2017 Volume 60 Issue 1 Pages 22-31
Purpose: Clinically, resin composite repair for dentin hypersensitivity with substantial defects such as wedge-shaped defects is commonly performed a few days after applying the densensitizer to dentin. In this study, we investigated the influence of pre-treatment of dentin densensitizers on bond strength.
Materials and Methods: We applied three desensitizers (MS coat ONE, F Varnish, and Nanoseal) on an artificial model of hypersensitive dentin using human premolars, and observed the surface structure by scanning electron microscope (SEM). Then, the specimens to which the three desensitizers had been applied were treated with Clearfil Mega Bond FA. We morphologically observed by SEM the surface of dentin which had been treated with the primer. Furthermore, the micro-tensile bond strength (μTBS) for the specimens which were incrementally built up by resin composites was measured in a universal testing machine. The interface between resin and dentin of specimens was observed by SEM and confocal laser scanning microscope (CLSM).
Results: The surfaces of specimens to which each desensitizer had been applied showed morphological characters having the effects of suppressing hypersensitivity. Regarding μTBS, there were no significant differences among all groups. In the group of MS coat ONE, MS coat ONE was not completely removed by the application of Mega Bond FA primer. Although the penetrations of the primer into dentin tubules were small, the thickness of the bond layer was greater. The specimens of F Varnish showed the functions of self-etching adhesive systems, because the varnishes had been partially removed by Mega Bond FA primer. In the group of Nanoseal, Mega Bond FA primer was almost removed by Nanoseal, and penetrated deeply into the dentinal tubules.
Conclusion: The three desensitizers used in this study had no effect on the bond strength of self-etching adhesive systems to the artificial model of hypersensitive dentin.
