Additional heat-curing of light-cured composite resin for inlay restoration

The purpose of this study was to evaluate the effect of heat application after light curing on some physical properties of composite resin for dental inlay. Specimens each were additionally dry heat-cured at various temperatures for 15 min after initial light curing, and other specimens were not heat-cured as a control. Fracture toughness, bending strength, bending elastic modulus, coefficient of thermal expansion, hygroscopic expansion, microhardness, water absorption and solubility were determined. Fracture toughness, bending strength and bending elastic modulus were significantly higher when heated at 80-120 degrees C than the control. The coefficient of thermal expansion, hygroscopic expansion, microhardness and solubility were significantly improved than those of the control when heated, while water absorption was not significantly altered by dry heat-curing. These results indicate that the physical properties of composite resin, except water absorption, were improved significantly when heated after initial cure.