Bisphosphonate Associated Osteonecrosis (BONJ) is a serious intra oral complication that every dentist should be aware of in their clinical practice.

Bisphosphonate-Associated Osteonecrosis of the Jaw: An update for clinical practice

Bisphosphonates are a class of drugs prescribed to help with the treatment and prevention of resorptive bone diseases such as osteoporosis. These drugs are also prescribed to help with conditions that cause bone fragility or bone destruction as a result of bone metastasis associated with breast and prostate cancers. Second and third generation bisphosphonates such as Zometa (zoledronate), Reclast (zoledronate), Aredia (pamidronate), Boniva (ibandronate), Actonel (risedronate) and Fosamax (alendronate) are the drugs most commonly seen in clinical practice that may be associated with  BONJ. Second and third generation bisphosphonates inhibit enzymes that are involved with osteoclastic bone resorption. These class of drugs can be taken by mouth or intravenously. When taken parenterally (IV) the bioavailability is higher which can increase the incidence of BONJ. The literature reports the occurrence of Biphosphonate Associated Osteonecroiss to be anywhere from .08 – 20 % (a wide range) for those taking these drugs IV. The oral intake of bisphophonates reports an incidence of less than .05%. Although the occurrence of BONJ with oral bisphonates is very low, the complication is still a possibility and should be taken under consideration. Fosamax is a very commonly prescribed oral bisphosphonate that we will often come across as dental professionals.

Clinicians should always review a complete and thorough medical history with their patients and take note of this class of drugs. The timeline of when these medications were first prescribed and whether they were taken IV or orally is important information to ascertain in the initial examination. There are also reports that the concurrent use of steroids with bisphophonates can be an added risk factor for BONJ.  Most case reports of BONJ have involved a traumatic dental procedure such as an extraction, however several case reports exist where patients taking these drugs have developed spontaneous BONJ without a known dental cause. Endodontic therapy is preferred over extraction for most patients with a history of IV bisphosphonate use. Surgical procedures are reported to have an increased risk for these patients and should  be avoided if possible. For non-restorable teeth, removing the clinical crown and treating the roots endodontically with a coronal seal may be advisable as opposed to extracting the tooth. In developing  a treatment plan for patients with a history of IV bisphosphonate use, consultation with the patient’s medical team and an oral surgeon are also recommended.

Bisphophonate associated osteonecrosis tends to appear in the mandible more often than the maxilla. An ulcerative lesion is usually evident with underlying exposed bone. The bone becomes infected causing pain and at times swelling. The necrosis is usually refractory and can be very difficult to treat. Treatment modalities used for radiation induced necrosis are not always helpful with cases of BONJ. There are screening tests available for the purpose of assessing a patients susceptibility for BONJ, however the literature I have come across questions the validity and benefit of these screening procedures.

As clinicians we must have a sound knowledge of our patients medical history before moving forward with any treatment. I hope this blog helps provide information about the Bisphosphonate class of drugs so that we can make the best treatment decisions for our patients. Further information on the AAE’s position statement can be downloaded HERE.

By Dr. Michael Sherman

**In writing this blog, much of the information was originally published by the AAE in their Colleagues for Excellence, Fall 2012 edition

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