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Anatomical Assessment of the Inferior Alveolar Canal and Anterior Loop and Measuring its Distance to Mental Foramen in Patients Referred to Radiology Clinics of Shiraz in 2017

Ali Rahimi, Alireza Tabbakh, Alireza Tabbakh


Knowledge about inferior alveolar canal (IAC) position is very important in dental surgical procedures of the mandible. It has a close relation to mandibular molar teeth. Anatomic imaging of the mandibular canal prior to surgical procedures, such as implant placement and sagittal split osteotomy, is essential for the best result and minimal complications.

Purpose: The aim of this study is to determine normal variations of the mandibular canal and mental foramen in a selected population.

Material and methods: A total of 668 high qualities CBCT images of edentulous and dentate patients aged from 15 to 75 were evaluated. CBCT projections were analyzed in different planes (tangential, cross-sectional, and axial). Bifid mandibular canal, presence of anterior loop, the level of cortication and mental foramen variations were identified in cross-sectional and axial views.

Result: 668 images, 238 males and 430 females, were evaluated. Statistical analysis did not show a significant correlation between prevalence of bifid mandibular canal, anterior loop and mental foramen in both sides with age and sex (p>0.05). A significant relationship was seen between right mandibular canal cortication and age (p=0.003). Anterior loop was detected in 90.5% of cases, and its length was 3.34  while accessory mandibular canal was observed in 4.6% of patients only.

Conclusion: This study showed that there are numerous anatomical variations of the mandibular canal, mental foramen and anterior loop. Dentists should be familiar with these variations in order to prevent treatment complications and success of mandibular related dental procedures.


inferior alveolar canal; mandibular canal; mental foramen; anterior loop; CBCT


Greenstein G, Cavallaro J, Tarnow D. Practical application of anatomy the dental implant surgeon. J Perio. 2008, 11: 837-839

Carter R B, Keen E N. The intra mandibular course of the inferior alveolar nerve. J Anat. 1971, 108(3):433-440

Moiseiwitsch JRD. Position of the mental foramen in a North American, white population. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998, 85(4):457-64

Wadu SG, Penhall B, Towsend GC. Morphological variabilitu of the human inferior alveolar nerve. Clin Anat. 1997, 10(2):82-87

Haveman CW, Tebo HG. Posterior accessory foramina of the human mandibular. J Prosthet Dent. 1976, 35:462-468

Chavez ME, Mansilla J, Pompa JA, et al. The human mandibular canal arises from three separate canals innervating different tooth groups. J Dent Res. 1996, 75:154-160

Langlais RP, Broadus R, Glass BJ. Bifid mandibular canals in radiographs. J Am Dent Assoc. 1985, 110:923-926

Rouas P, delbos Y, Nancy J. Pseudo multiple and enlarged mandibular canals: the evidence-based response of cone beam computed tomography. Dentomaxillofac Radiol. 2006, 217-218

Igarashi C, Kobayashi K, Yamamoto A, Morita Y, Tanaka M. Double mental foramina of the mandibular on computed tomography images: a case report. Oral Radiol. 2004, 20:68-71

Auluck A, Pai K M. Trifid mandibular nerve canal. Dentomaxillofac Radiol. 2005, 34(4):259

Nortje CJ, Farman AG, de V Joubert JJ. The radiographic appearance of the inferior dental canal: an additional variation. Br J Oral Surg. 1977, 15:171-172

Langlaiis RP, Broadus R, Glass BJ. Bifid mandibular canals in radiographs. J Am dent Assoc. 1985, 110:990-992

Oliver E. Le canal dentairinferieuret son nerf chez ladulte. Ann Anat Pathol. 1927, 4:975-987

Nortje CJ, Farman AG, Grotepass FW. Variations in the normal anatomy of the inferior dental (mandibular) canal: a retrospective study of panoramic radiographs from 3612 routine dental patients. Br J Oral surg. 1977, 15:55-63

Grover PS, Lorton L. Bifid mandibular nerve as a possible cause of inadequate anesthesia in the mandibular. J Oral MaxillofacSurg. 1983, 41:177-179

Sicher M, Bruls Du. Oral Anatomy. J Anat. 1990, 169:266-277

Scarf WC, Farman AG, Sukovic P. Technical Description of CBCT from University of Manchester: Clinical applications of cone-beam computed tomography in dental practice. Journal of the Canadian Dental Association. 2006, 72(1):75-80

Hatcher DC. Operational principles for cone-beam computed tomography. Journal of the American Dental Association. 2010, 3:3S-6S

