From Biosis 10, May 2006
Dr. Verigin’s Comment:
Mercury in Dental Amalgam: A Risk or Not?
by Gary M. Verigin, DDS, CTN
When the Journal of the American Medical Association (JAMA) published a pair of amalgam studies in April 2006, headlines around the world declared that mercury fillings had been found “completely safe.” But a quick review of the two studies suggests otherwise.
The New England Children’s Mercury Amalgam Trial involved 534 randomly selected children, ages 6 to 10, treated among five community dental clinics in Boston and one in Farmington, Maine. None of the kids had ever been exposed to mercury, and each had at least two back teeth that were decayed and in need of fillings. Divided into two groups of 267, one set of children had their teeth restored with resin-filled composite, while the other had their teeth restored with mercury amalgam. During the five year span of the study, if a child developed more cavities, the fillings would be done with the same material as before.
The study’s objective was to compare neuropsychological aspects and renal (kidney) function between the two groups. The researchers looked at outcomes such as memory and visuomotor ability, as well as renal glomerular function across the five years of data. They concluded that, by these measures, there were no statistically significant differences between groups. They did find that children in the amalgam group had higher mean urinary mercury levels, but since there were no real differences in IQ and like measures, they declared that mercury fillings posed no risk.
The second study took place in Lisbon, Portugal. It involved 507 children, aged 8 to 10, who had at least one decayed permanent tooth. One group of 254 received resin-filled composites, while the other 253 received mercury amalgam restorations. The objective was to assess the safety of mercury fillings as measured through the neurobehavioral assessments of memory, attention/concentration and motor/visuomotor abilities. The researchers also measured nerve conduction velocities. At seven years follow-up, the research team found that while children in the mercury group had higher urinary mercury levels, there were no other statistical differences.
I am deeply concerned and strongly believe that the general public and outside interest groups – such as the American Medical and Dental Associations, state medical and dental associations, insurance companies and social welfare agencies – will glance at these studies’ modest conclusions and assume that the use of mercury in dentistry is “risk-free.”
Mercury has been used as a dental filling material for more than 150 years. Yet it’s also widely recognized that mercury is a highly reactive metal with toxic properties. We have not used this material in our office since the early 1980s, when my awareness was finally and fully engaged by the vast amounts of research. Much of it we received from our colleagues in Germany, who were practicing what they called “biological dental medicine.” This research was instrumental in my co-founding what’s now called the International Academy of Biological Dentistry and Medicine with Dr. Ed Arana in 1985.
In both current mercury studies, the researchers annually plotted their subjects’ urinary mercury levels. For the first two years, as expected, the results showed a steady increase in the mercury levels of the amalgam group children. Then the results turned strange. These elevated mercury levels actually dropped until they were almost the same as those of the mercury-free children.
How could this be?
Writing in Clinical Preventive Dentistry, Chew, Soh, Lee and Yeoh noted that each average sized 1 gram amalgam filling contains 500,000 micrograms of mercury – about 53% of the total volume, on average. Through research, they concluded that with such a filling emitting a toxic 5 micrograms of mercury per day – emissions generated by chewing and grinding – it would take 100,000 days for all the mercury to be vaporized. As they say, “Do the math!” (Answer: about 274 years!) And how long is the average lifespan of an amalgam filling according to insurance standards? About 10 years.
So why the drop in mercury levels? The kidneys are the primary route of excretion here. I surmise that they are taking a major hit, becoming less effective at removal. I would expect more mercury to be stored. After all, the urinary mercury levels were measured without the intake of chelating agents, thus making the data unreliable. Moreover, recent research shows that over 90% of excreted mercury goes through the fecal rather than urinary route.
Most likely, the children’s basic regulative systems became less flexible, more rigid. The autoregulatory pathways – liver, kidneys, skin, mucous membranes – all take part in the excretion of any toxin, including mercury. However, the detoxification process depends on variables such as genetics, gender and nutritional status. Thus, some people are less able to excrete mercury than others, even if they live in the same city, region or country, as in the current studies. Each will have a different diet with vastly different antioxidant and mineral intakes, as well as many of the chelators of mercury found in high quality protein.
A better measure of the effects of mercury would involve the immune system – something that was not mentioned in either study. The literature is packed with research on this. Mercury and other heavy metals with negative magnetic charges are powerful immune system suppressors. Under such conditions, the friendly microbes in our tissues undergo drastic changes. The major scavenging cells and immune response recognition cells, such as macrophages, have a lessened ability to render antigens harmless.
But instead of looking at this, the researchers focused on IQ.
They also focused on otherwise healthy children, even as the Centers for Disease Control report that 1 in 6 American children have some form of neurological disorder such as autism. Children so affected do not effectively excrete mercury. To exclude them – the individuals most susceptible to mercury toxicity – from the study is yet another major failing.
That said, it is my conviction that neither study as designed should have been performed at all. If living beings needed to be tested, then the experiments should have been done on some other form of primate, not human children. To subject unsuspecting children and their parents to such experimentation is the very definition of cruelty.
I question the ethics of these studies. I wonder if these researchers even remember the humanitarian motto of our profession: Doctor, do no harm unto your patient.
You don’t need much imagination to read between the lines of these studies. From my perspective, their main purpose is to justify the continued use of mercury in fillings and serve the economics of the dental industry. After all, an average dentist can place three or four mercury fillings in the same time as a single composite.