Nonextraction treatment of upper canine-premolar transposition in an adult patient.

This article reports the successful treatment of a unilateral maxillary canine and first premolar transposition without the extraction of the premolar in an adult patient. A female patient, 21 years and three months of age, had moderate crowding in the upper arch with complete transposition of the canine and first premolar. After distal movement of the upper molars with a lingual arch and headgear appliance, the upper left first premolar and canine were transposed. Thirty-eight months after the placement of preadjusted appliances, the transposed canine and premolar were reordered in the proper positions. The total active treatment period was 49 months. After two years of retention, the occlusion is generally stable.