Scientists specialising in the thermoelectric behavior of materials have been unable to determine whether or not the thermoelectric potentials generated by metal dental restorations are large enough to dissipate electrical energy through the nerves in people's heads.
Experts in thermoelectricity attending the 13th International Forum On Thermoelectricity held in Kiev, February 2009, undertook to answer questions regarding the thermoelectric behavior of metal dental resorations.
However so far there has been no information forthcoming.
The latest developments in the debate can be followed at the website of the International Thermoelectric society at:
Best regards to all,
Keith P Walsh
PS, The thermoelectric effect is a natural phenomenon whereby dissimilar metals in contact with each other are able to generatee an electric current whenever their points of contact are subjected to a temperature difference.
There is no electrolysis involved.
***********************************************It looks like I was wrong.
It=92s been more than a year now and it appears that the scientific community, including the International Thermoelectric Society, is still completely ignorant of the thermoelectric properties of metal dental restorations. (In any case, I still haven=92t had any answers to the questions I put to Professor Anatychuk at last year=92s International forum on the matter.)
Let me explain the issue again.
Metal amalgams are used for filling cavities in people=92s (including children=92s) teeth.
And there isn=92t anyone anywhere in the world who knows what the thermoelectric properties or thermoelectric behaviour of these materials are.
An amalgam is not an alloy.
A dental amalgam is formed by mixing bits of a solid alloy with liquid mercury and allowing the mixture to harden, and the entire process normally takes place at room temperature.
Under these circumstances what you get is a material which is fundamentally different from metallic alloys in the respect that its internal microstructure displays a much greater degree of inhomogeneity than an alloy.
The solid amalgam may be accurately described as an inhomogeneous mixture of dissimilar metals.
For an illustration of the microstructure of a typical dental amalgam see:
The =93cores=94 of unreacted solid alloy in the dental amalgam have a different composition to that of the solid amalgam matrix in which they are held. The cores have no mercury in them at all, whilst all of the mercury used to form the material is contained within the surrounding matrix.
If you were to subject this material to a thermal gradient you would expect the difference between the thermoelectric properties of the cores and the surrounding matrix to give rise to a thermoelectric eddy current around each of the cores.
For an illustration of this type of thermoelectric eddy current see:
The question arises; is it possible that the very sensitive neurological tissue in the vicinity of teeth with amalgam dental fillings may be excited by the local electromagnetic fields associated with the thermoelectric eddy currents induced in the amalgams whenever they are subjected to a temperature gradient (e.g. when eating ice- cream)?
And has anyone ever bothered to carry out experimental investigations in order to determine whether this effect can be detected with very sensitive instruments?
Apart from the fact that dental amalgams are inhomogeneous mixtures of dissimilar metals in their own right, dentists also sometimes screw metal alloy retaining pins into the root sockets of patients=92 teeth and encase the heads of the pins in amalgam, thereby creating the conditions for generating further thermoelectric potentials along the contours of the interface between the retaining pins and the amalgam.
In this instance there can be no excuse for not recognising the thermoelectric potential of the arrangement. Metal dental restorations are continually subjected to thermal gradients. The question arises; are the thermoelectric potentials generated by metal dental restorations comprising several different metallic materials in contact with each other large enough to dissipate electrical energy through the nerves in people=92s heads?
And has anyone ever bothered to carry out experimental investigations in order to determine what is the largest thermoelectric potential that can be generated by metal dental restorations?
Normal levels of electrical potentials generated by metal dental restorations can be routinely measured, see:
Dental materials scientists, and members of the dental profession in general, have a tendency to assume that these potentials are the result of =93galvanic activity=94, or electrolysis, and that they are only generated when the amalgam is in contact with an electrolyte, which is normally presumed to be saliva. So, when researchers William Schriever of the University of Oklahoma and Louis E. Diamond of the University School of Medicine, Oklahoma City measured amalgam potentials of comparable magnitude when they had taken care to ensure that they were not in contact with any saliva at all, they deduced that the electrolytic agent in the generation of the measured potentials must have been =93bone fluid=94 in contact with the hidden surfaces of the amalgam under the fillings. See:
I first asked questions about the thermoelectric behaviour of metal dental restorations in this forum more than ten years ago. In response, I received a series of what I thought were rather unscientific and condescending replies from Cronin B Vining, a prominent member of the thermoelectric community at the time. Mr Vining freely admitted that the substance of his replies was based largely on guesswork, see:
Cronin Vining=92s judgements on the thermoelectric behaviour of dental amalgams were made after only taking into account the percentage composition of the constituent metals which he had found in his search. He had completely ignored any consideration of the inhomogeneous nature of how these constituents are arranged in the material, a factor which we have already seen is of major significance to its thermoelectric behaviour.
And on subsequent questioning he also failed to address the question of how the combination of an alloy retaining pin with amalgam might behave under thermal gradients.
