AtlasBoneMedication-Related Osteonecrosis of the Jaws

Bone Diseases

Medication-Related Osteonecrosis of the Jaws

aka MRONJ · BRONJ

Exposed necrotic jaw bone persisting >8 weeks in a patient on antiresorptive or antiangiogenic therapy without prior head-and-neck radiotherapy.

Definition
Exposed bone >8 wk on antiresorptive
Site
Mandible > maxilla
Key
Prevention

§ overviewOverview

AAOMS 2022: exposed bone or bone probed through a fistula in the maxillofacial region persisting >8 weeks in a patient with current or previous antiresorptive/antiangiogenic drug exposure and no history of jaw radiation or obvious metastatic disease.

§ etiologyEtiology

  • 01Bisphosphonates (zoledronate, alendronate, pamidronate)
  • 02Denosumab
  • 03Antiangiogenics: bevacizumab, sunitinib
  • 04mTOR inhibitors

§ riskRisk Factors

  • 01IV route, high cumulative dose, oncology indication
  • 02Dental extraction, implant, periodontal surgery
  • 03Poor oral hygiene, denture trauma
  • 04Diabetes, steroids, chemotherapy, smoking

§ pathogenesisPathogenesis

Suppressed osteoclast function → impaired bone remodelling; reduced angiogenesis; oral microbial infection precipitates necrosis after minor trauma.

§ clinicalClinical Features

  • 01Exposed necrotic bone
  • 02Pain, swelling, halitosis, purulence
  • 03Loose teeth, sinus tracts
  • 04Mandible > maxilla (posterior)

§ radiographicRadiographic Features

  • 01Ill-defined osteolysis with sequestra
  • 02Persistent extraction socket
  • 03Thickened lamina dura, periosteal reaction

§ investigationsInvestigations

  • 01OPG, CBCT for extent
  • 02MRI/CT for advanced staging
  • 03Cultures for superadded infection

§ classificationClassification

  • 01AAOMS staging: Stage 0 (non-exposed), Stage 1 (exposed, asymptomatic), Stage 2 (exposed, symptomatic/infected), Stage 3 (extending beyond alveolus, pathological fracture, extra-oral fistula)

§ treatmentTreatment

  • 01Prevention key: dental screening BEFORE therapy; complete extractions with 4–6 wk healing
  • 02Stage 0/1: chlorhexidine mouthwash, analgesia, careful monitoring
  • 03Stage 2: antibiotics (amoxicillin/metronidazole), superficial debridement
  • 04Stage 3: sequestrectomy/resection with reconstruction
  • 05Drug holiday controversial — coordinate with oncologist; not evidence-based for denosumab
  • 06Adjuncts: PRF, teriparatide (non-oncology), ozone, hyperbaric oxygen (limited evidence)

§ complicationsComplications

  • 01Pathological fracture
  • 02Oro-antral/oro-cutaneous fistula
  • 03Chronic osteomyelitis
  • 04Loss of function

§ prognosisPrognosis

Difficult; prevention >> treatment. Stage 3 often requires major resection.

§ examKey Examination Points

  • 01Take a bisphosphonate history for EVERY extraction
  • 02Educate patients on oral hygiene before starting antiresorptives

§ revisionQuick Revision Summary

  • 01AAOMS 2022 · exposed bone >8 wk · prevention with pre-treatment dental clearance

§ vivaBDS Viva Questions

  • 01AAOMS diagnostic criteria?
  • 02Drug holiday — evidence?
  • 03Preventive protocol before IV bisphosphonate?

§ mcqsMCQs — Assessment (3)

Question 1

Duration of exposed bone required for MRONJ diagnosis:

Question 2

Highest-risk drug:

Question 3

Best preventive strategy:

References

  1. Ruggiero SL et al. AAOMS Position Paper. J Oral Maxillofac Surg 2022

Draft — pending faculty review. Educational use only; verify against current guidelines and primary sources before clinical application.