment with CPP-ACP crème

Abstract: The study aimed to investigate the effects of bacterial biofilms on changes in the surface microhardness of enamel treated with casein phosphopeptide—amorphous calcium phosphate (CPP-ACP) with and without fluoride. Human enamel blocks with incipient caries-like lesions were divided into four groups of 13: G1: Saliva (Control); G2: fluoride dentifrice (Crest™, 1100 ppm as NaF); G3: CPP-ACP (MI Paste; Recaldent™); and G4: CPP-ACPF (MI Paste Plus; Recaldent™ 900 ppm as NaF). The specimens were soaked in demineralizing solution for 6 h and remineralized in artificial saliva for 18 h alternately for 10 days. The dentifrice was prepared with deionized water in a 1 : 3 ratio (w/w) or applied undiluted in the case of the CPP-ACP group. The surface microhardness (SMH) was evaluated at baseline, after artificial caries, after pH cycling and treatment with dentifrices, and after incubation in media with Streptococcus mutans for biofilm formation. The biofilms were exposed once a day to 2% sucrose and the biofilm viability was measured by MTT reduction. The percentage of change in surface microhardness (%SMHC) was calculated for each block. The data were analyzed by nonparametric test comparisons (α = 0.05). The %SMHC values observed in G2 were different from those of G1, G3, and G4 (p < 0.05). After biofilm formation, %SMHC was positive in G2 and G4 when compared to G1 and G3, but resistance to demineralization after biofilm formation was similar in all groups. In conclusion, the presence of biofilms did not influence the treatment outcomes of anticaries products.

Evaluation of the remineralization capacity of CPP-ACP containing fluoride varnish by different quantitative methods

ABSTRACT Objective The aim of this study was to evaluate the efficacy of CPP-ACP containing fluoride varnish for remineralizing white spot lesions (WSLs) with four different quantitative methods. Material and Methods Four windows (3x3 mm) were created on the enamel surfaces of bovine incisor teeth. A control window was covered with nail varnish, and WSLs were created on the other windows (after demineralization, first week and fourth week) in acidified gel system. The test material (MI Varnish) was applied on the demineralized areas, and the treated enamel samples were stored in artificial saliva. At the fourth week, the enamel surfaces were tested by surface microhardness (SMH), quantitative light-induced fluorescence-digital (QLF-D), energy-dispersive spectroscopy (EDS) and laser fluorescence (LF pen). The data were statistically analyzed (α=0.05). Results While the LF pen measurements showed significant differences at baseline, after demineralization, and after the one-week remineralization period (p<0.05), the difference between the 1- and 4-week was not significant (p>0.05). With regards to the SMH and QLF-D analyses, statistically significant differences were found among all the phases (p<0.05). After the 1- and 4-week treatment periods, the calcium (Ca) and phosphate (P) concentrations and Ca/P ratio were higher compared to those of the demineralization surfaces (p<0.05). Conclusion CPP-ACP containing fluoride varnish provides remineralization of WSLs after a single application and seems suitable for clinical use.

In Vitro Cytotoxicity Test and Surface Characterization of CoCrW Alloy in Artificial Saliva Solution for Dental Applications

Abstract In order to evaluate its application as a dental prosthesis material, a CoCrW alloy was subjected to in vitro cytotoxicity test, surface characterization and electrochemical studies performed in artificial saliva and 0.15 mol.L-1 NaCl medium. The used techniques were: anodic polarization curves, chronoamperometric measurements, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) analysis and X-ray photoelectron spectroscopy (XPS). Cytotoxicity test was also performed. The electrochemical behavior of CoCrW alloy was compared in both studied media, from corrosion potential (Ecorr) to a 600 mV anodic overvoltage. From the electrochemical measurements it was observed that the CoCrW alloy in both media presents only generalized corrosion. SEM and EDS analysis showed that the alloy presents carbide niobium and silicon and manganese oxides as nonmetallic inclusions. XPS results indicated that cobalt does not significantly contribute to the passivating film formation. Cytotoxicity test showed no cytotoxic character of CoCrW alloy. These results suggest that the CoCrW alloy can be used as biomaterial to be applied as prosthesis in dental implants.

