Orthodontic treatment protocol versus Peer Assessment Rating: Assessing the quality of orthodontic treatment.

Objective: To apply the Peer Assessment Rating (PAR) to cases that have been assessed by the NHS Business Service Authority (NHSBSA) using the orthodontic treatment protocol (OTO), then compare the NHSBSA outcome assessment with weighted (W) and unweighted (U) PAR scores.

Design: Cross-sectional study.

Setting: UK.

Cases: Anonymised orthodontic cases submitted to the NHSBSA.

Methods: A sample of 30 reports from 2021/2022 were randomly selected to include different standard of treatment grades. The records were de-identified and the pre- and post-treatment study models were PAR scored by a calibrated assessor.

Results: The mean percentage change in PAR was higher in cases from green reports (W: 78%; U: 79%) than amber (W: 68%; U: 67%) and red reports (W: 65%; U: 65%). Alignment and poor buccal segment interdigitation were the most reported concerns for cases included in the red and amber graded reports. A residual increased overjet was the most common occlusal feature leading to PAR scores not being more than 70% improved. Only slight agreement was shown between OTP and PAR using the kappa statistic, and the chi-square statistical test found that outcome measures are statistically significantly different.

Conclusion: There are fundamental differences between OTP and PAR, and general agreement between them has not been demonstrated. The NHSBSA Report provides a more critical outcome assessment than PAR, identifying elements that are not assessed or measured by the PAR index.