Class II Division 1 malocclusion treatment with extraction of maxillary first molars:Evaluation of treatment and post-treatment changes by the PAR Index

OBJECTIVE To investigate occlusal result and post-treatment changes after orthodontic extraction of maxillary first permanent molars in patients with a Class II division 1 malocclusion. SETTING AND SAMPLE Retrospective longitudinal study in a private practice, with outcome evaluation by an independent academic hospital. Ninety-six patients (53 males, 43 females) consecutively treated by one orthodontist with maxillary first permanent molar extraction were studied, divided into three facial types, based on pre-treatment cephalometric values: hypodivergent (n = 18), normodivergent (n = 21) and hyperdivergent (n = 57). METHODS Occlusal outcome was scored on dental casts at T1 (pre-treatment), T2 (post-treatment) and T3 (mean follow-up 2.5 ± 0.9 years) using the weighted Peer Assessment Rating (PAR) Index. The paired sample t test and one-way ANOVA followed by Tukey's post hoc test were used for statistical analysis. RESULTS PAR was reduced by 95.7% and 89.9% at T2 and T3, respectively, compared with the start of treatment. The largest post-treatment changes were found for overjet and buccal occlusion. Linear regression analysis did not reveal a clear effect (R-Square 0.074) of age, sex, PAR score at T1, incremental PAR score T2-T1, overjet and overbite at T1, and facial type on the changes after treatment (incremental PAR score T3-T2). CONCLUSIONS The occlusal outcome achieved after Class II division 1 treatment with maxillary first permanent molar extractions was maintained to a large extent over a mean post-treatment follow-up of 2.5 years. Limited changes after treatment were found, for which no risk factors could be discerned

In-training assessment using direct observation of single-patient encounters: a literature review

We reviewed the literature on instruments for work-based assessment in single clinical encounters, such as the mini-clinical evaluation exercise (mini-CEX), and examined differences between these instruments in characteristics and feasibility, reliability, validity and educational effect. A PubMed search of the literature published before 8 January 2009 yielded 39 articles dealing with 18 different assessment instruments. One researcher extracted data on the characteristics of the instruments and two researchers extracted data on feasibility, reliability, validity and educational effect. Instruments are predominantly formative. Feasibility is generally deemed good and assessor training occurs sparsely but is considered crucial for successful implementation. Acceptable reliability can be achieved with 10 encounters. The validity of many instruments is not investigated, but the validity of the mini-CEX and the ‘clinical evaluation exercise’ is supported by strong and significant correlations with other valid assessment instruments. The evidence from the few studies on educational effects is not very convincing. The reports on clinical assessment instruments for single work-based encounters are generally positive, but supporting evidence is sparse. Feasibility of instruments seems to be good and reliability requires a minimum of 10 encounters, but no clear conclusions emerge on other aspects. Studies on assessor and learner training and studies examining effects beyond ‘happiness data’ are badly needed