A patient who received head and neck radiotherapy 10 years ago now requires extractions followed by a new denture. What is the MOST important information to obtain from the treating physician?

Correct answer: A. The anatomical field irradiated and the total radiation dose delivered

• A. CORRECT. Osteoradionecrosis risk is governed by two variables: whether the jaws were inside the treatment field, and how much dose they received. Risk climbs steeply above roughly 60 Gy, and the posterior mandible is the classic site because of its dense cortical bone and comparatively poor collateral blood supply. Knowing the field and dose determines whether extractions can proceed conventionally, whether they need atraumatic technique with primary closure and antibiotic cover, whether hyperbaric oxygen should be considered, and — critically — whether the patient should be steered toward tooth preservation instead. Note that the risk from radiation is LIFELONG and does not diminish with time.
• B. Remission status is relevant to overall prognosis and to whether extensive prosthetic rehabilitation is warranted, but it does not quantify the bone's capacity to heal after surgery.
• C. Completion of treatment matters oncologically but does not tell you what you need: the anatomical field and the cumulative dose to bone.
• D. Concurrent chemotherapy affects healing generally, but it is the radiation dose to bone that drives osteoradionecrosis risk specifically.

Note: Osteoradionecrosis mechanism: radiation produces hypoxic, hypocellular, hypovascular bone that cannot meet the metabolic demand of healing. Prevention is everything — ideally all questionable teeth are extracted at least 2 to 3 weeks BEFORE radiotherapy begins. Afterward, avoid extractions where possible, avoid periosteal stripping, and never let a denture flange traumatise the ridge.