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Isn't the mercury safely bonded to the other metals? How does mercury leak from an amalgam?

Alloys and chemical Bonding

A prominent website promoting the status quo within the medical world and championing the dental amalgam is (Try a Google search for "mercury fillings"). A quotation from their page on the amalgam:

"The difference between bound and unbound chemicals can be illustrated by a simple analogy. Elemental hydrogen is an explosive gas. Elemental oxygen is a gas that supports combustion. When combined, however, they form water, which has neither of these effects. Amalgam's ingredients are tightly bonded to each other. Although the types of chemical bonds in water and amalgam differ, saying that amalgam will poison you is just as wrong as saying that drinking water will make you explode and burst into flames."[1]

The writer at is betting his audience does not know or remember that water, like every "potentially explosive" organic molecule, is highly chemically active in the body, and hopes instead to invoke the image of a harmless glass of water.

First, it is false that 1) a bonded element is no longer reactive and 2) bonded elements will never spontaneously or reactively break apart and re-bind. Mercury bonded in an alloy always has the capacity to return to elemental mercury, be converted to its ionic form, and even to be methylated by bacteria in the mouth (see "Methylmercury" below). The science of biological chemistry is based on the reactions of molecules just like H2O within the environment of the body.

It is incorrect to assume that because the oxygen and hydrogen are covalently bonded to each other, they form an inert chemical species. On the contrary, H2O plays a fundamental role in many types of chemical reactions, in which 1) the covalent bond is broken and in 2) which hydrogen bonds are formed between intact water molecules and a multitude of species. Oxygen bound in water frequently returns to its elemental state as O2, while hydrogen is protonated to H+. The supposedly inert water molecule plays regulatory roles in respiration, photosynthesis and countless other organic chemical transformations in which the covalent bond is split.

Mercury is no exception. The alloy it forms with silver, tin, copper, and zinc, is by no means permanent and inert (after all, the degree of homogenization within the alloy is subject to how well the dentist mixed the ingredients, by hand!). Like all chemical bonds, they are breakable and subject to the reactivity of their environment.

This Canadian study summarized the path of mercury vapor:

"During the past decade medical research has demonstrated that this Hg is continuously released as vapor into mouth air; then it is inhaled, absorbed into body tissues, oxidized to ionic Hg, and finally covalently bound to cell proteins".[2]

Any metal introduced to a biological system has the capacity to interact with that system, because many metals play critical roles in a variety of cellular processes. Metals of the same outer valence but with higher affinity for a particular binding site will intercede and replace the metals normally present within the biological system. This is how heavy metals toxify and accumulate in the body.

Remember, mercury was not chosen as the base of the dental amalgam alloy because it provides maximum stability (a stainless steel dental filling would be ideal). Mercury was chosen because it allows the creation of a filling at a relatively low temperature (due to the unique property of mercury to remain in a liquid state at room temperature).


It is well known (and uncontested) that the mercury in dental amalgams escapes and vaporizes all the time, every day. These researchers state it plainly:

"elemental mercury evaporates from liquid metallic mercury continuously from [the] dental amalgam. Thus, biodegradation of mercury amalgam, as the authors state, is an unnecessary condition because amalgam is intrinsically instable. In unstimulated condition, a single dental amalgam in a tooth is able to generate a level of mercury vapor measurable by atomic absorption spectroscopy."[3]

When fillings are agitated even by simple chewing, the rate of vaporization soars.[3,4]

In fact, people who chew gum (especially nicotine gum) are at much greater risk of mercury poisoning if they have dental amalgams. One study declared that within the group of regular chewers, "significant correlations were found between P-Hg or U-Hg [mercury levels in blood and urine] on the one hand and the number of amalgam surfaces on the other"[4]

Even admits that chewing vigorously for ten minutes: "may generate tiny amounts of mercury from the fillings." They go on, however, to assure us that: "Although this exposure lasts for just a few seconds and most of the mercury will be exhaled rather than absorbed by the body..."[1]

This is not true, and another example of how poorly informed the most avid supporters can be, despite their pompously indignant and condescending attitude. It is in fact well-known among researchers that due to the low vapor pressure and lipophilic property of elemental mercury, "some 80% of inhaled mercury vapour is retained."[5] And while some will claim that the vapor is less dangerous than methylmercury, this group (scientists currently involved in creating the German policy regarding amalgams) go so far as to say: "mercury, in particular mercury vapor, is known to be the most toxic nonradioactive element, and is toxic even in very low doses."[6]

