Jaw Osteonecrosis and Use of Bisphosphonates
We know that many of our patients have been hearing reports in the media about serious jaw infections that occur after dental treatment in patients that are taking drugs used to treat osteoporosis. There has been a lot of confusion about what the problem actually is and how often it is occurring, and we know that some patients have mistakenly thought that the way to reduce their risk of this condition is to avoid dental treatment.
We have taken the time to review the literature about this problem and have presented our findings in this article to answer some of the most frequent questions patients have about this subject. We have also included a link to the American Dental Association expert panel recommendations for patients who want further information. Patients may also want to share the ADA report with their physicians. Since much of this information is very new and is found in dental literature rather than medical literature, many physicians may not have heard about these dental recommendations.
What is the problem?
Reports of jaw osteonecrosis, or jaw bone death, have been associated with the use of bisphosphonates. There have been approximately 2400 cases reported. The vast majority of these cases are related to intravenous bisphosphonate use in cancer treatment, but there have been some cases associated solely with oral use of these drugs, which are prescribed for osteoporosis and some other bone related diseases.
What is osteonecrosis?
Osteonecrosis is bone death. In this condition, the blood supply to the bone becomes disrupted and this can lead to the bone destruction. When a necrotic bone becomes infected, it does not heal.
What are the drugs involved with this condition?
Bisphosphonates administered as IV’s were reported around 2003 to be associated with this osteonecrosis. Reports of this condition related to oral administration of bisphosphonates began to surface around 2006. Oral bisphosphonate drugs used in the United States include Fosamax, Boniva, and Actonel.
What is the incidence of this condition from oral drug administration?
As noted above, the vast majority of osteonecrosis cases are related to IV administration of the drug during cancer treatment. The risk of developing osteonecrosis from Fosamax, one of the most frequently used medications, is reported to be 0.7 cases per one hundred thousand person-years exposure according to Merck, the manufacturer of this drug. Merck has reported 170 cases of osteonecrosis worldwide related to its drug Fosamax. Currently twenty-two million people take Fosamax. It is estimated that other bisphosphonates carry similar risk levels.
How is dental treatment related to this disease?
One review showed that 82% of bisphosphonate related osteonecrosis cases developed after a dental procedure that involved trauma to bone, such as an extraction or other oral surgery. Basic dental procedures such as fillings, root canals, or crowns are not related to this condition and these treatments should not be avoided or postponed by patients taking these drugs. What appears to be happening with the oral surgery cases is that an infection that occurs after treatment can not heal, presumably because the bone has had its blood supply disrupted, causing necrosis, or death, of the bone.
How do bisphospohonate drugs work to prevent osteoporosis and how are they related to osteonecrosis of the jaw?
All bones in the body lose old bone and build new bone through a cycle. Bones have cells called osteoclasts that remove bone and cells called osteoblasts that add new bone. This cycle is important because it provide a continuous turnover of bone mineral to keep bones healthy. In osteoporosis, the osteoclasts remove more bone that the osteoblasts replace, so there is a loss of bone.
Bisphosphonates work by acting on the osteoclasts to reduce their action. This results in less bone being destroyed and hence an increase in bone mass and thickness. It does result in less bone turnover, but ideally this change in turnover would result in bringing the bone building and resorption back into balance. Long term studies of these drugs have shown that this is the case, with no indication of oversuppression of bone turnover. Some other small studies, however, have found some rare cases where the drug may have reduced the osteoclasts so much that there is little or no turnover of bone. When this happens, the lack of turnover causes the blood supply to the bone to be suppressed. Without an adequate blood supply, if the bone becomes infected, healing may be difficult or impossible. It is theorized by some that because the jaw bone has a better blood supply than other bones, it may take up more bisphosphonate, which could cause the oversuppression of osteoclasts in some cases that could lead to bone death.
What risk factors are associated with development of jaw osteonecrosis?
At this time, there is no direct cause and effect relationship and no way of knowing who is at risk of developing the disease. However, some factors that have been showing up include use of oral glucocorticoids or estrogen, long term use of bisphosphonates, age over 65, and periodontal disease.
Does osteonecrosis occur only in the jaw or is it systemic?
At this time, it is unknown whether this condition is specific to the jaw bone. It is showing up there probably because it is an area of bone that is more likely to become infected due to dental problems, and because the bone is more likely to be exposed in dental treatment. The fact that the jaw bone has a good blood supply and more of the drug may be depositing in this bone may also be a contributory factor.
