Questions have arisen regarding the use of bisphosphonates, a medication that is more commonly being used in the treatment of osteoporosis particularly in women. There is some concern about jawbone tissue dying with certain dental surgical procedures. The following paragraphs were excerpted from The January 2008 issue of the Journal of the American Dental Association.
Since the initial reports of osteonecrosis of the jaws (ONJ) associated with bisphosphonate therapy, several studies have tried to establish the prevalence and incidence of this lesion. Results, for both orally and intravenously administered bisphosphonates, are equivocal and vary greatly.
In this January 2008 issue of JADA, findings from one study of 7,714 women with postmenopausal osteoporosis who were randomized into two equal groups were reported. The treatment group received intravenous bisphosphonates (zoledronic acid 5 milligrams) once each year, while the control group received a placebo over a period of three years. Two cases of ONJ were identified, one in each group. The authors concluded that once-per-year administration of intravenous bisphosphonates was not associated with an increased risk of developing ONJ.
Another study used a different approach to determine the frequency of inflammatory or necrotic adverse bone conditions in the jaws. They assessed medical claims data from more than 714,000 people to determine the prevalence of jaw pathologies among patients with osteoporosis and patients with cancer-and whether that prevalence was related to the method of bisphosphonate administration used.
According to their findings, patients with conditions requiring intravenous bisphosphonates had a much higher risk of developing adverse conditions in the jaw compared with patients taking oral bisphosphonates. This finding is similar to those of previous case-controlled studies.
These two articles contribute to a growing body of knowledge that, in time, may clarify the epidemiology of an oral lesion that has puzzled scientists for the past five years. However, these studies do not help clarify the potential adverse effects of dental treatment in patients taking bisphosphonates.
Osteonecrosis of the jaws has been described in patients taking several different forms and brands of bisphosphonates. As very few people develop this type of lesion, it is unclear whether there are predisposing factors that influence its development beyond the presence of bisphosphonates, or whether there exist certain protective qualities. It appears likely that patients with ONJ have other underlying factors that contribute to this sometimes devastating condition.
Different risk factors for ONJ have been proposed-cancer, periodontal and other dental diseases, cancer therapy, palatal tori, glucocorticosteroid therapy, duration of bisphosphonate therapy, potency of the administered bisphosphonates, older age, female sex, and dental extractions or other dental trauma. It is not always clear how these different underlying conditions, medical treatments or dental therapies contribute to ONJ, or whether these risk factors have a synergistic effect.
On the basis of their mechanism of action, it is highly plausible that bisphosphonates may have a direct role in the development of osteonecrosis, but they also may be a marker in patients who are susceptible to osteonecrosis owing to other circumstances. For example, patients receiving chemotherapy for cancer already are highly susceptible to various oral lesions, including inadequate healing after oral trauma. It is not surprising, therefore, that we find more people with ONJ in this patient population compared with patients who have osteoporosis.
In Grbic and colleagues’ study, the two people who developed osteonecrosis had uncontrolled type 2 diabetes mellitus or were taking glucocorticosteroids. Both diabetes mellitus and glucocorticosteroids affect bone remodeling.
One major difficulty with epidemiologic research data on ONJ is the lack of standardized diagnostic criteria. An exposed bone that fails to heal after six to eight weeks in a patient taking bisphosphonates is considered bisphosphonate-associated ONJ. This is one of the major limitations of Zavras and colleagues’ study, as the researchers could not identify lesions specifically associated with bisphosphonate therapy. No histopathologic marker or other method has been validated with a high enough sensitivity and specificity to be used to establish a definitive diagnosis of bisphosphonate-associated ONJ.
It appears likely that patients with osteonecrosis of the jaw have other underlying factors that contribute to this sometimes devastating condition.
The take home lesson from this is that there seems to be very little likelihood of having osteonecrosis of the jaw from dental surgical procedures. The likelihood seems to be even less for those taking an oral form of the medication. The affliction of ONJ seems to be more common in those with other predisposing conditions. It is evident that more study needs to be done.
If you have or are currently taking a form of these medications, a close coordination of your physician and dentist would be warranted before any surgical procedure is performed, for example a tooth extraction.
