Osteonecrosis of the Jaws (ONJ)

Osteonecrosis of the Jaws (ONJ) is a condition where the bone in the jaw becomes devitalized (dead) and the bone becomes exposed to the oral cavity. ONJ is a rare condition that can occur in association with a variety of conditions, including cancer and its treatments. Depending on the stage, ONJ can occur without symptoms or it can be associated with infection and pain.

Why does ONJ occur?

Doctor auscultating the neck of a patient

Within bone tissue, there are specific cells that break down and re-build the bones to release minerals into the bloodstream and maintain bone strength. Patients whose cancers have spread to the bones are often treated with antiresorptive medications that are designed to block this destruction of the bone tissue and prevent complications. In this patient population, ONJ is thought to occur due to the inhibition of the bone destruction and rebuilding process associated with certain cancer treatments. Other treatments such as radiation can also lead to necrosis.

Who is at risk of developing ONJ?

Antiresorptive medications are most often used in a general population to treat weak bones, a condition commonly referred to as osteoporosis. Antiresorptive medications are also used in the management of cancers that have spread to or involve the bone. While almost any cancer can spread to the bone on occasion, some of the most common types of cancers that spread to the bone include prostate cancer, breast cancer, lung cancer, and kidney cancer. Multiple myeloma also usually has bone involvement.

Approximately half of patients with cancer that has spread to the bone experience skeletal complications such as fractures or the need for radiation or surgery. These patients may also develop pain or elevated levels of calcium in the bloodstream. In this group of cancer patients, antiresorptive drugs are often used to prevent these types of skeletal complications, as research has shown that the use of antiresorptive drugs can decrease the risk of developing bone complications by over 50%.

While these are important medications used to manage and control cancer, patients who are taking any of these medications should be aware that they are at risk of developing ONJ.

Some specific examples of ONJ-associated medications include intravenously (IV) administered medications such as zoledronic acid (Zometa) or pamidonate (Aredia) or the injectable medication denosumab (Xgeva).

Other medications, such as “antiangiogenic” cancer drugs, can less commonly be associated with ONJ. Antiangiogenic medications aim to prevent the growth of new blood vessels within tumors. This class of drugs includes bevacizumab (Avastin) and sunitinib (Sutent), amongst many others, which are medications used to treat kidney cancers such as renal cell carcinoma and gastrointestinal cancers. Antiresorptive medications in lower doses can often be given by mouth or by injection for the treatment of weak bones (osteoporosis and osteopenia), and ONJ is much less common at these lower doses.

Because ONJ can detrimentally affect quality of life and is associated with increased risk of death, it’s important to know the signs, symptoms and risk factors. ONJ is more common in the lower jaw (mandible) than the upper jaw (maxilla). Local risk factors for ONJ include oral surgical procedures such as tooth extraction, periodontal surgery or implant placement, and the presence of dental disease. Denture use is also associated with a risk of ONJ. Systemic factors such as steroid use, diabetes and tobacco use may also increase the risk of ONJ.

How do I prevent ONJ?

Early screening and appropriate dental care is recommended for all patients who will be receiving an antiresorptive or antiangiogenic medication as part of their cancer therapy. A consultation with a dental professional who is experienced in the management of cancer patients receiving these medications is recommended prior to starting therapy. Studies have shown a decrease in the incidence of ONJ in patients who are in optimum oral health.

During cancer care, it is important to maintain optimum oral health by practicing good oral hygiene, using fluoride to prevent tooth decay and seeing your oral healthcare team for preventive care when appropriate. Any sign of infection in the jaw such as pain or swelling should be addressed immediately by alerting your oncologist and the appropriate dental professional. If possible, oral surgical procedures should be avoided unless determined to be necessary by a dental professional who is experienced in the management of ONJ.

Should I stop taking antiresorptive or antiangiogenic medications to prevent ONJ?

No. These medications should never be stopped without the knowledge of your oncologist. The benefits of taking these medications often outweigh the low risk of developing ONJ which is approximately 1-2% (1-2 people out of 100). In addition, certain therapies, such as bisphosphonate medications, can remain present in bone for many years, meaning that stopping them is unlikely to reduce the risk of ONJ.

If ONJ occurs, how is it treated?

Treatment of established ONJ aims to eliminate pain, control infection and limit progression of the necrotic bone. Depending on the clinical stage of ONJ, treatment strategies can range from management with antibiotics and pain medications to surgical removal of areas of dead bone.

At Weill Cornell Medicine and NewYork-Presbyterian, we provide supportive, specialty oral care before, during and after cancer treatment. To learn more about the services we offer, click here. To make an appointment with a dentist at our center who specializes in treating cancer patients, please call Dr. Heidi Hansen at 212-746-5115.

Special thanks to Heidi Hansen, DMD, for her contributions to this article.

For additional information about oral care during cancer therapy, visit the below links:

American Association of Oral and Maxillofacial Surgeons

National Cancer Institute

American Dental Association


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