加成型硅橡胶一次法 两次法印模三维精度比较

Three-dimensional accuracy of one-step versus two-step putty-wash addition silicone impression technique

目的比较加成型硅橡胶一次法、两次法印模的精度。方法采用重、轻体成分的加成型硅橡胶采用一次法和两次法分别制取同一实验模具的印模,检验比较所取印模对已行烤瓷全冠预备的21牙冠颈缘复制精度上的差异;灌注石膏模型后,游标卡尺测量主模型及石膏模型上各标志点的距离,对测量数据进行统计学分析。结果两次法印模在对牙冠颈缘复制精度上效果优于一次法印模,两者有显著差异。在线性变化率上比较,一次法印模的变化率均比两次法要大,但与原始数据比较无明显差异。结论加成型硅橡胶印模材料使用两次法印模优于一次法印模。

Objective To compare the three-dimensional accuracy of one-step putty-wash with two-step putty-wash addition silicone impression techniques. Methods A crystal master model containing one full ceramic crown abutment preparation（at no.21 position） was used as the positive control.The impressions of the master model were made using one-step and two-step putty-wash technique,respectively.Rank-sum test was employed to evaluate the variance between the control model and its impressions made by two techniques.The stones dies were poured from impressions of the master model.Vertical and horizontal dimensions between marks on the master model and stone dies were measured with electronic caliper.Data were statistically analyzed to compare the means of percentage changes.Results The accuracy of replication in shoulder continuity of two-step impressions was higher than that of one-step impressions,and the difference was statistically significant.The percentage deviation of one-step technique was bigger than that of two-step technique;however there was no statistical significance.Conclusion Three-dimensional accuracy of the two-step putty-wash addition silicone impression technique is higher than one-step impression technique.