FDA: Mercury fillings are safe

[pgwenthold]

Thanks to Tomblvd, the dentist. I love hearing from people who know about this stuff.

 

[Tomblvd]

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.

How convenient.

You completely ignore absorption, ignore measurements of blood plama levels, ignore excretion rates in urine and respiration, and, most importantly, ignore thousands of epidemeological studies looking at amalgam and illness.

Toxicology does not work that way.

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?

Please do not lie about what I said. You made the statement "the mercury leaches out over time leaving the silver behind." That is a completely false statement. As I stated earlier, minute amounts of mercury vapor are given off when chewing or grinding usually, but only in amounts measured in parts per million or even billions in some instances. Certainly not enough to completely evaporate from the tooth leaving the silver behind as you said.

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?

What bacteria that is part of the normal oral flora converts elemental mercury to methylmercury? So I have to eat something that increases "leeching" and then breathe through my nose as I do so in order for the mercury vapor to be digested by some bacteria and then converted into methylmercury? You have created a Rube Goldberg type of mechanism here for amalgams to be dangerous. It is silly in the extreme.

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.

Again you lie about what I said. My quote:

"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."

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.

Children have become seriously ill and even died from vaccines. It is extremely rare and doesn't change the fact that on the whole, kids are better off vaccinated. On the other hand, aside from very, very rare allergies to amalgam, I am aware of no specific harm to any child who received a dental amalgam. You are making an absurd comparison.

 

[paximperium]

Thanks to Tomblvd, the dentist. I love hearing from people who know about this stuff.

Agreed.

 

[Tomblvd]

You're both most welcome.

 

[Eggs Ackley]

How convenient.
You completely ignore absorption, ignore measurements of blood plama levels, ignore excretion rates in urine and respiration, and, most importantly, ignore thousands of epidemeological studies looking at amalgam and illness.

Please do not lie about what I said. You made the statement "the mercury leaches out over time leaving the silver behind." That is a completely false statement. As I stated earlier, minute amounts of mercury vapor are given off when chewing or grinding usually, but only in amounts measured in parts per million or even billions in some instances. Certainly not enough to completely evaporate from the tooth leaving the silver behind as you said.

I didn't ignore them. I simply tried to set up a hypothetical where the matter could be settled without them. For example, if there were no mercury in a filling to begin with, we wouldn't be talking about measuring blood mercury levels to determine whether the non-mercury-containing fillings were causing mercury poisoning. The same would be true if the mercury could be shown to stay in the filling to within some calculable limit. I don't know what this limit would be but it wouldn't be necessary for all of the mercury to leave the filling to raise a concern. So your continual carping on my repeating of the claim that I've read that most of the mercury leaves over time seems like a ruse to me. I've already admitted that appears not to be the case and if didn't already thank you for improving the state of my knowledge I'm happy to do so now. But, it also seems that at least some of the mercury does leave the filling by one way or another and I don't see the crime in my being curious about how that amount would compare to toxic dosages.

I challenge you to find where I've said that even if all the mercury left the filling it would be absorbed or even if all of it were absorbed it would be toxic.

What bacteria that is part of the normal oral flora converts elemental mercury to methylmercury? So I have to eat something that increases "leeching" and then breathe through my nose as I do so in order for the mercury vapor to be digested by some bacteria and then converted into methylmercury? You have created a Rube Goldberg type of mechanism here for amalgams to be dangerous. It is silly in the extreme.

What is silly is your supposition that just because we sometimes exhale through our mouths that should help to convince me that there's no danger from evaporating mercury.

Now you are saying exhaling or not is irrelevant because there is no well-understood or documented means of absorption through mouth tissues? Why didn't you say that in the first place?

You should really stick to the simple facts that no harm has been found or demonstrated and no measurements have demonstrated toxic exposures, and that this has now been further supported by a federal meta-study. I don't mean to minimize the importance of this and if I had to put a mercury filling in my kid I probably wouldn't have mech of a care about it, on that account.

Again you lie about what I said. My quote:

"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."

OK on rereading you never did say specifically that all the mercury stays in the filling, only that it doesn't subtantially leach out. That's nice to know but simply saying exposure is in the ppm or ppb (which is it?) range doesn't fully assuage my concern. Apart from what is an obviously toxic level measured in the blood, which I am sure is well documented from Japanese events, there is the (reasonable-sounding) claim by the anti-amalgam people that the mercury gets tied up in specific organs like the brain and so measuring it in the blood isn't valid. I don't accept their claims at face value either but they don't seem that crazy. It seems quite a different question of what is a safe blood level from what is the blood level that causes obvious neurological symptoms. But, if amalgam fillings don't elevate blood levels above the background level in their absence that would be a useful thing to know. Then you just have to rule out that it is accumulating in other tissues than the blood and you're done.

Children have become seriously ill and even died from vaccines. It is extremely rare and doesn't change the fact that on the whole, kids are better off vaccinated. On the other hand, aside from very, very rare allergies to amalgam, I am aware of no specific harm to any child who received a dental amalgam. You are making an absurd comparison.

[/QUOTE]


I think it is quite apt. In both cases any risks associated with the treatment must be weighed against the benefit. It only supports the case for amalgam fillings in the we have a clear benefit but less demonstrated risk. This is how I meant it. I'm surprised you're taking me to task for this. Perhaps you should calm down and try to read my posts more carefully.

 

[Tomblvd]

I didn't ignore them. I simply tried to set up a hypothetical where the matter could be settled without them.

This is what you said:

"and then assuming that all that was missing was absorbed."

