Hydrolytic degradation of composite resins: effects on the microhardness

Abstract

The purpose of this investigation was to evaluate the microhardness of two laboratory-processed composites (Artglass; belleGlass) and two direct placement composites (Filtek Z250; Alert), after aging in distilled water. Twenty cylinders (8 mm diameter; 2 mm height) per tested material were prepared and stored in 10 ml of distilled water. Five Knoop hardness measurements were made on the surface of the specimens with a Miniload Hardness Tester under a load of 50 g for 30 s at 10 min, 24 h, 30 and 90 days. Statistical analysis was perfomed using two-way ANOVA, followed by a SNK multiple comparison test (p < 0.05). The analysis showed statistically significant difference among hardness means recorded at the different aging time and the tested materials. It may be concluded that all materials presented hydrolytic degradation due to aging in aqueous environment.

Keywords

• composite resin
• hydrolytic degradation
• microhardness