Evaluation of mineral content of tooth enamel after application violet led associated with 35% hydrogen peroxide

Abstract

Background: The aim of this study was to evaluate the microhardness and quantify the presence of minerals (Calcium and Phosphorous) of tooth enamel submitted to bleaching with violet LED light, either associated with 35% hydrogen peroxide gel, or not. Methods: Bovine incisors were selected and divided into 4 Groups according to the bleaching technique used: C- Without bleaching (Control); VL- violet LED; HP- 35% Hydrogen Peroxide; HP+VL- 35% Hydrogen Peroxide + violet LED. The response variables were surface microhardness (n = 12), Energy Dispersive Spectroscopy (EDS) (n = 6) and scanning electron microscopy (SEM) (n = 3). Results: The 2-way ANOVA test with repeated measures showed that there was difference in the microhardness values of enamel in the specimens in all of the Groups when the values measured in the initial and final time intervals were compared, however, without significant differences between the values of the different treatments in both time intervals. The results with reference to EDS were analyzed with the 1-way ANOVA test. There was difference among the Groups only in the Ca%, with Group HP obtaining the lowest values, with significant difference from those of the C Group. SEM images showed a smooth, homogeneous enamel surface and similarity among the Groups, irrespective of the treatment performed. Conclusions: Therefore, it was concluded that the changes caused in enamel by the use of violet LED Light, either associated with 35% hydrogen peroxide, or not, did not differ from those of non-bleached tooth enamel, showing absence of harm to the mineral content of tooth enamel resulting from the use of violet LED.