Occlusal outcome of orthodontic treatment.Angle Orthod. 1998 Oct; 68(5):439-44.AO
The aim of this study was to evaluate the overall quality of orthodontic treatment in a university clinic. Dental casts of 1870 patients (799 males and 1071 females) were evaluated at the pretreatment and posttreatment stages using the PAR index. The mean age was 13 +/- 4.1 years at the pretreatment stage and 16 +/- 3.9 years at the posttreatment stage. At both stages, mean and standard deviations of the (weighted) PAR scores were calculated, along with the percentage reductions in the weighted PAR scores. The percentage of perfect scores (score = 0) of the different components of the PAR index was calculated. The analysis of variance and t-test were used to compare quality of treatment for the variables of treatment period and gender, respectively. The mean weighted PAR scores were 27.6 +/- 10 and 7.7 +/- 6.1 for the pretreatment and posttreatment models, respectively. The mean percentage improvement was 68.9%. The mean treatment duration was 3.0 +/- 1.4 years. Great improvement was noted in 42.8% of the sample, while 49.1% of the sample showed moderate improvement, and 8.3% either did not improve or became worse. The improvement of the PAR score at the posttreatment stage could, to some extent, be explained by the treatment period: The more recent the period the better the quality.