Sir, the presence of bifid mandibular canals is an unusual but not rare occurrence. The mandibular canal transmits the inferior alveolar nerve and inferior alveolar artery. Variations of normal canal anatomy have been reported with an incidence ranging from 0.08% to 65%.1

A 42-year-old Caucasian lady was referred to the oral surgery department at Manchester Dental Hospital by her general dental practitioner with recurrent pericoronitis associated with her impacted lower left third molar. Division of the mandibular canal which was initially noted on panoramic radiography (Fig. 1) instigated more detailed investigation. Cone beam CT scanning (Figs 2-3) revealed two branches of the inferior alveolar canal, with a superior branch penetrating the distal root of the wisdom tooth and emerging from a foramen on the superior aspect of the buccal bone just distal to the crown of the tooth. The particular morphology of the nerve relative to this tooth precluded any possibility of removal of only the crown. After full discussion with the patient, especially of the increased risks of nerve damage during removal, the tooth was carefully removed under general anaesthesia. At post-operative review, no inferior alveolar or lingual nerve damage was present.

Figure 1
figure 1

Panoramic radiograph showing division of the mandibular canal

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Figure 2-3
figure 2

The cone beam CT scan

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Clinicians must be aware of the implications of this variance in anatomy. Inadequate anaesthesia may be a problem, especially in cases where there are two mandibular foramen. Third molar surgery must be carried out with extreme care as 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 recognise the presence of this anomaly.