Resumo Estudos eletroquímicos, caracterização de superfície e teste de citotoxicidade in vitro foram realizados da liga CoCrW em meios de saliva artificial e NaCl 0,15 mol.L-1, com o objetivo de avaliar a sua aplicação como material de prótese dentária. Foram usadas como técnicas, curvas de polarização anódica, medidas cronoamperométricas, espectroscopia de impedância eletroquímica (EIE), microscopia eletrônica de varredura (MEV), espectroscopia por energia dispersiva de raios X (EDS) e espectroscopia fotoeletrônica de raios X (XPS). O teste de citotoxicidade também foi realizado. O comportamento eletroquímico da liga CoCrW foi comparado nos dois meios estudados desde o potencial de corrosão (Ecorr) até uma sobretensão anódica de 600 mV. Foi observado, a partir de medidas eletroquímicas, que a liga CoCrW se encontra passivada em uma ampla faixa de potencial e que a sobretensões mais elevadas apresenta apenas corrosão generalizada nos dois meios. Análises por MEV e EDS mostraram que a liga apresenta inclusões não metálicas de carbeto de nióbio, de óxidos de silício e de manganês. Os resultados de XPS indicaram que o cobalto não contribui significativamente para a formação do filme passivo. O teste de citotoxicidade mostrou que a liga CoCrW não se apresenta citotóxica. Estes resultados sugerem que a liga estudada pode ser usada como biomaterial a ser aplicado como prótese sobre implantes dentários.

In vitro re-hardening of artificial enamel caries lesions using enamel matrix proteins or self-assembling peptides

ABSTRACT Objectives To assess the re-hardening potential of enamel matrix derivatives (EMD) and self-assembling peptides in vitro, hypothesizing that these materials may increase the mineralization of artificial carious lesions and improve hardness profiles. Material and Methods Forty-eight enamel samples were prepared from extracted bovine lower central incisors. After embedding and polishing, nail varnish was applied, leaving a defined test area. One third of this area was covered with a flowable composite (non-demineralized control). The remaining area was demineralized in an acidic buffer solution for 18 d to simulate a carious lesion. Half the demineralized area was then covered with composite (demineralized control), while the last third was left open for three test and one control treatments: (A) Application of enamel-matrix proteins (EMD - lyophilized protein fractions dissolved in acetic acid, Straumann), (B) self-assembling peptides (SAP, Curodont), or (C) amine fluoride solution (Am-F, GABA) for 5 min each. Untreated samples (D) served as control. After treatment, samples were immersed in artificial saliva for four weeks (remineralization phase) and microhardness (Knoop) depth profiles (25-300 µm) were obtained at sections. Two-way ANOVA was calculated to determine differences between the areas (re-hardening or softening). Results Decalcification resulted in significant softening of the subsurface enamel in all groups (A-D). A significant re-hardening up to 125 µm was observed in the EMD and SAP groups. Conclusions This study showed that EMD and SAP were able to improve the hardness profiles when applied to deep demineralized artificial lesions. However, further research is needed to verify and improve this observed effect.

Preventive effect of toothpastes with MMP inhibitors on human dentine erosion and abrasion in vitro

ABSTRACT The use of gels and mouthrinses with MMP inhibitors (chlorhexidine, and green tea extract) was shown to prevent erosive wear. The aim of this study was to analyze the protective effect of toothpastes containing MMP inhibitors on dentine loss induced by erosion in vitro. Material and Methods Five groups each containing 12 specimens of human root dentine were prepared. The specimens were subjected to 1 min erosion by immersion in a cola drink, 4 times a day, for 5 d. Each day, after the first and last erosive challenges, the specimens were brushed for 15 s with a slurry of dentifrice and water (1:3) containing placebo, 1,100 ppm fluoride, 0.61% green tea extract, 0.12% chlorhexidine or 0.004% chlorhexidine (commercial toothpaste). Between the acid challenges, the specimens were stored in artificial saliva with remineralizing potential until the next treatment. Dentine loss was determined using profilometry. Data were analyzed using one-way ANOVA after log transform (p<0.05). Results The mean wear values (μm) were as follows: placebo 1.83±0.53; 0.61% green tea extract 1.00±0.21; fluoride 1.27±0.43; 0.12% chlorhexidine 1.19±0.30; and 0.004% chlorhexidine 1.22±0.46. There was a significant difference in wear between placebo and all the treatment toothpastes, which did not differ from each other. Conclusion The results suggest that toothpastes containing MMP inhibitors are as effective as those based on NaF in preventing dentine erosion and abrasion.

