What is MRONJ?

Medication-related osteonecrosis of the jaw (MRONJ) is a rare side effect of anti-resorptive and anti-angiogenic drugs.

MRONJ is characterised by:

  • exposed bone, or bone that can be probed through an intraoral or extraoral fistula, in the maxillofacial region that has persisted for more than eight weeks
  • a history of treatment with anti-resorptive or anti-angiogenic drugs
  • no history of radiation therapy to the jaw or no obvious metastatic disease to the jaws

Although the majority of cases of MRONJ occur following a dental intervention which impacts on bone, some can occur spontaneously.

Signs and symptoms of MRONJ include:

  • delayed healing following a dental extraction or other oral surgery
  • pain
  • soft tissue infection and swelling
  • numbness
  • paraesthesia
  • exposed bone

Patients may also complain of pain or altered sensation in the absence of exposed bone. However, be aware that some patients may be asymptomatic at presentation, with MRONJ lesions an incidental finding.

A history of anti-resorptive or anti-angiogenic drug use in these patients should alert practitioners to the possibility of MRONJ.

Here is a list of anti-resorptive and anti-angiogenic drugs currently prescribed in the UK.

MRONJ is a rare condition, with an incidence of between 1 in 1000 and 1 in 10,000 in the osteoporosis patient group. The risk in cancer patients is around 100 times greater.

The risk of MRONJ should be discussed with patients but it is important that they are not discouraged from taking anti-resorptive or anti-angiogenic drugs or from undergoing dental treatment.

For more information on the incidence of MRONJ in the different patient groups, refer to the full guidance.