Bilateral Maxillary Canine Transposition Using Segmental Arch Technique

Objective: To evaluate effects of orthodontic treatment in bilateral maxillarycanine transposition using segmental arch technique.Materials and Method: A case with class Ⅰ malocclusion was selected fromDalian Ortho clinic in2009, who was a male,11.1years old. There was bilateralmaxillary canine transposition and the molar relationship of both sides was mesial edgeto edge.The maxillary canines are retained deciduous teeth. Bilateral second deciduousmolars were retained. The patient was treated by extraction of the deciduous maxillarycanines with segmental arch technique. Analysis of pre and post-treatment lateralradiographs was done in a week.25typical measurements were selected from Tweedand Beida analysis, so as to observe the changes from pre-treatment topost-treatment.Results: The course of orthodontic treatment is27months. Comparing thechanges between pre-treatment and post-treatment: the transpositioned maxillarycanines were moved to their original positions. Root resorption of maxillary canines andlateral incisors not seen. Tooth axis was good. Periodontal state of maxillary dentitionwas also good. The molar relationship was changed to class Ⅰ.SNA increased0.5°.SNB was not changed. ANB increased0.5°.NA-PA increased1.5°.FMIAdecreased3°.The soft tissue profile showed improvement。Li-E decreased by1.5mmand Z angle decreased from85°to83°。The patient and his parents were satisfied withthe result after orthodontic treatment.Conclusions: For this patient, who had bilateral maxillary canine transposition,we can get a good therapeutic effect by using “T-loop” segmental arch technique andedgewise technique to control the teeth three-dimensionally and the transpositioned canineswere corrected without root resorption. Periodontal state of maxillary dentition was good.