(TC20) External Root Resorption Associated With Familial Expansile Osteolysis in a Pediatric Patient

External root resorption (ERR) in the adult dentition is a dynamic and pathological process that can result in tooth loss through the continued action of osteoclastic cells. Teeth are covered with unmineralized protective layers, pre-cementum and pre-dentin. Loss or alteration of the protective layers due to traumatic injuries followed by an inflammatory response is required for ERR to occur. There are many causes of ERR, including genetic disorders such as familial expansile osteolysis (FEO), which is accompanied by middle ear deafness in childhood, bone dysplasia, and premature loss of teeth due to increased resorption. FEO is a rare autosomal dominant disorder due to mutations of the TNFRSF11A gene which encodes the receptor activator of nuclear factor-kappa B (RANK). The mutation in the TNFRSF11A gene can result in the unregulated formation of RANK independent of the RANK/RANK Ligand pathway and the continued formation of osteoclastic cells. The purpose of this table clinic is to describe a case of a 10-year-old pediatric patient suffering from middle ear deafness who was later diagnosed with FEO. She presented to the dental clinic with advanced ERR on multiple permanent teeth. The diagnostic procedures she underwent, and subsequent treatments, are described here. It is advised that systemic abnormalities and genetic testing be considered when local etiologic variables cannot account for the cause of ERR.