Evaluation of Knoop hardness of composite resin after surface treatments

Abstract

The purpose of this study was to evaluate the surface Knoop hardness of three different com- posites (Z-100, Alert and Revolution) under two photoactivation situations: at environment conditions and co- vered by a lubrificant gel (KY). One half of the samples photoactivated at environment conditions were polished (WP) and the other half, not (NP). Ten samples of each group were made, which were divided into the following groups: G1 – Z-100 / NP; G2 - Z-100 / KY; G3 - Z-100 / WP; G4 - Alert / NP; G5 - Alert - KY; G6 - Alert / WP; G7 - Revolution / NP; G8 - Revolution / KY and G9 - Revolution / WP. Five readings of Knoop hardness were obtained in each sample using a micro hardness tester HMV-2000 (Shimadzu). The results were submitted to Anova and Tukey’s test (5%). It was veri- fied that for Z-100 samples, all sur- face treatments were statistically different. The highest means were obtained by G3, followed by G2 and G1. Alert samples, presented the highest mean on G6, which differed from G4 and G5. Revolution sam- ples showed statistical difference for all treatments with G9, sho- wing the highest mean, followed by G8 and G7. Key words: composite resins, dental polishing, permanent den- tal restoration.