下颌前牙根管变异的锥形束CT研究

目的 运用锥形束CT(CBCT)研究下颌前牙的根管变异情况。方法收集250例患者的1352颗下颌前牙的CBCT资料,运用配套软件对牙齿的冠状面、矢状面以及横断面进行影像学分析,统计和分析牙根数目、根管数目、根管类型、对称性分布等。结果 下颌切牙均为单根,下颌尖牙双根发生率为1.45%。下颌中切牙、侧切牙、尖牙双根管发生率分别为17.34%、34.08%、9.05%。双根管的发生呈对称性分布,一侧出现双根管时,对侧同名牙也为双根管的概率下颌侧切牙最高,为77.78%,中切牙次之,为72.97%,尖牙为64.00%。按照Vertucci根管分型,共观察到除Ⅳ型和Ⅷ型外的6种根管类型,其中以Ⅰ型为主,为80.00%,其次为Ⅲ型,为16.51%。结论下颌前牙根管系统复杂多变,其中下颌侧切牙双根管发生率最高,双根管以Vertucci Ⅲ型为主,锥形束CT是诊断下颌前牙根管变异的有效手段。
Objective To investigate variations of the root canal in mandibular anterior teeth using cone-beam computed tomography (CBCT). Methods A total of 1 352 CBCT images of mandibular anterior teeth from 250 patients were collected. The number of roots and root canals, root canal configurations and symmetry of root canals were investigated and analyzed statistically. Results All of the incisors had only one root while 1.45% of the canines had two roots. The prevalence of two root canals in mandibular central incisors, lateral incisors and canines were 17.34%, 34.08% and 9.05%, respectively. The frequency of symmetry of teeth with two canals was highest in lateral incisors (77.78%), followed by central incisors (72.97%) and canines (64.00%). Six Vertucci root canal configurations were observed except type Ⅳ and type Ⅷ, and typeⅠ(80.00%)was most frequent, followed by type Ⅲ (16.51%). Conclusion Mandibular anterior teeth have complex root canal systems and Vertucci type Ⅲ is the most frequent type in mandibular anterior teeth with two canals. The mandibular lateral incisor has higher prevalence of two canals. CBCT was an effective method for diagnosis of complex root canal system