The objective of this study was to analyse recently treated orthodontic patients to evaluate the quality of treatment in the graduate orthodontic clinic at the Ohio State University and determine what factors correlate to the how cases are finished.

Models of 229 patients were scored using the peer assessment rating (PAR) index. The cases were divided into groups, well-finished cases, which are those that had a PAR score reduction by at least 22pts or for those that started with a score less than 22pts a final PAR score of 0 and not well-finished cases. Cephalometric data, treatment age, treatment type, treatment time, faculty, payment type, motivation, initial hygiene impression, and failed appointments were recorded. Statistical analyses completed included a multiple logistic regression.

The total percent of cases of improvement in PAR was 45.4%, 48.5%, 6.1% for greatly improved, improved and not improved respectively. The pre-treatment upper and lower anterior alignment, overjet, overbite and midline deviation were significantly related to the quality of treatment outcome (P<0.05). The total PAR reduction rate was similar between full-time and part-time teachers, but when categorised, it showed a difference with a decrease by a multiplicative factor of 8.200. However, this statistical difference is not significant after adjustment with other covariates (P=0.69).

Patients who start with more upper or lower anterior crowding, overjet, overbite, or midline deviation may be difficult to correct than cases that does not have those characteristics. Also, there may be difference between part- and full-time faculty regarding treatment efficiency in orthodontic graduate clinic.