Cone-beam computed tomography evaluation of impacted and transmigrated mandibular canines: a retrospective study

The purpose of this study is to evaluate CBCT images of impacted mandibular canines in detail and to discuss implications for diagnosis and treatment.

CBCT images of dental patients applied between December 2015 and December 2017 were evaluated retrospectively. 2591 CBCT images, including mandible in their field of view, were determined and evaluated regarding the presence of mandibular canine impaction. 66 impacted mandibular canines of 58 patients were analyzed in detail regarding their location, morphology, associated pathologies, and their relationship with the neighboring anatomic structures, the role of these factors on transmigration, as well as treatments applied. The Pearson Chi square test was used between the groups.

Transmigration was observed in 53% of impacted mandibular canines. Teeth with transmigration were localized horizontally, below the apex of adjacent teeth frequently, and had no contact with mandibular cortical bone mostly. 62% of mandibular canines were in contact/proximity with the incisive mandibular canal. The most applied treatment for transmigrated teeth was surgical removal, followed by radiographic monitoring, but orthodontic traction was not preferred in any case. For non-transmigrated teeth, the most applied treatment options were surgical removal, orthodontic traction, and radiographic monitoring, respectively. Autotransplantation was not preferred in any case of impacted teeth. Vertical position of the crown tip (p < 0.05) and the presence of deciduous mandibular canines and their resorption showed significant relation to transmigration (p < 0.05).

Transmigration is common among impacted mandibular canines. Resorption of adjacent teeth roots was one of the possible complications of impaction and likely contact/proximity of incisive mandibular canal with impacted mandibular canines, which may pose difficulties in surgical treatment, can be better detected by CBCT.