This article was published almost 2 decades ago in Exp Mol Pathol.
1990 Jun;52(3):291-9.  Why are Dentists still using mercury based
amalgams?

Traces of Mercury in Organs from Primates with Amalgam Fillings.
Danscher G, Hørsted-Bindslev P, Rungby J.
Department of Neurobiology, University of Aarhus, Denmark.

In order to trace possible accumulations of mercury, three vervet
monkeys received occlusal amalgam fillings, three others maxillary
bone implants of amalgam, and three untreated monkeys served as
controls. One year later all animals were sacrificed by transcardial
perfusion with glutaraldehyde. Tissue sections from different organs
were subjected to silver amplification by autometallography and
analyzed at light and electron microscopical levels. It was found that
amalgam fillings (total, 0.7-1.2 g) caused deposition of mercury in
the following tissues: spinal ganglia, anterior pituitary, adrenal,
medulla, liver, kidneys, lungs, and intestinal lymph glands. In
monkeys with maxillary silver amalgam implants (total, 0.1-0.3 g),
mercury was found in the same organs except for liver, lungs, and
intestinal lymph glands. Organs from the three control animals were
devoid of precipitate. To evaluate whether silver released from the
corroding amalgam fillings added to the staining pattern, tissue
sections were exposed to potassium cyanide prior to being
autometallographically developed. This treatment removes all traces of
silver, leaving mercury sulfide accumulation untouched. By comparing
sections that had been exposed to cyanide with untreated parallels no
difference was seen in the pattern confirming that mercury was the
only catalyst present in the tissue. These results strongly support
what has been suggested previously that dental fillings in primates
cause absorption of mercury released from amalgam fillings through
lungs and intestinal tract, and that depending on exposure mercury is
distributed to most organs and will eventually be found in the central
nervous system. The present data also show that silver released from
the corroding filling is not absorbed.

PMID: 2115006 [PubMed - indexed for MEDLINE]

http://groups.google.com/group/sci.med.dentistry/msg/f560aa96975cb8a5?hl=en&

Recently, Caulk Company, manufacturers of Dispersalloy, published the latest
Materials Safety Data Sheet (MSDS) and their Direction For Use (DFU) which
includes contraindications to the use of dental amalgam.
(.http://www.caulk.com/MSDSDFU/DispersDFU.html February 1998)

[no longer available]

I just happen to still have it.

**** the manufacturers are now acknowledging the intrinsic dangers of this
material.***** The legal implications of this latest development are far
reaching. If you continue to use dental amalgam you may be playing legal
roulette with your assets.

Caulk state that dental amalgam should not be used:
1. In proximal or occlusal contact to dissimilar metal restorations.
2. In patients with severe renal deficiency.

3. In patients with known allergies to amalgam.

4. For retrograde or endodontic filling.

5. As a filling material for cast crown.

6. In children 6 and under.

7. In expectant mothers.

The Caulk Co. home page also warns that mercury may be a skin sensitizer,
pulmonary sensitizer, nephrotoxin and neurotoxin and, further, cautions that
the number of amalgam restorations for one patient should be kept to a
minimum.

Caulk has also published the Material Safety Data Sheet (MSDS) for mercury.
Of
particular importance, are some statements made in "Section VIII - Control
Measures, Inhalation, Chronic: Inhalation of mercury vapour over a long
period
may cause mercurialism, which is characterized by fine tremors and erethism.
Tremors may affect the hands first, but may also become evident in the face,
arms, and legs. Erethism may be manifested by abnormal shyness, blushing,
self
consciousness, depression or despondency, resentment of criticism,
irritability
or excitability, headache, fatigue, and insomnia. In severe cases,
hallucinations, loss of memory, and mental deterioration may occur.
Concentrations as low as 0.03 mg/m3 have induced psychiatric symptoms in
humans. Renal involvement may be indicated by proteinuria, albuminuria,
enzymuria, and anuria. Other effects may include salivation, gingivitis,
stomatitis, loosening of the teeth, blue lines on the gums, diarrhea,
chronic
pneumonitis and mild anemia. Repeated exposure to mercury and its compounds
may
result in sensitisation. Intrauterine exposure may result in tremors and
involuntary movements in the infants. Mercury is excreted in breast milk.
Paternal reproductive effects and effects on fertility have been reported in
male rats following repeated inhalation exposures."

Ivoclar/Vivadent go further in their contraindications. They state that
their
amalgam is:

1. Not only contraindicated for expectant mothers but also for nursing
mothers.

2. Not only contraindicated for patients with severe renal deficiency but
for
all

patients suffering from any reduced kidney function.

The Australian Dental Association is now in a difficult, if not untenable,
position. The prevailing ADA position is that patient exposure to mercury
from
amalgam dental fillings is medically insignificant. At the same time major
amalgam manufacturers are exhibiting public warnings.

All dentists must now acknowledge the contradictions between ADA policy and
amalgam manufacturers' public warnings.

