Saturday, October 08, 2011


I am always amazed when apparently intelligent people willfully suspend logic and/or ignore facts and data in order to support the 'party line.'  This happens way too often in politics and religion, and surprisingly is also happens sometimes in science.  The examples in politics and religion are TNTC and you can provide your own.

In science, there are a couple of examples that are quite interesting.  One is how a mathematical descriptor of cancer growth became an entrenched paradigm with little supporting data, and how the research of our motley crew in Colorado Springs challenged the paradigm.  I will write about this in another post.  The second example is how dental amalgam has been generally accepted as the standard filling material for decades with little concern about the biological effects of the components of the restorative material.  Challenges to the use of amalgam have been growing - hence - amalgam wars.

Immunology was one of the courses that I taught to undergraduate students at the University of Colorado at Colorado Springs [UCCS].  It is a fun course to teach [many new and non-intuitive concepts] and many topics have a direct bearing on student interests and experiences.  One semester, Hal Huggins showed up in my class.  Because of his age and wardrobe, he stood out, but I really did not pay too much attention because UCCS has a large contingent of 'non-traditional' students.  After class one day early in the semester, Hal stayed afterwards to introduce himself and to explain his interest in immunology.  I clearly remember being taken aback by the conversation.  He described his long-standing battles with the American Dental Association [ADA] about the use of amalgam, and innocently commented, "You do know that 'silver' fillings are about 50% mercury, don't you?"  Well, like millions of Americans, I did not, and actually thought that silver fillings were probably silver - duh?  But, as a scientist, I did know that mercury is one of the most toxic metals known, and naturally thought, why would dentists be putting this stuff in people's mouths?

Hal wanted to understand the workings of the immune system because he believed that many of the adverse effects of amalgam were caused by the interaction of mercury with the cells and molecules responsible for immune protection.  He admitted that he was a clinician and not a scientist, but felt that perhaps science could support his claims about the health effects of amalgam.  Hal took additional courses at UCCS and completed a masters degree, but to make a long story fairly short, he never became patient enough to pursue the science but rather continued to be much more of a proselytizer preaching the evils of amalgam.  For reasons summarized below, I believe that Hal's claims have some merit, but I was unable to rein in Hal's enthusiasm and sense of urgency when it came to translation of lab science to clinical practice.  Indeed, I got into some hot water with the CU administration because I was taking our research initiatives through the proper University review committees, and Hal started working before they were complete - bad form :-)  Thereafter, I always tried to be supportive of Hal's work, but had to make a clear separation.

So - what is the path that led me to conclude that amalgams are not for me?  I could go through the 100's of research papers that demonstrate how mercury is released from amalgam, how mercury from amalgam spreads through the body and is deposited in various cells and organs, especially neurons, the adverse biological effects of mercury, and on and on.  However, I am simply going to present below a portion of the work of attorney Sandy Duffy presented at the website Campaign for Mercury Free Dentistry.  Personally, I think that the amalgam wars are winding down.  Many dentists no longer use amalgam, particularly since other materials have been developed that perform similarly to amalgam for restorations.  However, be sure to go to the News section of the website that demonstrates that there is a long way to go before amalgam disappears from dental practice in this country.

