Effects of nanobarium titanate on physical and mechanical properties of poly(methyl methacrylate) denture base nanocomposites

The aim of this study was to (1) fabricate polymethyl methacrylate (PMMA) nanocomposites having better mechanical strength, (2) investigate the effects of nanobarium titanate (NBT) loadings (1-9 wt%) on tensile and flexural properties, and (3) evaluate surface roughness and hardness of the PMMA nanocomposites. The NBT was treated using a titanate coupling agent. Density, polymerization shrinkage (PS), surface roughness, and hardness were investigated. Tensile and flexural properties of PMMA nanocomposites were also evaluated. The roughness values of PMMA nanocomposites were significantly lower than those values proposed as a reference for clinical use (<200 nm). Moreover, the flexural modulus of the NBT/PMMA nanocomposites increased with increasing filler loadings. A remarkable increase in the tensile modulus values of filled PMMA was also observed (p < 0.001). In the case of higher filler content, tensile modulus remains unaffected by filler incorporation. The tensile and flexural strength improved with increasing concentration of NBT up to 5 wt% and then decreased by an additional amount of NBT introduced into the nanocomposite resin. However, the tensile and flexural strength values of NBT/PMMA nanocomposites were higher than the PMMA matrix (p < 0.001). Such enhancements obtained with titanate-treated NBT could lead to the promotion of the dental composites' longevity.