The influence of operator changes on orthodontic treatment times and results in a postgraduate teaching environment

There is some concern that patients treated by postgraduate students during their speciality training may be disadvantaged in the quality of treatment result and subject to longer treatment times if they are treated by more than one operator. This study analysed the pre- and post-treatment study models of orthodontic patients from a district general hospital department, debonded by one junior member of junior staff in the calendar years 1991 and 1992. All patients were treated using the same pre-adjusted edgewise appliance in both arches. Two groups of patients were identified: patients whose treatment was started and finished by the same operator (registrar A), and those whose treatment was begun by another operator (registrar B), but finished by registrar A. A random sample of 30 patients from each group was selected and the study models at the start and end of treatment were scored using the PAR (Peer Assessment Rating) Index. No significant differences were found between the average PAR scores for each group at the beginning of treatment, or between groups A and B at the end of treatment; the average treatment time for the patients treated by one operator was 17.67 months (SD 4.15 months), while the average treatment time for the patients treated by more than one operator was 26.1 months (SD 6.78 months). Statistically, this difference was highly significant (P < 0.001). A highly linear relationship (R2 = 0.92) was found between the percentage PAR score reduction and the initial PAR score. The findings and their implications are discussed.