Efeito da aplicação prévia ou adição de dessensibilizantes em géis de peróxido de hidrogênio no esmalte clareado

Abstract

This in vitro study evaluated the effect of 35% hydrogen peroxide (35HP) gels with different desensitizing agents on color, microhardness and roughness of bleached enamel. Forty enamel-dentin specimens (6x6x2 mm2) were obtained from twenty human molars. After color measurement with a spectrophotometer, the specimens were randomized into four groups (n= 10): 35HPw- 35HP without desensitizing agent; 35HPCa- 35HP with calcium; 35HPK- 35HP with 0.5% potassium nitrate; 35HPTFa- 35HPw + topical application of 5% potassium nitrate and 2% sodium fluoride (TFa). Specimens were evaluated for color (∆Eab* and ∆E00), Vickers microhardness (VHN) and, superficial and volumetric roughness (Ra and Sa, µm) using a 3D non-contact profilometer before and 1-week after bleaching. Data were analyzed by ANOVA and Tukey tests (p< 0.05). Both treatment groups promoted a significant whitening effect and there was no difference between them for any color parameters evaluated. All groups reduced significantly the VHN, but the 35HPK showed a reduction significantly major than the other groups. 35HPCa and 35HP+TFa did not avoid the of Ra and Sa increasing. It can be concluded that 35HP bleaching gels with different desensitizing agents did not affect the whitening efficacy. However, all treatments decreased the microhardness, the addition of calcium into 35HP gel and the application of TFa before bleaching did not revert the enamel roughness under in vitro conditions.