乙醇润湿对牙本质粘接界面渗透性的影响

Study on the micropermeability of resin-dentin bonding interfaces with ethanol-wet bonding technique

目的研究牙本质疏水性粘接前乙醇润湿对粘接强度和粘接界面渗透性的影响，以期更好地为临床提供指导。方法24颗无龋第三磨牙去除冠部釉质后暴露中层牙本质，利用随机数字表随机分成6个组（每组4颗）。所有操作过程均在模拟髓腔压力的情况下进行，对照组采用全酸蚀粘接剂（Adper Scotchbond Multi—Purpose）粘接；4个实验组分别用无水乙醇润湿牙面20s、1min、2min、3min，1个实验组使用梯度乙醇润湿牙面，5个实验组采用实验室配制的疏水性粘接剂粘接。固化24h后进行微拉伸强度检测，计算粘接强度。荧光染料罗丹明B于牙髓腔中荷载3h后采用激光扫描共聚焦显微镜观察粘接界面的渗透情况。结果与对照组相比，乙醇润湿20s组和1min组粘接强度[（21．02±7．23）MPa和（29．64±3．81）MPa]均显著低于对照组[（38．14±4．97）MPa]，差异有统计学意义（P〉0．05）；而乙醇润湿2min组[（38．40±5．03）MPa]、3min组[（37．26±4．68）MPa]和梯度乙醇润湿组[（40．12±5．95）MPa]的粘接强度与对照组接近，差异无统计学意义（P〈0．05）。激光扫描共聚焦显微镜观察显示，随着乙醇润湿时间的延长，荧光染料在混合层和牙本质小管侧壁的沉积逐渐减轻，其中梯度乙醇润湿组仅在混合层附近检测到少量荧光染料。结论在模拟髓腔压力的情况下，2min以上的乙醇润湿结合疏水性粘接剂可获得良好的粘接力，同时明显降低粘接界面的微渗透。

Objective To evaluate the micropermeability on bonding hydrophobic adhesive to dentin with ethanol-wet bonding under simulated pulp pressure. Methods Twenty-four intact human third molars were used in the study. After the enamel of occlusal surfaces was removed, the molars were randomly divided into six groups. Adper Scotchbond Multi-Purpose was used in the control group; in the experimental groups, the dentin surfaces were saturated with ethanol for 20 s （ group 1 ）, 1 min （ group 2 ）, 2 min （ group 3 ）, 3 min （ group 4） or with a series of increasing ethanol concentrations before application of hydrophobic adhesive （ group 5 ）. All the bonding procedures were done under simulated pulp pressure. After 24 hours, micro-tensile bond strength test were performed on the specimens. Bonding interfaces were observed under laser scanning confocal microscope （LSCM） after the pulp chamber were filled with a water-soluble fluoroprobe rhodamine B for 3 hours. Results Compared with the control group [ （38. 14 ± 4.97 ） MPa ], bond strengths in group 1 [ （ 21.02 ± 7.23 ） MPa ] and group 2 [ （ 29. 64 ± 3.81 ） MPa ] were statistically lower （ P 〉 0. 05 ）, while bond strength in group 3 [ （38.40 ± 5.03 ） MPa], group 4 [ （37. 26± 4. 68 ） MPa] and group 5[ （40. 12 ± 5.95 ） MPa] were similar to the control group （P 〈 0.05 ）. The images taken by LSCM showed that with extension of ethanol-wet time, the deposition of fluorescent dye in hybrid layer and along the dentinal tubules decreased gradually. Especially in group 5, only spare fluorescent dye deposition could be detected in the hybrid layer. Conclusions Dentin saturated with ethanol for more than 2 min before bonding hydrophobic adhesive to dentin could provide favorable bond strength and decreased the micropermeability of bonding interfaces under simulated pulp pressure.