Osteonecrosis of the jaw.

The first bisphosphonate (etidronate) was approved by the FDA in 1977; alendronate was approved in 1995 for the prevention and treatment of osteoporosis. Bisphosphonates have emerged as the agents of choice for the treatment of osteoporosis and have proved useful in the treatment of skeletal complications of malignancy (hypercalcemia, bone metastases) and have been used long-term in millions of patients. Osteonecrosis of the jaw (ONJ) is a newly described condition (2003) defined as exposed bone in the maxillofacial area, not associated with radiation or any other known cause and not healing for 8 weeks. Most cases have followed dental extraction, another invasive dental procedure, or poorly fitting dentures. Although most cases are painful and it can be progressive, approximately one-third of cases are painless and some do resolve. Although ONJ occurs exclusively or almost exclusively in patients receiving bisphosphonate therapy, a causal association has not been shown, and the mechanism is not clear. In patients receiving high-dose i.v. bisphosphonates for malignant diseases, ONJ may occur in 5 to 10% over 3 years. It does occur in patients receiving oral or i.v. bisphosphonates for osteoporosis, but is rare in that setting; about 1 case per 100,000. Treatment is conservative (antimicrobial mouthwash, antibiotics for secondary infection, limited debridement). Preventive strategies should include good dental hygiene for all patients and completion of elective invasive dental procedures before initiating high-dose i.v. bisphosphonate therapy for cancer. Patients with osteoporosis receiving lower-dose bisphosphonate therapy do not require special precautions, but should be informed of the low risk of this complication.