FDA: Mercury fillings are safe

[Tomblvd]

I want to mention also, fillings routinely need to be replaced after some decades in your mouth, it seems. In my case keeping at least most of the ones I replaced wasn't an option.

No, they do not "routinely" need replacing. It is entirely dependent on the individual situation. As I have already stated, I've seen many silver fillings (still with the mercury intact) that were 50 years old and perfectly serviceable.

And again, I have had composite plastic for I think 20 years and can only recall one needing maintenance. It turned out to be patchable in place. This I think is never the case with amalgam. The whole thing would have to be drilled out and replaced, correct?

That is completely wrong. There is no reason an amalgam filling can't be repaired, either with more amalgam, or composite resin. I do it nearly every day in my practice.

For not knowing dentistry, you seem to like to make a lot of definitive statements.

 

[Tomblvd]

It was something less than a claim of certainty on my part. Regardless of how I put it precisely I meant that this was something I had read. And I read it again just now while searching around about it, with the word "leaching" used. So I think my recollection is accurate here.

Your statement was that the mercury leached out of the filling "leaving the silver behind". The direct implication was that all the mercury left the filling. That is simply not the case.

There are many of these kinds of claims out there, of course, on the web. I don't consider them reliable either but they are certainly earnest and some of the people behind them claim to have credentials.

Earnestness has nothing to do with accuracy. And credentials in the absence of fact is worthless.

It's part of the argument on these sites that mercury that's absorbed in the body isn't excreted well through the urine.

Seems to me it should be easy to test the mercury content in old fillings by removing a sample. Then assuming the mercury content was known initially one could determine the rate of leaching or evaporation. Also it seems to me that if the mix is too mercury rich there would be some substantial initial release.

Well it just goes to show that it's a complicated subject and I think it's a good use of my tax dollars to do a meta-study of what the situation is. I continue to think it needs to be assessed by disinterested parties and I only hope the FDA can be relied on to remain so.

Everything you talk about has been done, over and over again. I'll repeat that the OP is regarding the FDA review of over 200 studies investigating all aspects of mercury in dental amalgam. Honestly, I'm not sure how much more you could possibly want.

 

[Eggs Ackley]

No, they do not "routinely" need replacing. It is entirely dependent on the individual situation. As I have already stated, I've seen many silver fillings (still with the mercury intact) that were 50 years old and perfectly serviceable.

That is completely wrong. There is no reason an amalgam filling can't be repaired, either with more amalgam, or composite resin. I do it nearly every day in my practice.

For not knowing dentistry, you seem to like to make a lot of definitive statements.

Definitive statements where? I definitely thought that, but I think I made it pretty clear it was only what I believed, and mostly based on my experience with them. That's why I wrote "I think". I never had a "silver" filling chip, the problem was decay getting under them. The plastic ones I have it has been the other way around. My amalgam fillings had to be replaced in any case, mostly.

 

[Eggs Ackley]

Your statement was that the mercury leached out of the filling "leaving the silver behind". The direct implication was that all the mercury left the filling. That is simply not the case.

I'm glad to be better informed about this. Mercury is a fascinating substance as are amalgams and I'm intersted in understanding them better, apart from their dental uses. The wikipedia article is fascinating.

After reading it, mercury still scares the heck out of me.

There is plenty to fear from lead, too, and much ridicule on the right of the idea that crime rates are related to lead exposures.

Everything you talk about has been done, over and over again. I'll repeat that the OP is regarding the FDA review of over 200 studies investigating all aspects of mercury in dental amalgam. Honestly, I'm not sure how much more you could possibly want.

I hope that is a better study than the one that said the space shuttle could go a hundred thousand launches between crashes.

 

[technoextreme]

Here is what I said:

I made nor make no special claims to expertise about toxity, but what I said is supported by wikipedia, for example. Mercury is a toxic heavy metal that is fairly easily absorbed and is highly regulated due to this fact. Elemental mercury is not the most dangerous form perhaps, but it is certainly not safe in elemental form, and it is essentially this form that is the type of exposure in amalgam fillings, is my understanding.

Its not in elemental form if its in a freaking alloy. You can eat elemental mercury and not poison yourself. Its only readily absorbed by breathing the vapors.

 

[Tomblvd]

Definitive statements where?

I want to mention also, fillings routinely need to be replaced after some decades in your mouth, it seems.

and

This I think is never the case with amalgam.

If there were nobody here to correct you, some would leave this thread thinking those were pretty definitive, weasel words notwithstanding.

