Hamed Najafi - Department of Biomedical Engineering, University of Tehran, Tehran, Iran
Farhood Najafi - Department of Resin and Additives of Institute for Color Science and Technology, Tehran, Iran
Babak Akbari Alashti - Department of Biomedical Engineering, University of Tehran, Tehran, Iran
Sina Shahabi - Department of Dental Materials, Tehran University of Medical Sciences, Tehran, Iran

Resin composites were first introduced for commercial dental restoration materials in the 1960s. The base ofthe resin is Bis-GMA and the filler of the composite commonly is Quartz. The best composition of filler is hybrid fillerwhich includes Micron and Nano particles of Quartz. In this research two new nanohybrid composite developed usingsame Bis-GMA/UDMA/TEGDMA monomers and same portion of micro/nano sized quartz but two different photoinitiators(Camphorquinone and BAPO).To determine the mechanical properties of the fabricated composites, flexuralstrength and flexural modulus of the composite were obtained and these data compared with the ISO4049 Standard. Asa result, BAPO is better than Camphorquinone using halogen lamp as the light-curing unit. Furthermore, mechanicalproperties of composites using BAPO as photo initiator are better than composites using Camphorquinone. It isnoticeable that the light curing unit in all over the research was halogen lamp.

Resin Composite; Silica; Quartz; Nano-hybrid;Photo initiator; Mechanical Properties