Effect of surface graft ratio of SiO2 on the physical and mechanical properties of resin-based dental restorative composites

摘要

The purpose of this paper was to evaluate the effect of surface graft ratio (GR) of silica on physical and mechanical properties of dental resin composites. By changing the amount of silane coupling agents (e.g. KH-570), a series of silica particles with different GR were synthesized and characterized by thermogravimetry analysis (TGA). The nanohybrids comprised of silanized micro-silica and nano-silica with similar GR were mixed with a matrix of bisphenol A diglycidylether methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (50/50 wt/wt). After curing with a LED cuing unit, flexural strength and compressive strength were measured by universal test machine. Vicker's hardness was measured by micro-Viker's hardness testing machine, and the dynamic thermomechanical properties were measured by dynamic mechanical analysis (DMA). Furthermore, fracture morphology was observed by field emission scanning electron microscopy (FE-SEM). The results showed that resin composites containing silanized nanohybrids had much better properties than composite containing unsilanized nanohybrids. DMA data indicated that the combination of inorganic and organic interphases was improved with the increase of GR, while FE-SEM images of fracture surface did not show differences.