Abstract
Dentin primers containing N-methylolacrylamide (MEAA) or N-methylolmethacrylamide (MEMA) , which were soluble in water and were readily photopolymerized in the presence of inorganic salts such as ferric chloride, were prepared to improve the bond strength of lightcured composite resin to dentin etched with a 10-3 solution. The bond strength was significantly increased by using all dentin primers except for the dentin primer containing 10wt% MEMA. The dentin primers containing 50wt% MEAA and 30wt% MEMA gave a higher bond strength than the dentin primer containing 35wt% HEMA.Also, when treatment was with dentin primer containing 50wt% MEAA or 30wt% MEMA, the bond strength to dentin etched with 10-3 solution was comparable to that to dentin etched with 10wt% citric acid solution. The acid-proof dentin layers were about 1μm thick at the interface between all resins and dentin as observed by SEM. The SEM revealed that the specimens after shear bond tests had an acid-proof dentin layer cohesive fracture, resin cohesive fracture and dentin cohesive fracture.
