FDA: Mercury fillings are safe

[MattusMaximus]

Good for the FDA! I can't wait to see the backlash from the alt-med woosters on this one...

Mercury in dental fillings not risky, officials say

Quote:

The U.S. government declared Tuesday that silver dental fillings contain too little mercury to harm the millions of Americans who have had cavities filled with them — including young children — and that only people allergic to mercury need to avoid them.

It was something of an about-face for the Food and Drug Administration, which last year settled a lawsuit with anti-mercury activists by posting on its Web site a precaution saying questions remained about whether the small amount of mercury vapor the fillings can release were enough to harm the developing brains of fetuses or the very young.

On Tuesday, the FDA said its final scientific review ended that concern. Still, the agency did slightly strengthen how it regulates the fillings, urging dentists to provide their patients with a government-written statement detailing the mercury controversy and what science shows. ...

Waiting for the alt-med "government, Big Pharma conspiracy machine" to start up in... 3... 2... 1...

Quote:

Anti-mercury activists accused the agency of bowing to the dental industry and said they would go back to court to try to force a change.

"FDA broke its contract and broke its word that it would put warnings for children and unborn children," said Charles Brown of Consumers for Dental Choice. "This contemptuous attitude toward children and the unborn will not go unanswered."

Whoops, too late

[Eggs Ackley]

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.

Also, it's an unnecessary risk in the sense that there are superior alternatives without toxic metals. I had all my amalgam fillings replaced with composite plastic a couple of decades ago. The dentist said the plastic fillings wouldn't last but nearly all of them have and now they are much improved anyhow.

With plastic fillings, less of the tooth needs to be removed, and if damaged they can often be repaired without having to dig out the whole thing and make an even bigger hole in the tooth. I've been very happy with mine and of course they look so much better.

[Amapola]

@Eggs Ackley: Well, in the article, they do address the reasons why amalgam is still the best choice in certain instances. Also they point out that the mercury used is a different kind, and that scientific studies show no harm from the amalgam.

As far as profit motive, one reason amalgam is used is because it is cheap and more people can afford it.

I'm glad for you if you've found a good alternative. That's terrific! I can't afford to use the alternatives, so I am happy to hear about the results of these tests.

[Miss_Kitt]

Eggs -- You get exposed to mercury by walking around and by breathing air. The blanket statement that "it's a very toxic poison" shows a limited understanding of issues of toxicity. Chlorine is toxic, but it's not harmful for you to sterilize clothing or surfaces with a bleach-water solution; in fact, it is often safer than not using the bleach.

Toxicity is a question of doseage, absorption, and retention. Metallic mercury or certain mercury compounds can be toxic in small doses -- but other mercury compounds are stable and readily excreted.

It's exactly that kind of "well, it's poisonous, so we'd better not risk it" thinking that contributes to a lot of fear-mongering, bad risk assessment, and bad public health practices like people refusing vaccines for fear of the (essentially non-existant) risk of damaging their kids' brains.

Just for my curiosity, where did you read that more tooth needs to be removed to install an amalgam filling than a porcelain one? And what kind of plastic is being used in your mouth? Most plastics are not highly resistant to acidity, heat, cold, and shearing stress.

Thanks for the citations, I look forward to seeing them, Miss_Kitt

[Tomblvd]

Originally Posted by Eggs Ackley

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.

As already pointed out, chloine is very toxic, yet you ingest table salt with no trouble.

If you are concerned about mercury poisoning, go after the seafood industry and leave us dentists alone.

Quote:

Low-level toxicity is probably difficult to demonstrate conclusively, and there is profit motive potentially involved.

Please tell me what this "profit motive" is, considering I can charge more for bonded resin ("plastic") fillings than amalgam.

Quote:

Also, it's an unnecessary risk in the sense that there are superior alternatives without toxic metals.

Are you sure? How do I place a bonded resing filling in an elderly patient with alzheimers, subgingivally in a bloody field? How about a 3 year old thrasing around?

Quote:

I had all my amalgam fillings replaced with composite plastic a couple of decades ago. The dentist said the plastic fillings wouldn't last but nearly all of them have and now they are much improved anyhow.

Do you realize how much mercury you were exposed to when the old filling were drilled out? It's alot more than if you had just left them be.

