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.