Medico-legally, the dentist who ignores manufacturer's public warnings
places
himself/herself in a precarious position. Dentists are obliged to be
familiar
with the information provided in MSDS's for the products they use and if
patients suffer ill effects from the product being used in a way which is
contrary to the manufacturer's directions, then the dentist may be liable
for
the consequences. In this situation it does not matter what the Australian
Dental Association says, as it is the dentist who will be held responsible.
You
may be interested to know that the American Dental Association has
recognised
such a possibility and in a recent case petitioned the court to release it
from
a suit filed jointly against a dentist and the AmDA,. The AmDA claimed that
it
owed no responsibility for the advice being given. The court granted the
petition, which left the dentist, who had relied on AmDA advice, as the sole
defendant. It is little comfort that you may be insured.

All dentists must be aware of the potential adverse effects of mercury
exposure
and must also be attentive to the potential effects in pregnant females and
nursing mothers. Before placing another amalgam filling, a dentist might be
well advised to establish that the patient has normal kidney function. It is
not clear whether taking a medical history will suffice or whether a kidney
function test might need to be requested. The galvanic effect created by
placing different metals in a mouth with amalgam fillings has the potential
to
increase mercury release from all amalgam fillings. This also has
implications
not generally considered when placing stainless steel orthodontic appliances
in
a patient with amalgam fillings. The use of metal pins with amalgam may need
to
be reconsidered. If amalgam is contraindicated in a six year old, the next
question must surely be - at what age is amalgam safe? The scientific
research
shows clearly that mercury is toxic to all people, at all levels. The Agency
for Toxic Substances and Disease Registry in the USA lists mercury as one of
the twenty most hazardous substances to human beings. The ATSDR's current
allowable Minimal Risk Levels (MRL) for acute exposure are 0.02 mcgm/m3 and
for
chronic exposure 0.014 mcgm/m3. Compare this with published research,
indicating amalgam mercury vapour concentrations in the mouth, as high as
87.5
mcgm/m3. The absorption rate of inhaled mercury vapour is extremely high,
approximately 80% of the inhaled dose, reaching the brain tissue within one
blood circulation cycle. The toxic threshold for mercury vapour 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. The World Health
Organisation, in 1991, made it clear that there is NO safe level of mercury
vapour and that amalgam represents the greatest source of mercury to the
general population.

The spectre of potential liability for adverse effects from dental amalgam
is
now a reality.

ASOMAT recently made a 4 page submission to the Federal Executive of the
Australian Dental Association offering confidential background briefings
about
the latest research to all Executive members and any other officers or
committees. ASOMAT's submission was conciliatory and asked for the lines of
communication to be opened so that the ADA could stay informed about ALL the
research. Our offer of cooperation was peremptorily rejected.

Any dentist faced with patients wanting the removal of amalgams from their
mouths should note that specific protocols exist for the safer removal of
amalgam. Unless you are familiar with these protocols, it is not recommended
to
proceed with the wholesale removal of dental amalgam. You may create more
problems than you solve.

It would be appropriate for you to contact your insurer and ask the specific
question..." If I use amalgam contrary to the specific warnings and
contraindications stated by the manufacturer and my patient suffers effects
known to be associated with mercury exposure, will you cover me fully for my
legal costs and any damages in the event that the patient sues me? "
Whatever
the answer, get it in writing!

ASOMAT's concern has always been that dentists and patients be fully
informed.
We are very worried that the profession is badly prepared to deal with these
quickly changing circumstances, especially in light of a recent press
conference in Sweden on the 19th February 1998. At that time the Swedish
Council for Planning and Coordinating Research, a body commissioned by the
Swedish Government to review the literature on amalgams, stated the
following..
"Mercury from amalgam may damage the brain, kidneys and the immune system of
a
great number of people. The effects in foetus and children are of most
concern." Those are the conclusions of a report soon to be handed to the
Government. "There is no conflict any more", says Gunnar Goude from the
board
of the Swedish Council for Planning and Coordinating Research (FRN), after
reviewing the comprehensive documentation from the four seminars. "There is
total agreement among the Board members that it is time to move forward and
leave amalgam.

Toxic effect of heavy metals on cells isolated from the rat adrenal
and testis.

Ng TB, Liu WK.
Department of Biochemistry, Faculty of Medicine, Chinese University of
Hong Kong, Shatin.

Heavy metals including mercury, cadmium, cobalt, and copper (100
microM) exerted an adverse effect on the viability of isolated rat
adrenal capsular (zona glomerulosa), adrenal decapsular (fasciculata
and reticularis), and Leydig cells of the testis, with mercury being
the most potent. Due to the decreased cell viability there was a
parallel reduction in corticotropin-stimulated corticosterone
production by adrenal decapsular cells and luteinizing hormone-
stimulated testosterone production by Leydig cells. The results
indicated a direct toxic action of these heavy metals on steroid-
producing cells in the adrenal gland and the testis. Other metals
tested, including lead, zinc, aluminum, chromium, iron, nickel, and
lithium, did not exert any deleterious effect on cell viability or
hormone-induced steroidogenesis in adrenal and Leydig cells when
tested up to a concentration of 100 microM.

PMID: 2155192 [PubMed - indexed for MEDLINE]