Effects of Nanofillers on Mechanical Properties of Fiber-Reinforced Composites Polymerized with Light-Curing and Additional Postcuring

Abstract

Background The purpose of the present study was to evaluate the effect of nanofillers on the mechanical properties of 2 sizes (diameters 0.6 and 0.9 mm) of conventional and nanofilled fiber-reinforced composites (FRCs) polymerized with conventional light-curing and additional postcuring. Methods The FRCs samples were divided into 8 groups (10 specimens each). Conventional FRCs with glass fibers preimpregnated with polymethyl methacrylate (groups 1, 2, 3 and 4) and FRCs with impregnating solution containing 32% nanofilled resin (groups 5, 6, 7 and 8) were tested in 2 different sections (0.6 and 0.9 mm in diameter). Two different polymerizations were analyzed: hand light-curing for 40 seconds with an halogen light, and additional postcuring for 25 minutes in a light-curing oven. Each sample was evaluated with a 3-point bending test on a universal testing machine, after 48 hours of dry storage. All of the data were statistically analyzed. Results After oven postcuring, nanofilled FRCs exhibited significantly higher load values than conventional FRCs. No significant differences were found when comparing conventional and nanofilled FRCs after hand light-curing. Moreover, 0.6-mm FRCs showed significantly lower load values than 0.9-mm FRCs, both for conventional and nanofilled FRCs. Conclusions Nanofilled FRCs showed higher load values after additional oven postcuring.