Abstract
OBJECTIVE: The aim of this study was to evaluate the effects of the addition of low-silicon dioxide nanoparticles (nano-SiO(2)) on the flexural strength and elastic modulus of polymethyl methacrylate (PMMA) denture base material. MATERIALS AND METHODS: A total of 50 rectangular acrylic specimens (65 × 10 × 2.5 mm(3)) were fabricated from heat-polymerized acrylic resin. In accordance with the amount of nano-SiO(2), specimens were divided into the following five groups (n = 10 per group): a control group with no added SiO(2), and four test groups modified with 0.05, 0.25, 0.5, and 1.0 wt% nano-SiO(2) of acrylic powder. Flexural strength and elastic modulus were measured by using a 3-point bending test with a universal testing machine. A scanning electron microscope was used for fracture surface analyses. Data analyses were conducted through analysis of variance and Tukey's post hoc test (α = 0.05). RESULTS: Compared with the control group, flexural strength and modulus of elasticity tended to significantly increase (p ˂ 0.001) with the incorporation of nano-SiO(2). In between the reinforced groups, the flexural strength significantly decreased (p ˂ 0.001) as the concentrations increased from 0.25 to 1.0%, with the 1.0% group showing the lowest value. Furthermore, the elastic modulus significantly increased (p ˂ 0.001) at 0.05% followed by 1.0%, 0.25%, 0.5%, and least in control group. CONCLUSION: A low nano-SiO(2) addition increased the flexural strength and elastic modulus of a PMMA denture base resin.