目的 采用解剖学方法,测量第一前磨牙桩道预备前后根管壁厚度,指导临床合理选择桩道预备器械.方法 收集上下颌第一前磨牙各30颗作为实验样本,用游标卡尺测量原始及分别用1、2、3号P型钻桩道预备后末端剩余根管壁的厚度.结果 牙根各项指标测量值均呈正态分布,对于双根管上颌第一前磨牙和单根管下颌第一前磨牙,3号P型钻预备后,近远中末端根管壁厚度均小于1 mm,颊根的差异无统计学意义(P>0.05),腭根和下颌第一前磨牙牙根的差异有统计学意义(P<0.05);对于单根管上颌第一前磨牙,2号P型钻预备后,近远中末端根管壁厚度均小于1 mm,远中壁差异有统计学意义(P<0.05).结论 桩道预备时,双根管上颌第一前磨牙颊根可用3号P型钻,腭根和单根管下颌第一前磨牙可用2号P型钻,而对于单根管上颌第一前磨牙只能用1号P型钻.%Objective The residual dentin thickness of first premolars were measured by anatomical methods before and after post preparation, the data from which can help clinicians to choose proper sizes of peeso drill. Methods 30 first maxillary premolars and 30 first mandibular premolars were collected. Walls of 4 mm short of the apex were respectively measured before and after post preparation with peeso drills number 1-3. Results The measurement results of all indexes assumed a normal distribution. For two-canal first maxillary premolars and single-canal first mandibular premolars, the average residual mesial and distal thickness of root walls 4 mm short of the apex were less than 1 mm after post preparation by number 3 peeso drill. The buccal root had nonsignificant differences(P＞0.05). The palatine root and the first mandibular premolars had significant differences (P＜0.05). For single-canal first maxillary premolars, the average residual mesial and distal thickness were less than 1 mm after post preparation by number 2 peeso drill. The distal wall had significant differences (P＜0.05). Conclusion In post preparation, for the buccal root of two-canal maxillary premolars, the maximum size of peeso drill was number 3, and for the palatine root and first mandibular premolars, the size was number 2, and for single-canal maxillary first premolars, the size was number 1.
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