I definitely thought that, but I think I made it pretty clear it was only what I believed, and mostly based on my experience with them. That's why I wrote "I think". I never had a "silver" filling chip, the problem was decay getting under them. The plastic ones I have it has been the other way around. My amalgam fillings had to be replaced in any case, mostly.

The plural of anecdote is not data.

 

[Eggs Ackley]

Its not in elemental form if its in a freaking alloy. You can eat elemental mercury and not poison yourself. Its only readily absorbed by breathing the vapors.

The claimed exposure from the fillings is usually to the vapors given off. This seems an exposure to the elemental form to me.

You can drink mercury if you like but I'll refrain, thanks.

If it's so safe why are special procedures needed for cleaning it up? From wikipedia:

See also: Mercury poisoning
Mercury and most of its compounds are extremely toxic and are generally handled with care; in cases of spills involving mercury (such as from certain thermometers or fluorescent light bulbs) specific cleaning procedures are used to avoid toxic exposure.[77] It can be inhaled and absorbed through the skin and mucous membranes, so containers of mercury are securely sealed to avoid spills and evaporation. Heating of mercury, or compounds of mercury that may decompose when heated, are always carried out with adequate ventilation in order to avoid exposure to mercury vapor. The most toxic forms of mercury are its organic compounds, such as dimethylmercury and methylmercury. However, inorganic compounds, such as cinnabar are also highly toxic by ingestion or inhalation of the dust.[78] Mercury can cause both chronic and acute poisoning.

 

[jasonpatterson]

If it's so safe why are special procedures needed for cleaning it up?

He never said that it was safe, only that the elemental form is not absorbed easily except in vapor form, which is entirely true, if you research it. The danger with mercury spills from fluorescent bulbs and thermometers is that so little mercury is present that it can form very small droplets. Because of their high surface area to mass ratio, they readily evaporate and form a vapor, which can be absorbed into the body. In liquid form, the stuff is fairly innocuous. The reason why liquid spills on the ground or into bodies of water are treated so seriously is that bacteria convert the metallic form to methylmercury, which is FAR more toxic stuff.

The relative safety of liquid mercury doesn't mean that I would want my kids playing with it, but I also wouldn't want them playing with gasoline, which is known to be a toxic substance both in its liquid and vapor forms, requiring special cleanup procedures. The difference is that if someone spilled a bit of gasoline in a school, the school wouldn't tear up the floor or hire a special cleaning company to come 'decontaminate' the area. As noted previously, it's all a matter of level of exposure and the level at which that exposure actually becomes dangerous.

Though my knowledge of mercury in fillings is far from comprehensive, the only substantiated danger I've ever heard of regarding amalgam fillings is in the case of unscrupulous undertakers who have stolen gold and 'silver' teeth from corpses. The mercury can be boiled off of the amalgam on a kitchen stove, but doing this creates large amounts of mercury vapor and causes chronic mercury poisoning and death. You'd think this would be difficult if the mercury had 'leeched out' and left only the silver behind... I can't find the original story.

I do know that crematoria are starting to remove filled teeth from corpses because of mercury pollution caused by the smoke as well. Feel free to rebut with something like, "I never said that all of the mercury was removed, this argument has no point."

 

[technoextreme]

If it's so safe why are special procedures needed for cleaning it up?

As someone pointed out I didn't say it was safe more than the last time I had this debate I ended finding out cases where kids accidentally ate the stuff and had no ill effects.

The claimed exposure from the fillings is usually to the vapors given off. This seems an exposure to the elemental form to me.

Dam it. My PHD research area is disturbingly enough related to this. Unfortunately, not enough for me to really bite into the physics.
EDIT:
Interestingly enough I just debunked a claim I found on the Skeptic blog about this very topic. It apparently is very easy to prove that amalgam gives off mercury vapors if you don't know how to use equipment correctly.

 

[MattusMaximus]

Eggs, have you ever heard of the concept of chemical concentration? In enough quantity, even water is lethal, you know.

I have to say, mercury is a very toxic poison and having it in your mouth where it is being absorbed over an extended period, and in the young, sounds like an inherently risky proposition. I don't doubt there are demagogues who would exploit people's fears but that doesn't preclude that there is some basis for concern. Low-level toxicity is probably difficult to demonstrate conclusively, and there is profit motive potentially involved.

So because there's no evidence of danger, there's evidence of danger? Ever heard of the argument from ignorance?

Nice way to end with a veiled reference to the Big Pharma conspiracy, too.

