上颌第三磨牙根形态与根管形态的研究

目的：寻找上颌第三磨牙根形态及根管形态的规律。方法：使用传统的牙透明技术,充分显露该牙髓腔外形,在体式显微镜下读取根管系统的形态,并统计分类。结果：103颗上颌第三磨牙,融合根占72%,分叉根占28%;完全融合型牙根单根管（1-1型）多见,不完全融合牙根中双根管（2-2）和三根管（3-2;3-3）为主;分叉根型中近中颊根分为双管型常见;根尖分歧和根管侧枝在各型根管中均可见到。结论：上颌第三磨牙融合根常见,但根管形态多样。

Study on Morphology of Root and Root Canal in Maxillary Third Molars

Objective：To find out the morphological regularity of root and root canal in the maxillary third molar. Methods：Through transparent specimen of teeth,the shape of root and root canal was observed under stereomicroscope. Results：Among 103 teeth,72% had fused roots and 28% had separate roots,heperfusion roots showed mainly single canal,but hepofusion roots were double or three canals. Double canals were observed easily in mesiobuccal roots. Disobuccal and platal roots were mainly single canal. Lateral canal,apical ramification（multifurcation） and anastomoes between the root canals were popular in all types of canals. Conclusion：The fused root is mostly observed and root canal systems are comparatively complex in the maxillary third molar.