A growing number of lawsuits are being filed against the manufacturers of popular products like Super Poligrip and Fixodent, alleging that the zinc in the adhesives is leading to serious neurological problems — and in one case, death.
The suits claim that denture adhesive manufacturers GlaxoSmithKline (Super Poligrip) and Procter & Gamble (Fixodent) failed to adequately warn consumers that ingesting the high levels of zinc found in many of their products could be dangerous.
Zinc is an essential mineral found in foods such as shellfish, meat, beans and cereals, and it's also sold in supplement form. Zinc helps wounds heal, keeps the immune system functioning properly and is required for proper sense of taste and smell. In denture products, zinc helps dentures adhere better to the gums.
Background: Chronic, excess zinc intake can result in copper deficiency and profound neurologic disease. However, when hyperzincemia is identified, the source often remains elusive. We identified four patients, one previously reported, with various neurologic abnormalities in the setting of hypocupremia and hyperzincemia. Each of these patients wore dentures and used very large amounts of denture cream chronically.
Objective: To determine zinc concentration in the denture creams used by the patients as a possible source of excess zinc ingestion.
Methods: Detailed clinical and laboratory data for each patient were compiled. Tubes of denture adhesives were analyzed for zinc content using dynamic reaction cell-inductively coupled plasma-mass spectrometry. Patients received copper supplementation. Copper and zinc levels were obtained post-treatment at varying intervals.
Results: Zinc concentrations ranging from about 17,000 to 34,000 µg/g were identified in Fixodent and Poli-Grip denture creams. Serum zinc levels improved in three patients following cessation of denture cream use. Copper supplementation resulted in mild neurologic improvement in two patients who stopped using denture cream. No alternative source of excess zinc ingestion or explanation for hypocupremia was identified.
Conclusion: Denture cream contains zinc, and chronic excessive use may result in hypocupremia and serious neurologic disease.