May 5, 2009 -- Thirty- four million Americans rely on dentures to replace their missing teeth. But a small number of denture wearers have had difficulty with balance and walking -- a medical mystery that some experts have linked to their denture creams.
Denture cream is used to hold false teeth -- dentures -- in place. About a third of denture-wearers use it, and most consider it like any other everyday beauty or hygiene product, such as toothpaste or shampoo. But some doctors say "excessive" use of denture cream may force people who were once independent to use wheelchairs or walkers just to get around.
For Ellen Isaacs, it began with a tingling in her toes. Four years later, her balance was gone and simple tasks have become impossible. After multiple rounds of tests, Ellen's neurologist, Dr. Rachel Nardin of Beth Israel Deaconess Medical Center in Boston, eventually concluded that denture cream was the source of the problem. "Stopping the denture cream use was a key part of her treatment," said Nardin.
Isaacs said that for at least 10 years she applied Super Poligrip to her dentures once a day and kept them in overnight. But what she didn't realize was that the cream contained zinc, which can cause serious illness in high doses. "I would have never equated use of denture cream to what was going on with my body, said Isaacs.
Doctors say too much zinc drives down copper levels in the body. This sets up a chain reaction that affects the spinal cord and makes it hard to walk and maintain balance. Nardin said, "Small amounts of denture cream are certainly safe for people. It's people whose dentures are ill-fitting, who are using excessive amounts ... who are at risk of running into trouble with zinc toxicity."
The authors of a 2008 study published in the Journal of Neurology theorize that long-term denture cream overuse was the culprit in the cases of four patients who had unexplained limb weakness and poor balance. Dr. Sharon Nations, who led the study, is an associate professor in the department of neurology at the University of Texas Southwestern Medical Center. "The patients were using at least two tubes of denture cream a week. ... So, it was long exposure to very high amounts of denture cream that led to their problem."
The FDA does not require that manufacturers list the amount of zinc, so the researchers tested the products themselves. The zinc varied from 17 to 34 milligrams per gram of denture cream. Significant amounts, according to the researchers. Dr. Jaya Trivedi, also an associate professor in University of Texas Southwestern Medical Center's neurology department, said, "If you have poorly fitting dentures, then seek professional help. Go and see your dentist, because we don't want them to be using large amounts of denture cream to keep the dentures in place." The researchers said more study is needed.
Denture Cream Requires No Warning Label
Dental professionals say if dentures fit properly, consumers should need very little, if any, cream at all. Denture cream is considered a class 1 medical device by the FDA, so it does not require a warning label.
Last week, attorney Eric Chaffin in New York, filed lawsuits on behalf of Isaacs and four other denture cream users against a pair manufacturers, Glaxo Smith Kline, the company that manufactures Poligrip, and Proctor and Gamble, the company behind the Fixodent products.
The suits allege that the companies failed to warn consumers about the risk. At least 10 similar lawsuits have been filed around the country in the last three years. "What we hope to see happen is to actually get a warning label on the product. ... Unfortunately there's not the awareness out there, and I attribute that in large part to the lack of warning label on the product itself," said Chaffin.
In court papers obtained by ABC News, the companies have denied their products are at fault -- saying there is no scientific proof that denture cream can cause zinc-related illnesses. Glaxo Smith Kline said, "Our product, Super Poligrip, is safe and effective for daily, long-term use when used as directed." Proctor and Gamble said, "All Fixodent products undergo rigorous scientific evaluations and safety testing. ... All Fixodent products are made, packaged and labeled in accord with FDA manufacturing practices."
Isaacs says the companies have a responsibility to the public. "They give you a diagram of how to apply it. But there's no warning. Had there been a warning, I wouldn't be like this." The once-active 60-year-old hopes to one day shed the walker that's become her security blanket. But for now, her cherished independence is gone. "That's devastating. That's the really hard part."
If you're unsure of how much denture cream to use, dental professionals toldl us to use three to four dime-size dots in key places on the denture. They say you can tell you're using too much if the cream oozes when you put the dentures in place. The Consumer Healthcare Products Association says one tube should last as long as 10 weeks.
For instructions on how to apply denture adhesives, head to the American College of Prosthodontists by clicking here.
Denture Cream Companies Respond to Findings
The FDA is looking into the Journal of Neruology study, and is comparing the findings to complaints it received about denture creams. The FDA encourages anyone with problems to report their experiences by calling 888-INFO-FDA or by going to its Web site at www.fda.gov.
ABC News received the following statements from Glaxo Smith Kline and Proctor and Gamble.
Statement from Glaxo Smith Kline:
In response to your request, GSK Consumer Healthcare is aware of an article in Neurology from June 2008. As noted in the article, the reports involved "markedly excessive" use of denture adhesive on a chronic basis.
Our product, Super Poligrip, is safe and effective for daily, long-term use when used as directed.
Denture adhesives such as Super Poligrip include zinc for improved adhesive strength -- it helps the product hold better.
Zinc is also an essential mineral, and is naturally present in many foods such as beef, chicken and nuts as well as in many supplements and over the counter products.
As the article suggests, consumers who use excessive amounts of denture adhesive due to ill-fitting dentures should seek professional (dental) care. They should not use more than directed.
Statement from Proctor and Gamble:
All Fixodent products undergo rigorous scientific evaluations and safety testing. We continually monitor the safety of our products once in market. We are not aware of any case where denture cream has been definitively linked to a health effect from zinc. Fixodent contains ingredients that are generally recognized as safe in the amounts used. All Fixodent products are made, packaged and labeled in accord with FDA manufacturing practices.
A small amount of zinc is used in Fixodent to help the denture stay in place securely so our consumers can eat, chew and talk more confidently. Zinc is a common ingredient in many over-the-counter products, a variety of foods and is a vital part of our daily diet. In fact, zinc supplements are commonly sold.
Fixodent users may ingest a small amount of the product. However, we estimate the amount of zinc a consumer would ingest from daily usage of Fixodent is less than the amount of zinc in most daily multi-vitamins and comparable to six ounces of ground beef. Still, we are doing all we can to make sure our consumers know how to use Fixodent properly. Furthermore, we are monitoring and updating our website, our packaging, and our communication to dental professionals when necessary. We also encourage anyone who has further questions or concerns to visit our website at www.fixodent.com.