Multicentre evaluation of impacted and transmigrated canines: A retrospective study

Objectives: The present multicentre study assessed the prevalence and patterns of impacted and transmigrated maxillary and mandibular canines in a Turkish subpopulation. Methods: The study identified 1625 patients who had impacted teeth from a group of 10,700 patients (referred to three university hospitals between January 2014 and December 2015) and examined the accompanying records, panoramic and periapical radiographs, and cone-beam computed tomographic images (if available). An impacted canine was considered to be transmigrated when at least part of the tooth had crossed the midline. Results: Out of 1625 patients, 163 (10.0%) had impacted canines (comprising a total of 170 affected teeth). Impacted canines were found in the maxilla in 114 patients (69.9%) and 49 patients (30.1%) showed mandibular canine impaction. Thirty-eight patients (2.3%) had transmigrated canines, of which twenty (52.6%) were located in the mandible, while 18 (47.4%) were found in the maxilla. No significant difference was evident between the genders, the site (right/left) and the impacted/transmigrated canines (p > 0.05). However, it was determined that canine impaction was significantly more frequent in the maxilla than in the mandible (p < 0.05). In addition, of the 38 patients presenting with transmigrated canines, eight (21.6%) had a history of alpha thalassemia. Conclusions: Canine transmigration occurs in both the mandible and maxilla. The prevalence of impacted/transmigrated canines in the studied population was 10.0% and 2.3%, respectively. The mechanism of transmigration of maxillary canines remains unclear and requires further investigation. However, a possible correlation with genetic disorders (like alpha thalassemia) should not be overlooked.