Effect of multiple application of dentin bonding agent on marginal integrity of resin composite

The purpose of the present study was to examine the effect of multiple application of dentin bonding agent to the adhesive surface on the marginal integrity of resin composite. The effect of multiple applications was evaluated by measuring the wall-to-wall polymerization contraction gap and by SEM observation. Multiple application of dentin bonding agent was found to prevent formation of the contraction gap. Although monomer penetration into the enlarged collagen network has been widely discussed as the possible mechanism of the dentin bonding agent and dentin primer, the true detailed mechanism of the dentinal bonding agent and dentin primer should be consistently explained by the prevention of monomer diffusion into the dentin and water contamination of the adhesive interface.