The Latest on Amalgams and Thermoelectrics

Paul O wrote:


But that's assuming you had a serious interest in proving your crackpot theory correct. If you knew your theory was indeed crackpot, you wouldn't want to have it tested, because of the likely null result. Instead, the smart thing to do would be to use your theory as a needle to incessantly harass your critics in various newsgroups. You can keep throwing it in their faces because you know they don't have data to refute it, and you can continue to feel smug in your delusion that you have some measure of scientific respectability, despite what real scientists who've read your drivel may say.
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So if it's not thermoelectrics then how do you think that amalgam dental fillings generate electrical potentials with magnitudes of up to 350 millivolts?
See:
http://book.boot.users.btopenworld.com/dutch.htm
How about "galvanic activity"?
Well, people who've been to dental school tell us that as a result of "galvanic activity" new amalgam fillings quickly form a layer of metal oxide which adheres to the surface of the amalgam and prevents any further galvanic activity taking place. That's because dental materials scientists tell them that this is so.
I don't have any reason to believe that this is incorrect. The trouble is I think that the students in dental schools are then simply left to form the false idea that this accounts for ALL of the electrical behavior of metal amalgam fillings - and it doesn't, it can't.
For a start, metal oxides do not make particularly good electrical insulators. So although the layer of oxide on the surface may prevent the amalgam from undergoing any further "galvanic" corrosion, it does not insulate the tooth from electrical potentials generated within the filling by other means, for example by thermoelectric phenomena (I still believe Cronin B Vining of the International Thermoelectric Society when he says that "all materials generate thermoelectric emf" - and of course this effect is greatest when there are dissimilar conductors in contact with each other), or even by "faradaic activity".
Michael Faraday discovered the laws of electromagnetic induction more than 150 years ago. How come no-one has ever published the results of anyexperimental investigations to determine whether or not the electromagnetic behavior of dental amalgams is able to dissipate electrical energy through the nerves in people's heads?
If you go to:
http://book.boot.users.btopenworld.com/potentials.htm
- you will see a scan of a dental chart into which a dentist has entered the values of the electrical potentials he has measured in each individual amalgam in the teeth of a patient. The highest value entered is 260 millivolts. Thats just over a quarter of a volt. Dentists who make these measurements record values such as this in amalgams routinely. And the resting potential of the human neurological synapse is only 70 millivolts.
Here's a couple of further points to consider:
It appears that the electrical potentials in amalgam fillings quickly regenerate after being discharged, see:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids !03035&doptstractPlus
- and the potentials generated by amalgam fillings are generally much larger than those generated by gold ones, see:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids465773&dopt stractPlus
One thing that your apparent determination to remain ignorant in these matters has made me wonder is whether or not you have any amalgam fillings in your own teeth. You know, in your desperation to maintain your own self-image as an intelligent person you might be inclined to reject any amount of scientific evidence which tends to suggest theat you too are in fact just another ignorant patient (victim?) of just another ignorant dentist.
Whatever the case, I think you should be able to see now than if you do have any amalgams in your teeth then you can expect the electrical potentials in them to measure anything up to 350 millivolts. (And it doesn't make any difference if the static voltages generated by walking across a polyester carpet are measured in thousandes of volts, that's not comparing like with like - the discharge of such a voltage would not light an ordinary flashlight bulb for any appreciable time at all, whereas a battery of only a few volts does the job for many hours).
So if you do have any amalgams in your teeth you might want to consider this. Do you ever feel anxious, depressed or unfulfilled? Well of course if you told your doctor this then his most likely response might be to say that "it's just stress". Well maybe it isn't "just stress". Maybe its the low level but perpetual discharge of electrical energy through the nerves in your head which is caused by the electrical potentials generated by the fillings in your teeth. And perhaps in most cases that's exactly what "stress" is.
Anyway, there's a letter written by a (former?) dental materials scientist in which he too reveals a complete ignorance of thermoelctric phenomena, see:
http://book.boot.users.btopenworld.com/brown.htm
In it he says:
" ... what we always need are two electrodes ( an anode and a cathode), an electrolyte (solution of ions) and an electrically conducting connection ..."
Do yourself a favor and see if you can answer this one simple question honestly - he was wrong wasn't he?
And don't forget the new bit. Professor L I Anatychuk of the Ukraine Academy of Sciences believes that the thermoelectric effect in metals is enough on its own to stimulate neurological synapses in animal tissue. He says so in his paper "Seebeck or Volta?", which was published in the Journal of Thermoelectricity, No.1, 1994.
Have you read it yet?
Keith P Walsh
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If you haven't done the tests, how do you know the fillings are generating anything?

