[Influence of thermal cycling on the adhesive strength of adhesive resin cement].

The purpose of this study was to examine the influences of thermal cycling on the adhesive strength of the adhesive resin cements. Four kinds of adhesive resin cements, which belonged to the commercial composite resin inlay products, were used for the study. They were CR Inlay Cement, Duo Cement, Dual Cement and P-30 diluted with Enamel Bond. The shear adhesive strengths to tooth substance and composite resin inlay were measured. Adhesive strength to etched enamel : CR Inlay Cement showed the highest values of 274 kg/cm2 after immersion in water at 37 degrees C for 24 hours and 230 kg/cm2 after 300 thermal cycles at 4 degrees C for 3 min and at 60 degrees C for 3 min. Adhesive strength to etched dentin : P-30 diluted with Enamel Bond showed the highest values of 64 kg/cm2 after 24-hour immersion in water, and 63 kg/cm2 after 300 thermal cycles. Adhesive strength to composite resin inlay : CR Inlay Cement showed the highest values of 310 kg/cm2 after 24-hour immersion in water, 306 kg/cm2 after 300 thermal cycles, and 297 kg/cm2 after 1000 thermal cycles. Adhesive resin cements other than CR Inlay Cement, showed a decrease in adhesive strengths to tooth substance and composite resin inlay after thermal cycling. Especially, Dual Cement and Duo Cement showed considerable decreases.