Estabelecimento de protocolos in vitro e in situ para estudos de erosão dentária / Establishment of in vitro and in situ protocols for dental erosion studies

O objetivo foi comparar uma formulação de saliva artificial com e sem mucina (in vitro) com a saliva humana (in situ) na inibição da desmineralização (subprojeto I) e no reendurecimeto de lesões de erosão (subprojeto II), e a influência do tipo de dispositivo intrabucal (mandibular X palatino) no desgaste erosivo do esmalte (subprojeto III). No subprojeto I, blocos de esmalte bovino foram selecionados pela dureza de superfície e randomizados entre os grupos: GI - saliva humana (n=30), GII - saliva artificial sem mucina (n=15), GIII - saliva artificial com mucina (n=15) e GIV - água deionizada (n=15). Quinze voluntários utilizaram o dispositivo palatino por um período 2 horas (GI). Nos grupos GII, GIII e GIV, os blocos foram imersos em suas respectivas soluções por um período de 2 horas. Imediatamente após, tanto os blocos do grupo in situ quanto dos grupos in vitro foram submetidos ao desafio erosivo inicial com ácido cítrico 1% (pH 3,6) por 4 minutos. A microdureza final foi mensurada para determinar a porcentagem de perda de dureza. No subprojeto II, os blocos, após seleção, foram erodidos in vitro e randomizados entre grupos como no subprojeto I. Para a erosão, os blocos foram imersos em ácido cítrico 1% (pH 3,6) por 4 minutos. A seguir, no grupo GI, 15 voluntários utilizaram dispositivos palatinos durante 2 horas. Nos outros grupos os blocos foram imersos nas salivas artificiais com (GIII) e sem mucina (GII) e água deionizada (GIV) por 2 horas. A precipitação de minerais sobre o esmalte foi avaliada por meio da porcentagem de recuperação de dureza. No subprojeto III, após seleção dos blocos pela dureza, os mesmos foram aleatorizados em 2 grupos (n=20): GI - dispositivo palatino e GII - dispositivo mandibular. A ciclagem consistiu na imersão dos dois dispositivos em ácido clorídrico 0,01 M (pH 2,3) por 2 minutos, 4X/dia durante 5 dias. A perda do esmalte foi avaliada por perfilometria e os voluntários responderam a um questionário quanto ao conforto dos dispositivos. Nos subprojetos I e II, os dados foram submetidos aos testes ANOVA e Tukey e no subprojeto III foi aplicado o Teste T pareado (p<0,05). Nos subprojetos I e II observou-se que todas as salivas estudadas foram capazes de promover uma recuperação de dureza do esmalte e nenhuma diferença foi encontrada entre elas (p<0,05). No ensaio de desmineralização, a saliva artificial com mucina e a saliva humana (in situ) promoveram menor perda de dureza, não mostrando diferença entre elas (p<0,05). No subprojeto III os resultados mostraram que os blocos localizados no dispositivo palatino (GI) apresentaram maior desgaste erosivo quando comparados aos do dispositivo mandibular (GII). Além disso, todos voluntários relataram maior conforto no uso do dispositivo palatino. Considerando que o dispositivo palatino é mais confortável e resultou em maior perda de esmalte quando comparado ao mandibular, sugere-se o uso de dispositivos palatinos em protocolos in situ que queiram mimetizar pacientes com alto risco de erosão dentária. Para estudos in vitro, a saliva com mucina mostrou-se como uma boa substituta à saliva humana.(AU)

