Flaws in root resorption assessment algorithms: Role of tooth shape

Introduction: The purposes of this study were to analyze and critique the mathematical algorithms used in the clinical assessment of root resorption. Methods: Geometric constructions and derived mathematical expressions were used to investigate the influence of tooth shape on the relationships between tooth, root, and crown lengths and their respective sizes as measured on before and after radiographs. Results: The ambiguities of root-loss assessment protocols are demonstrated. Conclusions: Root resorption assessment algorithms are unsuited for their intended applications.