Title: Evaluation of Orthodontic Root Resorption in Short Root Anomaly
Donna Thomas (Presenter)
University of North Carolina
Ashley Hill, University of North Carolina
Sylvia Frazier-Bowers, University of North Carolina
Objectives: Orthodontic practices have witnessed an increase in pretreatment dental anomalies such as Short Root Anomaly (SRA). This relatively new variation may carry consequences that alter the orthodontic management and treatment for affected individuals. It has been suggested that SRA-affected teeth have an increased risk for external apical root resorption, but few studies have assessed the root resorption of SRA-affected patients following treatment. In order to test the hypothesis that SRA-affected teeth are equally susceptible to Orthodontically Induced External Apical Root Resorption (OIEARR) as non-affected teeth; we evaluated the amount of root resorption in a cohort of SRA patients after orthodontic treatment.
Methods: We utilized pre- and post-treatment radiographs to characterize the SRA phenotype and determined the proportion of teeth that experienced OIEARR. SRA teeth were classified as permanent teeth with short roots (crown to root ratio less than or equal to 1:1 with typical size and shaped crowns). Pre- and post-treatment radiographic samples of SRA affected teeth (n=96) were analyzed using a modified Malmgren and Levander scale to quantify root resorption (0: no change, 1: minor resorption, 2: moderate resorption, 3: severe resorption). Non-affected teeth of the same individuals (n=113) were also assessed.
Results: OIEARR was observed in 38% of SRA-affected teeth. Minor resorption was observed in 19.7%, moderate resorption was observed in 15.6%, and severe resorption was observed in 3.1% of affected teeth. OIEARR was observed in 7% of non-affected teeth. Mild resorption was observed in 0.8%, moderate resorption was observed in 0.3% and severe resorption was observed in 0.2% of unaffected teeth.
Conclusions: In our sample, SRA-affected teeth were more susceptible to root resorption than non-affected teeth. Although mostly mild root resorption was found, the consequence of OIEARR is greater in SRA-affected teeth given the initially low crown to root ratio.