Characterization of mesoporous silica nanoparticle composites at low filler content

Porous fillers are considered as an effective way to improve the mechanical properties of dental composites through the interlocking with organic matrix. In this paper, mesoporous silica (mobil crystalline materials-41) of different particle sizes was synthesized, modified, and added in bisphenol-A glycidyl dimethacrylate/triethylene glycol dimethacrylate resins to obtain composites at different loading levels. The influence of mesoporous filler concentration, particle size, and surface modification on the mechanical properties (flexural strength, flexural modulus, and Vickers microhardness) of composites has been investigated in detail. Compared to nonporous silica, mesoporous silica significantly improved composites' mechanical properties. Flexural strength and flexural modulus are increased by 44.5% and 33.4%, respectively, when filler mass fraction reaches 15wt%. Samples filled with silane-modified mesoporous silica show a higher flexural strength with the particle size decreasing from around 470 to 35nm. The results implied potential applications for dental composites filled with porous fillers.