Orthodontic Correction of Impacted and Transposed Upper Canines.

T canines have the highest reported incidence of dental transposition—most commonly with the first premolar, followed by the lateral incisor.1-8 Several authors have described cases in which canine transpositions were resolved or the teeth were aligned in their transposed positions. 9-11 To our knowledge, however, no one has reported treating a patient in whom bilaterally impacted upper canines were transposed with the lateral incisors and were also associated with severe root resorption of adjacent teeth. Canine transposition is one of the most common causes of tooth resorption. Typically, an upper lateral-incisor root is affected by ectopic eruption of the adjacent canine, although central incisors can also be involved.12 The apical and middle thirds of the incisor roots are most likely to be resorbed. In cases of severe root resorption, the risk of losing the incisor should be considered when planning treatment of the impacted canine. Extraction of the severely resorbed lateral incisor may be a better option than removal of the canine, especially when there is insufficient space for prosthetic replacement. On the other hand, one study found that removing the source of pressure resorption from an impacted upper canine could improve the long-term stability of the adjacent resorbed teeth.13 CASE REPORT