Hydrolytic stability of self-etch adhesives bonded to dentin

Functional monomers chemically interact with hydroxyapatite that remains within submicron hybrid layers produced by mild self- etch adhesives. The functional monomer 10- MDP interacts most intensively with hydroxyapatite, and its calcium salt appeared most hydrolytically stable, as compared with 4- MET and phenyl- P. We investigated the hypothesis that additional chemical interaction of self- etch adhesives improves bond stability. The micro- tensile bond strength (mu TBS) of the 10- MDP- based adhesive did not decrease significantly after 100,000 cycles, but did after 50,000 and 30,000 cycles, respectively, for the 4- MET- based and the phenyl-P- based adhesives. Likewise, the interfacial ultrastructure was unchanged after 100,000 thermocycles for the 10- MDP- based adhesive, while that of both the 4- MET- and phenyl- P- based adhesives contained voids and less- defined collagen. The findings of this study support the concept that long- term durability of adhesive-dentin bonds depends on the chemical bonding potential of the functional monomer.