The study examined the effect of light irradiation on the shear strength of self-adhesive resin cements. Five commercially available dual-cured self-adhesive resin cements were examined. Disk specimens (10 mm diam, 1 mm thick) with or without light irradiation were prepared for each cement (n＝10 under each experimental condition). The specimens were stored in deionized water up to 4 weeks one hour after the start of cement mixing. The shear strengths were determined using the punch tool of the universal testing machine at 1 hour, 24 hours, 1 week, or 4 weeks after the start of cement mixing. The shear strengths of specimens with light irradiation tended to be greater than those without light irradiation. Also, the shear strength of specimens increased with time up to 24 hours. Light irradiation of self-adhesive cements could be effective to achieve a stable shear strength in the early setting period.

This study investigated the penetration range of 3 types of calcium hydroxide reagents in root canals and its influence on the bonding strength of adhesive resin cement. Bovine root canals were filled with each type of calcium hydroxide reagents and ultrasonically washed in distilled water after one week. The specimens were examined using an electron probe microanalyzer. Bonding strengths of the adhesive resin cement with each type of calcium hydroxide reagents to bovine root canal dentin and resin composite built-up abutment were examined using shear bond tests. The results showed that calcium hydroxide reagents remained not only on root canal walls but also in the dentinal tubules. However, the bonding strength of adhesive resin cement did not significantly change regardless of treatment with calcium hydroxide reagents. Therefore, the results revealed that calcium hydroxide reagents in root canals remained inside the dentinal tubules, but did not affect the bonding strength of the adhesive resin cement.