What is MRONJ?

Medication-related osteonecrosis of the jaw is a fairly serious drug reaction, resulting in the gradual death of jaw bone. Following oral and maxillofacial or periodontal surgery, or endodontic therapy it can result in significant complication due to the reduced healing ability of the bone.

Which drugs cause MRONJ?

MRONJ is caused by either antiresorptive drugs (including bisphosphonates) that cause a reduced ability for the reabsorption of bone, or antiangiogenic drugs, which impair the formation of new blood vessels. While uncommon, MRONJ is a serious side effect of these drugs, and extra awareness should be used when treating patients with these conditions.

How do I prevent MRONJ?

There is no known effective prevention technique for MRONJ, therefore diligence in in watching for signs of MRONJ when treating patients on intravenous antiresorptive and/or antiangiogenic drugs is vital. Patients on these drugs for 3 years have an increased likelihood of developing MRONJ, and therefore increased awareness and caution should be exercised while treating them.

How do I diagnose and treat MRONJ?

The following table from the AAOMS 2014 guidelines summarizes the clinical findings and treatment strategies for MRONJ:

Staging and Treatment Strategies

*Exposed or probable bone in the maxillofacial region without resolution for greater than 8 weeks in patients treated with an antiresorptive and/or an antiangiogenic agent who have not received radiation therapy to the jaws.

**Regardless of the disease stage, mobile segments of bony sequestrum should be removed without exposing uninvolved bone. The extraction of symptomatic teeth within exposed, necrotic bone should be considered since it is unlikely that the extraction will exacerbate the established necrotic process.


MRONJ StagingCriteria* (>8 weeks)Treatment Strategies**Picture
At riskNo apparent necrotic bone in patients who have been treated with either oral or IV bisphosphonatesNo treatment indicated, Patient educationN/A
Stage 0No clinical evidence of necrotic bone, but non-specific clinical findings, radiographic changes and symptomsSystemic management, including the use of pain medication and antibioticsN/A
Stage 1Exposed and necrotic bone, or fistulae that probes to bone, in patients who are asymptomatic and have no evidence of infectionAntibacterial mouth rinse, Clinical follow-up on a quarterly basis, Patient education and review of indications for continued bisphosphonate therapy

Stage 1 MRONJ

Stage 2Exposed and necrotic bone, or fistulae that probes to bone, associated with infection as evidenced by pain and erythema in the region of the exposed bone with or without purulent drainageSymptomatic treatment with oral antibiotics, Oral antibacterial mouth rinse, Pain control, Debridement to relieve soft tissue irritation and infection control

Stage 2 MRONJ

Stage 3Exposed and necrotic bone or a fistula that probes to bone in patients with pain, infection, and one or more of the following: exposed and necrotic bone extending beyond the region of alveolar bone,(i.e., inferior border and ramus in the mandible, maxillary sinus and zygoma in the maxilla) resulting in pathologic fracture, extra-oral fistula, oral antral/oral nasal communication, or osteolysis extending to the inferior border of the mandible of sinus floorAntibacterial mouth rinse, Antibiotic therapy and pain control, Surgical debridement/resection for longer term palliation of infection and pain

Stage 3 MRONJ

Mandibular Fistula