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[Analysis on the reasons for orthodontic re-treatment].

Objective: To analyze the type of malocclusion which was more likely to cause undesirable orthodontic results and the reasons for orthodontic re-treatment. Methods: In this study, 202 patients who received orthodontic retreatment in School of Stomatology, China Medical University from 2004 to 2016 were collected. Forty-seven patients were teenagers under 18 years old, and 155 patients were adults over 18 years old. The chief complaint of all patients was analyzed. Seven orthodontic specialists were invited to analyze the reasons caused the orthodontic re-treatment according to the treatment records, plaster models, photographs, panoramic radiographs and lateral cephalograms. They were offered an evaluation form to fill in by their judgement. The reasons for orthodontic re-treatment and the problems related to previous orthodontic treatment were analyzed. Results: In 202 patients, the chief complaints were protrusion of the teeth [30.2% (61/202)], protrusion of the mandible [20.8% (42/202)], and irregularity of the teeth [17.8% (36/202)]. The proportion of patients chosen undesirable treatment design was 68.3% (138/202). The proportion of patient having unusual growth tendency was 24.3% (49/202). The proportion of patients with poor compliance during treatment and retention was 24.3% (49/202). Conclusions: In this study, the protrusion of the teeth, the protrusion of the mandible and the dental crowding were the main chief complaints for orthodontic re-treatment. Undesirable treatment design and unfavorable growth tendency were the main reasons for orthodontic re-treatment. Poor compliance of patients during the period of treatment or retention was an important reason for the patient to seek orthodontic re-treatment.