 

[GreyICE]

Eggs, have you ever heard of the concept of chemical concentration? In enough quantity, even water is lethal, you know.



So because there's no evidence of danger, there's evidence of danger? Ever heard of the argument from ignorance?

Nice way to end with a veiled reference to the Big Pharma conspiracy, too.

I dunno. I remain on the fence about this one. The theory that mercury might be dangerous is not exactly what we would call ground-breaking research. So the theory that mercury in one thing might be hurting us is not exactly woo, on the face of it.

Then again, our bodies can easily process low levels of mercury, which is what this is. Then again, it does far more damage to lungs and bloodstream than it does to gut, and it's in a tooth in your mouth.

Two years ago I got a filling and I used a composite non-mercury filling with some other advantages over the mercury (including a non-metallic color), and I don't regret it one bit. If I get another cavity, I'll get another just like it, or with an even better material, and that's that in my book.

 

[Eggs Ackley]

As someone pointed out I didn't say it was safe more than the last time I had this debate I ended finding out cases where kids accidentally ate the stuff and had no ill effects.

Dam it. My PHD research area is disturbingly enough related to this. Unfortunately, not enough for me to really bite into the physics.
EDIT:
Interestingly enough I just debunked a claim I found on the Skeptic blog about this very topic. It apparently is very easy to prove that amalgam gives off mercury vapors if you don't know how to use equipment correctly.

If it can be proven that after a long time the same amount of mercury is still in the filling as started out that would seem to rule out toxicity, so that would be the first question I'd want to answer. That is, does it stay put or not?

My willingness to buy into the toxity claim is/was based on tacit acceptance of the seemingly reasonable accompanying claim that the mercury leaches or evaporates out. I see both of these terms being used specifically on the anti-amalgam sites. There's a macroscopic amount to start with, it's an accumulative poison (they say and it sounds reasonable), and if it's gone missing that raises a potential for toxicity in my mind.

I took some metallurgy but I don't think amalgams ever came up in it. (or in chemistry either, as much as I had to take for engineering.) I can see I had some misconceptions about it (after reading on wikipedia) and I don't feel I understand them very well. But it's basically an alloy so there's a flexibility in the relative proportions that you don't have with a molecular compound (?). Alloys vary in their resistance to corrosion and since amalgam fillings visibly corrode and I wonder if that is a way for mercury to get loose. But it should be easy based on known toxicity of the most toxic organic forms to say that if no more than a certain amount gets loose, there can be no toxicity. I wonder if that would be a small or a large proportion of the starting mecury content.

That kid was apparently lucky he couldn't afford a jade mixer with his mercury cocktail. (from wikipedia):

One of China's emperors, Qín Shǐ Huáng Dì — allegedly buried in a tomb that contained rivers of flowing mercury on a model of the land he ruled, representative of the rivers of China — was killed by drinking a mercury and powdered jade mixture (causing liver failure, poisoning, and brain death) intended to give him eternal life.[15][16]

The best laid plans ....

(He had a government study saying it was safe, I guess)

 

[paximperium]

There's a macroscopic amount to start with, it's an accumulative poison (they say and it sounds reasonable), and if it's gone missing that raises a potential for toxicity in my mind.

Don't be silly. If this was the case, eating fish would be lethal and the Japanese would all be mercury poisoned.

Mercury like any other adsorb substance is excreted at a preset rate depending on its type form. As long as mercury is excreted more than it is adsorbed it does not accumulate. The most dangerous are the organic mercuries like methylmercury

You need to stop reading those anti-mercury websites. They are filled with lies.

That kid was apparently lucky he couldn't afford a jade mixer with his mercury cocktail. (from wikipedia):

One of China's emperors, Qín Shǐ Huáng Dì — allegedly buried in a tomb that contained rivers of flowing mercury on a model of the land he ruled, representative of the rivers of China — was killed by drinking a mercury and powdered jade mixture (causing liver failure, poisoning, and brain death) intended to give him eternal life.[15][16]

The best laid plans ....

(He had a government study saying it was safe, I guess)

What a non-nonsensical derail. Qin Shih Huang Ti along with a multitude of old world individuals such as Isaac Newton believed in Alchemy which believed that Quicksilver and other mercury compounds could lead to immortality. They ingested a tremendous amount of the stuff and it was in an organic form.

No one here has said that Mercury is safe under all circumstances.

 

[Eggs Ackley]

Don't be silly. If this was the case, eating fish would be lethal and the Japanese would all be mercury poisoned.

