ABSTRACT
The aim of this study was to determine the effect of filler particle size and nanoparticle addition on the bi-axial flexure strength [BFS] of the experimental resin-based composites [RBC] at varying deformation rates. In total, 9 RBC with different filler particle size and nanoparticle addition were investigated and for each RBC, 90 disc-shaped specimens [12 mm diameter, 1 mm thickness] were fabricated. All specimens were stored in distilled water at 37 +/- 1°C for one week prior to testing. The BFS of each RBC was determined at 0.1, 1.0, and 10.0 mm/min deformation rates [n = 30] in a universal testing machine. A general linear model [GLM] ANOVA highlighted a significant effect of deformation rate, filler particle size and nanoparticle addition on the BFS [P<0.001]. A general increase in BFS was identified with increasing deformation rate whereas a high volume percentage of nanoparticles and an increase in filler particle size led to a reduction in BFS. Two-way ANOVA revealed a significant effect of deformation rate [P<0.001] and nanoparticle addition [P<0.001] for BFS data sets for each RBC series with similar filler particle size. The deformation rate dependence of experimental RBC was not significantly affected by various combinations of filler particle size and nanoparticle addition