Study of the effect of H2O2 used in whitening treatments on human enamel wear resistance

Abstract

Tooth whitening treatments are based on the application of bleaching agents on the teeth surface, which can impair teeth health, due to its effect on enamel properties. The present work has the purpose of studying the effect of pH of H2O2 solutions on wear resistance of teeth. Friction coefficient, enamel microhardness, morphology and topography were also evaluated to better understand the induced changes. Three pH values (2, 4 and 6) of H2O2 solution were tested. First, human molars and premolars were disinfected, polished, cut in four equal pieces and darkened in a black tea solution. After, the teeth samples were bleached in 30% H2O2 solution with the different pH values. Vickers microhardness, surface roughness and wear measurements were performed before and after bleaching. The results showed that the enamel wear resistance depends on the solution pH: the lowest wear resistance was obtained for the sample bleached with H2O2 at pH 2.