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 Table of Contents  
CASE REPORT
Year : 2014  |  Volume : 1  |  Issue : 1  |  Page : 25-26

Bifid mandibular canal: Case report and review of literature


1 Department of Oral Medicine Diagnosis and Radiology, Vyas Dental College and Hospital, Jodhpur, Rajasthan, India
2 Department of Public Health Dentistry, Vyas Dental College and Hospital, Jodhpur, Rajasthan, India
3 Department of Oral Medicine, Rama Dental College, Kanpur, Uttar Pradesh, India

Date of Web Publication21-Oct-2014

Correspondence Address:
Sumit Bhateja
05072, Ats Advantage, Ahinsa Khand-I, Indirapuram, Ghaziabad - 201 014, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2394-2010.143322

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  Abstract 

Bifid mandibular canals are often unrecognized. The detection of these anatomical variations is important because of its clinical implications. Special attention has to be paid in surgical procedures involving the lower jaw. Purpose of the present article is to provide an extensive review of literature of this anatomical variation and also we present one such case report.

Keywords: Bifid mandibular canal, double mandibular canal, inferior alveoloar canal


How to cite this article:
Bhateja S, Arora G, Bhasin M. Bifid mandibular canal: Case report and review of literature. J Health Res Rev 2014;1:25-6

How to cite this URL:
Bhateja S, Arora G, Bhasin M. Bifid mandibular canal: Case report and review of literature. J Health Res Rev [serial online] 2014 [cited 2020 Oct 22];1:25-6. Available from: https://www.jhrr.org/text.asp?2014/1/1/25/143322


  Introduction Top


The mandibular canal transmits the inferior alveolar artery and nerve which is a branch from the third division of trigeminal nerve extending from mandibular foramen to mental incisival region. Dental and incisive branches leave the inferior alveolar nerve within the canal to supply all mandibular teeth and adjacent structures. Within the canal, the alveolar nerve is approximately 4 mm in thickness. A secondary collateral of the inferior alveolar artery vascularises the sheath and nerve as well as the bony tissue around the canal. [1]

The term 'bifid' is derived from the Latin word meaning a cleft into two parts or branches. Bifid mandibular canals originate at the mandibular foramen and might each contain a neurovascular bundle. The various types of bifid mandibular canals have been classified according to anatomical location and configuration. Smaller accessory canals might be seen in association with normal or bifid mandibular canals. [2]

Classification

Carter and Keen [3] examined dissected human mandibles and described three types of inferior alveolar nerve arrangement:

  • Type I: The inferior alveolar nerve is a single large structure lying in a bony canal
  • Type II: The inferior alveolar nerve is situated substantially lower down in the mandible
  • Type III: The inferior alveolar canal is separated posteriorly into two large branches, which together could be regarded as equivalent to an alveolar branch.


Nortje et al., [4] described three main patterns of duplication:

  • Type I: (Most common)-duplicate canals originating from a single mandibular foramen, usually the same size
  • Type Ia: The lower canal is sometimes smaller
  • Type Ib: The upper canal is the smallest of the two canals
  • Type II: A short upper canal extending to the second or third molar areas
  • Type III: (least common)-two canals of equal size, arising from separate foramina, that join in the molar area
  • Type IV: Is a double-canal variation in which the supplemental canals arise from the retromolar pad area and join the main canals in the retromolar areas.


Langlais et al., [5] developed a classification system according to anatomical location and configuration:

  • Type I: Represents unilateral or bilateral bifid canals that extend to the mandibular third molar area or the immediately surrounding area (38.6% of bifids)
  • Type II: Includes unilateral or bilateral bifid canals that rejoin within the ramus of the mandible (54.4% of bifids)
  • Type III: Is a combination of types 1 and 2 (3.5% of bifids)
  • Type IV: Two canals, each of which originates from a separate mandibular foramen, join to form one larger canal (3.5% of bifids).



  Case Report Top


A 43-year-old female patient reported to the Department of Oral Medicine and Radiology with a complaint of missing teeth and wanted to get them replaced with artificial set of teeth since 6 months. Anamnesis was non contributory. Intraoral examination revealed missing teeth with respect to (wrt) 18, 28, 37, 38, 46, 47, 48. Root stumps were present wrt 25, 26, 27. The patient was referred to take an orthopantomogram for further evaluation. Orthopantomogram revealed an impacted molar tooth wrt 28. The existence of bilateral bifid mandibular canal was also noticed [Figure 1].
Figure 1: Bilateral mandibular canal (Encircled in yellow color)

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The patient was advised surgical removal of the impacted tooth and root stumps under local anesthesia and thereafter referred to prosthodontic department for fixed prosthodontics.


