The aim of this study was to investigate the influence of light emitting diode (LED) laser with different irradiation time on the mechanical properties of conventional dental composite restoration. Experimental composites were prepared from rigid aromatic bisphenol A diglycidyl dimethacrylate (Bis-GMA) as base monomer, triethyleneglycoldim- ethacrylate (TEGDMA) as diluent monomer at the ratio (wt/wt) 60/40, 3-methacryloxypropyltrimethoxy silane (MPS) and hydroxyapatite (HA) as filler. The initiation system was based on the pair camphorquinone (CQ)/N, N dimet- hyl amino ethyl methacrylate (DMAEMA). The rectangular specimens (25 mm × 5 mm × 2.5 mm) were moulded in a stainless steel mold according to ISO standard 13586:2000. And the polymerization times were varied from 20 - 80 sec. The experimental results showed the best polymerization times (fracture toughness test) was used 60 seconds. Dental composite formulated with Bis-GMA: TEGMA and HA as filler presented the best compromise between different irradiation time.
