Definition and Overview
- MRONJ is the progressive death of the jawbone in individuals exposed to certain medications.
- It can occur after oral and maxillofacial surgery, periodontal surgery, or endodontic therapy.
- Medications that increase the risk of MRONJ include anti-resorptive drugs and anti-angiogenic drugs.
- Previously known as bisphosphonate-related osteonecrosis of the jaw (BRONJ).
- No known prevention for bisphosphonate-associated osteonecrosis of the jaw.

Signs, Symptoms, and Cause
- MRONJ can cause ulcers or areas of necrotic bone for weeks, months, or even years following a tooth extraction.
- Mild pain may be experienced due to inflammation of surrounding tissues.
- Other signs and symptoms include jaw pain, loose teeth, mucosal swelling, erythema, suppuration, soft tissue ulceration, trismus, non-healing extraction sockets, paraesthesia or numbness in the jaw, bad breath, and exposed necrotic jaw bone.
- Symptoms persist for more than 8 weeks.
- Patients may be asymptomatic.
- MRONJ can be associated with the use of intravenous and oral bisphosphonates.
- Scientists believe there is a correlation between jaw necrosis and exposure to bisphosphonates.
- Bone injury in patients using bisphosphonates may contribute to the development of MRONJ.
- Other medications and factors may also play a role in causing MRONJ.
- The exact cause of MRONJ is still unclear.

Risk Factors and Research Findings
- MRONJ is more commonly associated with intravenous administration of bisphosphonates.
- Dental treatment, duration of bisphosphonate drug therapy, and other concurrent medications increase the risk of MRONJ.
- Dental implants and previous treatment with anti-resorptive/anti-angiogenic drugs are also risk factors.
- Patients being treated for cancer have a higher risk, while those being treated for osteoporosis/non-malignant bone diseases have a lower risk.
- Drug holidays or stopping bisphosphonate use do not necessarily reduce the risk of MRONJ.
- The risk of MRONJ after dental extraction is higher in patients treated with antiresorptive drugs for oncological reasons compared to those treated for osteoporosis.
- Adjusted extraction protocols can decrease the development of MRONJ.
- Concomitant medications and pre-existing osteomyelitis are potential risk indicators for MRONJ.
- The risk of MRONJ is influenced by various factors and circumstances.
- Further research is needed to better understand and prevent MRONJ.

Medications Associated with MRONJ
- Anti-resorptive drugs inhibit osteoclast differentiation and function.
- Two main types of anti-resorptive drugs are bisphosphonates and denosumab.
- Bisphosphonates are administered orally or intravenously and reduce bone resorption.
- Denosumab is a monoclonal antibody administered subcutaneously that inhibits osteoclast differentiation and activation.
- Anti-angiogenic drugs interfere with blood vessel formation and are primarily used to treat cancer.

Management and Treatment Options
- Treatment involves antimicrobial mouthwashes and oral antibiotics to fight infection.
- Local resection of the necrotic bone lesion is often performed.
- Severity of osteonecrosis determines the treatment received.
- Conservative management includes antiseptic mouthwashes, analgesics, and teriparatide.
- Non-surgical management involves antimicrobial mouthwashes, systemic antibiotics, antifungal medication, and analgesics.
- Surgical intervention may be necessary for symptomatic exposed bone, fistula formation, and specific conditions.
- Other treatment options include hyperbaric oxygen therapy and ultrasonic therapy.
- Antibiotics are used to treat cases involving infections, with penicillin being the first-line choice.