Osteonecrosis of the Jaw (ONJ) is a rare dental bone condition in which an area of exposed jawbone shows no signs of healing after eight or more weeks of treatment. Typically the area becomes exposed following an invasive dental procedure (such as an extraction), or less commonly, as a result of prolonged friction between a denture and the skin of the jaw. Usually, the condition does not afflict individuals who are relatively healthy overall. Rather, it is most commonly found in individuals who take bisphosphonate drugs orally, or who receive the drug intravenously.

Causes of Osteonecrosis of the Jaw

Because bisphosphonate drugs are used to treat osteoporosis and to defend against cancer-related bone loss, ONJ most commonly affects individuals suffering from those ailments. But of those two groups, it is the cancer patients who are most at risk of developing the condition because, typically, they receive a higher dosage of the bisphosphonate drugs and do so intravenously, whereas osteoporosis patients take a smaller dosage orally.

Osteonecrosis of the Jaw is also known as avascular or aseptic necrosis of the mandible or maxilla, Jaw Death, Dead Jaw Disease or Bisphossy Jaw. The term “osteonecrosis” comes from the prefix “osteo-,” which means bone, and “necro,” which means dead. When the gum is worn away and the jawbone is exposed and blood flow to the area is compromised, the bone tissue begins to deteriorate. Once eight weeks of appropriate treatment have passed with no perceivable signs of healing, ONJ is diagnosed.

Symptoms of Osteonecrosis of the Jaw

ONJ is most often accompanied by pain or numbness in the affected area, and in some cases the jaw starts to feel heavy. Additionally, inflammation, drainage and infections elsewhere in the mouth are sometimes present. It is not enough, though, to diagnose ONJ based on these factors alone. It is only after the two unsuccessful months of treatment have passed that the condition can be called ONJ.

As already noted, ONJ is most commonly seen in cancer patients who receive bisphosphonates – such as Aredia or Zometa – intravenously. Bisphosphonates are antiresorptive medications, which means that they are used to slow or stop the reduction of bone density. When taken orally, only a small fraction of the medication actually reaches the bone; but when taken through an IV, about half of the total medicine reaches the bone. Also, in most known cases of ONJ, the cancer patients were also receiving chemotherapy and steroid treatments – both of which could be additional risk factors, but which have not been proven to be directly correlated at this time.

It is also important to understand that ONJ doesn’t usually just “pop up” on its own. Rather, in the overwhelming majority of cases it materializes only after some sort of trauma has occurred to the mouth. Usually that trauma comes in the form of a tooth extraction or dental implant, or less commonly, as a result of broken or ill-fitting dentures that continuously scrape the gums along the jawbone.

Preventing and Treating Osteonecrosis of the Jaw

All bisphosphonate users, especially those who have been receiving treatments for five years or more, should avoid dental surgeries whenever possible. At the very least, be sure to inform your dentist of what you are taking, and make sure to keep up with your regular dental checkups while brushing and flossing regularly. Once bisphosphonates are in your system, they stay present for a very long time. If you are preparing to start bisphosphonate treatments, it is strongly advised that you take care of all dental procedures beforehand.

Once ONJ has been diagnosed, the treatment options will depend on the severity of the problem. The first step is simple: germ-fighting mouthwashes and over-the-counter anti-inflammatory medications such as Motrin or Advil may be used to keep the mouth clean and free of pain. If the patient has developed secondary infections as a result of the ONJ, an oral antibiotic or antibiotic rinse will be prescribed. In the most severe cases, surgery is eventually required.