Despite reports about the risk of jawbone deterioration among individuals taking certain osteoporosis drugs, most patients are not at risk, according to the latest issue of the Harvard Women’s Health Watch.

Yet, since most of the problems have occurred among dental patients, experts say the best way to guard against osteonecrosis, or the death of jawbone tissue, is to avoid having to undergo procedures such as dental extractions and implants.

“The best treatment is prevention,” writes Dr. Celeste Robb-Nicholson, editor-in-chief of the Harvard publication, urging readers to “practice good oral hygiene.”

The oral bisphosphonates, Fosamax, Actonel, Boniva, Skelid and Didronel, are largely used to treat and prevent the brittle bone disease osteoporosis. Other more powerful drugs in the same class, Zometa, Aredia and Bonefos, are given intravenously and are used to treat bone pain and other cancer-related bone problems.

The first reports of osteonecrosis among users of the intravenous bisphosphonate, Zometa, appeared in 2003, according to a report from the American Dental Association.

The majority of cases were diagnosed after tooth extractions or other dental procedures were performed. Since then, however, cases of bisphosphonate-associated jawbone deterioration have also been reported among individuals taking oral forms of the bisphosphonate medications.

The reason for the association between the bisphosphonate drugs and osteonecrosis is not entirely known, but researchers speculate it may be due to the action of the drugs, which decrease the breakdown of bone, thereby making bones denser in the short term. However, since healthy bone constantly goes through a process of breakdown and formation (i.e. bone remodeling), reducing the breakdown of bone also inhibits the formation of new bone, such as that needed in the jaw after dental extractions or other trauma.

Considering the large number of women taking bisphosphonates - the ADA notes that 22 million prescriptions were written for Fosamax alone between May 2003 and April 2004 - the risk of osteonecrosis appears to be extremely low.

According to an estimate from the ADA, there are only about seven cases per year occurring among every one million individuals taking the oral drugs. Those most at risk are cancer patients on intravenous bisphosphonate drugs since more of the drug is available in the bloodstream when it is given intravenously than when it is given orally.

“As far as we know today, the benefits of bisphosphonates still outweigh the risks when they are used appropriately,” Robb-Nicholson writes.

Still, the editor adds, “we can’t predict who will develop osteonecrosis of the jaw.”

To help prevent the condition, Robb-Nicholson recommends that patients undergo dental extractions or implants before beginning bisphosphonate therapy or that they inform their dentist before undergoing such procedures if they have already begun to take a bisphosphonate. That way, the dentist may opt to preserve a tooth by performing a root canal, which does not involve any trauma to the bone, rather than an extraction, the editor explains.

According to Dr. Peter L. Jacobsen, a spokesperson from the American Dental Association, “anybody that’s taking any drug should always be aware and concerned about any potential problems.”

Most people should not be overly concerned about experiencing osteonecrosis due to their use of bisphosphonates, however, said Jacobsen, of the University of the Pacific in San Francisco, California, and a member of the ADA’s council on scientific affairs.

In fact, he told Reuters Health, the risk of such bone deterioration is “much less than walking across the street to get lunch” and either tripping on the street or getting hit by a car.

Still, he added, “take good care of your teeth so you’ll never have a problem.”

SOURCE: Harvard Women’s Health Watch, September 2006.