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

Effect of nano-hydroxyapatite containing desensitizers on dentin bonding performance of self-etch adhesive

目的评价含纳米羟基磷灰石(nano-hydroxyapatite,nHAp)脱敏剂对牙本质小管的封闭作用以及对自酸蚀粘接剂牙本质粘接性能的影响。方法收集48颗完整、无龋的第三磨牙,制备冠中部牙本质样本,10 g/L柠檬酸处理20 s,建立模拟牙本质敏感离体牙样本模型。根据牙本质粘接界面不同的脱敏处理方式随机分为4组,3个实验组分别用2种含nHAp的商品脱敏牙膏(BioRepair和Dontodent)和实验自制nHAp糊剂进行处理,对照组不进行脱敏处理。场发射扫描电镜(FESEM)观察各组脱敏剂对牙本质小管封闭的影响;比较脱敏处理方式对自酸蚀粘接剂Futurabond NR的牙本质微拉伸粘接强度的影响并分析断裂模式;激光扫描共聚焦显微镜(CLSM)评价脱敏处理对Futurabond NR粘接剂树脂的渗透效果的影响。结果FESEM显示3个实验组不同脱敏剂处理后牙本质小管都被明显地封闭。脱敏剂应用7 d后,脱敏剂颗粒的渗透深度明显增加,封闭程度更加完善。3组不同脱敏处理方式与对照组的微拉伸粘接强度之间无统计学差异(P>0.05)。CLSM实验结果表明,脱敏组和对照组具有相似的树脂突形态。结论含nHAp的脱敏牙膏和脱敏糊剂有效封闭牙本质小管的同时,不会影响Futurabond NR自酸蚀粘接剂树脂渗透和牙本质-树脂粘接强度。

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.Meanwhile,the application of these nHAp desensitizers has no adverse effect on resin infiltration and dentin bond strength of Futurabond NR self-etch adhesive.