Mercury like any other adsorb substance is excreted at a preset rate depending on its type form. As long as mercury is excreted more than it is adsorbed it does not accumulate. The most dangerous are the organic mercuries like methylmercury

You need to stop reading those anti-mercury websites. They are filled with lies.

I take accumulative to mean not zero excretion but that the rate of excretion is small compared to the environmental exposure in question. By your definition there are no accumulative poisons, just poisons.

Maybe you know that the amount of methyl mercury in fish is large enough that the cumulative dose would kill most Japanese if they weren't excreting it but I don't, at least offhand. It doesn't seem obvious on its face. It's just another reasonable-sounding claim like the ones on those websites.

What a non-nonsensical derail. Qin Shih Huang Ti along with a multitude of old world individuals such as Isaac Newton believed in Alchemy which believed that Quicksilver and other mercury compounds could lead to immortality. They ingested a tremendous amount of the stuff and it was in an organic form.

No one here has said that Mercury is safe under all circumstances.

Well people did say it was hardly toxic in liquid elemental form. The article only mentions mixing with jade. I think that's a suspension not an organic compound.

 

[Chris Haynes]

Actually, it's been on "the list" for quite a while now. I recall my father, many years ago, holding off on doing work on pregnant women, but it was, like most things, purely CYA. If you notice, they also recommend pregnant women avoid certain seafood for the same reason.
...

Several years ago I was pregnant and in a dentist's office. It had been determined though an X-ray that I had an inclusion in a molar that required attention. (hey! out of the 24 teeth I possess, I think I am doing very well that only four have any kind of structural maintenance, either from caries or that stupid "inclusion"... a carie that started inside the tooth!)

When the dentist learned I was pregnant he had me call my primary care doctor for clearance. Not for the amalgam, but for the pain medication.

That child is now fifteen years old and completely annoying normal.

 

[Tomblvd]

If it can be proven that after a long time the same amount of mercury is still in the filling as started out that would seem to rule out toxicity, so that would be the first question I'd want to answer. That is, does it stay put or not?

My willingness to buy into the toxity claim is/was based on tacit acceptance of the seemingly reasonable accompanying claim that the mercury leaches or evaporates out. I see both of these terms being used specifically on the anti-amalgam sites. There's a macroscopic amount to start with, it's an accumulative poison (they say and it sounds reasonable), and if it's gone missing that raises a potential for toxicity in my mind.

I took some metallurgy but I don't think amalgams ever came up in it. (or in chemistry either, as much as I had to take for engineering.) I can see I had some misconceptions about it (after reading on wikipedia) and I don't feel I understand them very well. But it's basically an alloy so there's a flexibility in the relative proportions that you don't have with a molecular compound (?). Alloys vary in their resistance to corrosion and since amalgam fillings visibly corrode and I wonder if that is a way for mercury to get loose. But it should be easy based on known toxicity of the most toxic organic forms to say that if no more than a certain amount gets loose, there can be no toxicity. I wonder if that would be a small or a large proportion of the starting mecury content.

You seem stuck on the idea of measuring the amount of mercury "remaining" in an amalgam after use for a number of years. But that won't give you any useful data, because not all of the minute amount of mercury given off is even absorbed. For some reason you make the assumption that all mercury is (1)completely inhaled, (2)completely absorbed and (3)completely bound by the tissues.

Given the fact that the vapor is in the mouth, and we exhale as much as inhale, that would cut the amount inhaled by half (roughly). Not all of the vapor is absorbed by the lungs, and is exhaled. And that that is absorbed is partly excreted.

The easiest and best way to measure mercury absorption is looking at things like blood plasma levels and excretion via urine samples. We have a very good selection of subjects to measure these things. Placing an amalgam and pulling the tooth and remeasuing it a decade or longer is an unnecessarily difficult test to perform and won't answer any of the relevant questions.

 

[technoextreme]

If it can be proven that after a long time the same amount of mercury is still in the filling as started out that would seem to rule out toxicity, so that would be the first question I'd want to answer. That is, does it stay put or not?

My willingness to buy into the toxity claim is/was based on tacit acceptance of the seemingly reasonable accompanying claim that the mercury leaches or evaporates out. I see both of these terms being used specifically on the anti-amalgam sites. There's a macroscopic amount to start with, it's an accumulative poison (they say and it sounds reasonable), and if it's gone missing that raises a potential for toxicity in my mind.

