目的: 对比评价两种改良式印章法辅助后牙直接法复合树脂牙合贴面修复的形态准确性。方法: 采用标准树脂牙右下第一磨牙54颗,制作硬质硅橡胶和透明硅橡胶两种印章复制牙冠外形,并进行牙合贴面预备及复合树脂牙合贴面修复。试验共分为9组:按照不同印章(硬质硅橡胶或透明硅橡胶)、牙合面预备量(1 mm或2 mm)和不同复合树脂材料(通用型复合树脂或整块充填复合树脂)分为8个实验组,对照组为CAD/CAM生物复制方法进行间接修复。牙合贴面修复完成后进行模型扫描,并与修复前原始牙冠形态的扫描数据进行3D比较,按牙合面及轴面分别计算均方根(root mean square, RMS)值。采用方差分析比较各组RMS值。结果: 牙合面RMS值硬质硅橡胶印章法组为(0.136±0.031) mm,透明硅橡胶印章法组为(0.130±0.024) mm,对照组为(0.130±0.009) mm,组间差异无统计学意义;轴面RMS值分别为(0.135±0.020) mm、(0.147±0.021) mm及(0.153±0.014) mm,硬质硅橡胶印章法组最小(P<0.05)。两种改良式印章法在2 mm厚的通用型树脂组牙合面平均RMS值最大,显著大于对照组(P<0.05)。结论: 使用两种改良式印章法辅助进行直接法牙合贴面修复具有较高的形态准确性,硬质硅橡胶印章法所得修复体的轴面形态更佳。当修复体牙合面厚度为2 mm时,使用整块充填复合树脂具有更准确的牙合面形态。

Objective: To evaluate the morphology accuracy of direct occlusal veneer using two types of modified stamp-technique, comparing the results of two types of stamp and different composite resin. Methods: Model scanner was used to get the original data from the standard resin teeth in plastic model. Two types of stamps were made: solid silicon stamp and transparent silicon stamp. In the study, 54 resin tooth were randomly divided into 9 groups: Groups 1-8 were restored by direct composite resin, using general and bulk-filled composite resin in occlusal veneer (1 mm or 2 mm) with two types of stamp-technique (the solid silicon, and the transparent silicon), and the control group was restored by indirect way using CAD/CAM composite resin restoration by biocopy technique to mimic the original shape of the teeth. After the resin teeth were prepared for occlusal veneer, the direct and indirect composite resins were restored. After the restoration was finished, the data were obtained again by the same model scanner in the plastic model. 3D comparisons were made using the original and restoration data, the average difference and the root mean square of difference (RMS) were recoded from the software. The RMS of all the groups were analyzed using one way ANOVA (α=0.05). Results: The RMS of occlusal surface in solid silicon stamp group was (0.136±0.031) mm, in transparent silicon group was (0.130±0.024) mm, and in control group was (0.130±0.009) mm. There were no significant difference. While the RMS of buccal/lingual surface in solid silicon stamp group was the smallest [(0.135±0.020) mm, P<0.05], and in transparent silicon group it was (0.147±0.021) mm, and control group (0.153±0.014) mm. The general composite resin using the two types of stamp had the largest occlusal RMS in 2 mm occlusal veneer, which were significantly larger than control group (P<0.05). Conclusion: The direct occlusal veneer using two types of modified “stamp-technique” had relatively good morphology accuracy. Direct occlusal veneer using bulk-filled composite resin made with two types of stamp technique had even more accurate morphology than using general composite resin. The solid silicon stamp had a better morphology accuracy in buccal/lingual surface than the transparent silicon stamp.