Classification of bifid mandibular canals using cone beam computed tomography

Abstract

The objective of this study was to classify the morphology of bifid mandibular canals and to evaluate their relationship with the roots of third molars, using cone beam computed tomography (CBCT) scans. The CBCT scans of 75 patients were analyzed and the bifurcations were classified according to Langlais et al. (1985). The relationship of bifurcation and third molars was established according to the following classification: class A -uninvolved, class B -close relationship, class C -intimate relationship and class D -absence of third molars. Data were submitted to descriptive statistics, and the results indicated that the patients' mean age was 48.2 (± 13.2) years. Unilateral bifurcation (Type 1) was the most frequent type (72.6%), followed by unilateral Type 2 (19.3%). Class D was the most frequent (57.33%), followed by class C (21.33%), class B (13.33%) and class A (8%). It could be concluded that most cases presented unilateral bifid mandibular canals extending to the third molar or adjacent regions, and when present, the roots seemed to be a continuation of the bifid mandibular canal.

Prevalence of bifid mandibular canal and its relationship with third molar in Indian population: A retrospective analysis

“…CBCT scans provide clearer images of the mandibular canal when compared to digital panoramic radiographs as they are free of overlap and other problems inherent to panoramic radiographs. [3] In the present study, CBCT images of 23 patients demonstrated bifid mandibular canal out of 408 CBCT images accounting for the prevalence of 5.63%. Males were found to be predominant over females for the presence of bifid mandibular canal.…”

“…Correr et al, in 2013, [3] found majority of bifurcations to be Type 1U showing Class C, i.e., intimate relationship with the roots of the third molar. However, in the present study, Type 2BC was the most common bifurcation seen followed by Type 1U, 1B, 2UR, 2UC, and Type 4 canal.…”

“…These errors include superimposition of bony structures, inadequate position of the patient, distortion of the radiograph and magnification of the device, bony condensation produced by mylohyoid ridge in the floor of the mouth, or anatomy of mylohyoid groove. [3,7] Thus, OPG aids in identifying the suspected bifid or trifid mandibular canals but not the confirmation. Due to superimposition of canals, buccal/lingual bifid canals cannot be identified in the panoramic radiographs.…”

“…CBCT images were categorized on the basis of gender and side, morphology of bifurcation according to Langlais et al [5] [ Figure 1] and relationship of bifid mandibular canal to third molar roots according to Correr et al [ Figure 2]. [3] …”

“…[2] Certain clinical implications are associated with bifid mandibular canal such as inadequate anesthesia being the most common complication followed by bleeding, paresthesia, traumatic neuroma during impacted mandibular third molar removal, implant placement, mandibular fracture reduction, denture fabrication, root canal treatment, etc. [3] After the inferior alveolar nerve block, if the anesthesia occurs only around the site of injection but not the lip or chin, then it is attributed to incorrect anesthetic technique. However, with the inferior alveolar nerve block, if the anesthesia occurs only in the lower lip and chin but not the teeth, it is indicative of the presence of bifid mandibular canal with accessory neurovascular bundle.…”