目的

研究牙体预备后脱敏剂的使用及酸蚀处理对牙本质粘接界面粘接强度的影响，拟为脱敏剂的临床应用提供实验依据。

方法

将90 颗完整的离体磨牙，切割暴露牙本质，用500 目的碳化硅水磨砂纸打磨以创建均一的玷污层。 按不同脱敏剂类型随机分为All-bond2 组（A）、Systemp 组（S）和对照组（C），其中每组按酸蚀时机不同再分为前酸蚀组（2）、常规酸蚀组（1）及不酸蚀组（0），共9 个小组。 各组根据脱敏剂类型的不同及是否酸蚀、酸蚀时机的不同，先后制作暂时修复体和永久修复体。 垂直粘接界面切割牙体，每牙制备出1 个1.1 mm × 1.1 mm × 8 mm 的直条形试件。 用MTS 万能测试机检测粘接强度。

结果

微拉伸测试中各实验小组的粘接强度（单位：MPa）分别为A-2（32.45±12.15）、A-1（27.36±10.23）、A-0（19.30±11.08）、S-2（31.03±13.47）、S-1（31.58±12.84）、S-0（14.93±10.66）、C-2（25.64±14.81）、C-1（27.47±14.37）、C-0（20.33±13.41）。 两种脱敏剂组分别和对照组粘接强度比较，差异均无统计学意义（P＞0.05）。 不酸蚀组的粘接强度最小，与前酸蚀、常规酸蚀组比较，差异均有统计学意义（P＜0.05）；前酸蚀组与常规酸蚀组相比较，差异无统计学意义（P＞0.05）。

结论

脱敏剂不会影响最终修复体的粘接强度；脱敏剂处理前是否酸蚀牙本质，不影响最终牙本质粘接强度。

Objective

To evaluate the influence of desensitizers on the bond strength of dentin interface with or without etching removing smear layers.

Methods

Ninety whole molars were selected.The enamel of the crown was removed to explore the dentin. Standardized smear layers were created with 500-grit silicon carbide （SiC） paper under running water. Teeth were stratified sampled randomly and divided into three groups according to the type of desensitizing agent：All-Bond 2 （Group A）， Systemp（Group S） and the control group （Group C）. Each group was divided into three subgroups：pre-etched group， normal-etched group and non-etched group. Provisional restorations and permanent restorations were made for the teeth of each group successively. All the teeth were sectioned to obtain bar-shaped specimens with boned surface area about 1.1 mm × 1.1 mm × 8 mm. The bond strength was tested in a MTS tester with a crosshead speed of 0.5 mm/min.

Results

In the microtensile bond strength （MTBS）test， the bond strength of each group was：A-2 （32.45±12.15） MPa， A-1 （27.36±10.23） MPa， A-0（19.30±11.08） MPa；S-2 （31.03±13.47） MPa， S-1 （31.58±12.84） MPa， S-0 （14.93±10.66） MPa；C-2（25.64±14.81） MPa， C-1 （27.47±14.37） MPa， C-0 （20.33±13.41） MPa. There was no significant difference among the application of All-bond2， Systemp， and control （P＞0.05）. The bond strengths of the non-etched groups were significantly lower than that of the pre-etched or normal-etched groups （P＜0.05）. However， there was no significant difference between the pre-etched or normal-etched groups （P＞0.05）.

Conclusions

The application of desensitizers would not reduce the bond strength between dentin and final restoration. There is no significant difference in bond strength with or without removing the smear layers before the application of desensitizing agent.