Influência do tratamento da dentina com hipoclorito de cálcio sobre a infiltração marginal de restaurações de resina composta

Abstract

The use calcium hypochlorite (CaOCl) has been proposed for dentin deproteinization before applying adhesive system by microtensile testing. This study aimed to evaluate microleakage (ML) of Class V composite resin restorations after treating the dentin with different concentrations of CaOCl. The following hypotheses were analyzed: deproteinization (DP) with CaOCl, as well as its concentration does not influence ML values. Intact human third molars received two cavities at the lingual/palatal and buccal aspects measuring 2.0 mm in high x 3.0 mm in width x 2.0 mm in depth and were randomly divided into 5 groups of 20 cavities each, according to the dentin treatment (n = 20): G1 (control 1) - no dentin treatment; G2 (control 2) - 10% NaOCl for 30 s; G3 - 10% CaOCl for 30 s; G4 - 15% CaOCl for 30 s; G5 - 20% CaOCl for 30 sec. The cavities were restored with an acetone based adhesive system and a light cured composite resin. The samples were subjected to 5000 cycles of thermal cycling at 5 and 55 C, sealed with nail varnish, immersed in the methylene blue dye for 4 h and sectioned in the middle of the restoration to produce two plates with 1 mm in thickness and four surfaces for evaluation. Two examiners evaluated the samples using a stereomicroscope at 20X magnification and attributed scores since 0 to 3 depending on the degree of infiltration. ML data were evaluated by Kruskal-Wallis test at 5% significance level which showed no statistically significant difference between the experimental groups (p = 0.68). It was concluded that 10, 15 or 20% of CaOCl lead to ML levels similar to DP technique with 10% NaOCl or conventional hybridization which is in agreement with the hypotheses of this study