Treatment of complete transposition of upper right canine and first premolar and scissors-bite on second molars by non-extraction and retention of the transposed positions

ABSTRACT Objective: This case report describes the successful treatment of a patient with a skeletal Class I malocclusion, complete transposition of the upper right canine and first premolar, and scissors-bite on the second molars, treated by non-extraction and retention of the transposed positions of the teeth. Case: The patient was a 10-year and 2-month-old girl, who was referred to our clinic. In Phase I treatment, dental crowding was improved by distal movement of the maxillary and mandibular first molars. In Phase II treatment, each scissors-bite on the bilateral second molar was treated and the canine and first premolar were aligned in the transposed position. Treatment results: Consequently, she acquired excellent occlusion and improved masticatory jaw movement. Three years after the active treatment, treatment results were stable with the use of removable retainers. Conclusion: Orthodontic treatment for scissors-bite may increase masticatory performance because it improves masticatory movement significantly. Additionally, orthodontic treatment of transposed teeth by retaining the transposed position without extraction could lead to satisfactory aesthetic and functional final results, which implies that it could be a valid treatment option.