MRONJ — MFDS Part 1 MCQ

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ModerateHuman DiseaseMRONJMFDS Part 1

A 62-year-old woman receiving intravenous zoledronic acid for metastatic breast cancer undergoes extraction of a mandibular molar. Eight weeks later, the socket remains unhealed and exposed bone is present. She has never received radiotherapy to the head and neck. Which is the most likely diagnosis?

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Correct answer: B — Medication-related osteonecrosis of the jaw

The most likely diagnosis is medication-related osteonecrosis of the jaw (MRONJ). Zoledronic acid is an antiresorptive bisphosphonate, and patients receiving antiresorptive treatment for cancer are at higher risk than those treated for osteoporosis. Tooth extraction is a common precipitating event. SDCEP advises that an extraction socket remaining unhealed at 8 weeks should raise suspicion of MRONJ and prompt referral to oral surgery or special care dentistry. Osteoradionecrosis is unlikely because there is no history of head-and-neck radiotherapy. Chronic suppurative osteomyelitis would more typically be associated with clinical evidence of infection. Mandibular metastasis and pathological fracture may cause pain, swelling, altered sensation or radiographic destruction, but neither best explains persistent exposed bone following extraction in a patient receiving zoledronic acid.

Reference: Scottish Dental Clinical Effectiveness Programme. Oral Health Management of Patients at Risk of Medication-related Osteonecrosis of the Jaw, sections 3 and 4.2. Published 2017; reviewed and extant March 2024. https://www.sdcep.org.uk/media/5cnbsel5/sdcep-mronj-guidance-extant-2024.pdf