Root resorption associated with ectopically erupting maxillary permanent canines: a computed tomography study.

The aims of this retrospective computed tomography (CT) study were to determine the occurrence of severe root resorption involving the pulpal canal of adjacent permanent teeth associated with ectopically erupting canines, and to verify the existence of related factors. The sample consisted of 255 consecutive patients (159 females and 96 males, mean age 18.4 and 16.8 years, respectively). Three hundred and thirty-four ectopic maxillary canines and adjacent teeth were analysed using CT images. Statistical significance was evaluated with chi-square and Fisher's exact tests. The results showed that severe root resorption of adjacent permanent teeth occurred in 17.7 per cent of ectopic canines and was equally common in females and males. Severe root resorption affected 12.6 per cent of the lateral incisors, 4.8 per cent of the first premolars, and 2.1 per cent of the central incisors. No relationship was found between the type or side of ectopic eruption, inclination of the longitudinal axis of the ectopic canine and the occurrence of severe root resorption. A significant relationship was found between a bucco-lingual position of the ectopic canine and root resorption (P < 0.05). Root resorption mainly occurred in the apical third (57.6 per cent) and apical and middle thirds (27.1 per cent). A significant relationship existed between the occurrence of root resorption and complete loss of space for the erupting canine (P < 0.05). No association was found between alignment of the upper permanent incisor and root resorption. A widened dental follicle occurred in 15 per cent of ectopic canines but did not cause root resorption of the adjacent permanent teeth. Since root resorption is asymptomatic, early detection by radiographic examination is essential for correct diagnosis and treatment.