Professor Anatychuk of the Institute of Thermoelectricity in the Ukraine believes that Alessandro Volta was the first person to demonstrate a thermoelectric effect when he re-produced Luigi Galvani=92s experiments with the frog=92s leg. (Presumably Galvani doesn=92= t warrant the credit for it because he had offered a spurious explanation based on =93animal electricity=94).
If professor Anatychuk is correct, and a single thermoelectric junction acting at ordinary temperature differentials generates a thermoelectric potential which is large enough to excite neurological cells in animal tissue, then this above all demonstrates the unquestionable necessity for investigating and establishing the size and effect of the thermoelectric potentials generated by metal dental restorations.
In my experience it is at this point in the argument that the apologists for dental amalgam begin to put forward the excuse that =93if dental amalgams were causing anyone any harm we would have recognised it=94.
Would we?
How would we?
It is ironic that dental amalgams were first introduced as a treatment for tooth decay around about the time that Thomas Johann Seebeck became the first person to demonstrate that the application of a temperature gradient to dissimilar metals in contact with each other gives rise to a local electromagnetic effect (and that this happens in the absence of any electrolytic action).
It can be reasonably argued that the widespread adoption of metal amalgams for treating cavities in teeth was quickly followed by the rise to prominence of psychiatric =93medicine=94 in our societies. And as far as I can tell no-one has any convincing scientific argument for concluding that the two things are not linked by the relationship of cause and effect.
If the thermoelectric potentials generated by metal dental fillings are large enough to dissipate electrical energy through the nerves in people=92s heads, then this would provide a perfectly plausible causal link between the two. And in the absence of any experimental evidence to indicate one way or the other, no-one has any idea whether the proposal of such a causal link is accurate or not.
Alternative valid explanations for the large rates of affliction from so-called =93psychiatric disorders which still persist today do not exist. Those of us alive today have all grown up in an era where the presence of amalgam fillings in teeth is commonplace, and the high incidence mental illness is regarded as =93natural=94.
Millions, if not billions, of dollars have been spent on research attempting to =93prove=94 that the causes of psychiatric disease are =93genetic=94 (so far without success), whilst at the same time nothing at all has been spent on investigating the physiological effects of thermoelectric batteries (metal dental fillings) in people=92s teeth.
The upper and lower mandibles where the teeth of human beings are set do not have any muscle tissue, but there are very sensitive organs nearby. The medical profession is also unable to explain the causes of a class of disorders affecting the area of the lower head which may be described as neurological rather than psychological, disorders such as tinnitus (ears), Meniere=92s disease (balance) and facial neuralgia.
Developing drugs which are partially successful in treating the symptoms of disorders such as these does not mean that their causes are understood. (And it can be demonstrated that the complaint of a permanent =93ringing in the ears=94 has a much longer history than that of loud rock music - many tinnitus sufferers apparently do not acknowledge that their condition has anything to do with listening to loud music =96 see:
Dentists don=92t know what thermoelectricity is.
They are taught in dental schools to believe that metals can only generate electrical potentials when they are involved in electrolytic reactions, see,
Many years ago I also contacted Professor Rowe in Cardiff about the question of the thermoelectric properties of dental amalgams, and he glibly replied that these properties would be easy to measure (it=92s so long ago that I no longer have a copy of his e-mail, but I expect that he remembers it as well as I do). So come on someone at ITS, take up the challenge and measure these properties. And publish the results. Measure the largest thermoelectric potential that can be generated by a metal dental restoration (but don=92t forget that dentists sometimes screw metal alloy retaining pins into the root sockets of patient=92s teeth and encase the heads of the pins in dental amalgam).
Don=92t wait for Professor Rowe to do it. He=92s too busy posing by his car.
In recent postings I=92ve made insinuations against Professor Anatychuk which were perhaps unfair. I know he=92s not a young man, and if he has now retired or is perhaps ill then I wish him well and acknowledge the importance of his work in thermoelectricity. But it looks as though, for whatever reason, he will not now be able to do the experimental work necessary to answer my questions (for example, what would have been the minimum temperature differential necessary for Volta to have applied to his apparatus in order to make the frog=92s leg jump, using only a single thermocouple junction?).
And from what I can gather Cronin B Vining is disillusioned with thermoelectricity altogether (can=92t say I=92m surprised).
What=92s needed is a young scientist with integrity who understands thermoelectricity from a scientific point of view and does not lack the courage to tackle a potentially controversial scientific issue with honesty, intelligence and fortitude.
Remember no scientist ever made a name for himself simply by regurgitating what others had told him (or her). Anyone who ever established a lasting reputation as a scientist did so by pursuing answers to things that they DIDN=92T understand.
Towards the end of 1992 I wrote a series of five letters enquiring about the electrical behaviour of metal amalgam dental fillings.
You can find them at:
And in extreme though not uncommon cases they are also able to cause permanent neurological injury which cannot be repaired simply by the removal of the fillings.
Metal amalgams are used for filling cavities in children=92s teeth.
And there isn=92t anyone anywhere in the world who knows what the thermoelectric properties of these materials are.
It=92s idiotic.
Keith P Walsh