In February 2011, the U.S. Food and Drug Administration (FDA) sent a letter to all denture adhesive manufacturers, recommending removal of zinc from denture adhesive products and/or making significant label changes to warn consumers of potential dangers. This was in response to a number of scientific studies that suggest that zinc contained in some denture adhesives may contribute to zinc toxicity and neurologic disease.
Zinc is a mineral which is necessary to maintain your health. It is required to help regulate growth and metabolism in tissues where new cell development occurs, such as in the bone marrow and the intestinal lining. However, an excess amount of zinc, known as hyperzincemia, can contribute to copper deficiency, zinc toxicity and neurological damage. In the August 2008 publication of Neurology, researchers at the University of Texas Southwestern Medical Center in Dallas, linked use of large amounts of zinc containing denture adhesives to symptoms of neuropathy and zinc toxicity. It should be noted that patients in this study used a minimum of two tubes of denture adhesive weekly. Other researchers in the Department of Neurology at Vanderbilt University report in Neurotoxicology November 2009, patients experiencing progressive neurological symptoms following chronic overuse of zinc-containing denture adhesives.
The two primary manufacturers of zinc-containing denture adhesives in the U. S. are GlaxoSmithKline, which makes Super Poligrip, and Proctor & Gamble, which makes Fixodent. A small amount of zinc is used in these products to provide denture hold. Last year, GlaxoSmithKline agreed to reformulate Super Poligrip to remove zinc.
In 2009 the American College of Prosthodontists (ACP) formed a task force to establish evidence-based guidelines for the care and maintenance of complete dentures. At the conclusion of their study, they published a guideline for denture care in the Journal of Prosthodontics (Vol 20, Supplement1, February 2011)
Even with well-fitting dentures, they found that denture adhesives, when properly used, can improve the retention and stability of dentures and help seal out accumulation of food particles under the denture. However, the authors of the article caution against improper use of zinc-containing denture adhesives due to adverse systemic effects. So as a precautionary measure, they advise patients not to use zinc-containing denture adhesives.
The ACP further states that denture adhesives should be completely removed from the denture and the oral cavity on a daily basis. If increasing amounts of adhesives are required to achieve the same level of denture retention, patients should see their dentist or prosthodontist to evaluate the fit and stability of the dentures. Annual checkups with the dentist or prosthodontist are advised for denture wearers to achieve optimal fit and function of the dentures
References:
Denture cream: an unusual source of excess zinc, leading to hypocupremia and neurologic disease. Nations SP, Boyer PJ, Love LA et al. Neurology.2008; 71:639-643
Myelopolyneuropathy and pancytopenia due to copper deficiency and high zinc levels of unknown origin II: the denture cream is a primary source of excessive zinc. Hedera P, Peltier A, Fink JK, el al. Neurotoxicology 2009; 30:996-999
Evidence-Based Guidelines for the Care and Maintenance of Complete Dentures: A Publication of the American College of Prosthodontists. Felton D, Cooper L, et al. Journal of Prosthodontics Vol 20, Supplement 1, February 2011
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