1. Mercury in dental amalgams chemically binds with the alloy metals and results in an inert substance. The ADA also frequently claims that the components of amalgams are analogous to sodium and chlorine which are hazardous in their pure form but combined to form ordinary table salt.
1. An amalgam is a mixture and the properties of the components remain the same, i.e. mercury remains highly toxic and vaporizes and leaches out of the amalgam. Table salt is a compound, i.e. a new product which has different properties from the components. Guzzi, et al, The Lancet, 360:2081, Dec 21/28,2002; David M. Eide (Grant High School chemistry teacher), The Oregonian, Letters to the Editor, Dec. 30, 2000.
2. If mercury is emitted from amalgams, it is only in very minute amounts.
2. The average amalgam weighs 1 gram and is 50% mercury. As much as 50% of the mercury in an amalgam has been found to have vaporized after 5 years, and 80% after 20 years. Pleva J, "Dental mercury - a public health hazard", Rev Environ Health 10(1):1-27 (1994); Pleva J, Mercury from dental amalgams: exposure and effects, Int J Risk & Safety in Med, 1992, 3: 1-22. An exacting study conducted in 1991 evaluated the amount of mercury emitted from a common amalgam in a test tube with 10 ml of water. This study showed that "the over-all mean release of mercury was 43.5 mcg per cm2/day, and the amount remained fairly constant during the duration of the experiments (2 years)." This was without pressure, heat or galvanism as would have occurred if the amalgams were in a human mouth. Chew, CL, et al, Long-term dissolution of mercury from a non-mercury-releasing amalgam, Clinical Preventative Dentistry, 13(3):5-7, May-June (1991).
3. The small amounts of mercury emitted from amalgams are not bioavailable.
3. Mercury vapor from amalgam is the single largest source of systemic mercury intake for persons with amalgam fillings. Average daily exposure for mercury is 3-17 ug. per day; for fish is 3 ug per day; for air it is .04 ug per day; and, for water .05 ug per day. WHO Document 118, p.36, 1991; A 1998 study by NIDR concluded that amalgams were the primary source of mercury in the urine of military personnel. A. Kingman et al, National Institute of Dental Research, "Mercury concentrations in urine and blood associated with amalgam exposure in the U.S. military population", Dent Res, 1998, 77(3):461-71.
4. There is no credible scientific evidence supporting a link between silver fillings and systemic diseases or chronic illnesses.
4. Dr. Murray Vimy, Clinical Associate Professor, Faculty of Medicine, University of Calgary, prepared a document which sets out dental journal articles from 1957 to 1984 which very clearly show that mercury amalgams cause gingivitis and periodontal disease. This document can be downloaded from the website: In turn, periodontal disease has been linked to cardiovascular disease and pre term, low birthweight babies. Greenwell H, et al, Emerging concepts in periodontal therapy, Drugs, 2002;62(18):2581-7. A 2001 scientific study corroborates the role of mercury in Alzheimer's. The researchers concluded: "…that this visual evidence [of neurodegeneration] and previous biochemical data strongly implicate mercury as a potential etiological factor in neurodegeneration." Leong, CW, et al, Retrograde degeneration of neurite membrane structural integrity of nerve growth cones following in vitro exposure to mercury, NeuroReport, 12(4):733-37, March 2001.
The "previous data" included a study in which the authors concluded that: "We believe one …[theory of the pathogenesis of Alzheimer's] could be mercury vapor to which the majority of individuals are continuously exposed [from dental amalgam]. By reducing levels of viable brain tubulin, mercury vapor could exacerbate the conditions related to the onset of symptoms identified with Alzheimer's." Pendergrass, JC, et al, Mercury vapor inhalation inhibits binding of GTP to tubulin in rat brain: similarity to a molecular lesion in Alzheimer diseased brain, NeuroToxicology 18(2):315-324 (1997).
Mercury is a potent neurotoxin and many peer reviewed scientific studies have found evidence that amalgam fillings may play a major role in central nervous system diseases such as depression, schizophrenia, memory problems, ALS and Parkinsons's,
A Canadian study found that blood levels of five metals, including mercury, were able to predict with 98% accuracy which children were learning disabled. Other studies found mercury causes learning disabilities and impairment, and lowers IQ. Marlowe, M, et al, "Main and interactive effects of metallic toxins on classroom behavior", J Abnormal Child Psychol, 1985, 13(2):185-98; Moon C et al, "Main and Interactive Effect of Metallic Pollutants on Cognitive Functioning," Journal of Learning Disabilities, April, 1985; Pihl, RO et al, "Hair element content in Learning Disabled Children", Science, Vol 198, 1977, 204-6; Gowdy JM et al, "Whole blood mercury in mental hospital patients", Am J Psychiatry, 1978, 135(1):115-7. Also see above website.
There are 1000's of other studies showing adverse health effects from mercury in general, and amalgam in particular.,,,,
5. If amalgam was bad for you, dentists would be the canary in the mine and, in fact, they have no more health problems than anyone else.
5. A CDSPI Report (supplies malpractice insurance to dentists) was published in the Journal of Canadian Dentists in 1994. It reports that suicide rates among dentists are double those of other professions; 20% of dentists at any given time are on long term disability due to mental or nervous conditions including depression, increased alcohol consumption, fatigue, insomnia, ulcers and heart problems. Female dentists have increased spontaneous abortion rates and increased breast pathology, compared to the general population. Wiksztrajis, Med Pr 24:248 (1967 Lithuania).
6. No other country has banned the use of dental amalgam.
6. Most other developed countries have issued limited bans, or mandated health warnings regarding the use of mercury amalgam including: Canada, Great Britain, France, Austria, Norway, Sweden, Switzerland, Japan, Australia and New Zealand. Swedish National Dept. of Health, Mercury Amalgam Review Panel, 1987; Heavy Metal Bulletin, Dec 2000, Vol 6, Issue 3. A Swedish National Mercury Amalgam Review Panel and a similar Norwegian panel found that "from a toxicological point of view, mercury is too toxic to use as a filling material." Id.; Press Release, Swedish Council for Planning and Coordinating Research (FRN), Stockholm, 19 February, 1998; Norwegian Board of Health, Report 2652,
