MRONJ | Medication or Bisphosphonate related osteonecrosis of the jaw

Key info

This document has been designed to improve understanding regarding treatment of the MRONJ (Medication or Bisphosphonate related osteonecrosis of the jaw ) and contains answers to many of the common questions. If you have any other questions not answered here or if you would like further explanations please ask Mr Schenberg or other members of staff.

What is medication or bisphosphonate related osteonecrosis of the jaw?

MRONJ (or BRONJ) has been defined by the American Association of Oral and Maxillofacial Surgery as a condition that has the following characteristics:

  • Current or previous treatment with antiresorptive or antiangiogenic agents;
  • Exposed bone or bone that can be probed through an intraoral or extraoral fistula(e) in the maxillofacial region that has persisted for more than eight weeks; and
  • No history of radiation therapy to the jaws or obvious metastatic disease to the jaws.

MRONJ may occur spontaneously or following local trauma to the jaw eg. tooth removal.

Its pathogenesis remains poorly understood and our ability to reliably predict the relative risk for each patient is limited.

Other factors that can influence the occurrence or aggressiveness of MRONJ include, but not limited to, the coexistent use of cytotoxic medications, immunosuppression, concomitant oral disease, smoking, diabetes, dental neglect, tori and dialysis 1,2,3,4.

Over the past years their has been an increase in the use of oral and intravenous bisphosphonates and other antiresorptive medications. They are used in the treatment of metastatic bone disease and osteoclast-mediated bone diseases such as osteoporosis, multiple myeloma and Paget’s disease. MRONJ has emerged as a significant potential treatment complication in recent years.

What is the incidence of MRONJ?

The incidence of MRONJ among patients who have received medications such intravenous bisphosphonates or denosumab for the treatment of various cancers is approximately 1%1.

For patients who have been treated with these or similar medications for osteoporosis, the incidence for MRONJ is far less.

What are the common symptoms?

MRONJ typically presents clinically with breakdown of the mucous membrane or gums overlying the jaw bone with subsequent bone exposure. This is accompanied with symptoms varying from painless areas of exposed bone, changes in sensation of the skin of the chin and lips and alveolar bone loss. Infections may occur. there may be orocutaneous fistula formation, severe jaw pain and pathological jaw fractures.

Radiographically, bony sclerosis and areas of lysis or sequestration can be observed although it is not uncommon to find little or no changes in radiographic appearance.

Histologically, areas of non-vascular necrotic bone can be observed within vital bone. Inflammatory infiltrates, bacteria, fibrotic and granulation tissue can also be seen.

MRONJ has been reported to occur more frequently among patients receiving intravenous aminobisphosphonates eg. alendronate, pamidronate, risedronate and zoledronate.

What treatment and management options are available?

Prevention of MRONJ is an important first step. It is important that all patients about to commence taking these medications are assessed by their dentist and complete any required treatment first. Ongoing frequent dental attendance is important after commencement of treatment.

Once established, MRONJ can be very difficult to manage. Treatment options are limited. Oral antibiotics and antiseptic mouthwashes are used at times of infections. Analgesics are used as required.

Surgical options should be delayed as much as possible. Surgery may result in a greater area of jaw bone becoming exposed. Surgical management is generally reserved for groups of patients with MRONJ who have ongoing infections and wide areas of exposed dead bone.

Further reading on MRONJ