In the present study, a composite composed of resin containing imidazole-GMA resin and a natural filler of silk powder (IGMSP) was used as an alternative to bis- phenol A-glycidyl methacrylate (Bis-GMA) dental composites. Dental composite was prepared by both optical and thermal polymerizations. FTIR, 1HNMR spectros- copy, and FESEM-EDX were used to identify the structure and morphology of the synthesized compounds. Thereafter, the thermal properties, water sorption and solu- bility, and anti-cancer and antibacterial activities of the composite were investigated. The structure of Imidazole-GMA resin as well as the successful surface modifica- tion of the filler with Si–O groups were confirmed with 1HNMR and FTIR spectra. Due to the use of natural filler of silk powder, the thermal resistance of the compos- ite was found to be relatively low. The water adsorption and solubility of composite were lower than Bis-GMA. The results of antibacterial properties and cytotoxicity of the composite were much promising due to the presence of imidazole compo- nents in the resin structure. This composite was shown to have a significant inhibi- tory effect on MCF7 cells (IC 50 = 11.4 μM, Maximum inhibitory effect 94.68%), and it was proved that Imidazole-GMA has significant effects on all three gram-negative (IZD 27–35 mm) and three gram-positive (IZD 22–29 mm) bacterial species.
