Another denture product has been linked to health problems. According to researchers at the University of Texas Southwestern Medical Center in Dallas, excessive amounts of denture cream can cause neurological problems because they contain zinc.
Last March, the Food & Drug Administration (FDA) said one person had died and at least 72 others were sickened as a result of allergic reactions to denture cleaners. The FDA blamed a bleach called persulfate, an allergen that is used in most denture cleansers, for the reactions. In many cases, patients suffered an allergic reaction after swallowing the cleaner, which is not recommended. The agency FDA asked manufacturers of denture cleansers to include a warning in the label about persulfates.
Now, In an article that appeared in the August issue of “Neurology”, the University of Texas research team has reported on four patients who used excessive amounts of denture cream on a daily basis. Denture cream contains zinc, which in excess, can deplete copper and lead to serious neurological problems. The researchers tested the denture creams the four patients used, and found zinc concentrations between 17,000 and 34,000 micrograms per gram. Based on the patients’ denture cream use, the researchers estimated that they were exposed to at least 330 mg of zinc daily, far more than the recommended daily allowance of 8 mg for women and 11 mg for men. The National Academy of Sciences stated in 2001 that the largest daily tolerable zinc intake is 40 mg.
The article noted that one tube of denture cream should last 3 to 10 weeks, but patients in the report were all using at least two tubes a week. Three had also lost their teeth at a relatively young age, meaning they had been used “extremely large amounts of denture adhesive daily for years.
According to the University of Texas researchers, all of the patients had abnormally high levels of zinc in their blood, accompanied by abnormally low levels of copper. Normal blood levels of copper range from 0.75 to 1.45 micrograms per milliliter (mL), but levels for the patients in the report ranged from less than 0.1 to 0.23 micrograms per mL. The top normal number for zinc blood levels is 1.10 micrograms per mL, but patients had levels ranging from 1.36 to 4.28 micrograms per mL.
One patient’s neurological symptoms included weakness in the hands and poor balance, while another had weakness in her arms and legs that made her wheelchair dependent, along with cognitive decline and urinary incontinence. These patients showed “mild neurologic improvement” after they quit using denture cream and began taking copper supplements.
Another patient took copper supplements but didn’t stop using denture cream. His copper levels improved, but his zinc levels remained too high and he showed no improvement in his neurological symptoms. The fourth patient, who took copper supplements and stopped using denture cream, showed improvement in copper and zinc levels, but no improvement in neurological symptoms.