Potencial clareador de diferentes técnicas de clareamento dental: efeitos em esmalte em resina composta

Abstract

The purpose of this study was to investigate the effect of the concentration of different bleaching gels on the color alteration of enamel samples restored with resin composite. Thirty-two bovine incisors were prepared into square-shaped samples (4 × 4 × 2 mm), which were bonded to resin composite (Opallis; FGM), resulting in tooth/resin samples (8 × 4 × 2 mm). The initial color of each sample was evaluated using a digital spectrophotometer (Vita Easyshade) and the CIE L * a * b * system. Next, all samples were stained in coffee solution for 7 days; color analysis was performed, followed by prophylaxis and superficial stain removal, and new color evaluation. So, each sample was randomly distributed in 4 groups (n=8), according to the product/bleaching technique used: Controle – none bleaching gel was applied; Consultório – gel containing 35% of hydrogen peroxide (Whiteness HP; FGM); Caseira – gel containing 16% of carbamide peroxide (Whiteness Perfect; FGM); and Caneta – gel containing 0,1% of hydrogen peroxide (Colgate Luminous White Advanced; Colgate). Each product was applied following the manufacturer instructions for use, during 3 weeks. The color of each sample was monitored weekly. All data were analyzed using ANOVA for repeated measures and Tukey (α=5%). The bleaching potential was superior for the enamel/dentin samples as compared to resin composite. The Consultório and Caseira bleaching techniques showed similar bleaching effect between each other, but superior to the Caneta bleaching technique. The Caneta bleaching technique resulted in minimun bleaching effect in enamel/dentin and only after 3 weeks of product application. Overall, the Caneta bleaching technique demonstrated color change values similar to the Control group. In conclusion, the contact time between the bleaching gel and the substrate seems to have more importance to the bleaching potential when compared to the concentration of the bleaching agent itself.