7. A few people can be allergic to amalgam, but there are only 50-100 reported cases.
7. In a clinical study, allergy tests performed on fourth year dental students found 44% of them allergic to mercury. E.G. Miller et al, "Prevalence of Mercury Hypersensitivity among Dental Students", J Dent Res. 64:Abstract 1472, p338,1985; D.Kawahara et al, "Epidemiologic Study of Occupational Contact Dermatitis in the Dental Clinic", Contact Dermatitis, Vol 28, No.2, pp114-5,1993. The Clifford Immune Reactivity Test is used to test dental patients for biocompatibility with dental materials. A review study of that test showed that 93% of patients tested were immune reactive to mercury. Clifford Consulting & Research, Inc, Dental Materials Reactivity Testing, Colorada Springs, Colo, & Peak Energy Performance, Inc., Dental Materials Biocompatibility Testing,
An important new study from the United Kingdom found that mercury can cause allergic and immunotoxic reactions, but there are no dose-response studies for immunologically sensitive individuals and, therefore, "it has not been possible to set a level for mercury in blood or urine below which mercury related symptoms will not occur." Kazantzis, G., Mercury exposure and early effects: an overview, Med Lav 2002 May-June;93(3):139-47.
8. The U.S. Public Health Service, including the National Institutes of Health, the Food and Drug Administration, the Centers for Disease Control and the World Health Organization have all concluded that amalgam is a safe and effective restorative material for dental fillings.
8. In 1993 the PHS Director, Dr. James O. Mason, in an introductory letter to the USPHS CCEHRP report states: "Because the possibility of adverse health effects resulting from the use of dental amalgam cannot be fully discounted based on available scientific evidence, I am requesting the National Institutes of Health, the Centers for Disease Control and Prevention, and the Food and Drug Administration to undertake an expanded and targeted program of research, professional and consumer education and product regulation." That report, at page 3 states: "In the absence of adequate human studies, the Subcommittee on Risk Assessment could not conclude with certainty whether or not the mercury in amalgam might pose a public health risk."
The USPHS, Agency for Toxic Substances and Disease Registry also has a publication entitled: Toxicological Profile for Mercury Update TP - 93-10 (1993) which specifically states that "the continuous exposure to mercury from amalgam fillings is not without risk to patients." At p. 25.
The American Dental Association never acknowledges that there is a 1999 Update of the USPHS publication which clearly states that amalgam is the primary source of human body burden.
Two presenters at an NIH/NIDR Technology Assessment Conference in 1991 presented significant documentation of adverse effects of mercury amalgams. The Final Statement of this conference was written by W.D. McHugh and the Conference Editor was Joyce a. Reese; both are dentists. The Final Statement from that Conference is not a strong endorsement of the safety of mercury amalgams. It states: "While the current evidence supports the concept that existing dental restorative materials are safe, it must be recognized that the supporting data are incomplete." (Advances in Dental Research, Vol. 6, page 143, Sept. 1992.)
One of the presenters of the adverse effects of mercury amalgam wrote to protest the Final Statement. The NIH responded to him thus: "The recognition of the paucity of data on the subject, especially with regard to mercury, was the reason for using the term 'Technology Assessment' rather than 'Consensus Development.' Our guidelines for a Consensus Development Conference do require the statement to be data-based to the extent possible …. In regard to the studies you presented being ignored, they were definitely considered and discussed at length, but not emphasized in the Final Statement."
In response to public uproar after the airing of the CBS 60 Minutes segment called: "Is there poison in your mouth?" the FDA held a Dental Products Panel Meeting on March 15, 1991. At page 208 of a transcript of that meeting, there is a list of Panel Recommendations. It includes: "Without the addition of any statements that reflect that the Panel feels that there is any unsafety [sic] to the use of dental amalgam as a restorative material, I would ask the Panel, now, that the information under review today, if that information raises questions that warrant further research. I will poll the Panel for a yes or no vote." All Panel members voted "yes," therefore all agreeing that questions about the safety of amalgams had arisen. The Panel made no declaration that amalgam was safe or harmless.
The latest FDA Consumer Update (December 31, 2002) informs consumers that Canada limits the use of mercury amalgam in pregnant women and it indicates that the FDA is reviewing the scientific studies related to the safety of mercury amalgam. While the FDA has up until now indicated that there was insufficient scientific proof that mercury amalgams cause adverse health effects, it has never declared mercury amalgam to be safe.
A World Health Organization (WHO) Scientific Panel in 1995 concluded that there is no safe level of mercury exposure. The Chairman of the panel, Lars Friberg stated that "dental amalgam is not safe for everyone to use." L.T.Friberg, "Status Quo and perspectives of amalgam and other dental materials", International symposium proceedings, G.Thieme Verlag Struttgart, 1995.
Additionally, the U.S. EPA found that mercury amalgam fillings which are removed from dental patients are hazardous waste and must be sealed airtight and disposed of as such. "Amalgam declared hazardous", Dentistry Today, February, 1989, p1.
And, finally, a Canadian Government study for Health Canada concluded that any person with any amalgam fillings receives exposure beyond that recommended by the USPHS standard. Mark Richardson, Environmental Health Directorate, Health Canada, Assessment of Mercury Exposure and Risks from Dental Amalgam, 1995, Final Report; G.M. Richardson et al, "A Monte Carlo Assessment of Mercury Exposure and Risks from Dental Amalgam", Human and Ecological Risk Assessment, 2(4): 709-761.

1 comment:

Bizzy Brain said...

The division between hard science and soft science is perhaps better described as the difference between actual science and non-science designed to look like the real thing.