Orthodontic outcomes assessment using the peer assessment rating index

The purpose of the present study was to gain more information on the assessment of orthodontic treatment using the PAR Index. The PAR Index was used to assess the study casts of 54 cases treated by 5 orthodontists who successfully completed Phase III of the American Board of Orthodontics. These peer-reviewed cases were considered to represent a subjective opinion of an excellent treatment standard. The PAR scores for the Board-accepted cases were then compared with the PAR scores of 51 cases consecutively treated by orthodontic graduate students. The pretreatment, posttreatment, and percent changes in PAR scores for the Board cases and the graduate student-treated cases were compared. The PAR Index scores and treatment duration were analyzed for the entire sample using general linear models techniques. Results of the study showed no statistically significant difference between the Board-accepted cases and the graduate student-treated cases for any single component of the PAR Index at either the pretreatment or posttreatment times. However, the percent reduction in the mean PAR score for the Board-accepted cases was significantly more than the reduction for the graduate student-treated cases (87.9%+/-9.5% vs 81.7%+/-15.3%). Analysis of treatment duration showed that a higher pretreatment PAR score and a greater percent reduction in PAR score were significantly associated with longer treatment durations.