下颌第二恒磨牙根管系统的形态学研究

目的了解下颌第二恒磨牙牙根及根管的类型,为提高根管治疗的效果提供解剖学依据。方法收集682例离体下颌第二恒磨牙,进行牙体测量,透明牙标本制作,分别对牙根及根管系统进行研究。结果 682例离体牙中双根牙最多,占55.13%(376/682),其中97例为C形根管,占14.22%。除外97例C形根管,585例离体牙的7种不同类型根管中,1-1型、2-1型、2-2型最多,近中根为85.64%(501/585),远中根为96.75%(566/585);近中根中双根管或单双根管混合型占72.14%(422/585),远中根中占18.29%(107/585);近中根的双根管口率为60.00%(351/585),远中根为15.73%(92/585);近中根的双根尖孔率为35.21%(206/585),远中根为13.50%(79/585)。根管侧支、管间侧支、根尖分叉的出现率分别为24.19%(165/682)、22.14%(151/682)和8.21%(56/682)。55.76%(416/746)的近中根根尖孔位于根尖顶,57.85%(383/662)的远中根根尖孔位于根尖顶。结论下颌第二恒磨牙根管的类型复杂,充分了解其根管解剖对提高根管治疗效果、减少根管遗漏有重要意义。

Morphological studies on the root canals of mandibular second molars

Objective To study the types of dental root and root canal of mandibular second molars so as to provide anatomical evidence for root canal therapy.Methods A total of 682 well-developed mandibular second molars were examined after decalcifying and clearing technique.Results 55.13%(376/682) of the 682 mandibular second molars had two roots.C-shaped canal system was found in 97 teeth(14.22%).Among seven categories of canal systems in the other 585 teeth,type 1-1,type 2-1 and type 2-2 were found commonly,with the incidence being 85.64%(501/585) in mesial roots and 96.75%(566/585) in distal roots.Double-canal type or the mixed form was examined in 72.14%(422/585) of mesial roots and 18.29%(107/585) of distal roots.60.00%(351/585) of mesial roots had double canal orifices and 35.21%(206/585) had two apical foramens,while 15.73%(92/585) of distall roots had double canal orifices and 13.50%(79/585) had two apical foramens.The incidence rate of lateral canal,transverse anastanose and apical delta were 24.19%(165/682),22.14%(151/682) and 8.21%(56/682),respectively.The apical foramina located at the apex of 55.76%(416/746) mesial roots and 57.85%(383/662) distal roots.Conclusion The canal systems of mandibular second molars vary considerably in their anatomical configuration.Therefore,it is very important to comprehensively learn anatomic knowledge of root canal for the clinical outcomes of root canal therapy.