Medication-related osteonecrosis of the jaw

Medication-related osteonecrosis of the jaw (MRONJ) is a serious condition involving the bone of the jaw, characterized by the presence of exposed bone in the mouth that does not heal within eight weeks in a patient who has been taking certain medication and has not received radiation therapy to the craniofacial region. MRONJ is associated with the use of bisphosphonates, a class of drugs used to treat osteoporosis and metastatic bone disease, among other conditions. However, other medications, such as denosumab and anti-angiogenic drugs, have also been implicated in the development of this condition.

Etiology and Pathophysiology

The exact mechanism by which these medications cause osteonecrosis of the jaw is not fully understood. It is believed that bisphosphonates, which have a high affinity for bone tissue, may impair bone remodeling by inhibiting osteoclast activity, leading to an accumulation of micro-damages and eventually bone necrosis. Denosumab, a monoclonal antibody that inhibits RANKL (Receptor Activator of Nuclear Factor κB Ligand), plays a crucial role in the regulation of osteoclasts and can similarly impair bone remodeling and repair.

Risk Factors

Several factors increase the risk of developing MRONJ, including:

• Duration and route of medication administration, with higher risk associated with intravenous administration and longer treatment duration.
• Dental procedures, such as tooth extractions, which can act as a local trigger.
• Poor oral hygiene and pre-existing dental disease.
• Use of corticosteroids and immunosuppressive therapy, which may compound the risk.

Clinical Presentation

Patients with MRONJ may present with pain, swelling, and infection of the soft tissues around the exposed bone. The exposed bone is usually visible in the mouth, but asymptomatic cases are also reported. Symptoms can range from mild discomfort to severe pain and can significantly impact the patient's quality of life.

Diagnosis

Diagnosis of MRONJ is primarily clinical, based on the history of medication use and the presence of exposed bone in the jaw that does not heal within eight weeks. Imaging studies, such as panoramic radiographs or CT scans, can be helpful in assessing the extent of bone involvement.

Management

The management of MRONJ focuses on reducing pain, controlling infection, and minimizing the progression of bone necrosis. Treatment strategies include:

• Conservative measures, such as oral rinses and antibiotics, for early-stage disease.
• Surgical debridement or resection for more advanced cases or when conservative treatment fails.
• Cessation or modification of the causative medication, in consultation with the prescribing physician, may be considered in some cases.

Prevention

Preventive measures are crucial and include thorough dental evaluation and treatment of any oral disease before initiating therapy with high-risk medications. Patients on these medications should maintain excellent oral hygiene and avoid invasive dental procedures whenever possible.

Conclusion

Medication-related osteonecrosis of the jaw is a challenging condition that requires a multidisciplinary approach for management and prevention. Awareness among healthcare providers and patients about the risk factors and early signs of MRONJ is essential for early diagnosis and effective treatment.