A Standardized Novel Method to Measure Radiographic Root Changes after Endodontic Therapy in Immature Teeth

Introduction: Outcome studies of endodontic treatment of necrotic immature permanent teeth rely on radiographic measures as surrogates of whether the treatment achieved regeneration/revascularization/revitalization. An increase in radiographic root length and/or width is thought to result in a better long-term prognosis for the tooth. In this study, a method to measure radiographic outcomes of endodontic therapies on immature teeth was developed and validated. Methods: A standardized protocol was developed for measuring the entire area of the root of immature teeth. The radiographic root area (RRA) measurement accounts for the entire surface area of the root as observed on a periapical radiograph. Reviewers were given instructions on how to measure RRA, and they completed measurements on a set of standardized radiographs. Results: The intraclass correlation between the 4 reviewers was 0.9945, suggesting a high concordance among reviewers. There was no effect of the reviewer on the measured RRA values. High concordance was also observed when 1 rater repeated the measurements, with an intraclass correlation value of 0.9995. There was no significant difference in RRA values measured at the 2 sessions by the same rater. Furthermore, significant differences in RRA were detectable between clinical cases that showed obvious continued root development and cases that did not demonstrate discernible root development. Conclusions: These results suggest that RRA is a valid measure to assess radiographic outcomes in endodontically treated immature teeth, and RRA should be useful in future clinical studies of regenerative endodontic outcomes.