Effect of dental bleaching on the microleakage of class V composite restorations

Abstract

Purpose: The purpose of this study was to evaluate the effect of bleaching agents on the microleakage of Class V composite restorations. Methods: Class V cavities were prepared on the buccal surface of 30 bovine incisors with the incisal margin located in enamel and the gingival margin located in dentin. The cavities were restored using the adhesive system Adper SingleBond2 and the composite Filtek Z250. After 24 h, the samples were finished, polished, thermocycled (500 cycles), and randomly divided into three groups (n=10): (G1) bleached with 35% Hydrogen Peroxide, (G2) bleached with 10% Carbamide Peroxide, and (G3) control group. After bleaching, the samples were coated with wax and nail polish varnish, immersed in 0.5% basic fuchsin for 24 h, and cut parallel to the long axis of the tooth at three reference points on the restoration. The slices were photographed to evaluate the dye penetration and scored for microleakage. Data were analyzed by Kruskal-Wallis test. Results: Microleakage was absent in more than 90% and 53% of the margins located in enamel and dentin, respectively. No significant difference in microleakage was found between control and experimental groups. Conclusion: The bleaching agents tested had no effect on microleakage at the adhesive interface in enamel or dentin.