A Clinical Study Of C-shaped Incidence And Canal System Of Mandibular Second Molars Of The Uygur And The Han Ethnic Group

Objective:The Purpose of this study was to compare the incidence of the C-shaped mandibular second molars and the anatomical features of C-shaped canal system in the Han ethnic group and the Uygur patients visited in the stomatological hospital. Methods: A total of 752 mandibular second molars being considered as needing root canal therapy were included in this study, which the Uygur are 432 and the Han ethnic group are 320. After taking their preoperative radiographs, we grand and cleaned the pulp cavities. Observe and record the form of root canal orifice by the operating microscope and then take the initial apical file radiographs of the verified C-shaped canal systems. The incidence of the C-shaped canal of the mandibular second molars and the anatomical structure of the C-shaped canal system were further analyzed. Results:Of the 752 mandibular second molars,168 were diagnosed as having C-shaped canal system based on the combination of the microscope and preoperative radiograph,66 and 102 of which were the uygur and the Han ethnic group respectively.157 C-shaped canals were diagnosed by the microscope,84,47and 26 of which were C1, C2 and C3. C1, C2 and C3 were 31,20 and 11 in the Uygur, and 53,27 and 15 in the Han ethnic group. According to the IAF films,73,61 and 34 were classified as radiographic typeâ… ,â…¡andâ…¢. Typeâ… ,â…¡andâ…¢were 29,22 and 15 in the Uygur group, and 44,39 and 19 in the Han ethnic group. Conclusions:The incidence of the C-shaped mandibular second molars in the Han ethnic group is higher than in the Uygur;the most common configuration of canal orifice are C1 and the anatomical structure of the C-shaped canal system are typel all in the Han ethnic group and the Uygur.