下颌恒磨牙根管系统形态学比较

A comparison of morphology on the canal system of mandibular molar

目的 了解根管的形态结构 ,为牙疾病治疗提供解剖学参考。方法 采用透明标本法对 4 6 0颗下颌磨牙的根管系统进行研究。结果 ①下颌第 1磨牙三根出现率为 15 .5 % ,下颌第 2、3磨牙融合根的出现率分别为2 0 .5 %和 6 3.3%。②在下颌磨牙分离根的根管类型中 ,第 1磨牙近中根多为Ⅳ类根管、第 2磨牙近中根多为Ⅲ类根管 ,第 3磨牙近中根多为Ⅰ类根管 ,而下颌磨牙远中根绝大多数为Ⅰ类根管。③在融合根中 ,均出现一定数量的C形根管和多口、多孔类根管。结论 下颌磨牙牙根变异多 。

Objective To study the root canal system morphology and provide anatomic facts for treatment of dental disease.Methods 460 mandibular molars were observed by transparent specimen and results of root canal system were compared.Results Three roots appeared in the 15.5 % mandibular first molars,fused root in the 20.5 % mandibular second molars and 63.3 % mandibular third molars.Most of mesial root contained type Ⅳ root canal.C-shaped canal,multiple opening and multiple foramen root canal were found in the fused root of the mandibular molar.Conclusion Mandibular molar has much dental root variation and fused root has more complex root canal system than separate root.