As previously stated, FDA relies on a report from 1993 (PHS, 1993) for quantification of mercury exposure from amalgam ranging between 1 and 5 μgs/day.
However, that exposure level represents only the average exposure in adults, associated with possessing an average of seven to ten amalgam-filled teeth. The FDA further assumes that this range of exposure occurs(and is safe) in children six years of age and older, as well as in adults. Given that the FDA final rule acknowledges that amalgam can be the single greatest source of exposure to mercury vaporin the U.S. population, it is astonishing that the FDA did not undertake a more quantitative and definitive analysis of exposure to mercury from amalgam, especially considering the billions offillings placed in millions (10s to 100s) of Americans (statistics as described by FDA).
The other questions that FDA should have answered are:
- Just how many American adults with amalgam fillings are receiving a dose greater than either the EPA RfC or the ATSDR MRL?
- Just how many American children under six years of age with amalgam fillings are receiving a dose greater than either the EPA RfC or the ATSDR MRL?
These questions are answered below.
National Institute of Dental and Craniofacial Research (NIDCR) publishes data collectedby NHANES on the average number of filled teeth in the American population (see, e.g) NIDCR possesses the data to permit an accurate accounting ofthe number of persons with filled teeth in the U.S. population. These data would permit anaccurate determination of mercury exposure across the full range of numbers of filled teethin the U.S. population. It is unfortunate that the FDA did not avail itself of that data. Itis also unfortunate that the deadline for submission of this document to the FDA provides insufficient time for the Holistic Dental Association to obtain that same data. However, given thecomparability of living standards between Canada and the US, we will apply available Canadiandata for these derivations here, as they will be comparable to the dental care/dental health status inthe U.S. population.
Based on data available from Health Canada (HC, 1995) on the proportion of various age groups bearing amalgam fillings, and 2009 US population census projections from the US Census Bureau the following number of Americans with amalgam fillings are evident:
- Up to 5.1% of American children aged 3 and 4 years of age may possess amalgam filled teeth, representing 428,000 American toddlers for whom the FDA considered it unnecessary to quantify their mercury exposure from dental amalgam. Of these toddlers, 260,000 would exceed the MRL-equivalent dose of mercury from their amalgam fillings, while 61,000 would exceed the RfC-equivalent dose for mercury.
- Up to 40.4% of American children between the ages of 5 and 11 may possess amalgam-filled teeth, bearing from one to sixteen amalgam-filled teeth, representing 11,386,000American children for whom the FDA considered it unnecessary to quantify their precise mercury exposure from dental amalgam. Of these children, 5,909,000 would exceed the MRL-equivalentdose of mercury from their amalgam fillings, while 3,205,000 would exceed the RfC-equivalentdose for mercury.
- Up to 59.3% of American teens between the age of 12 and 19 may possess between one and twenty-two filled teeth, representing 19,856,000 American teens for whom the FDA considered it unnecessary to quantify their precise mercury exposure from dental amalgam. Of these teens, 6,378,000 would exceed the MRL-equivalent dose of mercury from their amalgam fillings, while 2,965,000 would exceed the RfC-equivalent dose for mercury. Also in this agegroup, 9% (nearly 3 million American teens) have more than 10 filled teeth; in excess of the number of amalgam-filled teeth (and their associated dose and potential health effects) even considered by the FDA in their Final Rule.
- Up to 52.8% of the adult American population may possess between one and twenty-five filled teeth, representing more than 118 million Americans for whom the FDA considered it unnecessary to quantify their precise mercury exposure from dental amalgam. Of these, 43,550,000 would exceed the MRL-equivalent dose of mercury from their amalgam fillings,while 21,682,000 would exceed the RfC-equivalent dose for mercury. Also in this age group,19.5% (nearly 44 million Americans) have more than 10 filled teeth; in excess of the number of amalgam-filled teeth (and their associated dose and potential health effects) even considered by the FDA in their Final Rule.
- In all, between the young age groups ignored in the FDA Final Rule, and those with more than ten filled teeth, also ignored in the FDA final Rule, some 48 million Americans are receiving doses of mercury solely derived from their mercury fillings that exceed the MRL andthe RfC. FDA should be especially concerned about these conclusions in view of the additional environmental exposure to mercury that is occurring in this country. Laks reports that the total exposure of the U.S. population to mercury is on the rise.
“This study is the first to report that there is a rise in the mean blood I-Hg (defined as “blood inorganic mercury”) detection and I-Hg concentration within the US population over time.” Laks also reports that his study “indicates that I-Hg deposition within the human body is significantly associated with biomarkers for themain targets of chronic mercury exposure, deposition and effect: the liver, immune system, and pituitary. These correlations between chronic mercury exposure, I-Hg deposition, and biochemical profile markers for the targets of I-Hg deposition confirm strong links between exposure and associated disease.”
FDA’s Final Rule does not take into account this documented additional mercury derived from environmental (non-amalgam) sources and then compare that total mercury burden to the RfC and the MRL.