下颌恒磨牙根管系统的锥形束CT研究

目的：利用CBCT评估下颌恒磨牙根管系统解剖形态特征。方法：收集临床影像资料库中的下颌恒磨牙CBCT影像资料863例,记录牙位、牙根和根管数目,采用Vertucci分类法对根管构型进行分类描述。结果：①在558例下颌第一恒磨牙中,独立远舌根和四根管发生率分别为25.8%、51.4%,其中有48.1%第4个根管来自独立远舌根管。在双根牙中,93.9%近中根管是Ⅳ型,62.9%的远中根管是Ⅰ型。在三根牙中,94.4%的近中根管是Ⅳ型,98.6%的远颊根管和100%远舌根管是Ⅰ型。②在305例下颌第二恒磨牙中,融合根和C型根管的发生率分别为47.2%、41.6%。在双根牙中,66.0%近中根管是Ⅳ型,92.3%的远中根管是Ⅰ型。结论：CBCT可评价下颌恒磨牙根管系统解剖形态特征。下颌第一恒磨牙通常有4个根管,独立远舌根管的发生率较高,下颌第二恒磨牙融合根和C型根管的发生率均较高。

A CONE-BEAM COMPUTED TOMOGRAPHY STUDY OF MANDIBULAR PERMANENT MOLAR ROOT CANAL SYSTEM MORPHOLOGY

Objective： To evaluate the root canal morphology of mandibular permanent molars by using cone-beam computed tomography（CBCT）.Methods： 863 Mandibular permanent molars were examined by CBCT.Details of tooth position,the number of roots and canals,and the canal configuration were recorded.The root canal configuration was categorized and compared according to Vertucci’s criteria.Results： ①51.4% of the mandibular first permanent molars examined had four canals,48.1% of which,the fourth canal was in the separate distolingual root.25.8% had three roots,and all the third root was a separate distolingual root.In the two-rooted samples,93.9% of the mesial root canals were of type Ⅳ,and 62.9% of the distal root canals were of type Ⅰ.In the three-rooted samples,94.4% of the mesial root canals were of type Ⅳ,and 98.6% of the distobuccal and 100% of the distolingual root canals were of type Ⅰ.②47.2% of the mandibular second permanent molars examined had fused roots,and 41.6% had C-shaped canals.In the two-rooted samples,66.0% of the mesial root canals were of type Ⅳ,and 92.3% of the distal root canals were of type Ⅰ.Conclusion： CBCT scans allow the identification of anatomic features of the root canal systems.Mandibular first permanent molars commonly have four canals and a higher prevalence for a separated distolingual canal.Mandibular second permanent molars commonly have higher prevalence of a C-shaped root canal system.