title: Evaluation of treatment and post-treatment changes by the PAR Index.
abstract: To assess the outcome of orthodontic treatment, 224 cases treated in a postgraduate clinic were evaluated. Pre-treatment (T1), post-treatment (T2) and 5-year follow-up (T3) study casts were assessed by the Peer Assessment Rating (PAR) Index. The influence of various factors upon treatment and long-term outcome was analysed. According to the PAR Index, orthodontic treatment reduced the malocclusions on average by 76.7 per cent, and at follow-up the reduction was 63.8 per cent. Follow-up stability was good for 76.3 per cent of the cases. Some cases (4.0 per cent) even improved, while moderate to severe post-treatment relapse occurred in 19.7 per cent of the cases. Orthodontic treatment changed Angle Class I, II and III malocclusions to near ideal occlusion (PAR scores 4.4-6.8). No long-term interaction between the groups was discovered. Sex and extraction/non-extraction treatments did not significantly affect the results. The initial PAR score accounted for 77.8 per cent of the variation in treatment PAR score change (T1-T2), and for 61.8 per cent of the variation of long-term PAR score change (T1-T3). Age at treatment start accounted significantly for the variability of treatment changes (P < 0.001). The PAR score at the end of treatment had some explanatory importance (R2 = 0.099) for the long-term (T1-T3) result. However, PAR score changes in the follow-up period were difficult to predict.
authors.affiliation: Department of Orthodontics and Facial Orthopedics, University of Bergen, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Birkeland
authors.forename: J
authors.initials: J
authors.lastname: Furevik
authors.forename: O E
authors.initials: OE
authors.lastname: Bøe
authors.forename: P J
authors.initials: PJ
authors.lastname: Wisth
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006301:Health Services Needs and Demand; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D008311:Malocclusion, Angle Class I / Q000628:therapy; D008312:Malocclusion, Angle Class II / Q000628:therapy; D008313:Malocclusion, Angle Class III / Q000628:therapy; D003765:Models, Dental; D015588:Observer Variation; D009967:Orthodontic Appliances; D018704:Orthodontic Retainers; D009971:Orthodontics, Corrective; D018024:Peer Review, Health Care; D012008:Recurrence; D015203:Reproducibility of Results; D012690:Serial Extraction; D012737:Sex Factors; D016896:Treatment Outcome