Design and characterisation of dental resin restorative composites with Ac-Bis-GMA and bimodal silica nanostructures

Abstract

To solve the high viscosity of bisphenol A glycerolate dimethacrylate (Bis-GMA), its derivate Ac-Bis-GMA substituting acetyl groups for hydroxyl groups was synthesised by the esterification reaction and mixed with tri(ethylene glycol) dimethacrylate (TEGDMA) as polymer matrix to fabricate dental resin restorative composites. To improve the degree of conversion (DC), polymerization shrinkage (PS) and wear resistance of resin-based composite (RBC) 58–12 filled with commercial microsize and nanosize (M/N) SiO2 particles, bimodal silica nanostructures consisting of SiO2 nanoparticles (NPs) and SiO2 nanoclusters (NCs) were introduced as inorganic fillers. Resin composites with different mass ratios of silanized SiO2 NPs and SiO2 NCs were fabricated under the light polymerisation, and the effect of filler compositions on these two properties, wear resistance (wear volume and worn surface morphology), and cytotoxicity assay of resin composites was investigated in this work. The results suggested that resin composites reinforced with bimodal silica nanostructures at the optimum ratio presented the improved performance, especially for RBC 35–35 (SiO2 NPs:SiO2 NCs = 35:35, wt/wt), which resulted in 16% enhancement in DC and 19% reduction of PS, the smoother and flatter worn surface after 10 000 wear cycles, as well as the excellent cytocompatibility, compared with those of RBC 58–12.This effective and facile way might provide a new sight to develop dental resin restorative composites for clinical application.