Prevalence of tooth agenesis in adolescent Chinese populations with or without orthodontics.

Objective: To determine the prevalence of hypodontia in the general population and orthodontic population in adolescent Chinese Hans.

Methods: Two groups named the general population (6015 subjects) and the orthodontic population (2781 subjects) were investigated, respectively. The former came from the students of three general universities in North China and the latter came from patients coming to the Department of Orthodontics, Peking University School and Hospital of Stomatology for orthodontic consulting during the summer and winter holidays in 2008.