musculoskeletal and connective tissue disorders
Medication Related Osteonecrosis of the Jaw (MRONJ)
Introduction
Medication-related osteonecrosis of the jaw has no unanimously accepted definition or etiology but is generally held to be an oral lesion involving bare mandibular or maxillary bone present for ≥ 8 weeks related to medications. It may cause pain or may be asymptomatic. Diagnosis is by the presence of exposed bone for at least 8 weeks. Treatment is limited debridement, antibiotics, and oral rinses. Medication-related osteonecrosis of the jaw (MRONJ), formerly called bisphosphonate-related osteonecrosis of the jaw (BPONJ), is a rare and potentially debilitating condition. MRONJ is characterized by nonhealing exposed bone in patients with a history or ongoing use of Antiresorptive medications (particularly with high-dose IV administration), an antiresorptive agent (eg, MRONJ may occur spontaneously or after Osteonecrosis of the jaw (ONJ) or trauma. It occurs preferentially in the mandible (75% of cases) due to the course of the blood supply to the lower jaw. MRONJ may be a refractory osteomyelitis rather than true osteonecrosis, particularly when developing after bisphosphonate use. Most cases of MRONJ have been in patients with cancer treated with high-dose IV bisphosphonates; very few cases have been reported in patients receiving bisphosphonates for Osteoporosis with therapy duration over 4 years. The risk of developing MRONJ is higher in patients who have received antiresorptive medications for metastatic bone disease (< 5% [ Oral bisphosphonates are less lipid soluble and result in less accumulation in the bone. The risk of MRONJ in osteoporosis patients taking oral bisphosphonates is extremely low and is comparable to prevalence in the general population (approximately 1 case per 100,000 patient years [ References ]). Prevalence of MRONJ risk for long-term oral bisphosphonate therapy less than 4 years was 0.1%, and does not appear to exceed 0.21%, even for patients receiving oral bisphosphonate over 4 years ( 