Treatment time and occlusal outcome of orthognathic therapy in the East of England region

Objectives: To evaluate the process of combined orthognathic and orthodontic care. To identify factors that affect treatment time and percentage Peer Assessment Rating (PAR) reduction, and the PAR efficiency factor for such cases. Design and setting: Retrospective multi centre study of patients who underwent orthognathic treatment in the East of England region. Methods: Analysis of consecutive cases that underwent orthognathic surgery in 2008. Inclusion criteria included pre- and post-surgery orthodontic treatment. Results: Ten orthodontic units submitted data for a total of 118 patients. Within the sample, 64% were class III, 35% class II/1 and 1% class II/2. Overall extraction rate, excluding third molars, was 58%. Median age at bond up was 17 years. Mean total number of orthodontic attendances was 23. Median length of pre-surgical orthodontics was 23 months and post-surgical orthodontics was 7 months. Median length of total treatment was 29 months. Mean wait for surgery was 3·6 months. Diagnosis of incisor relationship and skeletal base, transfer of operator, total number of visits, tooth extraction and treatment unit affected treatment duration. Median pre- and post-treatment PAR scores were 43 and 4, respectively. Median change in PAR score was 38·5. Median per cent reduction in PAR was 90·6%. The median PAR efficiency factor (reduction in PAR score divided by treatment time in months) was 1·24. Diagnosis of incisor relationship and skeletal base correlated with percentage reduction in PAR score. Conclusions: Combined orthognathic treatment was effective. Factors affecting treatment duration and percentage reduction in PAR have been established.