Mercury amalgam fillings do not release toxic levels of mercury into the body, and are harmless.
by Brian Dunning
April 1, 2007
Also available in Chinese
When you go to the dentist and get a tooth drilled out, chances are he's going to fill the hole with an amalgam filling, which has been the gold standard of dentistry for more than 150 years. Amalgam fillings consist mostly of silver, tin, and mercury, in that order by volume, with some other stuff mixed in. Mercury was used in gold and silver mining because it readily absorbs those elements, keeping them securely bound chemically. Amalgam is the filling of choice of nearly all practicing dentists because they're cheap, durable, easy to work with, and generally considered safe. So safe, in fact, that the American Dental Association has never reversed that position in 150 years. It is acknowledged that amalgam fillings do release molecules of all constituent metals, but not in significant amounts. Wristwatches, rings, and other jewelry have been shown to introduce their surface metals into the body at at least the same rate, but as we know from the last several thousand years, this has never been aproblem for anybody. We're talking about infinitesimal levels.
Therein lies the disputed point. A small but very vocal minority of dentists and other people believe that the levels of mercury released from amalgam fillings is high, and in some cases that it's dangerous or even lethal.
I am personally acquainted with two people who suffered for years from chronic fatigue, and both reported immediate relief when they had their amalgam fillings removed from their teeth and replaced with ceramic fillings. It should be noted that Chronic Fatigue Syndrome, so far as we know, has no proven connection to heavy metal poisoning. Hal Huggins, DDS is a controversial author who has written a number of books warning about the dangers of mercury from amalgam fillings. Read the reviews of his books on Amazon, and you'll see that he has a huge following of believers singing Halleluias to him. Clearly, the belief that amalgam fillings cause toxic mercury poisoning is widespread and popular. Correspondingly, the belief that removal of amalgam fillings causes an immediate reversal of all symptoms is equally widespread.
Now, these people may indeed have experienced immediate relief upon having the procedure done — I know my two friends did. But I'm doubtful that their relief was not at least partially psychological. The human body has no mechanism for removing heavy metals from itself. This can only be done through chelation therapy, a lengthy and tedious process using the drug EDTA (contrary to folk wisdom, certain high-sulfur vegetables are not useful chelating agents). Replacing the fillings may have stopped the alleged introduction of new mercury, but it would not reduce any existing mercury levels in the body. If mercury poisoning is indeed the cause of the patient's problem, removal of the amalgam fillings would not produce any relief at all.
And, of course, nobody is exposed to more amalgam fillings than dental professionals. The lack of any increased level of mercury poisoning among dental professionals tends to cast additional doubt onto the claim that amalgam fillings representa significant source of mercury poisoning.
The most compelling evidence of the dangers of mercury leeching from amalgam fillings is the so-called "Smoking Teeth" video. You can see it if you search YouTube for "smoking teeth" or just go to iaomt.org. IAOMT is a group of dentists and other scientists who believe that amalgam fillings release toxic levels of mercury into the body, and they call themselves the International Academy of Oral Medicine and Toxicology. Their video shows a recently extracted tooth that contains an amalgam filling, and which has been dipped in water, held in front of a fluorescent screen, and illuminated with ultraviolet light. This is an easy way to show visually whatever vapors might be coming off of the tooth. Well, the video shows a constant dense smoke of vapor rising from the tooth. The video begins with the direct claim "All mercury silver fillings leak substantial amounts of mercury constantly. The amount increases with any kind of stimulation." The narrator proceeds to rub and heat the tooth, and the visible smoke rising from the tooth increases accordingly. The video is quite alarming, and even I felt a wake-up call when watching it.
But then it occured to me: Isn't mercury vapor (80Hg) a lot heavier than air (7N + 8O2)? Wouldn't mercury vapor drop to the floor like a rock, like CO2 mist from dry ice? Why would it be rising from the tooth? I even double checked my periodic table to be sure. I did a little bit of research on the web to see what I could find out. And, sure enough, everything I found confirmed my suspicion. Mercury vapor is much, much heavier than air. Whatever's rising from that tooth in the video can't possibly be mercury vapor. Discussing this with a friend, I learned that a simple yet thorough debunking of this video has already been done, by Dr. James Laidler, MD, and you can find his short but very clear article on his blog, at quackfiles.blogspot.com. If you doubt anything in Dr. Laidler's article, you can quickly glance at any periodic table of the elements and confirm it. The simple fact is that at body temperature, air weighs 1.2 grams per liter. Mercury vapor weighs 7.86 grams per liter, more than six times heavier than air. The vapor in the video is rising, fast enough to indicate that it weighs — oh, around .71 grams per liter. And guess what weighs that much? Water vapor. Remember they said on the video the tooth had just been dipped in water? That's right: This shocking video, the centerpiece of evidence in the case against amalgam fillings, points directly to a column of rising water vapor and tells you that it's mercury vapor, in direct contradiction to chemical fact. The credits on the video are from two IAOMT dentists, Roger Eichman, DDS and David Kennedy, DDS. According to an IAOMT representative, the video was made by Boyd Haley, PhD, a professor at the University of Kentucky. And guess what he's a professor of? Wait for it: Chemistry.
