PURPOSE: To obtain a dental hardenable material not only excellent in mechanical strength but also effective in preventing discoloration due to the adsorption of colored components by using an α-aminoacetophenone-based photopolymerization initiator as a photopolymerization initiator.

CONSTITUTION: The dental filling and restoring material contains (A) 100 pts.wt. polyfunctional acrylate-based monomer, e.g. a mixture of 60 pts.wt. 2,2-bis[4-(3- methacryloxy-2-hydroxypropoxy)phenyl]propane with 40 pts.wt. triethylene glycol dimethacrylate, (B) 100-900 pts.wt. inorganic filler, e.g. a silica-zirconia- based spherical particle and (C) 0.01-10 pts.wt. α-aminoacetophenone-based photopolymerization initiator, e.g. 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)- butanone-1. Furthermore, the resin composition for a denture base contains 50-500 pts.wt. organic filler as the component (B). This material is polymerized and cured by irradiation of light having 250-600nm wavelength region. When a higher curing depth is required, an α-diketone, especially camphorquinone is preferably used in combination.