The provision of orthodontic care in the general dental services of England and Wales: extraction patterns, treatment duration, appliance types and standards.

A systematic sample of 1010 cases was collected by the Dental Practice Board. The commonest type of treatment involved extraction of the first premolars followed by removable appliances. Treatment duration was on average 1.9 years, one-arch fixed appliances were started in an older age group and two-arch fixed appliance treatment took longer to complete than other appliance types. The best standard of treatment was achieved using upper and lower fixed appliances.