Medication-Related Osteonecrosis of the Jaw (MRONJ)

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 bisphosphonates Antiresorptive medications Osteoporosis is a progressive metabolic bone disease that decreases bone mineral density (bone mass per unit volume), with deterioration of bone structure. Skeletal weakness leads to fractures... read more (particularly with high-dose IV administration), an antiresorptive agent (eg, denosumab), or an antiangiogenic agent and no history of radiation exposure to the head and neck region. Very rarely, osteonecrosis of the jaw (ONJ) with the same clinical manifestations as MRONJ occurs in patients who have not been treated with bisphosphonates or antiresorptive or antiangiogenic agents.

MRONJ may occur spontaneously or after dental extraction Osteonecrosis of the jaw (ONJ) Postextraction problems are a subset of dental emergencies that require immediate treatment. These problems include Swelling and pain Postextraction alveolitis Osteomyelitis Osteonecrosis of the jaw read more 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 postmenopausal osteoporosis Osteoporosis Osteoporosis is a progressive metabolic bone disease that decreases bone mineral density (bone mass per unit volume), with deterioration of bone structure. Skeletal weakness leads to fractures... read more 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% [ 1 References 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... read more ]) compared to those receiving such drugs for osteoporosis (< 0.05% [ 2 References 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... read more ]).

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 [ 3 References 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... read more ]). 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 (4 References 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... read more ). Currently, otherwise-appropriate bisphosphonate use should not be discouraged. However, it seems reasonable to do any necessary oral surgery before beginning IV bisphosphonate therapy and to encourage good oral hygiene and regular dental care while patients are taking bisphosphonates (5 References 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... read more , 6 References 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... read more ).