The aim was to compare artificial saliva formulation with and without mucin (in vitro) with human saliva (in situ) on the inhibition of erosive demineralization (subproject I) and on the rehardening of erosion lesions (subproject II), and analyze the influence of the type of intraoral appliance (mandibular X maxillary) in enamel wear caused by erosive challenges (subproject III). In the subproject I, bovine enamel blocks were selected by initial surface hardness and randomized among the groups: GI - human saliva (n=30), GII - artificial saliva without mucin (n=15), GIII - artificial saliva with mucin (n=15) and GIV - deionized water (n=15). Fifteen volunteers wore palatal appliances for 2 hours (GI). In the GII, GIII and GIV groups, the blocks were immersed to the respective solutions for 2 hours. Subsequently, both in vitro and in situ blocks were subjected to initial erosive challenge in 1% citric acid (pH 3.6) for 4 minutes. Final enamel hardness was measured to determine the protective capacity of saliva tested by percentage of hardness loss. For the subproject II, after blocks selection, they were in vitro eroded and randomly among the groups as in subproject I. For erosion, the enamel blocks were immersed on 1% citric acid (pH 3.6) for 4 minutes. Then, in the GI, 15 volunteers wore palatal appliances for 2 hours. In the other groups the blocks were immersed in artificial saliva with (GIII) and without mucin (GII) and deionized water (GIV) for 2 hours. The minerals precipitation on the enamel was evaluated by the percentage of hardness recovery. On subproject III, after enamel blocks selection by surface hardness, they were randomly divided into 2 groups (n=20): GI - palatine appliance and GII - mandibular appliance. Erosive cycling consists in immersing of both devices in 0.01 M hydrochloric acid (pH 2.3) for 2 minutes, 4X/day during 5 days. The analysis of the wear was measured by profilometry and volunteers answered a questionnaire about the comfort of the devices. In the subprojects I and II, data were analyzed by one-way ANOVA and Tukeys test, and in the subproject III It was applied paired t-test (p <0.05). In subprojects I and II it was observed that all studied saliva promoted enamel rehardening and no difference was found between them (p <0.05). In the demineralization test, the artificial saliva with mucin and human saliva (in situ) provided lower enamel hardness loss, showing no difference between them (p<0.05). In the subproject III, the results showed that the specimens allocated in palatine appliance (GI) presented significantly higher erosive wear when compared to the specimens fixed in mandibular appliance (GII). In addition, all volunteers reported greater comfort in using the palatal device. Considering the palatal device is more comfortable and resulted in higher enamel loss when compared to the mandibular device, it is suggested the use of palatine appliances in in situ protocols who want to mimic a patient at high risk of dental erosion. For in vitro studies, the saliva with mucin might be a good substitute for human saliva.(AU)

Influência da erosão dentária na adesão de braquetes ortodônticos colados ao esmalte com diferentes materiais / The influence of dental erosion on bond strength of orthodontic brackets bonded to enamel with different materials

O diagnóstico das lesões incipientes de erosão em esmalte é difícil de ser realizado e, em situações clínicas, poderá ocorrer a colagem de braquetes em superfícies erodidas. Este trabalho in vitro avaliou a adesão de braquetes ortodônticos ao esmalte dentário bovino hígido e previamente erodido, utilizando dois materiais para colagem. Os fatores em estudo foram condição prévia do esmalte em 2 níveis (com e sem erosão) e tipo de material de colagem em 2 níveis (Transbond XT e Fuji Ortho LC). A amostra foi composta por 160 coroas de incisivos bovinos, sendo metade dela submetida a desafio erosivo para formação de lesões artificiais de erosão e a outra metade permaneceu hígida. Na ciclagem erosiva as coroas foram imersas 8X/dia em Coca-cola® (10 min), seguido da imersão em saliva artificial (2 h), durante 5 dias. A outra metade da amostra ficou em saliva artificial por 5 dias. Braquetes de incisivo central superior foram colados às coroas hígidas (H) e erodidas (E), seguindo orientações dos fabricantes de cada material. As variáveis de resposta foram resistência ao cisalhamento e índice de remanescente adesivo (IRA). Os dados de resistência ao cisalhamento foram analisados por ANOVA 2 critérios e Teste de Tukey (p<0,05). Os resultados, expressos em megapascal, não mostraram diferenças na resistência ao cisalhamento entre esmalte erodido e hígido, tanto no grupo colado com resina (RH = 15,25 +3,72; RE = 15,79 +4,41) quanto colado com ionômero (IH = 10,70 +3,73; IE = 11,26 +3,70). A resina apresentou resistência à colagem superior ao ionômero. Na comparação do índice de remanescente adesivo, por meio do teste de Mann Whitney, o esmalte erodido apresentou valores mais altos para o IRA, evidenciando uma maior quantidade de material remanescente no esmalte, tanto no grupo colado com resina (p=0,044) quanto com ionômero (p<0,001). Conclui-se que a presença da lesão de erosão não interfere na resistência ao cisalhamento de braquetes colados ao esmalte tanto com resina quanto com cimento de ionômero de vidro. No entanto, independentemente do material de colagem, o índice de remanescente adesivo evidenciou uma maior adesão ao esmalte com erosão.(AU)

