|Year : 2015 | Volume
| Issue : 3 | Page : 453-456
Bifid mandibular canal: An unusual presentation
Ajay Parihar1, Shilpa A Warhekar2, Harshakant P Gharote3, Ashish M Warhekar4
1 Department of Oral Medicine and Radiology, Government College of Dentistry, Indore, Madhya Pradesh, India
2 Department of Public Health Dentistry, Sri Aurobindo College of Dentistry, Indore, Madhya Pradesh, India
3 Department of Oral Medicine and Radiology, People's College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India
4 Department of Oral Medicine and Radiology, Modern Dental College and Research Centre, Indore, Madhya Pradesh, India
|Date of Submission||09-Apr-2015|
|Date of Acceptance||11-Nov-2015|
|Date of Web Publication||25-Nov-2015|
Ashish M Warhekar
Department of Oral Medicine and Radiology, Modern Dental College and Research Centre, Gandhi Nagar, Bijasan Road, Indore - 453 112, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Bifid mandibular canal could be an interesting variation in the mandible. This condition can pose complications during surgical procedures in the mandible, such as extraction of lower molars, placement of implants, and surgery. Therefore, identification of this variation is sometimes very crucial and can assist in minimizing postoperative complications. Hereby, we report the presence of bifid mandibular canal in the first molar region, an unusual presentation. The patient was evaluated for implant prosthesis using cone beam computed tomography (CBCT) that confirmed the bifid canal which was seen as an unusual radiolucency on intraoral periapical radiograph.
Keywords: Bifid mandibular canal, CBCT, dental implant
|How to cite this article:|
Parihar A, Warhekar SA, Gharote HP, Warhekar AM. Bifid mandibular canal: An unusual presentation. J Indian Acad Oral Med Radiol 2015;27:453-6
|How to cite this URL:|
Parihar A, Warhekar SA, Gharote HP, Warhekar AM. Bifid mandibular canal: An unusual presentation. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2022 Dec 5];27:453-6. Available from: http://www.jiaomr.in/text.asp?2015/27/3/453/170485
| Introduction|| |
The mandibular canal passes from the mandibular foramen to the mental foramen and transmits the inferior alveolar vessels and inferior alveolar nerve.  Analyzing the accurate position and course of the mandibular canal within the mandible and identifying the anatomical variations, such as the bifid mandibular canal or additional foramen, is very important for preventing potential complications during dental surgical procedures.  A double/bifid mandibular canal can lead to complications while performing an inferior alveolar nerve block for administering anesthesia to the mandibular region. Pain or discomfort may start because of bone resorption in patients who are wearing prosthesis or damage to the second canal may be caused after implant placement.  The existence of a bifid or double mandibular canal has been reported in various anatomical and radiographic studies. Its occurrence was found to be extremely rare, ranging from 0.08% to 0.95%.  Panoramic radiographs have been used to study the prevalence of bifid mandibular canal. The incidence of this condition has been variably reported as 0.4%, 0.08%, and 0.9%. ,
In contrast to panoramic radiography, computed tomography (CT) allows three-dimensional (3D) insight. Recently, cone beam computed tomography (CBCT) has been introduced in an effort to improve the performance of conventional CT, such as reducing the radiation dose, offering high spatial resolution, and decreasing the costs. As CBCT is gaining popularity, more anatomical aberrations of the mandibular canal will be recognized and presented three dimensionally.  This case report describes a patient with bifid mandibular canal in the right mandible with its termination on the crest of alveolar ridge in the molar region, which was an accidental finding during (CBCT) evaluation for implant prosthesis.
| Case Report|| |
A 32-year-old male was referred to Oracle CBCT Centre, Indore (Madhya Pradesh, India), for cone beam tomography of the mandible for placement of implants. His brief history revealed that 45 and 46 were extracted 6 months back with uneventful healing. He was having mild pain in 36 due to caries, which was subsequently treated with root canal therapy [Figure 1]. As the patient was willing for implant prosthesis, CBCT examination was advised. The image in the coronal section depicted a hypodense linear extension from the right alveolar canal up to the crest of 46. The tracing tool confirmed the extension of mandibular canal up to the crest [Figure 2]. This indicated the bifurcation of right mandibular canal. The panoramic reconstruction revealed that borders of the bifurcated canal were continuous with the superior margin of the canal [Figure 3]. Furthermore, the tracing of left inferior alveolar canal showed similar presentation in relation to first molar [Figure 3] and [Figure 4]. 3D reconstruction images also confirmed the presence of bilateral bifid canals [Figure 5] and [Figure 6]. Thus, radiographic diagnosis of bifid inferior alveolar canals in relation to 46 and 36 regions was confirmed. The patient was recalled after placement of implants and conventional radiographs were taken to confirm the location of implants [Figure 7].
