Effectiveness of home and in-office bleaching, in depth, with bleaching agents at different temperatures

Abstract

The aim of this study is to evaluate the bleaching treatment efficacy on color changes of enamel and opposite dentin exposed to different bleaching protocols. For this, the study will be divided in two experiments. For Experiment 1, the efficacy of bleaching treatment will be evaluated, varying the concentration of bleaching agents and samples thickness. Fifty fragments of bovine incisors, previously stained with a black tea solution, will be used. The samples will be randomly divided in 10 groups (n=5), in accordance with bleaching agents (10% carbamide peroxide - Whiteness Perfect, 4% - Whiteness Class, 20% - Whiteness HP Blue and 35% - Whiteness HP Blue and Whiteness HP Maxx hydrogen peroxide), and sample thickness (2mm and 3,5mm). For Experiment 2, the color changes of the specimens will be evaluated after treatment with the same protocols used in the Experiment 1, varying the temperature of the gels (22°C and 24°C). For this, fifty fragments of bovine incisors will be randomly divided in 10 groups (n=5), in accordance with bleaching agents cited above. The efficacy of bleaching will be measured using a spectrophotometer and sent to a software (CIE Lab). For both experiments, the color readings of enamel and opposite dentin will be performed before and after the staining, and after each bleaching session. Three bleaching sessions will be performed. In addition, two samples of each group will have the enamel surface evaluated in scanning electronic microscopy. The results will be submitted to ANOVA followed by the Tukey test (5%) in cases of normality and homogeneity of the data. (AU)