下颌第二磨牙牙根及根管形态学研究

The research on mandibular second molars morphology

目的:观察下颌第二磨牙牙根及根管类型。方法:收集临床上拔除的下颌第二磨牙86颗,通过透明牙方法,观察牙根的分类、根管的分型和侧副根管的发生情况。结果:86颗下颌第二磨牙中,有44颗双根牙,36颗融合牙,6颗三根牙。双根牙中,近中根管以2-2型居多,其次为1-1型,远中根管大部分为1-1型根管。36个融合牙中,C型根10个,2例近远中完全融合形成2-1型根管,剩余近远中有独立2根管,24例中近远中根管以1-1型常见。无论牙根形态如何,近中根管均有广泛的根管交通;结论:下颌第二磨牙牙根和根管形态具有多样性,给临床根管治疗带来困难。

Objective：To research regularity and significance on the root shape of mandibular second molars.Method：86 mandibular second molars were collected and classified and counted according to dental root-shapes and types of canals.Result：The mandibular second molars were divided into three types-double roots,three roots and fusedroot.There are double roots 51.1 %,three roots 7.0% and fusedroot 41.9 % in the specimen.In the mesial root of 44 double roots,the most common configuration types were type 2-2.In the distal root of these teeth,type 1-1 is the most frequent type.There are 10 C-shape canals among 36 fusion teeth.The prevalance of type 1-1 of the rest 24 fusion teeth which have separate mesial and distal canals is the highest.Despite of root morphology,accessory canals exist widely in mesial canals.Conclusion：The varieties of root and canals morphology have a relationship to root canal treatment.