Mouth Malady

January 20, 2009

USC School of Dentistry study is among the first to acknowledge correlation between common osteoporosis medications and jawbone death

According to a recent study by researchers at the USC School of Dentistry, even short-term use of common oral osteoporosis drugs may leave the jaw vulnerable to devastating necrosis, or death of the jawbone.

The study, which appeared in the Jan. 1 Journal of the American Dental Association, is the first large institutional study in the United States to investigate the relationship between oral bisphosphonate use and jawbone death, says principal investigator Parish Sedghizadeh, assistant professor of clinical dentistry at the USC School of Dentistry.

After controlling for referral bias and other health factors, nine of 208 School of Dentistry patients who take or have taken Fosamax for any length of time were diagnosed with osteonecrosis of the jaw (ONJ). Fosamax is the most widely prescribed oral bisphosphonate for people with osteoporosis.

Bisphosphonates are typically used to reduce the risk of bone fracture and to increase bone mass in people with osteoporosis. Other negative side effects have been reported in the past, including unusual fractures of the thigh bone, inflammatory eye disease and increased risk of atrial fibrillation—a type of abnormal heart rhythm.

The study’s results are in contrast to drug makers’ prior assertions that bisphosphonate-related ONJ risk is only noticeable with intravenous use of the drugs, not oral usage, Sedghizadeh says.

“We’ve been told that the risk with oral bisphosphonates is negligible, but four percent is not negligible,” he says. “This is more frequent than everybody would like to think it is.”

ONJ is characterized by pain, soft-tissue swelling, infection, loose teeth and exposed bone.

Most doctors who have prescribed bisphosphonates have not told patients about any oral health risks associated with the use of the drugs, despite even short-term usage posing a risk due to the drug’s tenacious 10-year half-life in bone tissue.

Lydia Macwilliams of Los Angeles said no one told her about the risk posed by her three years of Fosamax usage until she became a patient of Sedghizadeh at the School of Dentistry.

“I was surprised,” she says. “My doctor who prescribed the Fosamax didn’t tell me about any possible problems with my teeth.”

Macwilliams was especially at risk for complications because she was to have three teeth extracted. The danger for infection is especially pronounced with procedures that directly expose the jawbone, such as tooth extractions and other oral surgery.

This is because the infection is a result of a biofilm bacterial process. The bacteria infecting the mouth and jaw tissues reside within a slimy matrix that protects the bacteria from many conventional antibiotic treatments, and bisphosphonate use may make the infection more aggressive in adhering to the jaw, Sedghizadeh says.

After her extractions, two of the three extraction sites had difficulty healing due to infection, Macwilliams says. Luckily, with treatment as well as the rigorous oral hygiene regimen that USC dentists developed especially for patients with a history of bisphosphonate usage, the remaining sites slowly but fully healed.

“It took about a year to heal,” she said, “but it’s doing just fine now.”

Sedghizadeh hopes to have other researchers confirm his findings and thus encourage more doctors and dentists to talk with patients about the oral health risks associated with the widely used drugs. The results confirm the suspicions of many in the oral health field, he says.

“Here at the School of Dentistry, we’re getting two or three new patients a week that have bisphosphonate-related ONJ,” he says, “and I know we’re not the only ones seeing it.”

Sedghizadeh says they now screen every patient for bisphosphonate use and treat accordingly.

“We put patients on anti-microbial, anti-fungal rinse one week pre-operatively or post-operatively,” he says. “If they have been on bisphosphonates six months or a year or longer, then we have a prevention protocol which has been very, very effective.”

For more information on the USC School of Dentistry, or to make an appointment, visit: dentistry.usc.edu.