Comparative evaluation of secondary heat treatment and a high intensity light source for the improvement of properties of prosthetic composites

This study determined the hardness and water solubility of two prosthetic c omposites polymerized with three curing modes for the purpose of evaluating the influence of secondary heating and a high intensity light source on re sulting material properties. Two prosthetic composite materials (Artglass a nd Dentacolor) were cured with the following methods: (1) exposure by means of a photocuring unit with a xenon stroboscopic light source (Dentacolor X S) for 120s; (2) exposure with the xenon unit for 120 s, followed by heatin g in an oven (KL 100) at 100 degrees C for 15 min; and (3) exposure by mean s of a photo-curing unit with two metal halide lamps (Hyper LII) for 120 s. Knoop hardness and water solubility were determined according to standardi zed testing methods. Although post-cure heat treatment considerably elevate d the Knoop hardness number for both materials, the greatest hardness numbe r was generated with the use of the metal halide unit. Water solubility of the Dentacolor material was lowest when the material was cured with the met al halide unit, followed by the secondary heated group, whereas, solubility of the Artglass material was unaffected by the curing modes. This suggests that the use of a high intensity light source is more effective than the a pplication of secondary heating for improving the post-curing properties of composites.