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Science in the News

Study Finds Higher Incidence of Osteonecrosis of the Jaw in Alendronate Users

January 22, 2009


In a retrospective study from the University of Southern California (USC), four percent of female patients with a history of using the osteoporosis drug alendronate (Fosamax®) developed osteonecrosis of the jaw (ONJ). The study, published in the January 2009 Journal of the American Dental Association,1 was featured in online news coverage from WebMD,2 Medical News Today,3 and HealthDay News.4

The USC research team analyzed electronic medical records of dental patients treated at USC-based clinics to identify individuals with a history of alendronate use and to determine the prevalence of osteonecrosis of the jaw in patients who had also received oral alendronate. Of the 208 patients who had used oral alendronate, nine (four percent) had active ONJ and were being treated at USC for the condition.

Each of the nine ONJ cases occurred after either tooth extraction or denture-related mucosal ulceration. The nine patients affected by ONJ were Asian-American or Hispanic women between 63 to 80 years of age who had received oral alendronate therapy for durations ranging from one to 10 years. On the other hand, the USC researchers did not identify any cases of ONJ in patients without a history of oral alendronate use.

Since initial identification of bisphosphonate-associated ONJ cases in 2003, the ADA has closely monitored the published research literature and ONJ case reports related to patients with a history of oral or intravenous bisphosphonate therapy. Bisphosphonates are a class of bone-strengthening drugs used to inhibit bone loss associated with cancer, Paget’s disease of bone, osteopenia and osteoporosis. The USC investigators focused specifically on the incidence of ONJ in patients with a history of taking oral alendronate (Fosamax), the most widely prescribed oral bisphosphonate.

Overall, the USC study was a relatively small, retrospective evaluation, and the findings do not provide definitive evidence on either the prevalence of ONJ or risk factors for developing ONJ in individuals with a history of oral alendronate use. However, the study findings require close consideration because they suggest that the prevalence of ONJ may be much higher than previously reported among patients who have undergone invasive dental procedures (e.g., tooth extraction) or who wear dentures, and have previously or are currently using oral alendronate (Fosamax). The study also adds to a growing body of evidence that has associated invasive dental procedures that traumatize the bone, such as tooth extraction, with the development of bisphosphonate-associated ONJ.

Osteonecrosis of the jaw is an uncommon yet serious complication, and the study authors emphasize that additional research is needed to elucidate the relationship between oral bisphosphonate use and ONJ. Prospective, multi-institutional studies are required to improve our understanding of the pathophysiology of bisphosphonate-associated ONJ, and to determine how to minimize the incidence of this serious condition among susceptible patients. This recommendation is consistent with the ADA’s current position on bisphosphonates and ONJ. The results of the USC study need to be confirmed in other centers, but it adds to the rapidly expanding body of research evidence that will guide practitioners and patients in the future to facilitate safe and effective dental care of patients taking this important class of medications.

Based on the current ADA recommendations,5 patients receiving oral bisphosphonate therapy for osteoporosis generally will not require alterations in routine dental treatment, though they should be strongly advised to practice optimal oral hygiene and to receive routine dental examinations. Clinicians can also refer to the Oral Health Topic: Osteoporosis Medications and Oral Health for recommendations on the management of patients who receive intravenous bisphosphonates related to cancer therapy (developed by an expert panel convened by Novartis Pharmaceuticals Corporation).


1Sedghizadeh PP, Stanley K, Caligiuri M, Hofkes S, Lowry B, Shuler CF. Oral bisphosphonate use and the prevalence of osteonecrosis of the jaw: an institutional inquiry. J Am Dent Assoc. 2009 Jan;140(1):61-6. Accessed January 6, 2009.

2DeNoon DJ. Fosamax: higher risk of jawbone death? WebMD, January 2, 2009. Accessed January 6, 2009.

3Osteoporosis drug linked to bone death in jaw. Medical News Today, January 5, 2009. Accessed January 6, 2009.

4Oral bisphosphonate use linked to osteonecrosis of the jaw. HealthDay News, January 5, 2009. Accessed January 7, 2009.

5Updated recommendations for managing the care of patients receiving oral bisphosphonate therapy: an advisory statement from the American Dental Association Council on Scientific Affairs. Edwards BJ, Hellstein JW, Jacobsen PL, Kaltman S, Mariotti A, Migliorati CA; American Dental Association Council on Scientific Affairs Expert Panel on Bisphosphonate-Associated Osteonecrosis of the Jaw. J Am Dent Assoc 2008 Dec;139(12):1674-7.

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Science in the News is a service by the American Dental Association (ADA) to its members to present current information about science topics in the news. The ADA is a professional association of dentists committed to the public's oral health, ethics, science and professional advancement; leading a unified profession through initiatives in advocacy, education, research and the development of standards. As a science-based organization, the ADA's evaluation of the scientific evidence may change as more information becomes available. Your thoughts would be greatly appreciated.

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