内蒙古地区成人下颌第一磨牙根管形态的三维研究

目的：通过应用多层螺旋CT观察分析内蒙古地区成人下颌第一磨牙的根管形态及其变异情况,为临床治疗提供解剖学依据,同时探讨下颌第一磨牙根管形态是否存在性别与民族差异。方法：筛选内蒙古地区符合双侧健康下颌第一磨牙标准的蒙汉族成年人66名,共132颗下颌第一磨牙进行研究,应用多层螺旋CT扫描,利用Release 4.4后处理软件进行三维重建,分析下颌第一磨牙根管形态。结果：下颌第一磨牙2根发生率67.6%,3根发生率33.3%,2根2根管发生率6.1%,2根3根管发生率42.4%,2根4根管发生率18.2%,3根3根管发生率7.6%,3根4根管发生率25.7%。下颌第一磨牙远中舌根个体发生率33.3%,男女性别间发生率无统计学差异（P〉0.05）,蒙汉族间发生率有统计学差异（P〈0.05）。结论：内蒙古地区成人下颌第一磨牙牙根及根管形态多样且具有较大的变异性,同时变异存在民族差异。

THREE-DIMENSIONAL STUDY ON ROOT AND CANAL MORPHOLOGY OF MANDIBULAR FIRST MOLARS IN INNER MONGOLIA REGION

Objective：To provide the anatomy reference about the basic clinical therapy and explore the mandibular first molars whether there are differences between genders or nationalities, by using multi-slice computed tomography to evaluate root and canal morphology. Methods：A total of 66 Mongolian and Hans adults with healthy, well-developed mandibular first molars were included. Totally,a number of 132 mandibular first molars were studied. The root and canal morphology were evaluated by multi-slice computed tomography scanning, the data was imported into workstation and made research on image reconstruction and multiplanar reconstruction by Release 4. 4 software. Results：The incidence rate of mandibular first molars with two separate roots was 67. 6%,three roots were identified in 33. 3%of mandibular first molars. Two canals in two separate roots were found in 6. 7%of mandibular first molars,42. 4%had three canals and 18. 2%had four canals. Three canals in three roots were found in 7. 6%of mandibular first molars,25. 7%had four canals. The RE（radix ento-molaris）individual incidence of mandibular first molars was 33. 3%. There is no statistical difference （P〉0.05）of incidence rate between male and female. There is statistical difference（P〈0.05）of incidence rate between Mongolian and Hans. Conclusions：The root and canal morphology of mandibular first molars are diversified and variability in Inner Mongolia Region. The variability is dis-tinguished between Mongolian and Hans.