|Figure 1: OPG showing missing 45, 46 with healed sockets and endodontically treated 36|
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|Figure 2: Coronal sections of right mandible from 43 to 47 region showing linear hypodense line extending from inferior alveolar canal with tracing (arrow)|
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|Figure 3: Coronal sections of left mandible from 35 to 37 region showing linear hypodense line extending from inferior alveolar canal (arrow)|
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|Figure 4: Panoramic reconstruction of thin mandibular section showing inferior alveolar canals bilaterally (arrow)|
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|Figure 5: 3D reconstructed cropped image of the right side of buccal surface of mandible|
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|Figure 6: 3D reconstructed cropped image of the left side of buccal surface of mandible|
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|Figure 7: Intraoral radiograph of the right mandibular region after implant placement|
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| Discussion|| |
The mandibular canal transmits the inferior alveolar nerve and the associated vessels. The canal typically extends from the mandibular foramen to the mental foramen. The terminal dental and incisive branches leave the inferior alveolar nerve within the canal to supply the teeth and adjacent structures. A terminal branch leaves the canal at the mental foramen to become the mental nerve.  Variations in the anatomy of mandibular canal can be in the form of bifid, trifid, double mandibular canal and pseudo bifid/double mandibular canal. The term "bifid" is derived from the Latin word meaning a cleft into two parts or branches.  A review of the available literature reveals that the occurrence of multiple inferior alveolar canals in the general population is about 1%. The bifid canal occurs infrequently, but is not thought of as rare. 
From an embryological viewpoint, the presence of mandibular canal variants has been explained by the fact that during embryonic development, there might be three inferior dental nerves innervating three groups of mandibular teeth. These canals are directed from the lingual surface of mandibular ramus toward different tooth groups. During rapid prenatal growth and remodeling in the ramus region, there is a spread of intramembranous ossification that commences where the inferior alveolar nerve divides into mental and incisive branches at around 7 weeks in utero. The extension of ossification posteriorly along the lateral border of Meckel's cartilage produces a gutter around the inferior alveolar nerve that eventually forms the mandibular canal. This theory further explains the occurrence of bifid/trifid mandibular canals in some individuals secondary to incomplete fusion of these three nerves. 
Inferior alveolar canal has been classified according to anatomical location and configurations. Nortjé et al.  reported that there were three main variants of mandibular canal division. Langlais et al.  classified the variations into four different patterns. The first included bifid canal extending to the area surrounding the third molar or to the tooth itself; the second included bifid canal arising from the same foramen, but forming two separate canals which rejoined to form a single canal anteriorly; the third type included a combination of the first two types; and the last type included two radiographically separate canals with separate origins that eventually fused into a single canal anteriorly. The present case might be appropriate for type I classification by Langlais; however, the area of location is the first molar. 
This condition has been proposed as one of the possible reasons for the failure of mandibular anesthetic technique while performing an inferior alveolar nerve block.  Fukami et al. revealed that the bifid mandibular canal of the retromolar region traverses close to the third molar and contains nerve bundles concurrent with an artery, suggesting that complications such as traumatic neuroma, paresthesia, anesthesia, bleeding, and hematoma might occur owing to damage to the canal. This should be considered, especially in dentoalveolar surgery involving the retromolar area, such as extraction of impacted mandibular third molars, or in sagittal split ramus osteotomies.  In the present case, the patient was intending to undergo implant prosthesis for the missing 46, but the location of bifid canal in that region posed difficulty in implant placement.
| Conclusion|| |
To conclude, bifid mandibular canal is an accidental finding which can be easily missed by routine conventional radiography. A specialized radiography technique like CBCT has helped to discern the bifid canal which can be a potential complication in procedures such as implant placement and other surgical procedures.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]