New research suggests that overuse of denture cream can cause gums to absorb hazardous trace metals, leading to neurological damage. In the medical journal Neurology, Dr. Sharon P. Nations of the University of Texas Southwestern Medical Center in Dallas and her colleagues reported on four denture-wearing patients who developed neurological problems.
All four patients experienced abnormally high levels of zinc in their blood, accompanied by abnormally low levels of copper. Denture cream contains zinc and the four patients habitually used “extremely large amounts” of the cream. Because of this, Nations and her team propose that excess denture cream use led to their neurological problems. Patients sometimes compensate for ill-fitting dentures by applying excessive amounts of denture cream.
A balance in the body between zinc and copper must be maintained in order to experience neurological health. Ingesting too much of either metal can cause depletion of the other metal. Normal blood levels of copper range from 0.75 to 1.45 micrograms per milliliter (mL); levels for the patients in the study ranged from under 0.1 to 0.23 micrograms per mL. Although 1.10 micrograms per mL is the highest normal number for zinc blood levels, patients in the study tested with levels ranging from 1.36 to 4.28 micrograms per mL. Testing revealed zinc concentrations were between 17,000 and 34,000 micrograms per gram in the denture creams the patients used. The researchers report that this is the only “plausible explanation” for their high zinc levels and copper deficiencies.
In one case, a patient’s symptoms included weakness in the hands and poor balance, another experienced sufficient weakness in her arms and legs that she was rendered wheelchair dependent. She also experienced cognitive decline and urinary incontinence. The patients indicated “mild neurologic improvement” after they stopped using denture cream and began taking copper supplements. Another patient took copper supplements but didn’t stop using denture cream. Although his copper levels improved, his zinc levels remained too high. No improvement in neurological symptoms was experienced in this case. The fourth patient took copper supplements and stopped using denture cream and showed improvement in copper and zinc levels, but showed no improvement in neurological symptoms.
Used as recommended, a tube of denture cream should last from three to 10 weeks, the researchers note; however, the patients in the report were all using at least two tubes weekly. Three of the four patients involved had also lost their teeth at a relatively young age, meaning they had been using “extremely large amounts of denture adhesive daily for years.” Based on patients’ denture cream use, the researchers estimate that they each were exposed to at least 330 mg of zinc daily, far more than the recommended daily allowance of eight mg for women and 11 mg for men. Meanwhile, in 2001, the National Academy of Sciences reported that the largest daily tolerable zinc intake is 40 mg. Nations and her team urge people who use excessive amounts of denture cream to compensate for ill-fitting dentures to seek professional assistance regarding the devices.