Effect of violet led associated with low-concentration hydrogen peroxide on enamel surface roughness

Abstract

Aim: The present study aimed to assess in vitro the effect of violet LED in tooth bleaching techniques associated or not with low-concentration hydrogen peroxide gel on enamel surface roughness. Methods: Fifty-two enamel fragments of bovine teeth were flattened and polished (4x4x3 mm) and divided into four groups according to bleaching treatment: VL- Violet LED; HP- 7.5% hydrogen peroxide; HP+VL- 7.5% hydrogen peroxide + violet LED; C- No bleaching (control). Before the treatments, all specimens were immersed in 20 mL of black tea for six days, changing solutions every 24 h to simulate the staining of specimens. Forty fragments were used to analyze surface roughness (n=10) and 12 fragments were used for the morphological analysis (SEM) (n=3). Results: The data were submitted to one-way ANOVA and a post-hoc Tukey test. The lower roughness values was observed for the group that did not receive bleaching treatment (C), differing significantly only from the group bleached with 7.5% hydrogen peroxide + violet LED (HP+VL) (p=0.0077). The remaining groups did not show significant differences in roughness values (p>0.05). The scanning electron microscopy analysis showed irregularities on the enamel surface regardless of the treatment received. Conclusion: The results showed that bleaching treatments with violet LED associated with low-concentration hydrogen peroxide gels (7.5%) increase the surface roughness of tooth enamel.