Medication-related osteonecrosis of the jaw

Medication-related osteonecrosis of the jaw (MRONJ) describes the bony destruction of the jaw with exposed bone present for greater than eight weeks in the presence of current or previous antiresorptive and/or antiangiogenic medication use, and in the absence of radiation therapy to the head and neck or obvious metastatic disease.  

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) was the initially described entity, but MRONJ is now the preferred term as other medications besides bisphosphonates have been implicated as aetiological agents 5,6

BRONJ is estimated to affect 1 in 10,000 to 100,000 in a patient taking oral bisphosphonates. It more commonly affects females and patients older than 60 years 1 although this likely represents the population receiving bisphosphonates 3

MRONJ is a painful process and before osteonecrosis becomes clearly evident the patient may present with the following symptoms and signs 2:

  • periodontal disease and non-healing mucosal ulcers
  • loose teeth
  • soft tissue infections

Established BRONJ manifests as necrosis of the jaw with exposed bone. 

The definite pathogenesis of MRONJ has not yet been established but is proposed to be related to bone remodeling suppression and antiangiogenic effects of these medications 3. Medications implicated in the formation of MRONJ include 5,6:

  • indicated for osteoporosis
    • bisphosphonates
    • denosumab
  • indicated for malignancy
    • tyrosine kinase inhibitors, e.g. sunitinib, sorafenib
    • bevacizumab (humanised monoclonal antibody)

The mandible is affected more commonly than the maxilla (2:1) although both can be affected at the same time 1-2

  • recent dental surgery (~65% of patients) 2-3
  • IV bisphosphonate use 2-3
  • long-term bisphosphonate use 3
  • concurrent bone metastases or multiple myeloma 1-2
  • dental or periodontal disease 3

Features are non-specific and include 1:

  • poorly defined lucent, mixed or sclerotic lesion
  • sequestrum
  • periosteal proliferation
  • destruction of adjacent structures

Plain films and OPGs may not demonstrate early disease 1,3

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Article information

rID: 6784
Tag: cases
Synonyms or Alternate Spellings:
  • Bisphosphonate related jaw necrosis
  • Bisphosphonate-related osteonecrosis of the jaw (BRONJ)
  • Bisphosphonate-related osteonecrosis (BRON)
  • Bisphosphonate osteonecrosis (BON)
  • Bisphosphonate-associated osteonecrosis of the jaw (BAONJ)
  • Bisphosphonate-related osteonecrosis of the jaw
  • Medication-related osteonecrosis of the jaw (MRONJ)

Cases and figures

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    Case 1: BRONJ
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