Prevalence evaluation and classification of bifid mandibular canals in CBCT exams in different facial types

George Borja De Freitas,Alessandra De Freitas E Silva,José Luiz Cintra Junqueira,Luiz Roberto Coutinho Manhães Júnior

doi:10.1590/1807-2577.10617

Abstract

Abstract Objetive The aim of this study is to establish the prevalence and classification of mandibular canal alterations using cone beam computed tomography (CBCT) in different facial types. This research was submitted and approved by the research ethics committee, registration number 2.065.839. Material and method The sample consisted of 90 CBCTs from the São Leopoldo Mandic Dental School database (Campinas-SP), divided into three groups according to brachycephalic, dolichocephalic and mesocephalic facial types. Result Of the 90 patients, 23 presented bifid mandible canals (25.6%), of which 60.9% were in males and 39.1% in females. In 39.1%, the canal bifurcation occurred towards the retromolar region (class D), 21.7% had a trajectory to an alveolar or upper direction (class C) and 13.1% were classified as C-E. For the remaining classifications (A, E, F and A-E), the frequencies were in the range of 8.7% to 4.3%. None of the 23 cases of mandibular canal bifurcation was classified as B (mesial direction). Conclusion According to the results obtained from this study, the prevalence of bifid mandibular canals was found to be 25.6%, with class D being the most prevalent for the retromolar region and the highest occurrence was unilaterally on the left side. When evaluating the occurrence of bifid mandibular canals in relation to facial types, brachycephalic patients were the most affected.

Highlights

Mandibular canals are intraosseous conduits, usually presenting as a single structure on each side of the mandible, beginning on the medial aspect of the ramus in the mandibular foramen and out through the mental foramen, with or without a continuous intraosseous path towards the anterior region as a single canal
The mandibular canal is characterized by a radiolucent band, delimited by two radiopaque lines[4], generally as a single structure, assuming different positions inside the body of the mandible, both in the upper-lower and mid-lateral directions, occasionally showing duplications or bifurcations along its path and, in some cases, trifurcations
The literature points to the importance of knowing the anatomy of the mandibular canal and its possible variations for the success of many dental procedures performed on the mandible, such as anesthesia, endodontics, periodontics, pediatric dentistry and more invasive procedures such as surgical exodontia, orthognathic surgeries, implant placement, among others[9,16,19,20,21]

Summary

Introduction

Mandibular canals are intraosseous conduits, usually presenting as a single structure on each side of the mandible, beginning on the medial aspect of the ramus in the mandibular foramen and out through the mental foramen, with or without a continuous intraosseous path towards the anterior region as a single canal. The mandibular canal is characterized by a radiolucent band, delimited by two radiopaque lines[4], generally as a single structure, assuming different positions inside the body of the mandible, both in the upper-lower and mid-lateral directions, occasionally showing duplications or bifurcations along its path and, in some cases, trifurcations. Because of this considerable variation in its course, it is difficult to predict the exact position of the inferior alveolar nerve[5,6]. Trans and postoperative surgical complications, anesthetic failures and implant placement failures may occur[9]

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