Quantitative assessment of root resorption in TAD-aided anchorage with and without RAP: A CBCT study on en masse retraction cases

INTRODUCTION: The purpose of this study was to evaluate the amount of root resorption with mini implant-aided anchorage, with and without inducing the regional acceleratory phenomenon (RAP) in en masse retraction cases using cone-beam computed tomography (CBCT). METHODS: Thirty patients requiring therapeutic extraction of all first premolars were included in the study and randomly divided into two groups of fifteen patients each (groups I and II). Patients of both groups underwent retraction using mini implants. In patients of group II, the RAP was initiated before starting retraction. For each patient, CBCT of the maxillary and mandibular anterior region was taken before treatment and after retraction to evaluate root length changes. RESULTS: The amount of root resorption post-retraction was lesser in group II as compared to group I for the maxillary canine, mandibular canines, and mandibular lateral incisors. When the amount of root resorption was scored according to the Malmgren index, a greater percentage of teeth in group I (17.8%) showed root resorption of score of 3 as compared to group II (6.1%). CONCLUSION: The results of the study show that the RAP caused reduced root resorption, but its effect was localized to the area where it was induced. When mini implants are used for absolute anchorage during en masse retraction, the RAP can be induced to reduce the root resorption that results from increased treatment time associated with implant-aided retraction.