AVALIAÇÃO ULTRAESTRUTURAL DO ESMALTE APÓS CLAREAMENTO DENTAL ASSOCIADO COM FLUOR

Abstract

The objective of this study was to evaluate the effects of two high concentration bleaching agents on human enamel surface, nanohardness and roughness. It was used 43 enamel blocks (3 mm2) that were ground flat (600 to 2000 grit) and polished with polishing pastes (1 and ¼). After if specimens were randomly divided into groups, according to the bleaching procedure: 1- Hydrogen peroxide 35% (HPF) and application of fluoride 1.23%, 2- Hydrogen peroxide 38% (OP) with fluoride in its composition. Bleaching agents were used according to manufacturer’s instructions.Three methodologies were utilized: nanohardness to observe surface hardness and elastic modulus; Atomic Force Microscopy (AFM) to observe surface roughness (Ra-Rz) and Scanning Electron Microscopy (SEM) to observe the enamel surface effects.The data had a normal distribution according to D’Agostino normality test, the nanohardness and AFM, were analyzed using one factor ANOVA Tukey’s test with significance level α=0,05 , and SEM data were transformed into percentage. Group OP had a decrease in the elastic modulus (GPa) after bleaching (098.2 ± 2.6), which was recovered at 14 days (102.7 ± 3.3). An increased roughness (Ra) (37.9±28.6 %) was observed and group HPF had an increased erosion on enamel surface (67%). It was concluded that fluoride incorporated into the bleaching agent or its topical application in no deleterious effects nanohardness on enamel surface. The fluoride incorporated results into the bleaching gel, a decreased the elastic modulus immediately after bleaching. Topical application of fluoride after using the bleaching agents increased the values of roughness and erosion of tooth enamel.