下颌第二恒磨牙C形根管的影像学分析

Radiological analyses of C-shaped root canals in mandibular second molars

目的通过比较分析离体下颌第二恒磨牙C形根管的X线片和锥形束CT(CBCT)表现,为临床诊疗提供参考。方法收集我院因牙周病拔除的下颌第二恒磨牙110颗,模拟临床拍摄颊舌向X线片,并进行CBCT扫描。统计C形根管的发生率及其类型。结果 110颗离体下颌第二恒磨牙中,通过X线片诊断为C形根管的46颗(41.81%),通过CBCT影像确诊为C形根管显示66颗(60.00%)。通过CBCT诊断为C形根管的离体牙中,其中Ⅰ类(融合型)26颗,Ⅱ类(对称型)22颗,Ⅲ类(不对称型)18颗。Ⅰ类中,C4截面形态主要在根管下段出现的频率较高,Ⅱ类中,C3在整个根管各段中出现的频率较高。Ⅲ类中,C1和C2主要出现在根管上段。结论具有C形根管的下颌第二磨牙基本可以通过X线片初步诊断,但如需了解其根管的详细信息则要通过CBCT扫描分析。

Objective The purpose of this study was to investigate radiographic features of the C-shaped canal system in mandibular second molars in vitro with X-ray films and CBCT,and provide reference for clinical diagnosis. Methods There were 110 extracted mandibular second molars for periodontal inflammation reasons in our clinic. After taking their buccal-lingual radiographs. Each tooth was scanned with CBCT. Analyze the rate of C-shaped root canals and their types through preoperative radiographs and CBCT. Results Among those 110 mandibular second molars,we could diagnose 46 teeth （41.81%）with C-shaped root canals through preoperative radiographs and 66 （60.00%）through CBCT. Each mandibular second molar with C-shaped canals diagnosed by CBCT was assigned to three categories ：Type I （ Merging Type,26） ,Type II （ Symmetrical Type, 22）, Type III（ Asymmetrical Type, 18 ）. CBCT showed that in the type I category,C4 canal configuration was mostly found in the lower area. In type II , C3 was the main canal shape over the whole canal length. In type III ,C1 and C2 were the main canal shapes in the coronal canal portion. Conclusions The mandibular sec- ond molars with C-shaped canal system have a series of radiographic characteristics,and it is possible to predict the presence and the configuration of most C-shaped canals by X-ray films. If you want to learn detailed information,CBCT will be needed.