IOW, ignore.

For example, if there were no mercury in a filling to begin with, we wouldn't be talking about measuring blood mercury levels to determine whether the non-mercury-containing fillings were causing mercury poisoning. The same would be true if the mercury could be shown to stay in the filling to within some calculable limit. I don't know what this limit would be but it wouldn't be necessary for all of the mercury to leave the filling to raise a concern. So your continual carping on my repeating of the claim that I've read that most of the mercury leaves over time seems like a ruse to me. I've already admitted that appears not to be the case and if didn't already thank you for improving the state of my knowledge I'm happy to do so now. But, it also seems that at least some of the mercury does leave the filling by one way or another and I don't see the crime in my being curious about how that amount would compare to toxic dosages.

And as I have pointed out ad nauseaum, if there were a problem with excess mercury leakage and absorption into the body, it would be easily measured. Considering the immense numbers of studies, it hasn't been shown to be the case. The FDA just recently reviewed many of the studies and came to the same conclusion.

Honestly, I don't know what more you want.

Remember in vivo studies are usually more reliable in situations like this than in vitro.

I challenge you to find where I've said that even if all the mercury left the filling it would be absorbed or even if all of it were absorbed it would be toxic.

Uh, here?

"and then assuming that all that was missing was absorbed."

What is silly is your supposition that just because we sometimes exhale through our mouths that should help to convince me that there's no danger from evaporating mercury.

Strawman, I never said that.

Now you are saying exhaling or not is irrelevant because there is no well-understood or documented means of absorption through mouth tissues? Why didn't you say that in the first place?

I never said anything of the kind, and I'm not even sure what you are talking about here.

What are you talking about?

You should really stick to the simple facts that no harm has been found or demonstrated and no measurements have demonstrated toxic exposures, and that this has now been further supported by a federal meta-study. I don't mean to minimize the importance of this and if I had to put a mercury filling in my kid I probably wouldn't have mech of a care about it, on that account.

Well.....great.

OK on rereading you never did say specifically that all the mercury stays in the filling, only that it doesn't subtantially leach out. That's nice to know but simply saying exposure is in the ppm or ppb (which is it?) range doesn't fully assuage my concern. Apart from what is an obviously toxic level measured in the blood, which I am sure is well documented from Japanese events, there is the (reasonable-sounding) claim by the anti-amalgam people that the mercury gets tied up in specific organs like the brain and so measuring it in the blood isn't valid. I don't accept their claims at face value either but they don't seem that crazy. It seems quite a different question of what is a safe blood level from what is the blood level that causes obvious neurological symptoms. But, if amalgam fillings don't elevate blood levels above the background level in their absence that would be a useful thing to know. Then you just have to rule out that it is accumulating in other tissues than the blood and you're done.

OK, I took some time to find some numbers for you and came across a website from a dentist that has them:

http://www.doctorspiller.com/mercury_3.htm#Inhaled_mercury

The most significant contribution to mercury assimilation from dental amalgam is via the vapor phase. The patient’s encounter with mercury vapor during insertion of the restoration is brief, and the total amount of mercury vapor released during function is far below the “no effect” level. The most reliable estimates suggest that mercury from dental amalgam does not contribute a significant amount to the total exposure of patients. The results of one study in which patients with amalgam restorations were monitored with mercury vapor detectors over a 24-hour period showed that the amount of vapor inhaled was 1.7 µg/day [millionths of a gram] . Three other studies have confirmed that the magnitude of vapor exposure for a patient with 8 to 10 amalgam restorations is in the range of 1.1 to 4.4 µg/day. The threshold value for workers in the mercury industry is 350 to 500 µg/day, depending on activity level, and is based on an exposure of 40 hours per week. [Note that these measurements are in "micrograms" of mercury found as inhaled vapor. This is in contrast to the "nanogram" units discussed above which relate to the amount of mercury found in blood serum...MS]

Mercury blood levels that were measured in one study indicated that the average level in patients with amalgam was 0.7 ng/ml [billionths of a gram] compared with a value of 0.3 ng/mL for subjects with no amalgam. This difference was found to be statistically significant (P 0.01). However, one should be aware of a study in Sweden that demonstrated that one saltwater seafood meal per week raised average blood levels of mercury from 2.3 to 5.1 ng/mL, a sevenfold increase (2.8 ng/mL) compared with that (0.4 ng/mL) associated with amalgam restorations. The normal daily intake of mercury is 15 µg from food, 1 µg from air, and 0.4 µg from water.​

Hopefully that will assuage your concerns...

...but I doubt it.

I think it is quite apt. In both cases any risks associated with the treatment must be weighed against the benefit. It only supports the case for amalgam fillings in the we have a clear benefit but less demonstrated risk. This is how I meant it. I'm surprised you're taking me to task for this. Perhaps you should calm down and try to read my posts more carefully.

Please give me the "demonstrated risks" for a child getting an amalgam. Or better yet, a benefit/risk analysis for amalgam.

The two situations are completely different.

 

[jasonpatterson]

However, one should be aware of a study in Sweden that demonstrated that one saltwater seafood meal per week raised average blood levels of mercury from 2.3 to 5.1 ng/mL, a sevenfold increase (2.8 ng/mL) compared with that (0.4 ng/mL) associated with amalgam restorations. The normal daily intake of mercury is 15 µg from food, 1 µg from air, and 0.4 µg from water. ​

Hopefully that will assuage your concerns...

...but I doubt it.

I betcha those fish had amalgam fillings though!