New Research Confirms the Majority of Americans' Mercury Exposure from Dental Amalgam Mercury Fillings Exceeds California Safety Limit

The International Academy of Oral Medicine and Toxicology (IAOMT) is raising awareness of research linking highly significant elemental mercury excretion to the presence of dental amalgam fillings in the mouth. These so-called "silver" fillings also called amalgams are actually 50% or more mercury and are widely used in the United States, in all branches of the military, low-cost insurance and disadvantaged children and adults.

In the present study, researchers David and Mark Geier reviewed the urinary mercury excretion of over 150 million Americans using the CDC's 2015-2018 National Health and Nutrition Examination survey (NHANES). The Geiers found a highly significant relationship between the number of dental amalgam filling surfaces in the mouth and amounts of mercury excreted. They compared the amounts of mercury being excreted to the current mercury minimum risk levels of both the US EPA and California's EPA.

It is important to note that the number of surfaces is not the same as the number of fillings. Each tooth has five surfaces, which means that a person with only one filling could have up to five surfaces.  

Daily mercury vapor doses from amalgam fillings were found to be in excess of safety limits for about 86 million adults.

Of the 91 million (57.8%) adults who had one or more surfaces of mercury fillings, the amount of mercury in their urine correlated significantly with the number of surfaces of amalgam. The Geiers wrote that, "Daily [mercury] Hg vapor doses from amalgams were in excess of the most protective California's Environmental Protection Agency (CalEPA) safety limit for about 86 million (54.3%) adults." The US EPA minimum risk level (MRL) for mercury is considerably higher than CalEPA's MRL due to the fact that by statute CalEPA's MRL must protect the vulnerable, not the average. However, 16 million adults are exposed to levels of mercury greater than the US EPA's MRL.

Similar information about excessive exposure was presented by the IAOMT at the FDA expert hearing on the safety of amalgam in 2010 and one dentist on the panel asked the experts from the Agency for Toxic Substances and Disease Registry (ATSDR) how much over the MRL can you go and still be safe. Dr. Richard Kennedy of ATSDR explained that one cannot exceed the MRL and still expect to be safe.

In September 2020, the Food and Drug Administration (FDA) updated risks of dental amalgam fillings for susceptible groups and identified fetal exposure during pregnancy as the most critical exposure and recommends no amalgam fillings for women from fetus to menopause because of that risk. Additionally, the FDA recommended that children, people with neurological disease such as multiple sclerosis, Alzheimer's disease or Parkinson's disease, people with impaired kidney function, and people with known heightened sensitivity (allergy) to mercury or other components of dental amalgam avoid having these mercury fillings placed.

"Toxic mercury vapors are continually off-gassed from dental amalgam fillings with stimulation such as chewing," explains David Kennedy, DDS, Past IAOMT President. "With the Geiers' new research joining the ranks of hundreds of other studies, it is abundantly clear that mercury from amalgams pose a danger to everyone, including unborn babies, patients, dentists, and dental employees."

The Geiers' study was partially funded by the IAOMT, a non-profit organization that evaluates biocompatibility of dental products, including mercury filling risks.