INTRODUCTION: Current methods to evaluate root position are either inaccurate (panoramic radiograph) or expose patients to relatively large amounts of radiation (CBCT). A method to evaluate root position by generating an expected root position (ERP) setup was recently reported but has not been validated. The purpose of this study was to quantitatively assess the accuracy and reliability of the ERP setup with adequate statistical power.

METHODS: This retrospective study included fifteen subjects who had completed phase II orthodontic treatment. An ERP setup was generated for all patients at post-treatment. The ERP setup was compared to the post-treatment CBCT scan which served as the control. The mesiodistal angulation and buccolingual inclination of all teeth in both the ERP setup and post-treatment CBCT scan were measured and compared. Bland-Altman analysis was used to assess inter-operator reliability, intra-operator reliability, and the agreement between the ERP setup and post-treatment CBCT scan.

RESULTS: Bland-Altman plots found high inter-operator and intra-operator reliability. Bland-Altman plots also showed strong agreement between the ERP setup and post-treatment CBCT scan. 11.8% of teeth measured for mesiodistal angulation and 9.6% of teeth measured for buccolingual inclination were outside of the ±2.5° range of clinical acceptability.

CONCLUSIONS: We have validated that the method to generate an ERP setup to evaluate root position during orthodontic treatment is accurate and reliable.