Maxillary canine-first premolar transposition in the permanent dentition. 
Maxillary canine premolar transposition is the most frequently reported transposition type, which many orthodontists face.  Although correcting the transposed tooth order is not advised after the eruption of the permanent tooth, several articles published in the last decade demonstrated nonextraction treatment of transposition using fixed mechanics.  This article describes the nonextraction treatment of a complete transposition between a maxillary left canine and a first premolar, using similar mechanics as suggested earlier.  The correct tooth order was established with a functional Class I canine and molar relationship at the end of treatment.  Although triangular cortical bone resorption at the vestibule of the canine root was detected on computed tomography at the end of treatment, spontaneous regeneration of bone tissue at the resorption area was present on the postretention computed tomography scan.