하악 제2대구치의 C형 근관계에 관한 연구

Abstract

C-shaped canals are known to present a complex canal anatomy with numerous fins connecting individual canals, thus requiring supplementary effort to accomplish a successful root canal treatment. This study examined the frequency of the C-shaped mandibular second molars and interrelation between the clinical records and radiographs to recognize them treated in the Department of Conservative Dentistry of the Chosun University Dental Hospital during a six-year period (1998-2004). This study reviewed the clinical records of 227 patients who underwent root canal treatment of the mandibular second molars. After opening the chamber, those cases with C-shaped orifices in the pulpal floor were selected, and the C-shaped root canal types were classified according to Melton's criteria. Three experienced dentists evaluated the radiographs of the C-shaped mandibular second molar on a viewer using a magnifying glass in order to determine if the root apex was fused or separated, the distal root canal was either centered or mesial shifted in the distal root, and if there was bilateral symmetry in a panorama. The data was analyzed statistically. The results were as follows: 1. In the clinical observations, 82 out of 227 teeth (36.12%) had C-shaped root canals, and there was a higher frequency of type Ⅱ (60.96%) than types Ⅰ (13.41%) and Ⅲ(25.61%). There were statistically significant differences in the frequency among the C-shaped root canal types (p＜0.01). 2. In the radiographic findings of the C-shaped mandibular second molars, 51 out of 82 teeth (59.76%) showed a fused root and 31 out of 82 (40.24%) showed separated root. There was a statistically significant difference in the root shape between the fused and separated root (p＜0.01). 3. In the radiographic findings of the C-shaped mandibular second molars, 16 out of 82 (19.51%) showed a centered root canal and 66 out of 82 (80.49%) showed a mesial shifted root canal in the distal root. There was a statistically significant difference in the distal root canal position between the centered and mesial shifted distal root canal (p＜0.01). 4. The panoramic findings of C-shaped mandibular second molars showed that 57 out of 74 (77.03%) had a bilateral symmetry. In conclusion, there is a high frequency of C-shaped mandibular second molars in Koreans. Simultaneous interpretation of the root shape and distal root canal using the preoperative, working length and post-treatment radiographs is important for diagnosing a C-shaped mandibular second molar.