This video demonstrates the vaporization of mercury:


The owner of an amalgam is exposed to three different forms of mercury:[7]

  • Elemental mercury: Hg0. This is the form in which mercury escapes the amalgam as vapor.
  • Ionic mercury (otherwise called mercuric mercury): Hg2+, derived from oxidation of mercury vapor.
  • Methylmercury: CH3Hg+. Also known as organic mercury, this is the most dangerous and poisonous form. Commonly found in fish. Methylated mercury has a high affinity for the thiol (SH) groups within the amino acid called cysteine, which normally participates in enzymatic reactions. Because of this disguise, methylmercury is easily transported around the body, where it interferes with essential cellular activity, including immune function.[8]

The FDA is currently in denial that the elemental mercury emitted from the dental amalgam is ever methylated in the body.[9] The argument is that elemental mercury has very little known binding sites or strong affinity in organic systems, and that it therefore passes mostly unabsorbed through the body. However, this is false.

The EPA recognizes that waste mercury from dental offices is methylated by bacteria in waste processing, and that this is furthermore a grave environmental threat.[10] This same bacterial process occurs in the mouth: "monomethylmercury [...] occurs in saliva in subjects with amalgams owing to biotransformation of inorganic mercury by oral bacteria."[3]

It has already been shown by multiple independent researchers that elemental mercury in the mouth is reduced to mercuric mercury (Hg2+), and then transformed into mono-methylmercury (CH3Hg+) and ethylmercury (CH3CH2Hg+) by oral bacteria,[11] such as Streptococcus mitior, S. mutans and S. sanguis.[3,12,13,14,15] This makes the dental amalgam a "continuous source of organic mercury, which is more toxic than inorganic mercury, and almost completely absorbed by the human intestine."[13]


The amalgam is not at all inert, and cannot even be said to be stable. It continually leaches mercury vapor into the mouth, which has been shown to not only have a direct effect on the health of the body, but also be converted into methylmercury, one of the most dangerous poisons on the planet.

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2. Lorscheider FL, Vimy MJ, Summers AO. Mercury exposure from "silver" tooth fillings: emerging evidence questions a traditional dental paradigm. FASEB J. 1995 Nov;9(14):1499-500.

3. Pigatto PD, Guzzi G. Oral lichenoid lesions: more than mercury. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005 Oct;100(4):398-400.

4. Sällsten G, Thorén J, Barregård L, Schütz A, Skarping G. Long-term use of nicotine chewing gum and mercury exposure from dental amalgam fillings. J Dent Res. 1996 Jan;75(1):594-8.

5. Gelbier S, Ingram J. Public Health. Possible foetotoxic effects of mercury vapour: a case report. 1989 Jan;103(1):35-40.

6. Mutter J, Naumann J, Guethlin C. Comments on the article "the toxicology of mercury and its chemical compounds" by Clarkson and Magos (2006). Crit Rev Toxicol. 2007;37(6):537-49; discussion 551-2.

7. Clarkson TW. The three modern faces of mercury Environ Health Perspect. 2002 Feb;110 Suppl 1:11-23.

8. Shenker BJ, Guo TL, Shapiro IM. Low-level methylmercury exposure causes human T-cells to undergo apoptosis: evidence of mitochondrial dysfunction. Environ Res. 1998 May;77(2):149-59.

9. FDA website on the dental amalgam

10. EPA whitepaper on the environmental threat of the dental amalgam

11. Pigatto PD, Minoia C, Ronchi A, Guzzi G. Mercury in saliva and scalp hair from dental amalgam. J Hazard Mater. 2010 Jul 15;179(1-3):1166-7. Epub 2010 Mar 31.

12. Heintze U, Edwardsson S, Dérand T, Birkhed D. Methylation of mercury from dental amalgam and mercuric chloride by oral streptococci in vitro. Scand J Dent Res. 1983 Apr;91(2):150-2.

13. Leistevuo J, Leistevuo T, Helenius H, Pyy L, Osterblad M, Huovinen P, Tenovuo J. Dental amalgam fillings and the amount of organic mercury in human saliva. Caries Res. 2001 May-Jun;35(3):163-6.

14. Moszczynski P Jr, Moszczynski P. Czas Stomatol. Health damage due to exposure to mercury vapour (Hg). 1989 Apr;42(4):233-8.

15. Pigatto PD, Guzzi G. Linking mercury amalgam to autoimmunity. Trends Immunol. 2010 Feb;31(2):48-9. Epub 2010 Jan 18.