Quote:

With plastic fillings, less of the tooth needs to be removed, and if damaged they can often be repaired without having to dig out the whole thing and make an even bigger hole in the tooth. I've been very happy with mine and of course they look so much better.

If you were given a choice, and made an informed decision, good for you. But if your dentist scared you into having all your amalgams removed because of "toxicity", he was breaking the law. I always give my patients the choice, and the pros and cons. There is nothing wrong with resin or amalgam fillings, but there are too many quack dentists scaring their patients into having all their silver fillings replaced. And that's bad.

[Subduction Zone]

I am old enough to have grown up with mercury thermometers, including oral ones. More than once we broke thermometers as kids and played a bit with the mercury balls. Even in chemistry classes in high school we did not have this mercury phobia. Now I would definitely not recommend playing with it every day, but a minor spill in the past would require a hazmat crew today. Today people are way too concerned with the toxicity of mercury. Mercury is the big bad wolf of today's oogie boogie medicine. It causes everything from autism to postpartum depression

[Eggs Ackley]

Originally Posted by Miss_Kitt

Eggs -- You get exposed to mercury by walking around and by breathing air. The blanket statement that "it's a very toxic poison" shows a limited understanding of issues of toxicity. Chlorine is toxic, but it's not harmful for you to sterilize clothing or surfaces with a bleach-water solution; in fact, it is often safer than not using the bleach.

Toxicity is a question of doseage, absorption, and retention. Metallic mercury or certain mercury compounds can be toxic in small doses -- but other mercury compounds are stable and readily excreted.

The fact that you think you can make an inference that my understanding is limited based on my making a true statement shows a limited understanding of the laws of inference.

Also, it's an obfuscation here to bring in the use of chlorine bleach versus not using it. I am not advocating forgoing dental treatment or drilling out the decay and leaving the holes empty. The question here is what is a safe and reasonable way to fill the cavity and pardon me for being cautious when the historical method is to fill them with an amalgam containing mercury.

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. Please correct me if I'm wrong. An amalgam is more like a solution than a chemical compound, seems to me. The mercury is not so tightly bound to the silver as, say, chlorine is to sodium in table salt. My understanding is that the mercury leaches out over time leaving the silver behind.

I'll stand by to be corrected by more knowledgable individuals.

Originally Posted by Miss_Kitt

It's exactly that kind of "well, it's poisonous, so we'd better not risk it" thinking that contributes to a lot of fear-mongering, bad risk assessment, and bad public health practices like people refusing vaccines for fear of the (essentially non-existant) risk of damaging their kids' brains.

Perhaps so but it is not as if either dentistry or medicine have a history of being squeaky-clean with regards to treatment safety. Mercury amalgam fillings are fairly archaic as well so most likely their safety was not well-established prior to their common usage. Some scrutiny is reasonably warranted, seems to me. The relevant question is, at what point should one decide that safety is fully or sufficiently established? So now the studies have been done and that's good news that a new upper limit on the toxicity of mercury amalgam fillings is established and it's not very high. Am I to be faulted for being cautious twenty years ago before the studies were done?

Originally Posted by Miss_Kitt

Just for my curiosity, where did you read that more tooth needs to be removed to install an amalgam filling than a porcelain one? And what kind of plastic is being used in your mouth? Most plastics are not highly resistant to acidity, heat, cold, and shearing stress.

Thanks for the citations, I look forward to seeing them, Miss_Kitt

I can't remember where I read that. What's important is whether it's right or not. The dentist above will probably correct me if I'm wrong but I haven't read his post in detail yet. I did not get porcelain fillings so far as I know.
Wouldn't these have to be set and glued into place? The plastic ones are like an expoxy resin that's put in soft and then hardens in place andunder UV light. They have held up very well and have been no more trouble, or less, than when I had various amalgam fillings.

[Toke]

I read of that discussion a few years ago in denmark, I think the conclusion was that dentists and their assistants may have been poisoned and needed better protective equipment.

[thull]

I need a little clarity on the issue, as i don't know much of the practices in dentistry.

