Touching a doorknob after walking on shag carpet will
cause far higher discharges, and this has no harmful
effect on humans or nerve endings. And who is to say
that the bound charge in an amalgam will even discharge
at all? No mechanism for charge accumulation or
discharge has been demonstrated, so claiming any health
effects related to this requires a leap of faith.
You're not comparing like with like here.
Static discharges of the type experienced after walking across a
carpet occur at potentials of up to thousands of volts.
But the amount of energy dissipated by the discharge wouldn't light a
flashlight bulb for any appreciable amount of time at all.
Everyday batteries which are able to drive a sustained current through
a flashlight bulb filament and keep it lit for many hours do so with
an operating potential of just a few volts.
The nature of the dissipation of the energies involved in these two
situations is dependent on a combination of variables and is very
different for each case.
That's why I keep making the point that in order to understand the
nature of any dissipation of electrical energy due to the generation
of electrical potentials by amalgam dental fillings it should be
necessary to carry out experimental investigations to measure it.
And this would include establishing by physical measurement that there
is no dissipation of energy at all.
It isn't enough to just rely on guesswork for answering these
Shall I tell you why?
It's because your guesswork might be wrong, that's why.
And amalgam dental fillings are placed in children's teeth.
As far as anybody can tell this statement might be true simply because
the experimental procedures which would be necessary in order to
demonstrate such effects have never been carried out.
And in the absence of any scientific evidence of any kind regarding
the matter then the only other logical possibility is that such
investigations have been carried out but the results are not
Keith P Walsh
PS, enquiries concerning the electrical behavior of metal amalgam
dental fillings can be found at:
Amalgam is not a capacitor it can not hold charge.
If it could we would use it instead of batteries.
the 350mV if that number is accurate I do not know, represents
a galvanic reaction between two or more metals. Depending on what the
metals are a different "eddie type current" is generated. The problem
is that in the human body everything generates a small potential
difference which averages to zero Volts.
Blood carrying iron moving through vessels passing through magnetic
field of the earth will generate some type of current much higher than
350mV I would imagine.
If you want to see this get a digital voltmeter hold one wire in one
hand and the second wire in the other hand. You will see a potential
difference that fluctuates that is all. even if you took amalgam scrap
you can not attach one electrode to silver and the other to murcury in
amalgam to measure this voltage the reading will be zero volts.
There is no way of measuring the current in Amalgam in someone's mouth
and attributing it to causing events in the brain. This whole topic is
pointless at this stage on the game.
It has been known for more than 160 years that metals, mixtures of
metals, and dissimilar metals in contact with each other are able to
dissipate electrical energy to their surroundings as a result of their
thermoelectric properties, and that it is not necessary for there to
be any electrolysis taking place in order for this to happen.
For an elementary description of the thermoelectric effect go to:
Keith P Walsh
Ummm, the thermoelectric effect requires two different metals in contact.
The net thermoelectric effect voltage of a discrete lump of any homogenous
metalic substance is zero.
If the only metal is amalgam, how could you have a thermoelectric effect?
Amalgam filling touching a gold or silver filling?
On Sun, 25 Jan 2004 23:48:57 +0000 (UTC), firstname.lastname@example.org
Well for a start this statement is factually incorrect.
The Penguin Dictionary of Physics gives the following description of
the "Kelvin (or Thomson effects)" under the general heading
""A potential difference is developed between different parts of a
single conductor if there is a temperature difference between them;
for a temperature difference dT between two points, the e.m.f. in this
element is udT (u = greek letter mu) where u is the Thomson
So you were wrong about that.
What complicates matters further in the case of dental amalgam is that
dental amalgam is not in fact a "homogeneous metallic substance".
Dental amalgam is an inhomogeneous mixture of dissimilar metals. See:
So you were wrong about that too.
And one might expect the thermoelectric behavior of this material to
differ from that of a homogeneous metallic substance accordingly.
You can get an idea of the kind of thermoelectric processes occuring
when an inhomogeneous material is subjected to a temperature gradient
(Fig. d is particularly instructive.)
Apparently, not only does the temperature gradient induce
thermoelectric eddy currents in the material giving rise to the
localised electromagnetic effects shown, but the reverse effect
whereby an applied electromagnetic field gives rise to induced eddy
currents and associated temperature gradients is also possible.
Dental amalgams are subjected to thermal gradients all the time.
And amalgam fillings are placed in children's teeth.
I believe that the thermoelectroic properties of dental amalgams
should therefore have been measured.
And I am confident that I am right.
Amalgam is an inhomogeneous mixture of dissimilar metals.
It has been common practice for dentists to screw metal alloy
retaining pins into the root sockets of patients' teeth and encase the
heads of the pins in amalgam, thereby providing further opportunity
for thermoelectric effects to occur at the interface between the
amalgam and the alloy.
