Facts about mercury, dental amalgams and health effects

Submitted by ASOMAT (Australasian Society of Oral Medicine and Toxicology)

For consideration by NRAC September 15th and September 16th, 1997

1. Dental amalgams are not a true alloy. They are made up of 50% mercury which is not locked into a set filling, but escapes continuously during the entire life of the filling in the forms of vapor, ions and abraded particles. This release is stimulated by chewing, brushing and hot fluids One study reported levels, of mercury vapor in the mouth, 54 times higher in the mouth of a patient with amalgams, after chewing, than the levels in the mouth of a patient without amalgams after chewing.
2. The absorption rate of inhaled mercury vapor is extremely high, approximately 80% of the inhaled dose, reaching the brain tissue within one blood circulation cycle.
3. The extreme toxicity of mercury is well documented. Current research is clearly demonstrating that inorganic mercury is just as toxic as organic mercury under various physiologic conditions.
4. The toxic threshold for mercury vapor has never been found. Even the US Environmental Protection Agency has so stated. The existing occupational standards are all specifically declared to be estimates only on the appearance of "clinically observable signs and symptoms." Statements by the dental profession that the amount of mercury exposure encountered by patients from dental amalgams is too small to be harmful are contradicted by the scientific literature and are totally indefensible. Dentists receive no training at all which would enable them to even look for symptoms relating to mercury toxicity.
5. Controlled, broad-scale scientific studies investigating the effects on the health of patients of mercury released from dental amalgam fillings have never been conducted. The true nature and full extent of effects are therefore unknown.
6. Mercury from amalgam fillings is stored principally in the kidneys, liver and central nervous system. This mercury has also been shown to cross the placenta and collect in fetal tissue. Studies show the level of mercury in liver, kidney and brain tissue of deceased Fetus, new-born and young children is proportional to the number of amalgam fillings in the mother's mouth. One such study concludes that "the elevated concentrations of inorganic mercury found in tissues of people with amalgam filings, derive mainly from these fillings and not from other theoretically possible sources."
7. Mercury from dental amalgam will also be transported across the breast milk of lactating women. in fact it has been demonstrated that breast milk increases the bio-availability of mercury to the newborn. Negative developmental effects have been shown (in animal models) in relation to these sources and concentrations of mercury.
8. The halftime for the elimination of a single dose of mercury is extremely long, certainly at least 30 days for the whole body - and perhaps as long as 10,000 days for the brain. Multiple small doses will therefore result in body accumulation.
9. Sheep and monkey studies have confirmed that the mercury from dental amalgams enters and accumulates in the patient throughout the body, including the brain.
10. Human autopsy studies have shown that the concentration of mercury in the brain is directly related to the number, size and age of amalgam fillings in the mouth
11. Mercury has been shown to interfere with Tubulin synthesis resulting in "neurofibril tangles" in the brain. Mercury specifically from dental amalgam, placed in rats' teeth, has been shown to affect tubulin synthesis
12. Mercury from dental amalgams has been shown to be related to antibiotic resistance in the gut and oral cavity.
13. Both Health Canada (1996) and the World Health Organization (1991) consider dental amalgam to be the single largest source of mercury exposure for the general public, with amalgam potentially contributing up to 84% (WHO, 1991) of total daily intake of all forms of mercury from all sources. Therefore, the level of exposure resulting from amalgam is not an issue of contention. The WHO also noted that for mercury vapor, a specific no-observed-effects level (NOEL) cannot be established i.e. no level of mercury vapor has been found that can be considered harmless.
14. Amalgam fillings have been associated in the scientific literature with a variety of problems such as periodontal problems (pyorrhea), allergic reactions, oral lichen planus, interference with the immune system as measured by the T-lymphocyte count, multiple sclerosis, fatigue, cardiovascular problems, skin rashes, endocrine disorders, eye problems. Blood mercury levels, significantly higher in amalgam patients than in non-amalgam patients, correlate with number and size of the fillings but return to normal when the fillings are replaced.
15. Claims by the Australian and American Dental Associations that the incidence of mercury allergy is less than 1% have never cited any references. Such claims are totally refuted by the scientific literature. Published peer reviewed studies show allergic reactions range from 5%-8% (Nth Am Derm Gp) up to 39% (Miller et al)
16. The earliest symptoms of long term, low level mercury poisoning are sub clinical and neurological. Consequently due to their subtlety, these symptoms are easily misdiagnosed.
17. Some recent studies show that at least 50% of dentists with elevated mercury levels had peripheral nervous disorders and that dentists have twice the rate of Glioblastoma than non-dentists.
18. Research shows female dental personnel have twice the rate of infertility, miscarriage and spontaneous abortion than the rest of the population
19. Mercury from dental amalgams crosses the placenta, accumulating in the fetus, and is also transferred through the breast milk to neonates.
20. Wolf et al in 1983 in the journal 'Neurotoxicology' stated.." It is generally agreed that if amalgam was introduced today as a restorative material, it would never pass FDA approval"
21. The German and Norwegian Health Departments have directed their dental professions to NOT use amalgams in pregnant women and the German Health Department has also directed that children not receive dental amalgams.
22. Canada Health, in the wake of the Richardson report, has stated similar views and has also added that people with kidney or neurological problems might consider alternative fillings as mercury is of particular concern in their cases.
23. A report, "Dental Amalgams and Human Health, current position" commissioned by the New Zealand Health Department has just been submitted to the NZ Government. It concluded that in some circumstances some people could be adversely affected by dental amalgam fillings.

Based on the peer-reviewed scientific literature we are currently able to state the following.

1. Mercury from dental amalgams is released from the fillings continuously and almost totally absorbed
2. Mercury from dental amalgams accumulates in the tissues throughout the body
3. Mercury from dental amalgams is very toxic and interferes with a variety of physiologic systems
4. Physiological effects and health changes can be demonstrated by the placement and removal of dental amalgams
5. There is evidence of health problems, related to mercury exposure, in the dental profession

Log in to read the rest of this article addressing the related topics below:

1. ASOMAT's POSITION and CONCLUSION
2. ASOMAT Contacts
3. EXECUTIVE SUMMARY OF RICHARDSON REPORT
4. Health Canada's Recommendations Concerning the Use of Dental Amalgam