The same IAOMT representative told me: "No one with any knowledge of these subjects could ever say that the video is quackery as these guys know their stuff and have presented to Congress on multiple times, and have used this video extensively in their campaign. (In all caps:) THE VIDEO IS AN IRREFUTABLE PIECE OF SCIENTIFIC FACT - PERIOD!" It appears that "irrefutable" has a new definition. Apparently now, it means "completely wrong and deliberately misleading." Unless he's asleep all day, you've got to figure that Prof. Haley knows that mercury vapor is far heavier than air, and would sink. I see that this comes down to three possibilities. (1) He's honestly wrong about something this flagrant, which seems unlikely; (2) He is deliberately lying in the video, which seems unlikely; or (3) He explains his position with some excuse like there is mercury vapor mixed in with the water you see rising. All right, let's assume it's number 3. Any mercury vapor would still fall; mercury vapor would not remain in solution with water vapor. So whatever vapor we see rising has nothing to do with the mercury amalgam filling said to be in the tooth in the video. Any tooth dipped in water would smoke in exactly the same way.
Now here's where I get confused. These guys are not selling anything. All indications are that they're genuinely concerned with people's health. They're educated professionals. Their hypothesis is a fringe idea, but that doesn't make it wrong. New discoveries often start on the fringe. But if all that's true, why did they make this video, which is full from beginning to end with flagrant errors and poorly presented evidence?
Now let me be very clear on one point: I'm not here to say that amalgam fillings are safe. I'm not making any claims about that one way or the other. What I'm saying is that these IAOMT people are supporting their claim badly, with bad science. The claim that amalgam fillings are unsafe may or may not be true, but the claimants have yet to produce any real evidence (that I've seen) that passes any close scrutiny. Just as another couple data points: IAOMT opposes the use of flouride, and they also say 85% of dentists are impaired by mercury poisoning. My dentists have never heard of anyone. I guess they must be too impaired to be able to tell. IAOMT might be right about all of this stuff; they're just not making a very good show of it.
I will go on the record right now with my personal opinion, whether you care what that is or not: I don't want anything with mercury going into my mouth when there are alternatives, especially when those alternatives look better cosmetically. In 2006 the FDA did overrule its previous position that amalgam fillings are safe, and say that more study is needed. That's not saying that they're unsafe, it's simply saying that more study is needed. I've had amalgam fillings in my mouth my whole life — I even remember playing with the raw mercury on a countertop when my dentist uncle put some of my earliest fillings in, which obviously isn't too good — and I don't have any mercury poisoning. I'm not about to get my fillings replaced, but I do choose ceramic fillings now; but mainly because they look better.
If you're among those considering having your amalgam fillings removed, don't take any unnecessary medical procedure lightly. Consult not only with fringe books and videos you find on the Internet, but also consult with your dentist and your family doctor. Also consider the greater surface area contact of wristwatches, rings, and other jewelry if you truly believe yourself to have heavy metal poisoning. Nobody's ever been proven to have significant levels of mercury in their body from amalgam fillings, so don't worry too much about it regardless.
Correction: An earlier version of this said that the causes of Chronic Fatigue Syndrome are well understood. This is not the case; much about it remains a mystery.
By Brian Dunning
Cite this article:
Dunning, B. "Mercury Fillings." Skeptoid Podcast. Skeptoid Media,
1 Apr 2007. Web.
22 Apr 2018. <http://skeptoid.com/episodes/4036>
References & Further Reading
Bailer, J., Rist, F., Rudolf, A., Staehle, H.J., Eickholz, P., Triebig, G., Bader, M., Pfeifer, U. "Adverse health effects related to mercury exposure from dental amalgam fillings: toxicological or psychological causes?" Psychological Medicine. 1 Feb. 2001, Volume 31, Number 2: 255-263.
Edlich, R.F., Cross, C.L., Wack, C.A., Long, W.B. 3rd, Newkirk, A.T. "The food and drug administration agrees to classify mercury fillings." Journal of Environmental Pathology, Toxicology and Oncology. 1 Oct. 2008, Volume 27, Number 4: 303-305.
Food and Drug Administration, HHS. "Class II special controls guidance document: dental amalgam, mercury, and amalgam alloy." Guidance Documents (Medical Devices). 28 Jul. 2009, Document number 1192: 14 pp.
Halbach, S. "Amalgam tooth fillings and man's mercury burden." Human & Experimental Toxicology. 1 Jul. 1994, Volume 13, Number 7: 496-501.
Luglie, P.F., Campus, G., Chessa, G., Spano, G., Capobianco, G., Fadda, G.M., Dessole, S. "Effect of amalgam fillings on the mercury concentration in human amniotic fluid." Archives of Gynecology and Obstetrics. 1 Feb. 2005, Volume 271, Number 2: 138-142.
Nerdrum, P., Malt, U.F., Høglend, P., Oppedal, B., Gundersen, R., Holte, M., Löne, J. "A 7-year prospective quasi-experimental study of the effects of removing dental amalgam in 76 self-referred patients compared with 146 controls." Journal of Psychosomatic Research. 1 Jul. 2004, Volume 57, Number 1: 103-111.
Osborne, J.W., Albino, J.E. "Psychological and medical effects of mercury intake from dental amalgam. A status report for the American Journal of Dentistry." American Journal of Dentistry. 1 Jun. 1999, Volume 12, Number 3: 151-156.
Wirz, J., Ivanović, D., Schmidli, F. "[Mercury loading from amalgam fillings] [Article in German]." Schweizer Monatsschrift für Zahnmedizin. 1 Dec. 1990, Volume 100, Number 1: 1292-1298.
Zimmer, H., Ludwig, H., Bader, M., Bailer, J., Eickholz, P., Staehle, H.J., Triebig, G. "Determination of mercury in blood, urine and saliva for the biological monitoring of an exposure from amalgam fillings in a group with self-reported adverse health effects." International Journal of Hygiene and Environmental Health. 1 Apr. 2002, Volume 205, Number 3: 205-211.
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