Magnetic Susceptibility of Dental Amalgams



I have some anecdotal evidence. I recently had an MRI of my head. Yeah, yeah, they found nothing! Anyway, I felt absolutely no effects from the high magnetic field in my fillings nor in my caps.
The technician told me that some people insist on wearing their shoes with nails in them. He reported that their feet then levitate. So the field is damn strong.
My 2 cents worth.
Al
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Thank you for your reply.
The excitation of the nuclei of atoms in MRI procedures is not simply dependent upon field strength.
The field strength influences the frequency at which the targeted nuclei will resonate, but the frequency of the incident radiation must also match this "resonant" frequency for the excitation required for MRI purposes to take place.
The variation of resonant frequencies for varying field strengths is different for the nuclei of different elements. In fact, each element (more accurately, each isotope of each element) has its own characteristic profile of "resonant" frequencies (called Larmor frequencies after the British scientist Sir Joseph Larmor (1857-1942)).
A table of NMR frequencies at different field strengths for different elements can be found on the website of the Massachusetts Institute of Technology at:
http://web.mit.edu/speclab/www/nmrfreq.html
You can see that the field strengths for this table have actually been chosen to match with convenient values of Larmor frequencies for hydrogen - H(1).
So, for argument's sake, if your MRI scan had been set up with a field strength of 5.8717 Tesla and a frequency of incident radiation of 250 MHz, then you would have expected the hydrogen nuclei in the region of your body under examination to "resonate" accordingly.
However, you would not have expected the nuclei of the mercury, silver or tin atoms in your amalgam fillings to have resonated significantly at all.
This is because the Larmor frequencies of Ag(107), Ag(109), Sn(115), Sn(117), Sn(119), Hg(119) and Hg(201) at this field strength are 10.116, 11.630, 81.749, 89.063, 93.181, 44.568, and 16.499 MHz respectively, and not 250MHz.
The Larmor frequencies for these nuclei will always be different from that of hydrogen, whatever the strength of the field. And it can therefore be ensured that only hydrogen nuclei are excited in an MRI procedure simply by ensuring that the incident radiation matches the Larmor frequency for H(1) at the chosen field strength.
Do you think that it should be possible to determine whether or not the nuclei of the atoms in your amalgam fillings might be excited by other, perhaps less mindfully engineered electromagnetic fields, such as those produced by visual display units, electrified railway lines, cellular telephones, etc., etc., etc.?
Keith P Walsh
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Unlikely for many reasons: reflection/absorption by tissue surrounding mouth; FCC interference rules which guarantee weak EM fields from consumer products; the inverse square law of dissipation of EM radiation away from a source; and low-Q resonances of metals and compounds which means they may be strongly attenuated and not significantly "ring".
And after all this, there is still no reason to claim that a lonely resonating tin atom implies a harmful health effect. The MRI is not mutating H atoms or causing people to die. I suspect your reasoning has become inverted. You hate amalgams and thus think they must be harmful.
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wrote:

REPLY
Anyone know the ADA CDT-4 code for Exciting amalgams?

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Joel M. Eichen, .
Philadelphia PA
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Where is Jan Drew when we need her. She is expert on poisonosity of amalgam.
JOEL
Well internet expert, anyway.

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Joel M. Eichen, .
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Where is Jan Drew when we need her. She is expert on poisonosity of amalgam.
JOEL
Well internet expert, anyway.

wrote:
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Joel M. Eichen, .
Philadelphia PA
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For God's sake, why don't you do a little homework then? Just look up the component compounds of amalgam in a CRC handbook, jot down their permittivity and permeability constants, and use the rule of mixtures to arrive at a composite material behavior.
Maybe if you did a few calculations your argument would be better received. My guess is that you are afraid that the hard science will prove you wrong. Why is it that fanatics never take the time to do the research themselves? For all the effort they spend promoting these crazy views, you would think they would have performed a little effort to make sure that their theories are on sound scientific ground. Instead, they try to dredge up the same old papers that have been refuted so many times in the past.
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My question is what metals exhibit magnetic properties besides Iron ?
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Cobalt, nickel, mild steel, SiFe, mumetal, and supermalloy. All of these have a relative permeability much larger than 1.0 and are thus high magnetic susceptibility compounds.
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SiFe = Ferrous Silica ?
Am unfamiliar with mumetal and supermalloy.
Are these metals that considered 'ferrous' metals ?
Just want to know because I don't believe that any of these metals are contained in any formulation of dental amalgam.
Some dental casting alloys do contain small ammounts of Indium, any magnetic properties there ?
Thanks for you time, WB
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Sorry SiFe is my lazy way of writing silicon iron. It's used a lot in transformers.

Check a CRC manual (I don't have one handy right here). Look up permeability which also might be referred to as mu (unit = henries/meter). Run of the mill iron has a mu of around 5000, and purified iron is around 200000. Supermalloy has a mu around 1 million. The general rule of thumb is that most materials on the face of the earth have a mu of 1.0 (essentially no magnetic susceptibility).
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Mumetal is shorthand for metal used on dairy farms .......... we said this already.

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Joel M. Eichen, .
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Mumetal is popular on dairy farms .......

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Joel M. Eichen, .
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First you should back up and admit that there is no scientific evidence that amalgams generate electrical potentials in the first place. Junk science can only lead to junk conclusions.
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Oh I have heard it thousands of times ~ wait a minute, its all from Keith!

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Joel M. Eichen, .
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Keith P Walsh wrote:

Strangely enough, just now on the Discover Channel program, Mythbusters, they measured a few millivolts being generated between gold and amalgam in a solution of vinegar and water with the same PH as a human mouth. They were trying to prove or disprove that Lucille Ball once received, as she claimed, WWII Japanese Morse code through her fillings.
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I said it once, I'll say it again, if you can hook me up with free XM Radio by getting some of these Extra-Mercury Fillings in my mouth, I want 'em!
SG
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XM radio requires exactly 745.190372 mV potential in your mouth, so make sure you get it done by a top notch dentist who specializes in hifi installation.
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Not by an alt.radio.frequency.amalgam.installer ......
wrote:

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Joel M. Eichen, .
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On Mon, 09 Feb 2004 03:38:48 GMT, "Suresh Goel"

Samuel F.B. Morse was Japanese?

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Joel M. Eichen, .
Philadelphia PA
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