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
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
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
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
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
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.
from dental amalgams is released from the fillings continuously and almost
from dental amalgams accumulates in the tissues throughout the body
from dental amalgams is very toxic and interferes with a variety of physiologic
effects and health changes can be demonstrated by the placement and removal of
evidence of health problems, related to mercury exposure, in the dental
ASOMAT's POSITION and CONCLUSION
It is ASOMAT's position that dental amalgams do not cause any particular
disease or illness. Rather it is our view that dental amalgams promote heavy
metal toxicity through a chronic and unrecognized accumulation of mercury in the
body. ASOMAT believes that this is a medical problem with a dental cause and
that this needs to be managed by the medical community. ASOMAT believes that
recommendations which would stop or severely limit the use of dental amalgams in
pregnant and fertile women, children, and those patients with kidney or
neurological problems would be an appropriate and prudent preventive response
based on the scientific literature of the moment. ASOMAT also believes that
current alliterative materials negate the previous need for amalgams, allowing
an immediate phase out of amalgams over a 2-3 year period which would allow time
for retraining of the dental profession and the teaching institutions. Training
in the recognition of mercury toxicity is also necessary.
It is appropriate to end this summary with a statement from the National
Research Council of the United States of America, which issued a report in 1978
entitled "An assessment of mercury in the Environment".
"Mercury compounds have no known normal
metabolic function and their presence in the cells of living organisms,
including human beings, represents contamination from natural and anthropogenic
sources. In view of the toxicity of mercury and the inability of researchers to
specify the threshold levels of toxic effects on the basis of present knowledge,
all such contamination must be regarded as undesirable and potentially
No information has come to light since the publication of this
statement in 1978 which alters this view.
President Dr. Roman Lohyn B.D.S.
81175 Collins Street, Melbourne ph: (03) 965~1660 Fax: (03) 96508161
Secretary Dr. Robert Gammal B.D.Sc
102/222 Pitt Street, Sydney ph: (02) 9264-5195 Fax: (02) 9283-2230
EXECUTIVE SUMMARY OF RICHARDSON REPORT
ASSESSMENT OF MERCURY EXPOSURE AND RISKS FROM DENTAL AMALGAM by G. Mark
Richardson. Ph.D., Medical Devices Bureau, Environmental Health Directorate,
Health Canada, August 18, 1995, Final Report (released November 27, 1995, in
Toronto, at the stakeholders' meeting)
Executive Summary: For Canadians with amalgam-filled teeth, it was
estimated that total mercury (Hg) exposure averages: 3.3 ug Hg/day in toddlers
(aged 3 to 4 years); 5.6 ug Hg/day in children (aged 5 to 11 years); 6.7 ug
Hg/day in teens (aged 12 to 19 years); 9.4 ug Hg/day adults (aged 20 to 59
years; and 6.8 ug Hg/day in seniors (aged 60+ years). Of this exposure, amalgam
was estimated to contribute 50% to total Hg exposure in adults, and 32 to 42%
for other age groups. Estimates, based on two independent models, of exposure
from amalgam alone were: 0.8 -1.4 ug Hg/day in toddlers; 1.1 - 1.7 ug Hg/day in
children; 1.9-2.5 ug Hg/day in teens; 3.4-3.7 ug Hg/day in adults and 2.1 - 2.8
ug Hg/day in seniors.
There are insufficient published data on the potential health effects of
dental amalgam specifically to support or refute the diverse variety of health
effects attributed to it. Numerous studies constantly report effects on the
central nervous system (CNS) in persons occupationally exposed to Hg. Virtually
all studies failed to detect a threshold for the effects CNS measured. A
tolerable daily intake (TDI) of 0.014 ug Hg/kg body weight day was proposed for
mercury vapor, the principal form of mercury to which bearers of amalgam
fillings are exposed. This TDI was based on a published account of sub-clinical
(i.e. not resulting in overt symptoms or medical care) CNS effects in
occupationally exposed men, expressed as a slight tremor of the forearm. An
uncertainty factor of 100 was applied to these data, to derive a reference dose
(TDl) which should, in all probability, prevent the occurrence of CNS effects in
non-occupationally-exposed individuals bearing amalgam fillings.
