Abstract

AZEVEDO, Mônica Regina de et al. Effect of different at-home bleaching agents in microhardness surface of resin composites: microhybrid X nanohybrid. Odontol. Clín.-Cient. (Online) [online]. 2012, vol.11, n.1, pp. 61-64. ISSN 1677-3888.

It was evaluated the effects of home bleaching agents on microhardness of microhybrid and nanohybrid composite resins. 30-of-body were made and divided into 6 groups (n=5). The groups G1 to G3 used a microhybrid CR (Opallis), while groups G4 to G6 used a nanohybrid CR (BrilliantNewLine). The bleaching agents used were: 6% hydrogen peroxide (PH) (White Class Cálcio) and 16% carbamide peroxide (PC) (Whiteness Perfect). After the specimens were prepared, the bleaching was realized as follows: G1 and G4: control group without bleaching agent, G2 and G5: PH - 28 days, G3 and G6: PC - 28 days, in accordance with the manufacturer's recommendations. After it, the microhardness test was performed. The data were statistically analyzed by ANOVA and Tukey's tests (5%). The results of microhardness (HV) and standard deviation of each group were: G1- 26.56±3.9; G2- 25.98±3.3; G3- 24.94±4.4; G4- 27.24±3.3; G5- 32.02±6.4 and G6- 37.72±8.1. The only group that showed significant differences to the anothers was the G6 (p<0.05), but did not differ significantly in relation to G5 (p=0.0058). It was concluded that the use of home bleaching agents didn't affect negatively the microhardness of the composite resins tested.

Keywords : Composite Resins; Hydrogen Peroxide; Tooth Bleaching; Hardness Tests.