The diagnosis of initial erosion lesions on enamel is difficult and in some clinical situations, the professional bonds brackets to eroded surfaces without noting.This in vitro study evaluated the bond strength of orthodontic brackets bonded to eroded and sound bovine enamel with two different materials. The factors under study were enamel condition in two levels (with and without erosion) and type of bonding material in two levels (Transbond® XT and Fuji Ortho LC). The sample consisted of 160 bovine lower incisor teeth, half of the specimens was subjected to erosive challenge to form artificial erosive lesions and the other half remained sound. In the erosive cycling tooth crowns were immerged 8x/day in Coca-cola® (10 min), followed by immersion in artificial saliva for (2 h), for 5 days. The other half of the sample was maintained in artificial saliva for 5 days. At sequence, brackets were bonded to eroded (E) and sound (S) enamel, according to manufacturing recommendations of each material. The response variables were shear bond strength and adhesive remnant index (ARI). Shear bond strength data were analyzed by Two-way ANOVA and Tukeys test (p<0,05). The results, expressed in megapascal, did not show any difference between eroded and sound enamel, in both composite resin (RS = 15,25 +3,72; RE = 15,79 +4,41) and glass ionomer (IS = 10,70 +3,73; IE = 11,26 +3,70) groups. Composite resin showed higher shear bond strength compared to glass ionomer cement. In the comparison of adhesive remnant index using Mann Whitney test, eroded enamel presented higher scores for ARI, showing greater amount of material remaining on enamel, in both resin (p=0,04) and ionomer (p<0,001) groups. It was concluded that the presence of erosion lesions did not interfere on shear bond strength of brackets bonded to enamel with composite resin or glass ionomer cement. However, independently of the bonding material, adhesive remnant index showed higher bond strength to eroded enamel.(AU)

Effect of green tea as a protective measure against dental erosion in coronary dentine

Abstract The aim of this study was to evaluate the effect of green tea as a protective measure on eroded dentin. Disks of human coronary dentin were selected based on surface hardness and randomly assigned to 3 groups (n = 10): DW - distilled water, CHX - 0.2% chlorhexidine digluconate, and GT - green tea. The disks were allowed to acquire pellicle for 2 hours and were then subjected to 3 cycles per day of demineralization (C6H8O7 0.05 M, pH 3.75, 60 s), treatment (DW or CHX or GT, 5 min) and remineralization (artificial saliva, 60 min) over a period of 3 days. Changes in the dentin were determined by loss of surface hardness (%SHL) and mechanical profilometry analysis at the end of each day. Data were analyzed by two-way ANOVA followed by Tukey’s test for %SHL and profilometry (p < 0.05). Significant reductions in dentin hardness loss were observed only for the CHX group when compared to the DW group (p < 0.05). However, there was no significant difference between the CHX and GT groups (p > 0.05). A significant difference was observed between DW and GT treatments for wear and roughness measurements (p < 0.05). The green tea extract solution was able to reduce the wear and roughness caused by dentin erosion under the conditions of this study.

Thickness and nanomechanical properties of protective layer formed by TiF4 varnish on enamel after erosion

Abstract The layer formed by fluoride compounds on tooth surface is important to protect the underlying enamel from erosion. However, there is no investigation into the properties of protective layer formed by NaF and TiF4 varnishes on eroded enamel. This study aimed to evaluate the thickness, topography, nanohardness, and elastic modulus of the protective layer formed by NaF and TiF4 varnishes on enamel after erosion using nanoindentation and atomic force microscopy (AFM). Human enamel specimens were sorted into control, NaF, and TiF4 varnish groups (n = 10). The initial nanohardness and elastic modulus values were obtained and varnishes were applied to the enamel and submitted to erosive challenge (10 cycles: 5 s cola drink/5 s artificial saliva). Thereafter, nanohardness and elastic modulus were measured. Both topography and thickness were evaluated by AFM. The data were subjected to ANOVA, Tukey's test and Student's t test (α = 0.05). After erosion, TiF4 showed a thicker protective layer compared to the NaF group and nanohardness and elastic modulus values were significantly lower than those of the control group. It was not possible to measure nanohardness and elastic modulus in the NaF group due to the thin protective layer formed. AFM showed globular deposits, which completely covered the eroded surface in the TiF4 group. After erosive challenge, the protective layer formed by TiF4 varnish showed significant properties and it was thicker than the layer formed by NaF varnish.

Color stability of ceramic brackets immersed in potentially staining solutions

OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions.METHODS: Ninety brackets were divided into 5 groups (n = 18) according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva). The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA), Radiance (American Orthodontics, Sheboygan, WI, USA), Mystique (GAC International Inc., Bohemia, NY, USA) and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA). Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0), 24 hours (T1), 72 hours (T2), as well as 7 days (T3) and 14 days (T4) of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%.RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations.CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions.

