中文摘要：

目的：通过显微CT技术测量陕西地区出土的3 000年前人上颌第二前磨牙的根管直径,并计算其根管锥度,期望为中国人牙齿的演化积累相关资料。方法：选择陕西地区出土的3 000年前15～25岁（平均18岁）人上颌第二前磨牙20个（单根管）,应用显微CT进行单个牙断层扫描,并测量其根管直径,根据公式计算各组根管锥度,应用SPSS17.0软件对数据进行统计分析。结果：20个上颌第二前磨牙根管近中远中向锥度分别为：-0.22,0.31,0.08;颊舌向冠、中及尖1/3段锥度分别为：0.13,0.33,0.12。近中远中向以中1/3段锥度最大,与冠段和尖段相比差异均有统计学意义（P〈0.05）,冠段与根尖段相比无统计学差异（P﹥0.05）;颊舌向亦以中段锥度最大,其次为冠段,尖段最小,3段间比较差异均有统计学意义（P〈0.05）。结论：3 000年前人上颌第二前磨牙根管自根尖起为自下而上的扁圆形,其近中远中向锥度远小于颊舌向锥度,根管并非为一连续的锥形;本研究为古人类牙齿形态学研究积累了相关数据资料。

英文摘要：

AIM： To obtain morphological data of permanent root canal taper of ancient human maxillary second premolars,by micro computed tomography（Micro CT）.METHODS： Twtnty single root canal permanent maxillary second premolars which were excavated from Shaanxi and identified to be about 2 000 B.C.were scanned by micro CT.Diameters of the cervical, middle,and apical third of the canals were measured.Root canal taper was calculated and analyzed.RESULTS： The average taper of the cervical,middle and apical third of these premolars was-0.22,0.31,0.08 mesio-distally and 0.13,0.33,0.12 bucco-lingually.In the mesio-distal direction,the taper of the middle segment was significant larger than that of the cervical and apical segments（P0.05）.However,there was no significant difference between the cervical and the apical segment（P〉0.05）.In the bucco-lingual direction,the taper of the middle segment was the largest,while the apical segment was the smallest.There were significant differences among the three segments（P0.05）.CONCLUSION： The results showed that an ovary shaped canal was common in these tooth root from up to down.The taper of the cananls in the buccolingual direction was greater than that in the mesio-distal direction.The root canals were not continuous.Our data provided information for the study of ancient Chinese tooth morphology.