Osteonecrosis of the Jaw

Osteonecrosis of the jaw (ONJ) is a condition in which part of the jaw bone is no longer alive and cannot regenerate itself due to a lack of blood supply. Most commonly, patients develop ONJ while undergoing bisphosphonate therapy (taking Fosamax, Aredia, Zometa or Actonel) and having an invasive dental procedure, such as a tooth extraction or root canal, or other dental prodecure performed. Rather than healing, the exposed bone begins to die. In some cases, serious infection and jaw pain can occur, and in extreme cases, jaw replacement surgery is required to remove the dead bone.

The most common signs and symptoms of ONJ include bone death, soft-tissue and jaw swelling, loosening of teeth, foul odors, drainage, exposed bone, and infection. In order to diagnose ONJ, doctors may perform panoramic and tomographic imaging. They may also take microbial cultures and tissue biopsies in order to rule out other kinds of infections. Early detection of ONJ is imperative to preserving the jawbone.

Bisphosphonates are a class of bone-strengthening drugs used to prevent bone metastases in patients with advanced cancers, as well as prevent bone loss in persons with osteoporosis. For cancer patients, bisphosphonates prevent metastatic cancer cells from dissolving bone. However, new cells will not grow unless older old ones are killed off. Bisphosphonates bond to bone surfaces and prevent osteoclasts (cells that breakdown bone) from doing their job. Because jawbones have rapid cell turnover, bisphosphonates can affect their ability to regrow. The result is that the jaw bone does not heal properly after any significant trauma (i.e., dental work) and patients become prone to infections and ONJ.

Between 2001 and 2003, two oral surgeons, Dr. Salvatore Ruggiero in New York and Dr. Robert Marx in Florida, began researching ONJ after seeing an unusual number of patients with deteriorating jawbones. After carefully studying the medical records and histories of their patients, the two surgeons discovered that only one common thread existed -- the patients had been treated with a bisphosphonate, either Fosamax, Aredia, Zometa or Actonel.

By September 2003, both Dr. Ruggiero and Dr. Marx had published articles regarding the link between ONJ and bisphosphonates. To date, more than 400 articles have been published on the subject and more than 4,000 cases of ONJ have been reported worldwide. In response to investigations by the United States Food and Drug Administration, both Novartis and Merck have changed the labels on their respective drugs to warn physicians about ONJ.

The following articles provide a more in-depth look at ONJ and bisphosphonate use:

National Osteoporosis Foundation:
www.nof.org/patientinfo/osteonecrosis.htm