Precuring of self-etching bonding agents and its effect on bond strenght of resin composite to dentin and enamel

Objectives: To evaluate and compare shear bond strength of 3 self-etching bonding agents to enamel and dentin when the bonding agent is light cured before the application of resin composite or co-cured together with the resin composite. Method and Materials: One hundred twenty extracted teeth were wet ground to create a flat bonding area on enamel and dentin. Three bonding agents (Adper Prompt-L-Pop, Clearfil SE Bond, and Xeno III) were applied to either dentin or enamel according to the manufacturers' directions. In half of the specimens, bonding agents were light cured immediately after their application (Group PRC). The other half were not light cured until resin composite application (Group COC). Resin composite was placed into a Teflon tube and light cured over the adhesive. Specimens were stored in deionized water for 24 hours at room temperature before being loaded in shear until failure with an Instron testing machine. Shear bond strength (in megapascals) was analyzed with 2-factor ANOVA, separate single-factor ANOVA models for cure and material, and Tukey's Honestly Significant Differences multiple comparison procedure. All testing was performed at the 5% significance level (n=10). Results: Light-curing the adhesive separately produced significantly higher bond strengths to dentin (P .001) than did the co-cure method. Group PRC did not produce significantly different bond strengths to enamel (P = .420). Conclusions: Pre-curing of self-etching adhesives before curing of the resin composite produces greater bond strength to dentin. The curing technique has no significant effect on enamel bond strength of self-etching adhesives. Keywords: bonding agents, adhesives, resin bonding