March 29, 2010. Winston Salem, North Carolina.. After 14 years of using Poligrip denture cream to keep his teeth in place, Johnny Howell became disabled due to nerve damage from high zinc levels that may have been caused by the cream. His nerve damage is so severe that Mr. Howell had to quit his job as a mechanic and must now use a cane or walker to get around his house, which he rarely leaves, and only with assistance.. The walker Mr. Howell uses when he leaves the house. It is too large to use in the house so he has a cane.