Most microfilled composite resins are relatively resistant to generalized wear; however, they commonly exhibit poor resistance to localized wear becaues of debonding of prepolymerized particles from the resin matrix. A copolymerized new composite resin, in which the filler particle trimethylolpropane-trimethacrylate is chemically bonded to the resin matrix, is evaluated. Epic-TMPT was subjected to both generalized and localized wear tests that revealed that its wear resistance was higher than that of other composite resin systems. Epic-TMPT in posterior occlusal cavities showed less than 8 um of wear for each restoration, 1 year after placement. Placement of Epci-TMPT into large anterior abfraction lesions withour mechanical retention, with surface etching, and subject to severe traumatic occlusion resulted in 87% retention 1 year after plaement. In vivo usage biocompatibility tests demonstrated nopulpal irritation or inflammation when Epic-TMPT was placed on vital dentin of crown preparations with complete enamel removal.