RESUMO
Objetivo: Avaliar o efeito da clorexidina (CLX) na umectabilidade da dentina hígida e afetada por cárie por um sistema adesivo convencional simplificado. Material e Método: Foram preparadas superfícies planas de dentina em 60 molares hígidos, dos quais 30 foram artificialmente cariados. Para cada condição de substrato, hígido e afetado por cárie, as superfícies foram divididas em 3 grupos (n=10): com smear layer (SL), sem SL impregnada com água e sem SL impregnada com CLX. A remoção da SL foi realizada pela aplicação de ácido fosfórico por 15 s. Sobre a dentina desmineralizada foram aplicados 20 uL de água destilada ou digluconato de CLX a 2% por 60 s. Em seguida, uma gota do sistema Single Bond 2 foi depositada sobre cada superfície. Ângulos de contato entre a superfície da dentina e o adesivo foram mensurados por meio de um goniômetro e os dados submetidos aos testes de ANOVA e Tukey (?=0,05). Resultados: Maiores ângulos de contato foram obtidos sobre a dentina hígida em comparação a afetada por cárie (p<0,05), independente do tratamento da superfície. Para ambos os substratos, ângulos de contato estatisticamente superiores foram obtidos para a dentina coberta com SL (p<0,05). A remoção da SL resultou em redução significante dos ângulos (p<0,05) e nenhuma diferença foi encontrada entre os ângulos produzidos sobre a dentina desmineralizada impregnada por água ou por CLX (p>0,05). Conclusão: A umectabilidade da dentina afetada por cárie foi maior do que a da dentina hígida, sendo que a mesma não foi influenciada pela aplicação de clorexidina.
Aim: To evaluate the effect of chlorhexidine (CHX) on the wettability of sound and caries affected dentin by a simplified adhesive system. Material and Methods: Flat coronal dentin surfaces were produced on 60 sound molars, 30 of which were artificially decayed. The teeth were divided randomly into 3 groups (n = 10) with smear layer (SL), without SL impregnated with water and without SL impregnated with chlorhexidine. The SL removal was performed by phosphoric acid etching for 15 s. 20 uL of distilled water or 2% chlorhexidine digluconate were applied on the demineralized dentin for 60 s. Then, a drop of Single Bond 2 was deposited on each surface. Contact angles between dentin surface and adhesive was measured by means of a goniometer and data were submitted to ANOVA and Tukey tests (? = 0.05). Results: Higher contact angles were obtained on sound versus caries affected dentin (p <0.05), regardeless of the surface treatment. For both substrates, contact angles statistically higher were obtained for dentin covered with SL (P <0.05). The SL removal resulted in significant reduction of the angles (P <0.05) and no difference was found among angles produced on demineralized dentin impregnated with water or chlorhexidine (p> 0.05). Conclusion: Caries affected dentin wettability was higher than sound dentin and that characteristic was not influenced by chlorhexidine application.
RESUMO
The aim of this study was to evaluate the mechanical stability of resin-dentin bonds produced in vivo in the presence of chlorhexidine. Children presenting at least one pair of contralateral primary molars with occlusal carious lesions were enrolled in the study. After cavity preparation and phosphoric acid etching, dentin was treated with 5 microl of either 2% chlorhexidine (experimental group) or deionized water (control group) [corrected].Thirteen pairs of teeth were restored and were collected after physiological exfoliation. The periods in oral function after restoration were divided as follows: up to 30 d; and 1-5, 10-12, and 18-20 months. Beam-shaped specimens (0.81 mm(2)) were obtained and subjected to microtensile bond-strength testing. A significant decrease of the bond strength was observed in the control group starting at the 1-5 month period (30.6%), while in the experimental group this decrease started only after 10-12 months of function (26.3%). The use of chlorhexidine as an adjuvant to the adhesion to dentin did not produce any detrimental effect to the immediate bond strength and was capable of reducing the rate of resin-dentin bond degradation within the first few months after restoration.