[Mandibular osteoradionecrosis: sword of Damocles of radiotherapy for head and neck cancers?].

Radiotherapy of head and neck cancer is efficient but may have severe late effects. Although unfrequent, mandibular radionecrosis is the most dreadful. A cascade of events leads from hyposialia to bone destruction through extensive caries and trauma linked to tooth removal. Prevention is based on oral hygiene and use of daily topical fluorides. Antibiotics and hyperbaric oxygen can be effective as a conservative management. Progressive osteonecrosis is best treated by mandible resection and reconstruction with microvascular free bone flaps. Patient compliance to prophylaxis is of major importance. The need for periodic follow-up under the supervision of the radiation oncologist is stressed and illustrated by a clinical case having experienced disastrous consequences.