A Comprehensive Review of Differences between Osteoradionecrosis and Medication-related Osteonecrosis of the Jaw

Two severe and challenging-to-treat side effects of head and neck cancer (HNC) oncological treatments are osteoradionecrosis of the jaws (ORNJ) and medication-related osteonecrosis of the jaws (MRONJ). In both cases, the bone loses vitality and develops in an area that cannot heal, which is exposed through the skin or mucosa; in more severe cases, fistulas and jaw fractures may coexist. They are similar in that they complicate medical and surgical treatments (such as radiation therapy or medications) and cause osteonecrosis of the jawbone. Despite many clinical similarities, they differ in etiology, histopathology, radiological features, and staging systems, leading to different treatment approaches. Despite having relatively low incidences, both have a detrimental effect on HNC patients' quality of life by causing various potentially unwholesome symptoms like pain, tooth loss, swelling, erythema, ulceration, dysphagia, trismus, or paresthesia. Because distinguishing ORNJ and MRONJ, two devastating complications of different origins with a similar presentation pattern and gross appearance, can be difficult, the purpose of this review is to discuss the major differences in their definitions, staging systems, clinical findings, underlying pathophysiologic mechanisms, histopathology, and treatment options.