Medication-related osteonecrosis of the jaw (MRONJ) is the bone death of areas of the upper and lower jawbones (exposed through gum tissue) that occurs in people with a history or ongoing use of certain medications. It may occur with or without pain.
MRONJ is a rare and potentially debilitating condition characterized by nonhealing bone in people who have taken or are currently taking medications for osteoporosis or other bone conditions, particularly, bisphosphonates. MRONJ can also occur in people who take anticancer medications that inhibit the growth of new blood vessels. This condition differs from osteoradionecrosis, which is a similar condition caused by radiation of the head and neck, and osteonecrosis of the jaw (ONJ), which occurs without a medication-related cause.
MRONJ may occur spontaneously or after a tooth extraction, or injury to a tooth or the jaw. The lower jaw (mandible) is most often affected because of its lesser blood supply when compared with that of the upper jaw (maxilla). In some cases, MRONJ may be a form of bone infection called osteomyelitis rather than true osteonecrosis, particularly when it develops after bisphosphonate use.
Most cases of MRONJ occur in people with cancer who were treated with high doses of bisphosphonates given by vein. People receiving oral bisphosphonates for postmenopausal osteoporosis have also been reported to have MRONJ. The overall risk of MRONJ in people in this second category is very low. However, doctors encourage anyone who needs oral surgery to have it done before initiating bisphosphonate therapy and to practice good oral hygiene and receive regular dental care while taking bisphosphonates.
Symptoms and Signs of MRONJ
Medication-related osteonecrosis of the jaw may be present for long periods of time without causing any symptoms. Typical symptoms include pain and pus-filled discharge from the exposed bone, usually in the lower jaw (mandible) or, much less often, the upper jaw (maxilla). The teeth and gums may be involved. Fistulas, which are abnormal channels that drain pus, may develop.
Diagnosis of MRONJ
A doctor's evaluation
The doctor diagnoses medication-related osteonecrosis of the jaw when exposed necrotic (dead) bone is present in the jaw for at least 8 weeks.
Treatment of MRONJ
Limited debridement (removal of damaged or dead tissue)
Antibiotics
Because medication-related osteonecrosis of the jaw (MRONJ) is challenging to treat, it should be managed by an oral surgeon who has experience treating MRONJ.
Because surgical removal of the affected area of the jaw may worsen the condition, the doctor will not usually recommend it as initial treatment.
