The use of occlusal indices in assessing the provision of orthodontic treatment by the hospital orthodontic service of England and Wales.

This retrospective study was carried out to assess the need for orthodontic treatment and the standard of treatment provided by a sample of 17 hospital-based orthodontic departments. A total of 1630 sets of patients records were collected and analysed for orthodontic treatment need and standard of treatment with the Index of Orthodontic Treatment Need and the PAR index, respectively. The data were analysed with a variant of analysis of covariance using linear modelling techniques. In general terms it appeared that the hospital service provided treatment of a high standard, in terms of dento-occlusal change, to a caseload of patients that were in need of treatment. The effectiveness of treatment provision was influenced by the grade of operator, the choice of treatment methods and by the departmental attitudes and aspirations.