A new dimension in managing the troublesome transmigratory canine

Canine impactions occur 20 times more frequently in the maxilla in comparison to the mandible.¹ Transmigration of a permanent mandibular canine is rarely symptomatic² and is rarely suspected when the deciduous canine is retained beyond its normal exfoliation time.

When a permanent mandibular canine is significantly ectopic, it may not be identified on intra-oral radiographs, whilst a panoramic radiograph is unlikely to provide accurate information on the bucco-lingual position, proximity to incisor roots, and existence of pathology related to the canine.³ When permanent mandibular canines transmigrate, the distance they travel depends on the length of time before diagnosis. It should be noted that the tip of the canine may be detected to be crossing from the midline to the distal root of the first permanent molar on the opposite side.⁴ Moreover, they may be associated with a variety of pathologies, including dentigerous cysts and extensive root resorption of adjacent teeth. The destructive nature of transmigratory mandibular canines makes intervention almost always advisable in order either to prevent or limit root resorption. However, this treatment strategy has historically been dependent upon information provided by 2D radiographs. 3D imaging provides an opportunity to re-evaluate whether or not surgical removal of transmigratory mandibular canines is always desirable.