Within the article they single out young children and fetuses. Since being pregnant has a very short list of drugs that have been shown to cause no damage to the unborn baby and a huge list of "we don't know and it's probably unethical to find out". I have no qualms about adding certain fillings to that big list. However my confusion is over the children claim. Are fillings even used with baby teeth or are they just pulled out and the kids live without that tooth for a few years?

[Tomblvd]

Originally Posted by thull

I need a little clarity on the issue, as i don't know much of the practices in dentistry.

Within the article they single out young children and fetuses. Since being pregnant has a very short list of drugs that have been shown to cause no damage to the unborn baby and a huge list of "we don't know and it's probably unethical to find out". I have no qualms about adding certain fillings to that big list.

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.

Quote:

However my confusion is over the children claim. Are fillings even used with baby teeth or are they just pulled out and the kids live without that tooth for a few years?

As I stated in my first post, amalgam is used a lot on small kids when you don't have a lot of cooperation from the patient. Seeing as how a 3 or 4 year old would have to go without the tooth until they are around 12, pulling the tooth just for a cavity isn't even an option.

[Eggs Ackley]

Originally Posted by Tomblvd

As already pointed out, chloine is very toxic, yet you ingest table salt with no trouble.

If you are concerned about mercury poisoning, go after the seafood industry and leave us dentists alone.

With this level of argumentation you are not making me more comfortable that amalgam fillings are safe. It is reasonable to consider sodium chloride part of what we are made of and of couse it is essential to our survival. Mercury is not such. Also, if the mercury levels in seafood are clearly dangerous (and I am not granting that is true but perhaps you are?) then please explain how that should reassure me that the exposure from amalgam fillings is of no consequence?

Originally Posted by Tomblvd

Please tell me what this "profit motive" is, considering I can charge more for bonded resin ("plastic") fillings than amalgam.

You are not giving dental services including amalgam fillings away for free, I don't think. If you can't do them it seems it will not clearly help your business. Plus, they've been in use for a long time and so it's not unreasonable to expect some resistance to stopping their use just on that account, even if they cannot be proven safe.

Originally Posted by Tomblvd

Are you sure? How do I place a bonded resing filling in an elderly patient with alzheimers, subgingivally in a bloody field? How about a 3 year old thrasing around?

Also not a sound argument for the safety of amalgam fillings.

Originally Posted by Tomblvd

Do you realize how much mercury you were exposed to when the old filling were drilled out? It's alot more than if you had just left them be.

I don't know but I'd be interested to know if the new studies addressed this. Certainly it would be a reasonable trade to consider among those who already have them. Is your claim that the exposure would be more by removal substantiated in a study somewhere or is that just your belief?

It's not relevant to the question of whether they should be used in the first place, in any case.

Originally Posted by Tomblvd

If you were given a choice, and made an informed decision, good for you. But if your dentist scared you into having all your amalgams removed because of "toxicity", he was breaking the law. I always give my patients the choice, and the pros and cons. There is nothing wrong with resin or amalgam fillings, but there are too many quack dentists scaring their patients into having all their silver fillings replaced. And that's bad.

My dentist was dead against it, as I hinted at above. I read a book that seemed convincing and sincere enough at the time. Like I said it was about
20 years ago and I didn't have the benefit of any studies that have happened in the meantime or the internet for researching it. Some or all of my childhood amalgam fillings were needing replacement and I think I had also read about advances in composite plastic fillings. Anyhow they have been great and since you make more money off them perhaps we can agree that they are a viable option for anyone who can afford them and wants to reserve judgement or forego an extensive investigation into the absoluteness of the safety of mercury amalgam fillings.

[Tomblvd]

Originally Posted by Eggs Ackley

I'll stand by to be corrected by more knowledgable individuals.

See post #5.

Quote:

Perhaps so but it is not as if either dentistry or medicine have a history of being squeaky-clean with regards to treatment safety. Mercury amalgam fillings are fairly archaic as well so most likely their safety was not well-established prior to their common usage. Some scrutiny is reasonably warranted, seems to me. The relevant question is, at what point should one decide that safety is fully or sufficiently established? So now the studies have been done and that's good news that a new upper limit on the toxicity of mercury amalgam fillings is established and it's not very high. Am I to be faulted for being cautious twenty years ago before the studies were done?

