Polymer research Lab., School of Chemical Engineering, Iran University of Science and Technology, Tehran, Iran


Background: This research studied mechanical properties of silica-based nanocomposite as a strong restorative material through flexural test method.
Objectives: The purpose of this study was to evaluate the effect of weight fraction, silanization and filler size on the flexural properties of silica-based dental nanocomposite.
Methods: The prepared composites were made of light-cured copolymer based on Bisphenol A glycolmethacrylate (Bis-GMA) and Triethylene glycoldimethacrylate (TEGDMA) at proportion of 50:50 which reinforced by silica filler. The effect of silanization and weight fraction of the filler was studied with samples containing 10 wt% (n (10)), 20 wt% (n (20)) and 30 wt% (n (30)) nanosilica filler. Samples silanized with (γ-MPS) were also tested. Flexural properties were evaluated with Three-Point Bending test. Flexural strength of the nano SiO2 based composites were also compared to micro silica glass composites. Flexural data were analyzed with one-way analysis of the variance.
Results: The sample with 10 wt% (n (10)) had equal strength as the sample with 30 wt% (n (30)) nanosilica filler. Modulus of the sample n (30) was higher than the other samples, but its toughness was significantly lower. Silanization had not expected positive effect on the flexural properties.
Conclusions: Adding low amount of nanosilica improved mechanical properties of the resin composite. Silanization of the particles enhanced workability of the paste, but mechanical properties decreased significantly. Reduction in the size of the filler to nano scale caused better flexural strength in comparison to micro glass silica composites.