Evaluation of inferior alveolar canal course using cone-beam computed tomography

“Nothing is more fundamental to treating patients than knowing anatomy.” The head-and-neck regions are anatomically complex areas of the body. This considerable anatomical and functional complexity makes radiographic interpretation of this region a challenging task.[1] Conventionally, maxillofacial radiological studies, regardless of the imaging technique, provided only a two-dimensional view of complicated three-dimensional (3D) structures and have limitations such as magnification, distortion, superimposition, and misrepresentation of structures. However, with the recent technological advancement, radiological imaging has moved toward 3D and interactive imaging applications.[2] Introduction of 3D imaging modalities such as computed tomography (CT) and cone-beam CT (CBCT) has revolutionized our ability to virtually dissect maxillofacial structures. A major concern related to dental CT is the high radiation dose. CBCT technique provides a relatively high isotropic spatial resolution of osseous structures with a reduced radiation dose compared with CT scans. Introduction CBCT has made it possible for the clinician to more accurately evaluate the anatomy of the dental structures.[3] Inferior alveolar canal (IAC) is a critical anatomical structure which poses great variation in its course and configuration.[4] The IAC houses the inferior alveolar nerve (IAN), the inferior alveolar artery, and inferior alveolar vein. The knowledge of the exact course of the IAC, its neurovascular bundle and its anatomical variations are of great importance during surgical procedures such as third molar surgery, implant placement, osteotomy, and orthognathic surgery to avoid a high risk of Abstract Background and Objective: Radiographic interpretation of inferior alveolar canal (IAC) and other anatomical structures of the mandible are very important, since the injury to these structures during surgical procedures may pose complications. The present study evaluates the course of the IAC and its variations both in the vertical and buccolingual dimension and to analyze the related anatomical structures of the mandible, using cone-beam computed tomography (CBCT). Methodology: Three-dimensional scans of the 80 dry human mandibles were obtained using CBCT. The images were evaluated for the course of the IAC, in vertical and buccolingual dimensions. The images were analyzed for the presence of bifid mandibular canal and anterior mandibular structures such as median lingual foramen and canals, lateral lingual canals, for the visibility of incisive canals, and incidental findings. Results: Course of the IAC was observed as progressive descent in 36.9%, straight projection in 33.1%, and catenary like configuration in 30%. The evaluation of the buccolingual dimension showed three types of the canal as sharp turn pattern in 59.4%, curved soft exit in 35%, and straight exit in 5.6%. Bifid canals were found in 57.5% and median lingual foramen was noted in 96.3%. Median lingual canal, lateral lingual canal, and incisive canal were found in 87.5%, 20.6%, and 96.3%, respectively. Bilateral accessory mental foramen was found in one sample. Conclusion: The study revealed the interpretation of multiple mandibular anatomic structures, their variations and a range of measurement data using CBCT. This knowledge helps the clinician for precise treatment planning for implant placement and to avoid possible implications during any surgical procedures.