Color stability of dental enamel bleached with violet LED associated with or without Low concentration peroxide gels

摘要

Background: This study aimed to evaluate the in vitro color of dental enamel bleached with the violet LED, associated with or without low-concentration of peroxide; analyzed in two time intervals: 24 h later and 6 months after the treatment.Methods: Ninety fragments of bovine teeth (6 & times; 6 mm and 3 mm thick) were randomly divided into 6 groups according to bleaching treatment: NB & ndash; no bleaching, VL & ndash; Violet LED, HP-7.5 % hydrogen peroxide, H P + VL & ndash; 7.5 % hydrogen peroxide + violet LED, CP & ndash; 22 % carbamide peroxide, CP + VL & ndash; 22 % carbamide peroxide+ violet LED. The color change was analyzed by using a spectrophotometer, at time intervals of 24 h and 6 months after performing the bleaching techniques (n= 12). Scanning electron microscopy (SEM) was performed to veri f y the enamel surface morphology after treatment (n = 3).Results: The color change data were analyzed using ANOVA and a post-hoc Tukey tests (alpha = 0.05). The VL group showed chromatic changes after 24 h of treatment, however the groups submitted to bleaching gel treatments associated with or without violet LED (C P + VL, CP, HP, H P + VL) showed the highest color change values at a l l time intervals analyzed, with color stability after 6 months of treatment for the CP + VL group. Scanning electron microscopy analysis showed the greatest change in enamel surface for Groups CP and HP.Conclusions: It could be concluded that violet LED had immediate bleaching effect without promoting significant changes in enamel morphology, however the association with carbamide peroxide 22 % showed color stability and greater bleaching efficacy than the use of violet LED alone, af ter 6 months.