Evaluation of surface roughness of resin-based composites submitted to different light-activation protocols and bleaching agents

Abstract

This study evaluated the surface roughness (Ra) of methacrylate and silorane-based composites submitted to different light-activation protocols and bleaching agents. The samples were divided into 12 groups (n=10) according to the composite (Filtek Z250 - 3M Espe, Filtek P90 - 3M Espe and Opallis - FGM); to the light-activation protocol (1000 mW/cm² X 18 s (S) and 3200 mW/cm² X 6 seconds (PE)); and bleaching agent (hydrogen peroxide at 6% and hydrogen peroxide at 35%). Roughness test were carried out at the following set times: initial (R1), after polishing (R2) and 24 hours after bleaching (R3). Data obtained were submitted to the statistical analysis. The results showed that higher values of Ra in R1 were obtained by Filtek P90 composite, differing significantly of the other samples, which showed similar results among them. There was significant decrease of Ra in R2 under all the conditions, except by the Opallis composite, independently on the light-activation protocol, and Filtek Z250 light-activated by PE protocol. There were no difference between R2 and R3 for all the composites and any light-activation protocol. It was possible conclude that bleaching agents did not interfere in significant way on surface roughness of the composite evaluated.