OBJETIVO: avaliar a estabilidade da cor de cinco tipos de braquetes cerâmicos após imersão em soluções potencialmente corantes.MÉTODOS: noventa braquetes foram divididos em 5 grupos (n = 18) de acordo com a marca comercial dos braquetes e as soluções em que foram imersos (café, vinho tinto, Coca-Cola e saliva artificial). Os baquetes avaliados foram Transcend (3M / Unitek, Monrovia, CA, EUA), Radiance (American Ortodontia, Sheboygan, WI, EUA), Mystique (GAC International Inc., Bohemia, NY, EUA) e Luxi II (Rocky Mountain Orthodontics, Denver, CO, EUA). Alterações cromáticas foram analisadas com o uso de um espectrofotômetro de reflectância e por inspecção visual, em cinco intervalos de tempo específicos. Os momentos de avaliação foram: 24 horas (T1), 72 horas (T2), 7 dias (T3) e 14 dias (T4) de imersão nas soluções. Os resultados foram submetidos à avaliação estatística com análise de variância e correção de Bonferroni, bem como a uma análise do perfil multivariada para amostras independentes e pareadas, com nível de significância de 5%.RESULTADOS: a duração do período de imersão influenciou na alteração de cor de todos os braquetes testados, mesmo admitindo-se que essas alterações nem sempre puderam ser observadas visualmente. Diferentes comportamentos foram observados em cada solução de imersão; no entanto, braquetes imersos em um mesmo tipo de solução progrediram de forma semelhante, apesar das pequenas variações.CONCLUSÕES: a coloração se tornou mais intensa com o tempo, e todos os braquetes sofreram alteração de cor nas soluções imersas.

Avaliação da interação do TiF4 com a hidroxiapatita e esmalte bem como o efeito sobre a des-remineralização do esmalte dentário com lesão de cárie artificial in situ / Interaction of TiF4 varnish with enamel and hydroxyapatite and its effect on the de-remineralization of pre-demineralized enamel in situ

Este estudo teve como o objetivo avaliar in vitro o efeito do tratamento com vernizes de tetrafluoreto de titânio (TiF4) e fluoreto de sódio (NaF) (ambos com 0,95%, 1,95% e 2,45% F) sobre 1) a quantidade de F- liberada em água deionizada e saliva artificial, por período de 12h; 2) os tipos de compostos formados pela interação com a hidroxiapatita (neste caso, com soluções ao invés dos vernizes); 3) a porcentagem de elementos presentes na superfície do esmalte bovino e humano, hígidos (H) e desmineralizados (DES); 4) a quantidade de CaF2 sobre a superfície do esmalte bovino e humano, H e DES. Adicionalmente, 5) o efeito dos vernizes de TiF4 e NaF sobre a remineralização do esmalte bovino, em diferentes condições in situ, foi avaliado. Para etapa 1, a liberação de F- foi quantificada por eletrodo de íon específico. Na etapa 2, pó de HAP produzido por precipitação foi tratado com soluções fluoretadas. Os compostos formados foram avaliados por espectroscopia de infravermelho e difração de raios-X. Nas etapas 3 e 4, as superfícies tratadas com os vernizes foram analisadas por MEV- EDAX e por biópsias básicas, respectivamente. Vinte voluntários (n final=17) participaram do ensaio in situ com 3 fases cruzadas, os quais utilizaram aparelhos palatinos contendo amostras de esmalte bovino desmineralizadas tratadas com vernizes de TiF4, NaF ou placebo. As amostras foram submetidas a diferentes condições de des-remineralização (presença ou não de tela plástica; variação da frequência de aplicação de sacarose 20%) e à exposição ao dentifrício fluoretado. O volume mineral e profundidade da lesão foram avaliados por microradiografia transversal (TMR). 1) Os vernizes de TiF4 (1,95 e 2,45% F) liberaram mais fluoreto comparados aos vernizes de NaF tanto em água como em saliva artificial, sendo a diferença significativa nas primeiras 6h de contato (p<0,0001). 2) O TiF4 causou alteração na estrutura da HAP e induziu à formação de novos compostos como TiO2 e Ti (HPO4)2. 3)...

