下颌前磨牙牙根形态和根管系统的锥形束CT研究

Study on root and canal morphology of mandibular premolars by cone-beam computed tomography

目的采用锥形束CT(Cone-beam computed tomography,CBCT)研究下颌前磨牙牙根及根管系统解剖形态特征。方法回顾148例患者288颗下颌第一前磨牙和218颗下颌第二前磨牙的CBCT影像,分析牙根和根管系统形态,采用Vertucci等提出的分类法对根管构型进行分类。结果 288颗下颌第一前磨牙单根牙285颗,双根牙2颗。三根牙1颗;根管Ⅰ型占77.78%,Ⅱ型0.34%,Ⅲ型2.08%,Ⅳ型0.69%,Ⅴ型14.58%,Ⅶ型1.04%,Ⅹ型0.69%,C型2.78%。218颗下颌第二前磨牙全部为单根;根管Ⅰ型占98.17%,Ⅴ型占1.83%。结论下颌前磨牙大多数是单根单根管。下颌第一前磨牙根管系统具有较大的变异性。下颌第一前磨牙多根管类型主要是Ⅴ型,C型根管的检出率也较高。而下颌第二前磨牙多根管的发生率远低于下颌第一前磨牙。多根管的分歧发生在根中或根尖1/3处。CBCT可用于下颌前磨牙复杂根管形态的评价。

Objective To evaluate the root and canal morphology of mandibular premolars using cone-beam computed tomography（CBCT）. Methods CBCT images of 288 mandibular first premolars and 218 mandibular second premolars from 148 patients were retrospectively analyzed. The numbers of roots and canals were recorded,and root canal systems were categorized according to Vertucci（1984） and other scholars＇ criteria. Results The results showed that 285 mandibular first premolars had one root,2 had two roots,and 1 had three roots. The incidence of typeⅠ canal configuration of mandibular first premolars was 77.78%,type Ⅱ 0.34%,type Ⅲ2.08%,type Ⅳ 0.69%,type Ⅴ 14.58%,type Ⅶ 1.04%,and type Ⅹ 0.69%. The prevalence of C-shaped canal was 2.78 %. All 218 mandibular second premolars had one root. Type Ⅰ was 98.17%,type Ⅴ1.83%. Conclusion Most mandibular premolars have one root and one canal; the root canal system of mandibular first premolars has great variability. The type of multiple canals in mandibular first premolars is mainly Type V; and the prevalence of C-shaped canal is high. The mandibular second premolars have a lower rate of canal variation compared with the first. Root canal bifurcation occurs in the middle of the root or in one third part of root tip in most bicanal mandibular premolars. CBCT scanning can be used in the evaluation of mandibular premolars with complex canal morphology.