Fixodent can cause zinc poisoning when people use it in amounts that greatly exceed the recommended dosage, according to Andrew Weil, M.D. The Fixodent package warns users to follow usage directions carefully and that excessive, prolonged usage can lead to serious health issues.
In a study described by WebMD, people with zinc poisoning due to excessive use of Fixodent and other dental adhesives experienced numbness and difficulty moving their legs. The patients then developed similar problems in their arms and progressed to balance problems. The neurological symptoms dissipated when some of the individuals discontinued use of the dental adhesive, but others still suffered some residual impairment.
People who use Fixodent as directed are unlikely to develop zinc poisoning, according to Procter & Gamble, Fixodent's manufacturer. The average Fixodent user absorbs about 2 milligrams of zinc per day, while the adult recommended daily allowance of the mineral is 8 to 11 milligrams.