This study involved a statistical survey of 507 patients（male: female ratio, 1:2.2）who were diagnosed with jaw deformity at the Department of Orthodontics, Fukuoka Dental College Medical and Dental Hospital over the past 20 years（2002-2021）.
1．There was an annual increase in the number of patients diagnosed with jaw deformity. The number of diagnosed patients decreased temporarily as a result of COVID-19, followed by a reactionary increase. This suggests a significant social influence on the treatment of jaw deformity.
2．The mean patient age at the first visit was 23.8±8.1 years（range: 12-56 years）, and patients in their 50s were first seen in 2015.
3．Approximately half（47.9%）of the patients with missing teeth had missing molars.
4．Among patients with jaw deformity, 69.0% had mandibular prognathism.
5．The most common extraction site in presurgical orthodontic treatment was the bilateral maxillary premolars. Compared with before 2014, more bilateral premolar extractions were performed after 2014, involving both the maxilla and mandible. Among patients with mandibular prognathism, the proportion of bilateral first and second premolar extractions increased after 2014, involving both the upper and lower jaws. These findings suggest that approval of orthodontic anchor screw use in 2014 for insurance coverage influenced the selection of extraction sites in patients with mandibular prognathism.