If a patient stops taking a bisphosphonate before dental treatment, does that help prevent osteonecrosis?
Since bisphosphonates remain in the body for years, it is believed that discontinuing the drug before dental procedures would have no effect on the risk of developing osteonecrosis.
What are the recommendations for dental treatment for patients on oral bisphosphonate therapy?
Since there are no specific criteria for high risk subgroups for the development of osteonecrosis, all patients receiving bisphosphonate therapy must be considered at risk. Patients should realize that the risk of developing osteonecrosis associated with oral bisphosphonate use is low and generally occurs when a patient has serious dental prblems that require oral surgery.
The most important recommendation for all patients taking these drugs is to be conscientious about dental care- both at home and in the dental office. Most dental procedures should not be avoided or postponed since doing so can increase the risk of bone infection or the need for extraction or oral surgery. \
The following guidelines are recommended based on the report from the American Dental Association and personal recommendations from this office regarding preventive dental care.
- A thorough dental examination is necessary before beginning bisphosphonate treatment, if possible, or as soon as possible after treatment begins to determine dental problems, and all dental problems should be eliminated before beginning treatment with the drug.
- Once a patient is receiving one of these drugs, it is important to maintain a strong preventive care program of dentistry. Recommendations below detail the components of ideal dental care.
- Regular preventive visits two to four times per year based on dental needs
- Fluoride use to strengthen teeth- in office fluoride, prescription strength fluoride toothpaste for at home use augmented with calcium phosphate paste
- Xylitol gum or rinse (Biotene) use to reduce decay causing bacteria
- Dental management of tooth erosion and xerostomia; monitoring of patient medication use that could be related to reduction of saliva flow
- Dietary management of practices that lead to dental problems such as high sugar diet, heavy use of sugary beverages, or use of diet drinks
- If a patient develops periodontal disease, aggressive non surgical treatment is advised to prevent it from progressing to bone involvement.
- Prompt attention to restorative care such as fillings or crowns is important to reduce the possibility of tooth fracture, which could necessitate an extraction.
- Use of bridgework or removable dentures is the treatment of choice to replace missing teeth; implants are not advised.
- Root canal therapy is recommended as the recommended treatment whenever possible instead of extraction for abscessed teeth.
- If an oral infection does advance to bone involvement, treatment should not be postponed because delaying treatment could cause the infection to worsen and potentially cause osteonecrosis.
- Whenever possible, extractions or other dental procedures that traumatize bone should be avoided. If oral surgery cannot be avoided, use of antibacterial chlorhexidene rinse is recommended for up to two months after surgery.
Where can one find further information about osteonecrosis, osteoporosis, or bisphosphonate therapy?
The expert panel recommendation report from the American Dental Association contains excellent information and a good list of references. Because we recognize that patients in this community are sophisticated and want the most informative information available, we have linked to this report primarily designed for professionals. www.ada.org.
An informative website on osteoporosis is www.nof.org, the website of the National Osteoporosis Foundation.
For those looking for highly technical research information, www.asbmr.org, the website for the American Society of Bone and Mineral Research is available.
Should I (or someone I know) stop bisphosphonate therapy because of this possible side effect?
This discussion is meant only to inform patients about the possible dental related risks of bisphosphonate use and is not intended to make any judgment about the use of these drugs for medical conditions. Osteoporosis is a serious disease and is related to fractures, and these drugs have been shown to significantly reduce the risk of fractures in patients with osteoporosis. Numerous long term studies have shown these drugs to be effective in treatment of osteoporosis and other conditions. The National Osteoporosis Foundation supports the use of bisphosphonate drugs despite this possible rare side effect.
Nevertheless, the risk of osteonecrosis does exist, and patients should take care to understand their dental risks if they are taking one of these drugs. Patients with dental conditions such as advanced periodontal disease, impacted wisdom teeth, bony exostoses (protruding jaw bone with thin tissue covering), or other dental problems that could affect the jaw bone should eliminate those risks before beginning treatment with one of these drugs, or if already in treatment, should strive to maintain excellent dental care both at the dental office and at home, following the recommendations provided in this article.
If you have a concern about taking one of the bisphosphonate drugs, you should discuss those concerns with your physician. Since much scientific information about this side effect is very recent and has been published mainly in dental literature, many physicians may not have the most current information about this issue. You may want to take a copy of the American Dental Association recommendations with you when you go to the doctor to aid in discussion. We also have available for physicians copies of several articles that were referenced in the American Dental Association report.