  Discussion Top


The presence of a bifid or duplicated mandibular canal must be considered at the time of realizing any surgical procedure in the area of the mandibular ramus and the mandibular body, such as dental extractions, reduction of fractures, placement or removal of implants, including root canal treatment. In these cases there is possibility of injuring the inferior alveolar nerve, which importance increases upon checking the study published by Sato et al., [6] which demonstrates by macroscopic dissection and computerized tomography (CT) scans, the lower artery, vein and alveolar nerve (principal trunks) were in close contact to the apexes of the second molar. [7] The number of duplicated mandibular canal cases was higher than that reported in other studies, as Sanchis et al., [8] where there was a prevalence of only 0.35% of mandibular canal duplications.

A review of the available literature revealed that the occurrence of bifid canals is unusual but is not thought of as being rare. The clinical relevance of this issue is to remind clinicians of the variable anatomy of the mandibular canal. Bifid mandibular canals may have some important clinical implications. Inadequate anesthesia may be possible with any bifurcation type, but especially when there are two mandibular foramens. [9]

When third molar surgery has to be carried out, extreme care must be used when there are bifid canals to the molar area. The tooth may infringe on or be within the canal itself. As a second neurovascular bundle may be contained within the bifid canals, complications such as traumatic neuroma, paraesthesia and bleeding could arise because of failure to recognize the presence of this anomaly and its implications. [10] In other surgical procedures such as mandibular osteotomy, the complexity of the surgery increases with the addition of a second neurovascular bundle. [9]

Furthermore, in cases of trauma, all mandibular fractures should be handled with care to ensure that the neurovascular bundle is lined up exactly to avoid impingement when the fracture is reduced. The alignment becomes much more difficult with a second neurovascular bundle located in a different plane. As alveolar bone resorbs to the proximity of the mental foramen, patients with mandibular prostheses may experience discomfort because of the pressure placed on the neurovascular bundle. This may also be a problem in the third molar and retromolar pad areas in the cases where the mandibular canal duplicates to the molar region. The study of this anomaly is obviously important in surgical procedures involving the lower jaw. [9]


  Conclusion Top


Bifid mandibular canals are present in a very tiny segment of the population. It is often unnoticed even though they can be recorded in panoramic radiographs The main purpose of this article is to call attention to an apparently harmless anomaly which can induce complications when surgery has to be performed.

 
  References Top

1.Poirot G, Delattre JF, Palot C, Flament JB. The inferior alveolar artery in its bony course. Surg Radiol Anat 1986;8:237-44.   Back to cited text no. 1
[PUBMED]    
2.Oliver E. Le canal dentair inferieur et son nerf chez l'adulte. Ann Anat Pathol 1927;4:975-87.   Back to cited text no. 2
    
3.Carter RB, Keen EN. The intramandibular course of the inferior alveolar nerve. J Anat 1971;108:433-40.   Back to cited text no. 3
[PUBMED]    
4.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.   Back to cited text no. 4
    
5.Langlais RP, Broadus R, Glass BJ. Bifid mandibular canals in radiographs. J Am Dent Assoc 1985;110:923-6.   Back to cited text no. 5
[PUBMED]    
6.Sato I. Ueno R. Kawai T, Yosue T. Rare courses of the mandibular canal in the molar regions of the human mandible: A cadaveric study. Okajimas Folia Anat Jpn 2005;82:95-101.  Back to cited text no. 6
    
7.Lara JS, Quezada AS, Jaime Valenzuela JP. Mandibular canal duplication prevalence, digital panoramic radiography analysis. Int J Odontostomatol 2010;4:207-13.   Back to cited text no. 7
    
8.Sanchis JM, Peñarrocha M, Soler F. Bifid mandibular canal. J Oral Maxillofac Surg 2003;61:422-4.  Back to cited text no. 8
    
9.Claeys V, Wackens G. Bifid mandibular canal: Literature review and case report. Dentomaxillofac Radiol 2005;34:55-8.   Back to cited text no. 9
    
10.Patel N, Andresen E. Bifid mandibular canals. Br Dent J 2013;215:201.  Back to cited text no. 10
    


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Abstract
Introduction
Case Report
Discussion
Conclusion
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