This study aimed to evaluate the in vitro effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) varnishes (both with 0.95%, 1.95%, 2.45% F) treatment on the 1) F- release in deionized water and artificial saliva for 12h period; 2) types of compounds formed by the interaction with hydroxyapatite (in this case, solutions were tested instead of varnishes); 3) percentage of the elements on bovine and human, sound (S) and demineralized (DE), enamel surface; 4) F- uptake (CaF2 deposition) on human and bovine, S and DE, enamel surface. Additionally, 5) the effect of TiF4 and NaF varnishes on bovine enamel remineralization, in different in situ conditions, was assessed. In study 1, the F- release was measured by ion specific electrode. In study 2, HAP powder, produced by precipitation, was treated with fluoride solutions. The compounds formed were evaluated by infrared spectroscopy and X-ray diffraction. In studies 3 and 4, the surfaces treated with the varnishes were analyzed by SEM-EDAX and basic biopsies, respectively. Twenty volunteers (final n=17) participated of the in situ study with 3 crossover phases, in which they wore palatal appliances containing bovine demineralized enamel samples treated with TiF4, NaF or placebo varnishes. The samples were subjected to different de-remineralization conditions (presence or absence of plastic mesh and variation in frequency of application of 20% sucrose) and exposure to fluoride dentifrice. Themineral content and lesion depth were evaluated by transverse microradiography (TMR). 1) The TiF4 varnishes (1.95 and 2.45% F) released more F- compared to NaF varnishes in both water and artificial saliva, and significant difference was found in the first 6h (p<0.0001). 2) The TiF4 caused change in the HAP structure and induced the formation of new compounds such as TiO2 and Ti (HPO4)2. 3) The TiF4 varnishes induced the formation of a coating layer rich in Ti and F, with microcracks in its extension, on the enamel...

Avaliação da interação do TiF4 com a hidroxiapatita e esmalte bem como o efeito sobre a des-remineralização do esmalte dentário com lesão de cárie artificial in situ / Interaction of TiF4 varnish with enamel and hydroxyapatite and its effect on the de-remineralization of pre-demineralized enamel in situ

Este estudo teve como o objetivo avaliar in vitro o efeito do tratamento com vernizes de tetrafluoreto de titânio (TiF4) e fluoreto de sódio (NaF) (ambos com 0,95%, 1,95% e 2,45% F) sobre 1) a quantidade de F- liberada em água deionizada e saliva artificial, por período de 12h; 2) os tipos de compostos formados pela interação com a hidroxiapatita (neste caso, com soluções ao invés dos vernizes); 3) a porcentagem de elementos presentes na superfície do esmalte bovino e humano, hígidos (H) e desmineralizados (DES); 4) a quantidade de CaF2 sobre a superfície do esmalte bovino e humano, H e DES. Adicionalmente, 5) o efeito dos vernizes de TiF4 e NaF sobre a remineralização do esmalte bovino, em diferentes condições in situ, foi avaliado. Para etapa 1, a liberação de F- foi quantificada por eletrodo de íon específico. Na etapa 2, pó de HAP produzido por precipitação foi tratado com soluções fluoretadas. Os compostos formados foram avaliados por espectroscopia de infravermelho e difração de raios-X. Nas etapas 3 e 4, as superfícies tratadas com os vernizes foram analisadas por MEV- EDAX e por biópsias básicas, respectivamente. Vinte voluntários (n final=17) participaram do ensaio in situ com 3 fases cruzadas, os quais utilizaram aparelhos palatinos contendo amostras de esmalte bovino desmineralizadas tratadas com vernizes de TiF4, NaF ou placebo. As amostras foram submetidas a diferentes condições de des-remineralização (presença ou não de tela plástica; variação da frequência de aplicação de sacarose 20%) e à exposição ao dentifrício fluoretado. O volume mineral e profundidade da lesão foram avaliados por microradiografia transversal (TMR). 1) Os vernizes de TiF4 (1,95 e 2,45% F) liberaram mais fluoreto comparados aos vernizes de NaF tanto em água como em saliva artificial, sendo a diferença significativa nas primeiras 6h de contato (p<0,0001). 2) O TiF4 causou alteração na estrutura da HAP e induziu à formação de novos compostos como TiO2 e Ti (HPO4)2. 3)...