Bigger question is why you haven't gone to your local university and found a professor, as I've previously explained, to do the tests for you? Are you afraid of the results?

Which dentists? Why are they doing the tests? If they are doing the tests, the results should be published and your questions answered. Remember the results have to be verifiable and repeatable.

How does the electrical potential discharge? It's either there or not. Amalgams aren't capacitors.

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But you don't have a problem with gold ones? And how does gold generate a thermoelectric eddy current.

cmd=Retrieve&db=Pub
That's a really bad assumption. As I've posted previously, I've gone to my local university and convinced a professor to run these tests that you find to difficult to originate yourself.
has made me wonder is whether or

You're attempt to sweet talk me does not help your case. I've done my homework, why haven't you done yours? What are you afraid of?

You might think that, but you might be wrong.
(And it doesn't make any

And it's impossible to create those circumstances in your mouth. You can't have a sustainable temperature gradient that steep without causing damage to your mouth.

Even if I assumed that your conclusions are correct, which I don't, how does any electrical potential get across a non- conducting tooth to the nerve?

Nope.
Nope. Don't need to.

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ups.com:

I still assert that the unhomogenity of the mixture cannot do anything than create numerous "shorts" or eddy currents that offset each other...unless of course you are asserting that no matter how the material is mixed the homogenities are always the same.
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On Dec 11, 11:11 pm, "It's all a bit strange"

It's a pity there aren't any experimental results to confirm your opinion.
Because without them it's just guesswork.
And guesswork on its own is not science.
Your guess might be wrong.
Keith P Walsh
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But I"ve told you. I went to the nearest University and found a professor willing to offer this as a project. Wasn't hard to request, wasn't hard to get done. Professor was happy for the suggestion of a new and interesting application of his field.
You should try it some time.
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On Dec 13, 8:08 am, "It's all a bit strange"

Has your professor given you any results?
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Yes, of course.
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On Dec 14, 5:15 am, "It's all a bit strange"

Well, of course, I could only presume that if the results you have been given are valid then they must be consistent with the fact that metal amalgam dental fillings generate electrical potentials with magnitudes of up to 350 millivolts. See:
http://book.boot.users.btopenworld.com/dutch.htm
But do they give any indication of the relative degrees by which these potentials arise as a result of galvanic (electrolytic), thermoelectric and/or faradaic (electromagnetic) activity?
Keith P Walsh
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wrote:

You can assume what you want. If you want to know for sure, and I suspect you don't, just go to the nearest University and find the department that best suits you and make a request for a study.
It really is simple...even for you.
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strange wrote:

