目的:比较使用DMG硅橡胶采用不同印模方法的印模颈缘精确度和耗时的差异.方法:选取全冠修复患者278例(424颗基牙),按随机数表分为一次印模法组、二次预先法组、二次薄膜法组及二次刮除法组4组,各组再根据预备基牙的数量,分为单基牙和多基牙2组.在备牙及二次排龈后完成最终印模,记录相应印模时间,并比较不同印模方法的颈缘清晰度.结果:不论单基牙或多基牙,二次预先法、二次薄膜法及二次刮除法3组之间颈缘清晰度无明显差异,但均优于一次印模法,差异具有统计学意义(P<0.05);印模耗时一次印模法组<二次预先法组<二次薄膜法组<二次刮除法组,差异具有统计学意义(P<0.05).结论:二次印模法更容易制得合格的印模,但耗时会延长,其中的二次预先法制取印模效果好,耗时较短,更容易掌握应用.“,”Objective:To evaluate the impression shoulder continuity and operating time of different impression methods. Methods:Two hundred and seventy-eight cases with 424 abutments treated by all-ceramic restoration were random-ly divided into 4 groups,and the impressions were prepared by one-step method,double pre method,double thin film method and double curettage method respectively. Each group were divided into two Single and Multiple subgroups according to the number of abutment. The cervical margin precision and operating time of the impressions was compared from tooth preparation to impression. Results:The accuracy of replication in shoulder continuity of 3 different two-step techniques were higher than that of one-step technique,and the difference were statistically significant,but there was no statistically significance difference among three different two-step techniques. The result of operation time was as followings,one-step method