Apply some common sense. The ancillary comments by some of the authors and the results of the JADA publication are in total disagreement with the vast majority of research published that looks at elevated mercury levels in subjects with amalgam fillings. For example, the NIH study on military men discussed above showed a very significant elevation of mercury in the blood that correlated with number of dental amalgams (6). Another recent publication demonstrated elevated mercury in the blood of living AD patients in comparison to age-matched controls (10). These studies clearly show that there should be increased mercury in your blood if you have amalgams and especially if you have AD and amalgams (6,10). Does not the brain have blood in it? This makes it a total mystery as to how could the authors of the JADA article not find elevated brain mercury levels in patient with existing amalgams and/or AD. Even cadavers have brain mercury levels that correlate with the number of amalgam fillings they had on death.

Further, if you are addressing the contribution of amalgams to brain mercury and AD wouldn’t it be important to divide the AD and control subjects into those with and without existing amalgams on death? In the JADA article this was not done and represents a major research flaw! That this was not done also arouses suspicion. I participated in submitting a letter pointing out this flaw to editors of JADA but they refused to acknowledge the letter and did not publish our comments. It is my opinion that the entire situation around this singular supportive publication of the ADA position on amalgams, brain mercury levels and AD represents a weak attempt at controlling the mind-set of well-meaning dentists, scientists, physicians and medical research administrators. It definitely impedes honest scientific debate. It also explains the cavalier attitude of the ADA and NIDCR about elemental mercury exposure and toxicity when compared to the more serious approaches taken by the EPA and OSHA.

With regards to the JADA article summary that “no statistically significant differences in brain mercury levels between subjects with Alzheimer’s disease and control subjects.” Here I must quote Mark Twain on honesty, “There are liars, damned liars and statisticians.” Comparing the level of mercury in the AD versus control alone using straightforward statistics previously showed a significant difference on mercury levels in AD versus control subjects (14a,b, 15). However, there are anomalies, confounders and other factors that can be considered in this situation, especially if you don’t like the initial results. This allows one to invoke a Bon-Feroni statistical manipulation. With Bon-Feroni you include the comparison of one pair of data (that may be statistically significantly different taken alone, e.g. mercury levels in the brains of AD versus control subjects) with several other pairs of data rendering the difference statistically insignificant. One known weakness of the Bon-Feroni treatment of several coupled pairs of comparisons is that one very likely will miss a single comparison that is significantly different, and clever people know this. It is my opinion that application of the Bon-Feroni manipulation is what happened in this JADA study that reversed the previous significance of the mercury levels in AD versus control brain previously reported. Research previously reported by some of the very same researchers involved in the JADA study consistently indicated that mercury levels were higher in AD versus age-matched control brains (14a,b, 15). Only when an ADA dentist became involved did the results change to being insignificant. I think the data used in this JADA article and funded by NIH needs to be re-evaluated by a different statistician if we are to ever really know if the mercury levels in the AD brains differed significantly from controls.

The letter from the ADA President then lists four publications as proof of amalgams having no statistically significant negative effects. Two of these were published in Scandinavian Journals, another was a review of the literature in a Dental Journal, and one was the JADA article mentioned above. Sweden is well known to have led the world in the restriction and replacement of dental amalgams with non-mercury containing materials. Forces are pushing hard to get the use of amalgams accepted again in Sweden to eliminate this embarrassment to our ADA. The current situation in Sweden and some other European countries, Canada and Japan seriously questions the ADA contention of amalgam safety. What if people in Sweden become healthier without amalgams?

Additionally, the studies quoted by the ADA President were epidemiological studies. These are very complex as many confounders are included which make finding a statistically significant difference very difficult. So the results are negative, nothing found, and not surprising. However, they are in disagreement with numerous other similar reports and appear to be hand-selected to support the ADA position. One has to wonder, since the ADA President seemed to visit Swedish journals to support the ADA position, how he missed the research of the Nylander group in Sweden that showed increased mercury content in brains and kidneys of humans in relationship to exposure to dental amalgams (17,18). Also, the referenced studies in the ADA letter did not involve neurotoxicity, autism or neurological disease---which is the question at hand. Rather, they addressed fertility, reproduction and other systemic illnesses. Could not the ADA find references to focus on neurotoxiological studies? What about the 1989 study that showed elevated levels of mercury in 54 individuals with Parkinson’s disease when compared to 95 matched controls (16)? Further, one ought to consider who was doing these touted ADA studies and any vested interest they may have in the outcome. I am also aware of studies done in the U.S.A. by major research universities that would disagree with the conclusions drawn by the ADA on this subject yet these articles are not considered in the ADA letter.

