Bisphosphonates are a group of drugs that kill or disable cells called osteoclasts which resorb bone. Bisphosphonates are used to treat diseases in which osteoclasts cause the body harm. Osteoporosis is one of the most common of these diseases. They are also used to treat metastatic cancers and Paget's Disease. Bisphosphantes block the resorption of old bone, while still allowing new bone to be built. While this is beneficial in the treatment of osteoporosis, it can have detrimental effects in a person with periodontal disease or those who have had a tooth extracted. In these situations bone requires remodeling through the work of osteoclasts to enable healing to occur.
When you begin using bisphophonates the drug becomes highly concentrated in the oral cavity because the oral cavity has a very high turnover rate of bone. The high concentration of the drug kills so many osteoclasts that the bone cannot renew itself properly. As a result, when bone is exposed to trauma it may not be able to heal properly resulting in bone necrosis or bone death. This finding is called osteonecrosis of the jaw (ONJ). This complication was first observed in 2003 by oral surgeons treating patients for hypercalcemia related to multiple myeloma or metastatic breast cancer. All but one of the patients were given the injectable bisphophonates. The typical presentation of ONJ was in a non-healing tooth extraction socket with pain at the site or exposed jawbone.
The risk of ONJ from oral bisphosphonates is approximately 0.1%. The risk of ONJ from the IV form of bisphosphonates can range from 1-15% depending on the research. It is also important to know that the half-life of bisphosphonate medications is 10 years.
To reduce the risk of ONJ in patients taking bisphophonate medications it is recommended to treat all oral problems before it leads to tooth extraction. Infections of the gums, advanced periodontal disease and tooth decay should be addressed immediately. Patients on bisphosphonates are recommended to have frequent cleanings and examinations to evaluate for sharp areas on fillings, teeth and dentures.
Some of the most common bisphosphonate medications are pamidronate (Aredia), zoledronic acid (Zometa), ibandronate (Boniva), risedronate (Actonel) and alendronate (Fosamax),