The number of amalgam-filled teeth, for each age group, estimated to cause
exposure equivalent to the TDI were: 1 filling in toddlers; 2 filling in
children; 3 fillings in teens; and 4 fillings in adults and seniors. It was
recognized that filling size and location (Occlusal versus lingual or buccal)
may also contribute to exposure. However, data suggest that no improvement in
prediction of exposure is offered by any particular measure of amalgam load.
Therefore, the estimates of exposure derived from the number of filled teeth
were considered as reliable as those that might be based on size and position of
amalgam fillings, were such data available for the Canadian population.
Effects caused by allergic hypersensitivity to amalgam or mercury, including
possible auto- immune reactions, can not be adequately addressed by any proposed
tolerable daily intake. Individuals suspecting possible allergic or auto-immune
reactions should avoid the use of amalgam selecting suitable alternate materials
in consultation with dental care (and possibly health care) professionals.
Preface: This report has been prepared in response to concerns that exposure
to mercury from dental amalgam may adversely impact on health. Recent reviews
(USDHHS 1993, Swedish National Board of Health, 1994) have concluded that there
is no evidence to suggest that dental amalgam, specifically, is injurious to
health. However, the data base relating health impacts in humans or animals to
amalgam specifically is small and weak. This suggests that indirect evidence
relating mercury vapor exposure (the predominant form of mercury released by
dental amalgam) to human health effects (for which a large data base exists) is
a necessary basis for an evaluation of the possible health risks of dental
amalgam. In the reports previously mentioned, exposure to mercury arising from
amalgam was not adequately quantified, and a level of mercury vapor exposure
which is, in all probability, tolerable to the vast majority of persons bearing
amalgam fillings, was not defined. This report attempts to address these
This report is not exhaustive. Recent reviews on mercury (WHO 1990, 1991;
IARC 1993; ATSDR 1994) adequately review many aspects of mercury toxicity and
exposure. Instead, this report focuses on studies which report on health effects
in dental care practitioners and other occupational groups exposed to relatively
low levels of mercury. This report also examines recent research which
hypothesizes a link between mercury exposure, and thereby dental amalgam, and
Alzheimer's' Disease. This report concentrates on effects associated with long
term mercury vapor exposure (via inhalation) in humans. Other reviews (WHO 1990,
1991; IARC 1993; ATSDR 1994) examined acute and subchronic exposure in animals,
and all aspects of the toxicology of exposure to other forms of mercury via
other routes of exposure (ingestion, dermal absorption), in extensive and
adequate detail such that this is not repeated here.
Any medical or dental material, such as amalgam, will have associated with it
some degree of health risk. The purpose of this report is to attempt some
determination of what that risk is (i.e. what effect(s) it may cause), how
significant it is (i.e. what level of exposure should be free from effect), and
what proportion of the population might be at some degree of risk (i.e. how many
exceed the level considered to be free from effect).
Recommendations Concerning the Use of Dental Amalgam
( Health Canada, 1996a
1. Non-mercury filling material should be considered for restoring the
primary teeth of children where the mechanical properties of the material are
2. Whenever possible, amalgam fillings should not be placed in or removed
from the teeth of pregnant women.
3. Amalgam should not be placed in patients with impaired kidney function.
4. In placing and removing amalgam fillings, dentists should use techniques
and equipment to minimize the exposure of the patient and the dentist to mercury
vapor, and to prevent amalgam waste from being flushed into municipal sewage
5. Dentists should advise individuals who may have allergic hypersensitivity
to mercury to avoid the use of amalgam. In patients who have developed
hypersensitivity to amalgam, existing amalgam restorations should be replaced
with another material where this is recommended by a physician.
6. New amalgam fillings should not be placed in contact with existing metal
devices in the mouth, such as braces.
7. Dentists should provide their patients with sufficient information to make
an informed choice regarding the material used to fill their teeth, including information on the
risks and benefits of the material and suitable alternatives.
8. Dentists should acknowledge the patient's right to decline treatment with
any dental material.
piece was provided by Dr. Michael A. Baylin & Associates, Physiologic
3655A Old Court Road, Suite 8,
Baltimore, MD 21208 (410) 484-5266