This study aimed to evaluate the in vitro effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) varnishes (both with 0.95%, 1.95%, 2.45% F) treatment on the 1) F- release in deionized water and artificial saliva for 12h period; 2) types of compounds formed by the interaction with hydroxyapatite (in this case, solutions were tested instead of varnishes); 3) percentage of the elements on bovine and human, sound (S) and demineralized (DE), enamel surface; 4) F- uptake (CaF2 deposition) on human and bovine, S and DE, enamel surface. Additionally, 5) the effect of TiF4 and NaF varnishes on bovine enamel remineralization, in different in situ conditions, was assessed. In study 1, the F- release was measured by ion specific electrode. In study 2, HAP powder, produced by precipitation, was treated with fluoride solutions. The compounds formed were evaluated by infrared spectroscopy and X-ray diffraction. In studies 3 and 4, the surfaces treated with the varnishes were analyzed by SEM-EDAX and basic biopsies, respectively. Twenty volunteers (final n=17) participated of the in situ study with 3 crossover phases, in which they wore palatal appliances containing bovine demineralized enamel samples treated with TiF4, NaF or placebo varnishes. The samples were subjected to different de-remineralization conditions (presence or absence of plastic mesh and variation in frequency of application of 20% sucrose) and exposure to fluoride dentifrice. Themineral content and lesion depth were evaluated by transverse microradiography (TMR). 1) The TiF4 varnishes (1.95 and 2.45% F) released more F- compared to NaF varnishes in both water and artificial saliva, and significant difference was found in the first 6h (p<0.0001). 2) The TiF4 caused change in the HAP structure and induced the formation of new compounds such as TiO2 and Ti (HPO4)2. 3) The TiF4 varnishes induced the formation of a coating layer rich in Ti and F, with microcracks in its extension, on the enamel...

Bonding stability of adhesive systems to eroded dentin

This in vitrostudy evaluated the immediate and 6 months microshear bond strength (µSBS) of different adhesive systems to sound and eroded dentin. Sixty bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated into two groups: sound dentin (immersion in artificial saliva) and eroded dentin (erosive challenge following a pH cycling model comprising 4 ×/day Sprite Light® drink for 10 days). Then, specimens were reassigned according to the adhesive system: etch-and-rinse adhesive (Adper Single Bond), two-step self-etch system (Clearfil SE Bond), or one-step self-etch adhesive (Adper Easy One). Polyethylene tubes with an internal diameter of 0.76 mm were placed over pre-treated dentin and filled with resin composite (Z250). Half of the specimens were evaluated by the µSBS test after 24 h, and the other half 6 months later, after water storage at 37°C. Failure mode was evaluated using a stereomicroscope (400×). Data were analyzed by three-way repeated measures analysis of variance and Tukey’s post hoc tests (α = 0.05). After 6 months of water aging, marked reductions in µSBS values were observed, irrespective of the substrate. The µSBS values for eroded dentin were lower than those obtained for sound dentin. No difference in bonding effectiveness was observed among adhesive systems. For all groups, adhesive/mixed failure was observed. In conclusion, eroded dentin compromises the bonding quality of adhesive systems over time.

How erosive drinks and enzyme inhibitors impact bond strength to dentin

Concern has been raised about the bonding of restorative procedures to an erosive lesion, given the change in organic and inorganic composition and structure of this substrate. This in vitro study evaluated the effect of erosive drinks and an enzyme inhibitor (2% chlorhexidine digluconate – 2% CHX) on bond strength to dentin. Sixty sound human third molars were selected, and the occlusal enamel was flattened, exposing the dentin surface. The specimens were randomly divided into three groups: AS-Artificial saliva (control group), RC- Regular Cola and ZC- Zero Cola. Twenty specimens were immersed in their respective solution for 1 minute, 3 times a day, over the course of 5 days. After acid etching and before bonding with Adper Single Bond 2, half of the samples of each group (n = 10) were treated with 2% CHX, whereas the other half (n = 10) were not, forming the control group (CONV). All the specimens were restored with Filtek Z250 composite resin filled in Tygon tubes (0.48 mm2), yielding six microcylinders for microshear bond strength testing. Three composite resin microcylinders of each specimen were tested after 1 month, and the remaining microcylinders were tested after 6 months. Failure modes were determined using a stereomicroscope (40x). The data were statistically analyzed by three-way ANOVA and Tukey tests (α = 0.05). Overall bonding was reduced after 6 months, regardless of treatment. The 2% CHX enhanced bond strength after 1 month only in the ZC group, and did not enhance bonding performance to demineralized dentin by erosive protocol after 6 months in any group.