Dental amalgam has been used for over 150 years. In that time there has been literally thousands of studies looking at safety. It is known as one of the most studied compounds (healthwise) in history. And in study after study, no adverse effects have been shown. It is actually sad that they had to throw good money after bad in order to study something that has been studied to death already. But be that as it may, it has been shown to be safe for many decades, but that won't quiet the critics.

In addition, this isn't a new study done by the FDA, it is a review of over 200 older studies done. IOW, the evidence has always been out there.

[Eggs Ackley]

Originally Posted by Tomblvd

See post #5.

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. Please correct me if I'm wrong. An amalgam is more like a solution than a chemical compound, seems to me. The mercury is not so tightly bound to the silver as, say, chlorine is to sodium in table salt. My understanding is that the mercury leaches out over time leaving the silver behind.

I'll stand by to be corrected by more knowledgable individuals.


What part(s) of that paragraph are false, specifically?

[Tomblvd]

Posts crossed, here is a reply to my first:

Originally Posted by Eggs Ackley

With this level of argumentation you are not making me more comfortable that amalgam fillings are safe. It is reasonable to consider sodium chloride part of what we are made of and of couse it is essential to our survival. Mercury is not such. Also, if the mercury levels in seafood are clearly dangerous (and I am not granting that is true but perhaps you are?) then please explain how that should reassure me that the exposure from amalgam fillings is of no consequence?

You misunderstand, I said nothing about mercury levels in seafood being dangerous. They aren't. But the levels in seafood are MUCH higher than any residual levels given off by vapors in the mouth. And whether NaCl is essential is beside the point. A component of salt is also highly toxic at certain levels, that doesn't make salt toxic. The same goes for amalgam.

Quote:

You are not giving dental services including amalgam fillings away for free, I don't think. If you can't do them it seems it will not clearly help your business. Plus, they've been in use for a long time and so it's not unreasonable to expect some resistance to stopping their use just on that account, even if they cannot be proven safe.

Why would I fight the ban of a filling material if the replacement is more expensive? I can make more money. Also, in cases where I can't use bonded resin, there are other alternatives, but they don't hold up well at all and need to be replaced often. I'm sure some dentists would love to say "well, the gov't says I can't use silver anymore, so I have to use this stuff, but we'll have to replace it next year".

Quote:

Also not a sound argument for the safety of amalgam fillings.

I isn't meant as an argument for SAFETY. You said there are "superior alternatives". What are they?

Quote:

I don't know but I'd be interested to know if the new studies addressed this. Certainly it would be a reasonable trade to consider among those who already have them. Is your claim that the exposure would be more by removal substantiated in a study somewhere or is that just your belief?

It always helps to read the article:

"Removing the fillings actually releases more mercury vapor, FDA said."

Quote:

It's not relevant to the question of whether they should be used in the first place, in any case.

It. wasn't. meant. to.

You were the one crowing about having all your silver filling removed. I was just pointing out how counter-productive that was.

Quote:

My dentist was dead against it, as I hinted at above. I read a book that seemed convincing and sincere enough at the time. Like I said it was about
20 years ago and I didn't have the benefit of any studies that have happened in the meantime or the internet for researching it. Some or all of my childhood amalgam fillings were needing replacement and I think I had also read about advances in composite plastic fillings. Anyhow they have been great and since you make more money off them perhaps we can agree that they are a viable option for anyone who can afford them and wants to reserve judgement or forego an extensive investigation into the absoluteness of the safety of mercury amalgam fillings.

As I said earlier, as long as it isn't sold as a cure for a disease, or ridding the body of "toxins", there is nothing wrong with it. But amalgam remains a good option for many people and many situations.

[Tomblvd]

Originally Posted by Eggs Ackley

Here is what I said:




What part(s) of that paragraph are false, specifically?

This:

Quote:

My understanding is that the mercury leaches out over time leaving the silver behind.

I have seen fillings that are 50 years old and have never seen one that the mercury "leached out leaving the silver behind". The mercury is tightly bound in the amalgam (see where the word comes from?). Various quacks and unscrupulous trial lawyers have been trying to measure elevated mercury levels in people with amalgams forever, and haven't had much luck. As I said earlier, there aren't many health items that have been studies more, and no ill effects have been proven.

