Glossary

Biphosphonates are a class of drugs that are used to prevent the loss of bone density in cases of osteoporosis, or in cases of other bone problems where the density of bone is abnormal. Sometimes they are prescribed after an injury where there are abnormal bone fractures in the wrist, arm, spine, or hips. They are also given to patients who are at a higher risk of issues like osteoporosis or at a risk for bone loss due to taking certain medications like steroids. The most common bisphosphonates are alendronate, ibandronate, risedronate and zoledronic acid. Although these medicines can be helpful in patients with certain conditions, they do come with side effects. For example, the side effects of bisphosphonates include but are not limited to joint and muscle pain, heartburn, nausea, difficulty swallowing, irritation of the esophagus, and gastric ulcers. The medicine can also cause a serious side effect of osteonecrosis of the jaw bone.

Osteonecrosis of the jaw is a rare condition with many different causes. About 95% of cases of osteonecrosis could be attributed to high-dose, IV administered bisphosphonate therapy in cancer patients, while the remaining 5% were attributed to low-dose bisphosphonate therapy used for patients with osteoporosis. Osteonecrosis of the jaw is defined as an area of bone that is exposed to air, causing damage, and does not heal on its own within 8 weeks. It is not well understood how bisphosphonate therapy contributes to osteonecrosis of the jaw, because osteonecrosis can also occur in people who are not taking bisphosphonates. However, bisphosphonate-associated osteonecrosis (BON) can be clinically diagnosed in patients who have had an exposed area of bone in the maxillofacial area that has not healed within 8 weeks and who are currently taking bisphosphonates and are not receiving radiation. Also, other causes must be excluded, like periodontal disease and trauma.

Studies have shown that the use of bisphosphonate in patients with cancer is associated with osteonecrosis of the jaw. While osteonecrosis can be caused by a number of other factors, this particular form of the condition is called bisphosphonate-induced osteonecrosis of the jaw (BIONJ). Patients who have been on long term, high-dose bisphosphonates to manage different types of cancer (typically breast cancer, prostate cancer, and myeloma)are at risk for BIONJ if they get a tooth extracted. The bone becomes exposed to air and becomes necrotic after not healing on its own for several weeks. About 5% of patients with cancer who are also being treated with bisphosphonates will get bisphosphonate-induced osteonecrosis of the jaw, and the risk is lower in patients who do not have cancer. Physicians should recommend that their patients see a dentist prior to beginning bisphosphonate treatment as well as during treatment.

Bisphosphonate-related osteonecrosis of the jaw, or BRONJ, is a complication that may be experienced by a patient who has not received radiation treatments to the head or neck and who is under current or previous bisphosphonate treatment. The condition is characterized by exposed necrotic bone in the maxillofacial region that does not heal within eight weeks after diagnosis and proper care. Bisphosphonates are a class of drug that are prescribed to individuals at risk for bone resorption as experienced in osteoporosis, hypercalcemia of malignancy, and metastatic cancers which have spread to the bone. There is an established association between the use of these drugs and BRONJ though not all patients taking bisphosphonates will experiences this condition. Risk factors for developing BRONJ include route of administration (intravenous versus oral), duration of therapy, and type of bisphosphonate (nitrogen containing or not). The majority of individuals who develop BRONJ as a result of bisphosphonate received the drug intravenously.

Osteoporosis is a serious condition, and the most common metabolic bone disease in the world. The standard treatment for osteoporosis is oral bisphosphonates, which unfortunately can cause a host of unpleasant side effects. Common side effects include acid reflux, esophageal irritation, and stomach ulcers. One of the most serious side effects of this type of therapy is bisphosphonate-related osteonecrosis of the jaw (BRONJ). It’s not well understood how bisphosphonate therapy causes or contributes to BRONJ, but risk factors have been identified, such as steroid usage and dentoalveolar surgery. To isolate this condition from others, the American Society for Bone and Mineral research states that a BRONJ diagnosis can be made if a patient is currently being treated or has been treated with a bisphosphonate medication, has exposed bone in the maxillofacial region that has not healed in 8 weeks or more, and has no history of jaw radiation therapy.