Osteonecrosis of the Jaw from bisphosphonate therapy

Reports of bisphosphonate-associated osteonecrosis of the jaw (BON) associated with the use of Zometa (zolendronic acid) and Aredia (pamidronate) began to surface in 2003. The majority of reported cases have been associated with dental procedures such as tooth extraction; however, less commonly BON appears to occur spontaneously in patients taking these drugs.

Zolendronic acid and pamidronate are intravenous (i.v.) bisphosphonates used to reduce bone pain, hypercalcemia and skeletal complications in patients with multiple myeloma, breast, lung and other cancers and Paget’s disease of bone.

Several cases of BON have also been associated with the use of the oral bisphosphonates, Fosamax (alendronate), Actonel (risedronate) and Boniva (ibandronate), for the treatment of osteoporosis; however, it is not clear if these patients had other conditions that would put them at risk for developing BON.

The table below lists all oral and i.v. bisphosphonates currently on the market in the U.S.

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Clinical Presentation

The typical clinical presentation of BON includes pain, soft-tissue swelling and infection, loosening of teeth, drainage, and exposed bone3. These symptoms may occur spontaneously, or more commonly, at the site of previous tooth extraction. Patients may also present with feelings of numbness, heaviness and dysesthesias of the jaw. However, BON may remain asymptomatic for weeks or months, and may only become evident after finding exposed bone in the jaw.

Dental Management

It is important to understand that, based on the information currently available, the risk for developing BON is much higher for cancer patients on i.v. bisphosphonate therapy than the risk for patients on oral bisphosphonate therapy. Therefore, there are different recommendations for dental management of these patients.

For patients on oral bisphosphonate therapy

The risk of developing BON in patients on oral bisphosphonate therapy appears to be very low;4 however, though the risk is small, currently millions of patients take these drugs. Therefore, recommendations for dental management of patients on oral bisphosphonate therapy were developed by an expert panel assembled by the ADA’s Council on Scientific Affairs.

These panel recommendations focus on conservative surgical procedures, proper sterile technique, appropriate use of oral disinfectants and the principals of effective antibiotic therapy. There is currently no data from clinical trials evaluating dental management of patients on oral bisphosphonate therapy, and therefore, these recommendations are based on expert opinion only. A comprehensive oral evaluation is recommended for all patients about to begin therapy with oral bisphosphonates (or as soon as possible after beginning therapy).

These recommendations do not address treatment of patients on i.v. bisphosphonate therapy or patients with BON. Refer to the information below regarding their treatment.

For patients on i.v. bisphosphonate therapy

It is important for our office to be aware that while on treatment, invasive dental procedures should be avoided in patients receiving i.v. bisphosphonates, if possible. We will exercise our professional judgment, perhaps after consultation with your physician, in deciding whether invasive treatment is needed under the particular clinical situations. It is very likely that you would be referred to a surgical specialist for any invasive procedures.

The prescribing information for these drugs recommends that cancer patients:

• Receive a dental examination prior to initiating therapy with intravenous bisphosphonates (Aredia and Zometa); and
• Avoid invasive dental procedures while receiving bisphosphonate treatment. For patients who develop osteonecrosis of the jaw while on bisphosphonate therapy, dental surgery may exacerbate the condition. Clinical judgment by the treating physician should guide the management plan of each patient based on an individual benefit/risk assessment.

An expert panel convened by Novartis Pharmaceuticals Corporation (the manufacturer of Zometa and Aredia) in 2004, made the following recommendations for prevention, diagnosis and treatment of osteonecrosis of the jaw in patients on i.v. bisphosphonate therapy:

• Patients should be educated on maintaining excellent oral hygiene to reduce the risk of infection.
• Dentists should check and adjust removable dentures to avoid soft-tissue injury.
• Routine dental cleanings should be performed with care not to inflict any soft-tissue injury.
• Dental infections should be managed aggressively and nonsurgically (when possible).
• Endodontic therapy is preferable to extractions; and, when necessary, coronal amputation with root canal therapy on retained roots to avoid the need for extraction.

*Thanks to the American Dental Association for information relating to this article