Clinical assessment of orthodontic outcomes with the peer assessment rating, discrepancy index, objective grading system, and comprehensive clinical assessment

Purpose: The purpose of this study was to quantitatively assess orthodontic treatment outcomes in postgraduate orthodontic clinics at Okayama University (OU) and Indiana University (IU). Material: Using the peer assessment rating (PAR) index, the discrepancy index (DI), the American Board of Orthodontist's objective grading system (OGS), and the comprehensive clinical assessment (CCA), we evaluated pretreatment and posttreatment records of 72 patients from OU and 54 patients from IU. Results: The average pretreatment PAR score with United Kingdom weighting was 32 for OU subjects and 28 for IU subjects. Differences in maxillary and mandibular buccal alignment between schools were statistically significant (P <.01). The posttreatment PAR scores were 7 for OU and 4 for IU. The difference in overjet between schools was statistically significant (P <.05). The mean DI scores were 19 for OU and 17 for IU. OU patients scored significantly more DI points for crowding and mandibular plane angle compared with IU patients (P <.05). On the other hand, they lost significantly fewer DI points for overbite and occlusion compared with IU patients (P <.05). The mean OGS scores were 34 for OU and 33 for IU. Buccolingual inclination and overjet scores were significantly higher in OU patients compared-with IU (P <.05). The mean CCA score was approximately 4 points for both OU and IU. Conclusions: These data suggest that these indexes are useful for comparing treatment outcomes between clinics. They were able to identify specific problems in treating Asian patients.