Validity and Reliability of Peer Assessment Rating Index Measurement Derived from Digital and Plaster Models

Abstract

Aims: The aim of the study was to determine the validity and reliability of Peer Assessment Rating (PAR) index score derived from digital and plaster models of the same patient. Subjects and Methods: Thirty orthodontic plaster study models were digitalized using the 3Shape R700™ Orthodontic 3D scanner. PAR Index scoring was carried out on both the plaster and digital models by one independent examiner calibrated in the PAR Index. The measurements were repeated at a second sitting. Measurements were made on plaster models with the PAR Index ruler and on digital models with the 3Shape OrthoAnalyzer™ software. Statistical Analysis Used: Bland-Altman plots were used to test for validity and intraexaminer reliability. Results: For PAR Index score, overjet and overbite component scores, 28 out of 30 measurements were within 95% limits of agreement. Other components of the PAR Index score had all points within 95% limits of agreement. For intraexaminer reliability, digital models had 28 out of 30 measurements and plaster models had 27 out of 30 measurements that were within 95% limits of agreement. Conclusions: Digital models are a clinically acceptable alternative to plaster models in the measurement of the PAR Index. Improvement in software design is necessary to attain greater agreement in the measurement of the overjet and overbite components of the PAR index score between plaster and digital models.