At the end of the last publication the quote “Conclusions: No statistically significant correlation was observed between dental amalgam and the incidence of diabetes, myocardial infarction, stroke, or cancer.” How does this relate to an article published in the J. of the American College of Cardiology where the mercury levels in the heart tissue of individuals who died from Idiopathic Dilated Cardiomyopathy (IDCM) contained mercury levels 22,000 times that of individuals who died of other forms of heart disease? Where did this tremendous amount of mercury come from? Even a Bon-Feroni manipulation could not make this difference insignificant! Many who die of IDCM are well-conditioned, young athletes who drop dead during sporting events---and they live in locations and in economic environments where seafood is not a dietary mainstay. Perhaps the victims of IDCM are within the ADA Presidents “handful of individuals who are allergic to one of its components.”

“The National Institute of Dental and Craniofacial Research is currently supporting two very large clinical trials on the health effects of dental amalgam. Studies underway for several years each in Portugal and the Northeastern United States involve not only direct neurophysiological measures but also cognitive and functional assessments.” Do we really think that the NIDCR and associated ADA personnel are going to deliver up a conclusion to American parents saying “we put a mercury containing toxic material in your child’s mouth that lowered his/her I.Q. and made him more susceptible to neurological problems in comparison to the children whom we selected to not get exposed to this toxic material”? It is my opinion that most bureaucracies don’t have a brain or a heart, but they do have a very strong survival instinct. Therefore, the results presented from this study will likely follow previously ADA supported research, i.e. no significant results.

Since the NIDCR started this project only 4 years ago one has to ask why it took so long for them to get involved since the “amalgam wars” have been going on for scores of years? Was it the overwhelming amount of modern science showing mercury from amalgams being a major part of the daily exposure that forced their hand and they had to develop a defense? Would I trust the conclusions of this study without knowing who put it together and who did the statistics? Not any more than I trust the conclusions of the JADA article mentioned in ADA letter that stupendously concludes that mercury from dental amalgams does not get into the brain.

As was proven by the tobacco situation, trying to find any significant negative effect of one product (amalgams) related to any disease through epidemiological studies is very difficult and complex. To do this with mercury would be difficult because of the synergistic effect two or more toxic metals or compounds (e.g. cadmium from smoking) may have on the toxicity of the mercury emitted from amalgams. For example, one publication showed that combining mercury and lead both at LD1 levels caused the killing rate to go to 100% or to an LD100 level (12). An LD1 level is where, due to the low concentrations, the mercury or the lead alone was not very toxic alone (i.e., killed less than 1% of rats exposed when metal were used alone). The 100% killing, when addition of 1% plus 1% we would expect 2%, represents synergistic toxicity. Therefore, mixing to non-lethal levels of mercury plus lead gave an extremely toxic mixture! What this proves is that one cannot define a “safe level of mercury” unless you absolutely know what others toxicants the individual is being exposed to. The combined toxicity of various materials, such as mercury, Thimerosal, lead, aluminum, formaldehyde, etc., is unknown. The effects various combinations of these toxicants would have is also not defined except that we know they would be much worse than any one of the toxicants alone. So how could the ADA take any exception, based on intellectual considerations, to my contention that combinations of Thimerosal and mercury could exacerbate the neurological conditions identified with autism and AD? Autism and AD have clinical and biological markers that correspond to those observed in patients with toxic mercury exposure. Why would the ADA take this position? I personally feel like I have been in a ten-year argument with the town drunk on this issue. Facts don’t count and data is only valid if it meets the pro-amalgam agenda.

The ADA was founded on the basis that mercury-containing amalgams are safe and useful for dental fillings. This may have been an acceptable position in 1850. However, modern science has proven that amalgams constantly emit unacceptable levels of mercury. Especially as the average life span has increased from 50 to 75-78 years of age where AD and Parkinson’s become prevalent diseases. The ADA can try to verify its position using selected epidemiological studies. But the bottom line is that amalgams emit significant levels of neurotoxic mercury that are injurious to human health and would exacerbate the medical condition of those individuals with neurological diseases such as ALS, MS, Parkinson’s, autism and AD.

I am hoping that the ADA sent this letter to your committee and also placed it on the ADA web-site to indicate that they are now willing for a wide-open discussion to take place on the issue of dental amalgams. I, for one, would welcome a major scientific conference on this issue. The ADA should feel free to post my letter in response and address any issue they feel that I am mistaken about. However, in closing I urge your committee to push forward on the study of the potential dangers of mercury in our dentistry and medicines. This includes mercury exposures from amalgams, vaccines and other medicaments containing Thimerosal. The synergistic effects of mercury with many of the toxicants commonly found in our environment make the danger unpredictable and possibly quite severe, especially any mixture containing elemental mercury, organic mercury and other heavy metal toxicants such as aluminum.

Sincerely,

Boyd E. Haley
Professor and Chair
Department of Chemistry
University of Kentucky

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