Effects of SiO (2) Incorporation on the Flexural Properties of a Denture Base Resin: An In Vitro Study

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.