Your basing your beliefs under the assumption that it does leech out in the first place. This is the reason why I wish I knew more metallurgy:
http://www.fda.gov/ohrms/dockets/ac/06/slides/2006-4218s1-03.pdf

 

[Eggs Ackley]

Your basing your beliefs under the assumption that it does leech out in the first place.

It's not a belief so much as a concern about which I tend to err on the side of caution.

But yes, that is what I'm saying, if I become convinced that the mercury stays in place to the extent that even if all of what is missing were absorbed it could do no harm then I would no longer be concerned.

 

[Eggs Ackley]

You seem stuck on the idea of measuring the amount of mercury "remaining" in an amalgam after use for a number of years. But that won't give you any useful data, because not all of the minute amount of mercury given off is even absorbed. For some reason you make the assumption that all mercury is (1)completely inhaled, (2)completely absorbed and (3)completely bound by the tissues.

Given the fact that the vapor is in the mouth, and we exhale as much as inhale, that would cut the amount inhaled by half (roughly). Not all of the vapor is absorbed by the lungs, and is exhaled. And that that is absorbed is partly excreted.

The easiest and best way to measure mercury absorption is looking at things like blood plasma levels and excretion via urine samples. We have a very good selection of subjects to measure these things. Placing an amalgam and pulling the tooth and remeasuing it a decade or longer is an unnecessarily difficult test to perform and won't answer any of the relevant questions.

No I am not making any of the assumptions as you state, except as limiting cases to establish bounds on the toxicity. The bounds are established by first measuring the difference between what Hg went into the filling, and what is in there after a known period of time, and then assuming that all that was missing was absorbed. If this amount is not even a toxic dose, then no worries. If it is a toxic dose, that does not mean real danger necessarily, it just means more modeling is needed to establish what is the dose.

I was taking my cue from what you said that all the mercury stays in the filling but now you seem to be backtracking from that. Perhaps enough is given off then to possibly cause toxicity were it well absorbed?

I would guess or at least consider that possibly 1) the amount given off is not constant in time, and especially is probably much larger around the time of placement; and 2) the rate of absorption varies with the rate of leaching or evaporation, and whether the mechanism is leaching or evaporation or both.

For example, in the case of leaching, at a very low rate say, how do we rule out that bacteria in the mouth aren't converting it into methylmercury? Even with evaporation, if you are breathing through your nose, how do you establish that the mercury is not being reabsorbed into tissues in the mouth?

Also you tacitly imply that some of the mercury has leached out of the filling and into the tooth so to make the measurement we would have to pull the tooth. (So it could be done to cadavers.) This also goes against your claim that I should not worry because it's all bound up in the amalgam and raises the issue of whether it stays in the tooth or not. BTW, that it discolors the tooth due to migration is one of the reasons given on the cosmetic dentistry sites for getting plastic fillings.

Throughout this I have never said that I believed amalgam fillings are clearly a health threat that should be banned, or anything of the sort. I just said I was not personally convinced of their safety and that rather than worry about it I chose to get an alternative. Although I have discovered I had a few misconceptions about the whole process, my basic opinion has not changed that much and probably can't unless I spent a lot of time actually reading and researching the studies and their methodologies and so forth and that would take me far afield and be a lot of work and involve developing new areas of expertise and so forth and certainly I am not going to do that. My experience is that many if not most scientific or technological papers are flawed at one level or another if you look at them closely enough. They may still be basically correct but not always. Peer review is not perfect.

I am also pragmatic so even if there is some danger associated with them I would be weighing it against the dangers of the alternatives. Similarly in the case of vaccines, Jenny McCarthy notwithstanding, we know vaccines have some inherent danger (not of autism but of weird or allergic reactions and in the case of live polio vaccines (which I know are not used much anymore if at all) of acutally imparting the disease) but not using them is clearly more dangerous. So I am among the first in line getting my flu shot every year and I will be getting the H1N1 shot as soon as I can (assuming I don't get the H1N1 flu first), and if I ever have kids they will be getting them as well.

So, rather than say, as you appear to be saying, that even if there is some small danger to, say, children (because for obvious reasons they need more caution than Alzheimer's patients) we need to keep using them indefinitely because there is no reasonable alternative in that cohort, perhaps we might direct some research resources to developing safer alternatives, if the danger cannot be ruled out categorically.

 

[technoextreme]

It's not a belief so much as a concern about which I tend to err on the side of caution.

But yes, that is what I'm saying, if I become convinced that the mercury stays in place to the extent that even if all of what is missing were absorbed it could do no harm then I would no longer be concerned.

There is a difference between caution and paranoia.