Assessment of variations of mandibular canal using cone beam CT
콘빔시티를 이용한 하악관 변이에 관한 연구
Dept. of Dentistry/박사
AbstractAssessment of variations of mandibular canalusing cone beam CTSang-Sun HanDepartment of DentistryThe Graduate School, Yonsei University (Directed by Professor Chang-Seo Park D.D.S., Ph.D.) Anatomical variations of mandibular canal such as bifid mandibular canal, retromolar canal, and accessory mental foramen may be vulnerable to damage during surgical procedures in the mandible. The variations of mandibular canal are of clinical importance as they include neurovascular bundle. However, low prevalence of the variations has been reported in studies with panoramic radiograph. Recently, as the use of cone beam CT has gained popularity, it is now possible to confirm more anatomical variations of the mandibular canal that cannot be assessed with conventional imaging. The objective of this study was to investigate the prevalence and features of bifid mandibular canal, retromolar canal and accessory mental foramen in Korean people using cone beam CT. Cone beam CT images from total 446 patients were analyzed for the prevalence and configuration of the variations of mandibular canal on the reformatted images of panoramic, axial, cross-sectional, and sagittal sections Bifid mandibular canals were found in 12.6% (56 patients), and retromolar canals were found in 8.5% (38 patients). Accessory mental foramina were found in 8.1% (36 patients), the prevalence of accessory mental foramen in male was higher than in female with statistical significance (p<0.05). According to classification of course, type I of bifid mandibular canal and type A of retromolar canal appeared more frequently. Accessory mental foramina mostly were located on anterior-superior region of the mental foramina. In this study, the prevalence of bifid mandibular canal, retromolar canal, and accessory mental foramen was higher than that of previous reports using panoramic radiograph, and they are no longer considered as rare anatomic structures. Therefore special attention has to be paid for identification of the variations prior to surgical procedures involving the mandible. Cone beam CT with multiplanar reformatted images is considered as an effective modality for detailed evaluation of the presence and features of variations of mandibular canals.