Dental Amalgam, Mercury Contamination and What You Need to Know

By Gerald P. Curatola, D.D.S. Oral Health and Wellness Expert, Clinical Associate Professor, NYU College of Dentistry

Posted on | By Gerald P. Curatola, D.D.S. | Comments ()

When considering the history and the polarized positions surrounding the ongoing use of mercury-containing fillings in dentistry, it could be argued that it is time to “stop the insanity.” Dental amalgam is actually comprised of four metals – mercury, silver, copper and tin – with mercury, its most toxic element, also being its most significant component, approximately 50% by weight. Once believed to be “locked into the filling itself,” mercury vapor is now widely recognized to be emitted from the filling surface, but the actual harm of this vapor has been highly contested. 


While the use of mercury-free fillings, such as tooth-colored composite resins and ceramics, are becoming more prevalent and better performing, approximately 46% dentists in the United States still use mercury-containing dental amalgam. Since the Civil War, mercury-containing fillings (often called “silver” or “amalgam”) continue to be used extensively to fill dental cavities. A 2006 poll of 2,590 US adults found that 72% of respondents were not aware that mercury was a main component of dental amalgam, and 92% of respondents would prefer to be told about mercury in dental amalgam before receiving it as a filling. This could be compared to being given a drug today by a pharmacy without the mandated FDA prescribing information (contents, possible side effects, etc.). Unfortunately, many dentists continue to place mercury-containing fillings, with many patients remaining uninformed of its mercury content. 

Complicating the matter of mercury-containing fillings is the important fact that the greatest exposure of mercury vapor to the patient (and dentist) is when dental amalgams are first placed in the tooth and when they are removed. 

Mercury use in health, consumer, and industrial products has declined precipitously in all products over the past 30 years, but in dentistry, this decline has only been slight, such that dental fillings jumped from 2% of all mercury products two decades ago to over 20% in 2001. In 1991, the World Health Organization (WHO) confirmed that mercury contained in dental amalgam is the greatest source of mercury vapor in non-industrialized settings, exposing the concerned population to mercury levels significantly exceeding those set for food and for air. WHO also went on to state that mercury contained in dental amalgam and in laboratory and medical devices accounts for about 53% of total mercury emissions –  and about one-third of the mercury in the sewage system comes from dental amalgam flushed down the drain. The Association of Metropolitan Sewerage Agencies (AMSA) studied seven major waste-water treatment plants and found that dental uses were "by far" the greatest contributors of mercury load, on average contributing 40%, over 3 times the next greatest contributor. The Environmental Protection Agency (EPA) also declared that dental amalgam is a major source of mercury contamination in waste-water.

The health debate surrounding mercury-containing fillings is equally concerning and confusing. Peer-reviewed scientific studies have come to opposite conclusions on whether the mercury exposure from amalgam fillings causes health problems. While it would be appropriate that any medical device should be proven 100% safe BEFORE being placed in the human body, and all potential health concerns from a known toxic environmental hazard be fully investigated, dental amalgam continues to be used until enough ongoing research is accepted proving it is unsafe and unsuitable. 

Gerald P. Curatola, D.D.S.

Article written by Gerald P. Curatola, D.D.S.
Oral Health and Wellness Expert, Clinical Associate Professor, NYU College of Dentistry