Orth RC, Wallace MJ, Kuo MD. C-arm cone-beam CT: general principles and technical considerations for use in interventional radiology. Journal of Vascular and Interventional Radiology. 2008, 19(6):814-20

Mah JK, Huang JC, Choo H. Practical applications of cone-beam computed tomography in orthodontics. Journal of the American Dental Association. 2010, 141(3):7S-13S

Nikzad S,Azari A, Sabouri S. Double mandibular foramina and canal: report a case with interactive CT-based planning software. Iran J Radiol. 2008, 5(2):83-86

Norton MR, Gamble C. Bone classification: an objective scale of bone density using the computerized tomography scan. Clinical Oral Implants Research. 2010, 12(1):79-84

Mah P, Reeves TE, McDavid WD. Deriving Hounsfield Units using grey levels in cone beam computed tomography. Dentomaxillofacial Radiology. 2011, 39(6):323-35

Zografos J, Kolokoudias M, Papadakis E. The types of mandibular canal. Hell Period Stomat Gnathopathoprosopike Cheir. 1999, 5:17-18

Patterson JE. Bifid inferior alveolar canal. Oral Surg Oral Med Oral Pathol. 1973, 36-39

Leite GM, Lana JP, de Carvalho Machado V , Manzi FR, Souza PE, HortaMC. Anatomic variations and lesions of the mandibular canal detected by cone beam computed tompography. SurgRadiol Anat. 2014, 36(8):795-804

Leite GM, Lana JP, Carvalho Machado V, Manzi FR, Souza PE, Horta MC. Anatomic variations and lesions of the mandibular canal detected by cone beam computed tompography. SurgRadiol Anat. 2014, 36(8):795-804

Sanchis JM, Penarrocha Miguel, Soler F. Bifid Mandibular Canal. J Oral Maxillofac Surg. 2003, 61:422-424

Kim MS Yoon SG, Park HW, Kang JH, Yang SY, et al. A false presence of bifid mandibular canals in panoramic radiographs. Dentomaxillofac Radiol. 2011, 40(7):434-438

Apostolakis D, Brown JE. The anterior loop of the inferior alveolar nerve: prevalence, measurement of its length and a recommendation for interforaminal implant installation based on cone beam CT imaging. Clin Oral Implants Res. 2012, 23:1022-1030

Kaufman E, Serman NJ, Wang PD. Bilateral mandibular accessory formina and canals: a case report and review of the literature. Dentomaxillofac Radiol. 2000, 29(3):170-175

Su Kyoung Yu, Seog Kim, Shin Gu Kang, Jae Hyuk Kim, et al. Morphological assessment of the anterior loop of the mandibular canal in Koreans. Anat Cell Biol. 2015, 48(1):75-80

Koutouzis T, Wennstrom JL. Bone level changes at axial and non-axial positioned implants supporting fixed partial dentures; a 5-year retrospective longitudinal study. Clinical oral implants research. 2007, 18(5):585-90

Capote TS, Goncalves MA, Campos DB. Retromolar canal associated with age, side, sex, bifid mandibular canal, and accessory mental foramen in Brazilians panoramic radiographs. Anatomy Research International. 2015, 8:43-48

KarbasiKheir M, Hekmatian E. Cone-beam computed tomography evaluation of mental foramen variations; a preliminary study. Radiology Research and Practice. 2015, 4:36-47

Fabian M. Position, shape and direction of opening of the mental foramen in dry mandibulars of Tanzanian adult black males. Italian Journal of Anatomy and Embryology. 2007, 112(3):169-177

Ossenberg NS. Retromolarforamen of the human mandibule. Am J Phys Anthropol. 1987, 73:119-128

Powcharoen W, Chinkrua C. Cone-beam computed tomographic assessment of mandibular canal as predictors of intraoperative nerve exposure after third molar surgery. Anatomy Research International. 2015, 1654-1701

Panjnoush M, Mirzaey M, Tari M. Pre-implant linear tomography using film-screenand photostimulable phosphor plate in mandible. Journal of Dental Medicine. 2010, 23(2):128-133

Elias CN, Meirelles L. Improving osseointegration of dental implants. Expert review of medical devices. 2010, 7(2):241-256

Dubey RK, Gupta DK, Singh AK. Dental implant survival in diabetic patients; review and recommendations. National Journalof Maxillofacial Surgery. 2013, 4(2):142-150

Ylikontiola L, Moberg K, Huumonen S, Soikkonen K, Oikarinen K. Comparison of three radiographic methods used to locate the mandibular canal in the buccolingual direction before bilateral sagittal split osteotomy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002, 93(6):736-742

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