Nanoparticle-reinforced resin-based dental composites

Objective: TiO2 nanoparticles treated with the organosilane allyltriethoxysilane (ATES) are used to improve the mechanical properties of dental resin-based composites (RBCs, Z100, 3 M ESPE). Methods: TiO2 nanoparticles were sonically dispersed in an ethanol solution containing ATES. The modified particles were washed in pure ethanol and dried before being used as filler. Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) were used to analyze the nanoparticles. Five groups of composite resin specimens were prepared: one control group, and four groups using either modified or unmodified nanoparticles comprising 0.5% or 1.0% of the material by weight. The mechanical properties (microhardness and flexural strength) of all five groups of specimens were measured. Results: After modification, the particles' FTIR spectrum shows a new absorption doublet at 1200 and 1020 cm(-1). TEM images show that the modified particles have better dispersion, and that their clusters are small enough to create a homogeneous surface on dental RBCs. Composite resin specimens including modified nano-TiO2 have significantly better mechanical properties than the control group (P < 0.05). The improvement of adding 1.0 wt.% modified nano-TiO2 particles was better than that of 0.5 wt.%. Conclusions: Surface modification by the organosilane ATES influences the dispersion and linkage of TiO2 nanoparticles within a resin matrix, and the modified particles are found to improve the microhardness and flexural strength of dental RBCs. (C) 2008 Elsevier Ltd. All rights reserved.