Accessory mandibular canal: literature review and presentation of an additional variant.

Multiple mandibular canals of the bifid variety characterized by a single foramen and two nearly equal canals are unusual (occurrence less than 1%) but not rare. A more unusual case, the occurrence of two separate canals, has been mentioned only twice in the literature, once without documentation. An example of this condition has been found on a routine preoperative radiograph, and no other published examples of this condition could be found in a review of the literature. This case serves as a reminder that multiple canals do occur with some regularity.