Zero is such an uncompromising number.
If you want to invoke the science of electrodynamics, you really should quantify the effects involved. For instance, the resistivity of dental amalgam is known, and the grain size of silver in dental amalgam is also well-known.
What isn't as well-known is the temperature gradient across the body of the amalgam. Some labwork there seems to be in order, but for preliminary estimates you can highball it.
Once the gradient is known, you can easily enough calculate the total Thevenin potential difference and with the resistivity and grain size you can calculate the current distribution. That in turn allows you to calculate the net dipole that results from the temperature gradient, and with that and the conductivity of the fluids in the area you can calculate the current and its spatial distribution.
Alternately, you could take some dental amalgam and apply a temperature gradient along with the usual laboratory nanovoltmeter to get the Thevenin potential; the source impedance is of course easily measured. (I'm guessing that a nanovoltmeter would be adequate; picovoltmeters are a bit harder to come by.)
In any case you really shouldn't use unscientific handwaving terms like "offset each other." Yes, of course they "offset each other" -- but the real question is, "how much?"
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Excuse me for butting in before our friend "It's all a bit strange" has had a chance to respond to your comments, but would you be able to give me a reference for the resistivities of typical dental amalgams.
I've always had problems finding a reliable one.
For example, in the textbook "Restorative Dental Materials", edited by Robert G Craig and John M Powers and published by Mosby, I can find values of electrical resistivity for Human Enamel, Human Dentin, and several different types of Dental Cements - all given in perfectly appropriate (though not SI) units of ohm.cm
However, in spite of the fact that they have devoted an entire chapter of fifty pages to the properties and use of amalgam, there isn't any indication anywhere as to what the electrical resistivity of a typical dental amalgam is.
In fact, the ONLY place I've ever seen measured values quoted for the resistivity of amalgam is in the paper entitled "Resistivity of Silver- Tin Amalgams", by Richard J Schnell and Ralph W Phillips of the Indiana University School of Dentistry, which was published in the Journal of Dental Research in 1964.
See:
http://jdr.iadrjournals.org/cgi/reprint/43/4/501.pdf
But the trouble is these values are all quoted in units of "microhms per cubic centimeter". And this is not a valid unit for electrical resistivity (in spite of Don Kelly's protestations to the contrary).
Can you please refer me to values of the resistivities of dental amalgams given in the correct units?
(And please don't just say "Yes, of course I can." I'd like a bona fide reference to the published findings of experimental studies carried out to measure these properties.)
And by the way, would you expect the resistivity of a typical dental amalgam to vary from point to point within the material?
I think I would.
Best regards,
Keith P Walsh
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Keith P Walsh wrote:

It'll be between the values for metallic mercury and metallic silver. The two aren't mixed at the crystalline level, so there's no effect on electron mobility. If anything the intercrystalline mercury should improve the silver a bit.
That, or of course you could just take a filling and measure it.
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Walsh wrote:

This sounds like guesswork to me.
Do you know of any dental materials science textbook or published scientific paper which quotes values of electrical resistivity for typical dental amalgams in appropriate scientific units?
As you rightly suggest, these should be such simple measurements to make I can't believe that no-one has ever done it (and published their results quoting the measured values in the correct units).
Keith P Walsh
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Do it, Keith.
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Keith P Walsh wrote:

Walsh wrote:

Call it educated guesswork from someone who has both the education and experience to make an *accurate* educated guess.

No, for the simple reason that it's trivial and not interesting. There are, after all, an infinite number of possible material combinations. Unless one has a particular reason that its resistivity should be worth discussing, it's simply not worth the bother to publish it.
Frankly, the exact resistivity of dental amalgam isn't interesting, because it's not used in a way where the exact value of its resistivity matters. If you pass a milliamp through a 1 mm cube of silver, you get a 16 nanovolt drop. If you do the same through a 1 mm cube of mercury, you get a 960 nanovolt drop.
Since the drop through the adjacent fluids is orders of magnitude greater, it just doesn't matter.

It is easy to do. It's just not worth publishing.
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Walsh wrote:

As with any other material, the principal physical property in determining the thermoelectric behavior of a typical dental amalgam is its seebeck coefficient (measured in volts per kelvin).
Do you think you would be able to guess that too?
(Well I think you'd have to, because it appears that no-one has ever bothered to measure that either)
Keith P Walsh
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Walsh wrote:

Measure it, Keith.

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Keith P Walsh wrote:

No need to guess. Silver is 6.5 mV/C, mercury is 0.6 mV/C The difference is 5.9 mV/C
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Are you presuming that the seebeck coefficient of a typical dental amalgam can be deduced simply by taking the difference between the respective seebeck coefficients of elemental silver and elemental mercury?
Because if you are then I should point out that, according to the established principles of scientific endeavor, in the absence of any corroborating experimental evidence that's just guesswork.
And it makes me wonder if you understand how to conduct a scientific correspondence at all.
Where are your references?
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 generate electrical potentials as a result of their thermoelectric behavior.
Dental amalgam is an inhomogeneous mixture of dissimilar metals in its own right, see:
http://book.boot.users.btopenworld.com/setting.htm
Not only that, but 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.
What would you advise to be the best method to determine the greatest thermoelectric potential that such a construction could generate?
Carry out an experiment to measure it?
Surely you cannot be so arrogant as to suggest that our scientific understanding of this phenomenon should be satisfied by either your own or anyone else's guesswork.
Can you?
Keith P Walsh
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