Effect of bleaching gels formulated with sodium trimetaphosphate nano-sized on the color alteration, mechanical and morphological properties of dental enamel

Abstract

The objective of this study will be to evaluate in vitro the addition of a new bleaching agent containing sodium trimetaphosphate (TMP) nano-sized associated with 0.1% sodium fluoride and 35% hydrogen peroxide on color alteration, enamel mechanical and morphological properties. The bleaching gels will be: 1) 35% hydrogen peroxide (HP); 2) HP + 0.1% NaF (HP/F); 3) PH + 1% nano TMP (HP/TMP); 4) HP + 0.1% NaF + 1% TMP nano (HP/F/TMP) and 5) HP Blue 35% (FGM - Odontological Products: HP). The gels will be applied only once, during 3 sessions of 40 minutes / session, every 7 days, totaling 21 days. Before applying the gels and throughout the experiment, the discs will be treated with fluoride dentifrice of 1100 ppm twice a day, the discs will remain in artificial saliva, which will be changed daily. Then, the color change will be evaluated by quantified reflection spectrophotometry and the final surface hardness (SHF) will be determined to calculate the percentage of surface hardness loss (% SH), integrated subsurface hardness loss (”KHN), surface roughness (Ru), morphological analysis by Scanning Electron Microscopy (SEM) and X-ray Dispersive Energy (EDX). Variables with normal and homogeneous distribution will be subjected to analysis of variance (p <0.05). Otherwise, they will be submitted to the Kruskal-Wallis test (p <0.05). The multiple comparison test will be Student-Newman-Keuls. (AU)