[Tomblvd]

??

I'd say the delay in answering can only mean he comes up with the "smoking teeth" video as proof that mercury "leeches" out of the filling.

[Eggs Ackley]

Originally Posted by Tomblvd

This:



I have seen fillings that are 50 years old and have never seen one that the mercury "leached out leaving the silver behind". The mercury is tightly bound in the amalgam (see where the word comes from?). Various quacks and unscrupulous trial lawyers have been trying to measure elevated mercury levels in people with amalgams forever, and haven't had much luck. As I said earlier, there aren't many health items that have been studies more, and no ill effects have been proven.

Well I am not saying you are certainly wrong, but it didn't take too long to find an academic paper that directly contradicts your claim.

http://www.ripublication.com/ijpapv2/ijpapv2n3_1.pdf

'Jones et al. [1] proved that Mercury leaves dental amalgam
continuously throughout the lifetime of the filing. Mercury vapor is the main way that
mercury comes out of amalgam and is absorbed at a rate of 80% through the lungs
into the arterial blood [2, 3].'

Care to substantiate your claim beyond your say-so?

Edit: here is an interesting paper concerned with release of mercury into the environment from dental uses. It does say this:

Mercury in dental amalgam exists in a fairly
stable equilibrium, with only minute amounts
released into the surrounding environment.8-12

I would be interested to know how big is "minute" but it's unlikely I'll be able to get to those papers online.

http://www.dentalmercury.com/pdf/pap...infectants.pdf

[Eggs Ackley]

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.

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?

[Tomblvd]

Originally Posted by Eggs Ackley

Well I am not saying you are certainly wrong, but it didn't take too long to find an academic paper that directly contradicts your claim.

http://www.ripublication.com/ijpapv2/ijpapv2n3_1.pdf

'Jones et al. [1] proved that Mercury leaves dental amalgam
continuously throughout the lifetime of the filing. Mercury vapor is the main way that
mercury comes out of amalgam and is absorbed at a rate of 80% through the lungs
into the arterial blood [2, 3].'

Care to substantiate your claim beyond your say-so?

Nowhere in that paper does it make your claim that mercury is leeched out of the filling, leaving the silver (and other metals, I presume) behind. There is no doubt that the body absorbs mercury as the fillings wear, but, as you paper makes painfully clear, these levels are measured in the ppm or ppb range.

If mercury were "leeching" into the bloodstream, it would be a simple enough study to take urine samples from people with and without fillings and show highly elevated levels of mercury.

[Eggs Ackley]

Originally Posted by Tomblvd

Nowhere in that paper does it make your claim that mercury is leeched out of the filling, leaving the silver (and other metals, I presume) behind. There is no doubt that the body absorbs mercury as the fillings wear, but, as you paper makes painfully clear, these levels are measured in the ppm or ppb range.

If mercury were "leeching" into the bloodstream, it would be a simple enough study to take urine samples from people with and without fillings and show highly elevated levels of mercury.

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.

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.

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.

[Tomblvd]

Originally Posted by Eggs Ackley

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.

Quote:

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]

Originally Posted by Eggs Ackley

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.

Quote:

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.

Quote:

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]

Originally Posted by Tomblvd

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]

Originally Posted by Tomblvd

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.

Originally Posted by Tomblvd

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]

Originally Posted by Eggs Ackley

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]

Originally Posted by Eggs Ackley

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.

Quote:

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]

Originally Posted by technoextreme

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]

Originally Posted by Eggs Ackley

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]

Originally Posted by Eggs Ackley

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.

Quote:

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.

Originally Posted by Eggs Ackley

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]

Originally Posted by MattusMaximus

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]

Originally Posted by technoextreme

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]

Originally Posted by Eggs Ackley

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.

Quote:

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]

Originally Posted by paximperium

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.

Originally Posted by paximperium

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]

Originally Posted by Tomblvd

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]

Originally Posted by Eggs Ackley

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]

Originally Posted by Eggs Ackley

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/...-4218s1-03.pdf

[Eggs Ackley]

Originally Posted by technoextreme

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]

Originally Posted by Tomblvd

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]

Originally Posted by Eggs Ackley

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.