Pre-existing medication-related osteonecrosis of the jaw before dental extraction

Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse event, most commonly associated with dental extractions as a predisposing event. However, it is possible that established MRONJ may be existent before dental extractions and is mistaken for odontogenic disease. The provision of a dental extraction will lead to clinically obvious MRONJ with the cause being attributed to tooth removal. We present a case series of ten patients with pre-existing necrosis of the jaw before dental extraction.Retrospective data were collected on ten patients who presented to the oral surgery department between 2017-2021, diagnosed with pre-existing necrosis. A diagnosis of pre-existing MRONJ was made based on the identification of necrotic bone clinically, either with plain film or cone beam computed tomography (CBCT). Patients with pre-existing necrosis presented with a range of symptoms, including pain, swelling and tooth mobility. Plain film imaging revealed a variety of findings, including periapical radiolucency, periodontal ligament widening and bone loss. CBCT imaging confirmed a necrotic pattern of bone destruction confirming a diagnosis of pre-existing MRONJ.There is increasing evidence to suggest that local inflammation can be a predisposing factor for MRONJ development as opposed to surgical intervention. This case series provides early insight into the presentation of pre-existing MRONJ.