Ação do peróxido de hidrogênio a 35% sobre a microdureza de restaurações de resina composta a base de silorano

Abstract

Purpose: evaluate in vitro the action of three different bleaching with hydrogen peroxide at 35% on the Vickers hardness (MV) of composi-te restorations to silorane base. Methods: the composite resin used was the FiltekTM P90 (3M) and the bleaching were the Whiteness HPTM (FGM), Whiteness HP MaxxTM (FGM) e Whiteness HP BlueTM (FGM). Ten specimens of each group were prepared, totaling 40 specimens with the aid of a teflon bipartite matrix. The microhardness tests (MV) were performed employing a microhardness tester HMV-2T® (Shimadzu), and the calculation was obtained by considering the average of the four indentations of a face. The results were submitted to analysis of variance (ANOVA), using a criterion with the Tukey test. To measure statistical significance was considered p <0.0001. Results: the mean values and standard deviations obtained by the tested groups were: G1: 49.4500 (± 5.1073); G2: 29.0685 (± 4.9436); G3: 28.7975 (± 8.6736) and G4: 25.3535 (± 9.4033). There was a statistically significant differen-ce between the MV values when compared to the control group and experimental groups. (p <0.0001). However, when the three groups treated with hydrogen peroxide were compared with each other, the-re was no statistically significant difference. Conclusion: the oxidation process and subsequent hydrolytic degradation of the composite in the presence of hydrogen peroxide at 35% leads to lower but statisti-cally significant microhardeness values