Which of the following is a characteristic feature of osteoradionecrosis?

Osteoradionecrosis is primarily characterized by avascular necrosis of the bone, which occurs as a consequence of radiation therapy. In the context of radiation, the blood supply to the bone becomes compromised, leading to necrosis. The radiation damages not only the bone but also the surrounding tissues that provide critical vascular support, thus leading to a significant reduction in healing potential. As a result, areas of bone may become ischemic and necrotic, with the affected tissue being unable to respond to normal physiological processes or to fight off infections adequately.

While other considerations like delayed fracture healing can occur in patients who have received radiation therapy, it is not the defining characteristic of osteoradionecrosis itself. Similarly, pressure ulcers on the mandible or bacterial infections of periodontal tissues may arise in patients with compromised jaw bone health but do not specifically define osteoradionecrosis. The primary and distinguishing feature remains the avascular necrosis due to the influence of prior radiation treatment.