Concept of the Dentin Bonding System

Abstract

As demonstrated by Asmussen in 1975, the effectiveness of the dentin bonding system should be evaluated by observing the wall-to-wall polymerization contraction gap immediately after polymerization of the resin composite, which was restored in the cylindrical dentin cavity. We reported that the contraction gap width increased when the dentin cavity was decalcified by the acidic dentin conditioner or the functional monomer was eliminated from the dentin bonding agent. Therefore it was possible to speculate that the bonding between the resin composite and dentin cavity wall was established by the chemical interaction between the calcium in the dentin and the functional monomer in the dentin bonding agent. Furthermore, we reported experimental dentin primers that were aqueous solutions of the methacrylate derivatives and diols. We also defined that the contraction gap formation was completely prevented by a combined application of the optimized dentin conditioner, dentin primer, dentin bonding agent, and resin composite. To obtain the complete marginal integrity, the dentin should be conditioned with EDTA. Then the cavity should be primed with experimental materials (35% glyceryl mono-methacrylate, 45% erythritol methacrylate, 45% xylitol methacrylate, 62.5% ethyleneglycol, or 45% 1, 6-hexane diol). The commercial dentin bonding agents containing the 10 methacryloxy decyl dihydrogen phosphate or 4-methacryloxy ethyl trimellitate anhydride were recommended for use. The resin composite must flow into the cavity during polymerization, though only a few commerial materials are recommended.