The problem with the denture creams is that the products contain zinc. Excessive zinc intake can be harmful.
Denture cream lawyers are arguing that the zinc in the products, such as Poligrip and Fixodent, is causing neurological damage. One of the main theories of liability is that the manufacturers have known for years that excessive zinc is harmful yet added zinc to the products anyway.
The ABC News story mentions a 2008 study published in the Journal of Neurology. It theorizes that long-term denture cream overuse was the culprit in the cases of four patients who had unexplained limb weakness and poor balance.