纳米羟基磷灰石脱敏剂对自酸蚀粘接剂牙本质-树脂粘接性能的影响

Objective： To evaluate the dentinal tubular occlusion of nano-hydroxyapatite (nHAp) containing desensitizers and their influence on the dentin bonding performance of self-etch adhesive. Methods： Mid-coronal dentin specimens were prepared from 48 intact human third molars. They were immersed in 10 g/L of citric acid for 20 s to simulate sensitive teeth, and randomly divided into four groups. The control group received no desensitizing treatment. Three experimental groups were treated with two commercial nHAp containing desensitizing toothpastes (Biorepair and Dontodent) and an experimental pure nHAp paste, respectively. The effect of desensitizers on dentinal tubular occlusion was observed by the field-emission scanning electron microscope (FESEM). Each group was further bonded with Futurabond NR. The micro-tensile bond strength was tested and failure mode distribution was analyzed. Moreover, resin infiltration of the adhesive was evaluated under confocal laser scanning microscopy (CLSM). Results： FESEM revealed that all the desensitizers noticeably occluded the dentinal tubules. After application for 7 days, the penetration depth of desensitizing particles was obviously increased and the extent of occlusion was completer. The micro-tensile bond strength test showed no significant differences in bonding strength among the three desensitization groups and control group (P>0.05). CLSM demonstrated the similar morphology of resin tags was produced in the desensitized groups and control group. Conclusion： Nano-hydroxyapatite containing desensitizers could occlude dentinal tubules effectively.