GlaxoSmithKline might have failed to properly warn users of Super Poligrip and Poligrip, which are denture creams, of the risk of zinc poisoning and neurological injuries when consumers use Super Poligrip or Poligrip.

This is an ongoing investigation, pending multiple similar lawsuits and a potential class action lawsuit against GlaxoSmithKline.

GlaxoSmithKline manufactures PoliGrip and Super Poligrip, two denture creams used by millions as an adhesive for dentures. The FDA classifies PoliGrip and Super Poligrip and other denture creams as a Class I low-risk device. This means GlaxoSmithKline does not have to list ingredients, like zinc, on their products' labels. The FDA monitors Class I devices, so sources such GlaxoSmithKline and hospitals must report incidents of injury or death connected to a product, and manufacturing or product malfunctions

In August 2008, the journal "Neurology" reported on four patients suffering from neuropathy and other neurological symptoms typical of zinc poisoning and copper depletion. It was determined that excess use of dental creams could have been responsible for their symptoms. Additional reports from consumers and doctors may link the use of Fixodent to zinc poisoning.

In large doses, zinc can cause people to suffer nerve damage (neuropathy), copper deficiency, lethargy, and ataxia. Symptoms of neuropathy vary, but may include numbness or tingling in the feet, legs, hands, and/or arms; a reduction in strength or ability to move legs or feet, or arms and hands; unexplained pain in the extremities; a tendency to stumble or fall down; instability and lack of balance; or a change or decrease in walking stride.