I believe that the only scientific way to determine whether or not
these effects are significant is to measure them.
And again I am confident that I am right.
Keith P Walsh
PS, enquiries concerning the electrical properties of dental amalgams
can be found at:
Keith P Walsh
First of all the letters are talking about deal with a galvanic
reaction not a thermoelectric effect which you are describing. These
are 2 different things.
I gave you my comment of the Galvanic reaction earlier.
As far as your thermoelectric effect, that requires a thermal gradient
meaning one end of the amalgam filling must be heated and the other
end cooled at the same time. In the mouth that can never happen even
if the patient eats ice cream after drinking hot coffee. The gradient
needs to be applied at the same time. You are just trying to confuse
the issue by bringing in different effects of electromagnetics.
Amalgam is a homogenous mixture of several metals.
On 30 Jan 2004 20:28:15 -0800, email@example.com (Alexander
Vasserman DDS., BS.) wrote:
When Bates, Baker and Meakin of the University of Nottingham in the UK
wished to investigate the magnetic susceptibility of a NON-homogeneous
material they chose to use "amalgams of metals in dilute solution in
Are you saying that they made the wrong choice?
Keith P Walsh
PS, the abstract from the resulting paper reads:
"A description is given of a new apparatus and technique for
the examination of the magnetic susceptibility of a non-homogeneous
material, with particular reference to the investigation of amalgams
of metals in dilute solution in mercury. An important feature of the
apparatus is that the electromagnet has one pole tip with a
cylindrical surface and one pole tip with a plane face, so that when
an amalgam is placed in a vertical tube suspended from a torsion
balance, each portion of the amalgam is exposed to the same value of
the gradient of H2 in the direction along which motion of the tube is
possible; consequently, measurements can be made with amalgams which
separate on standing."
- and the whole thing can be purchased via;
Where's the temperature difference in the amalgam? None? Oh well,
you're wrong again. Why don't you figure out mu for an amalgam
and then see what kind of dT you would need for it to fry
a person's neurons. This is electromagnetics, and we need to
see equations and hard numbers, not haphazardly used definitions
which have no applicability.
Temperature gradient is ubiquitous in Nature.
Dental amalgams are subjected to temperature gradients all the time.
The latest thermoelectric wristwatch batteries are able to generate
voltages of up to 1.5 volts from a temperature gradient of only 1K.
Of course, one might not necessarily expect an accidentally
constructed thermoelectric battery to operate with the same efficiency
as a purpose-built one.
Nevertheless, levels of temperature gradient much greater than 1K are
commonplace in the human mouth.
Material properties are not "figured out".
They are measured.
I would expect any electrical potential arisng in a single homogeneous
metallic material due to its Thomson coefficient to be "small".
What makes the situation more complicated in the case of dental
amalgam is that dental amalgam is not a single homogeneous material,
it is an inhomogeneous mixture of dissimilar metals. See:
And it is generally the case that thermoelectric effects are much
larger where there are two or more dissimilar metals in contact with
The electrical potentials, currents and energy dissipations involved
in human neurological processes are also "small". (But not too small
to be measured.)
What is not in doubt here is that it has been demonstrated
experimentally that amalgam dental fillings generate electrical
potentials with magnitudes of up to 350 millivolts. See:
However, it appears that two questions which still remain unanswered
are, firstly, exactly how do these potentials arise, and secondly are
they able to dissipate electrical energy through the nerves in
With regard to the first question, dentists confidently tell us that
newly placed amalgam fillings quickly acquire a layer of metal oxide
on their exposed surfaces as the result of a small degree of
electrolytic corrosion, and that this layer adheres permanently to the
surface thereby preventing further electrolysis from taking place.
(I have no reason to doubt that this is the case.)
So for an answer it might be necessary to consider other phenomena by
which electrical potentials are induced in metallic materials. And two
which come to mind are thermoelectric phenomena and electromagnetic
phenomena (which we know are linked with each other).
Unfortunately (and some might suggest inexplicably) it appears that
neither the dental profession nor any other organisation in the world
knows anything at all about the thermoelectric or electromagnetic
properties of dental amalgams.
I wonder if this might be due in some part to the answer to the second
(Remember, if it can be shown that thermoelectric and electromagnetic
phenomena are between them not able to generate electrical potentials
as large as 350 millivolts in dental amalgams, then this does not
necessarily mean that this figure is false. It would simply make it
necessary for us to conclude that we still DO NOT understand where it
Keith P Walsh
PS, This thread started with an enquiry about the magnetic
susceptibility of dental amalgams.
In view of the fact that dental amalgam is an inhomogeneous mixture of
dissimilar metals, would you expect the magnetic susceptibility of the
material to vary from point to point within the material?
And, if so, would you expect to be able to establish scientifically
that it is not possible to measure this variation without ever having
bothered to try?
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