What About Mercury and those Silver Fillings?

by J. K. Hackbarth, DDS

Over the past few years there has arisen a controversy about the use of dental amalgam (silver) fillings in teeth. The controversy concerns the mercury content of the alloys used for these fillings. Silver alloys can be up to around 48% mercury. Everyone knows that mercury is toxic. The question is--does this present a health risk to dental patients?

Twenty years ago the official line (What we were told in dental school) was that the mercury was bound up in the alloy in such a way that it wasn't released. That statement was made simply because we couldn't measure the release of mercury into the body because of the limitations of then existing equipment. Now we know that that statement is not true--tiny amounts of mercury are released from silver fillings. The question then becomes--how much mercury is a health risk and, does the amount of mercury released present a health risk to the average individual?

Now this is where the controversy really heats up. People have come forward with their personal testimonies as to the benefits they have received by having the silver fillings removed from their teeth. These stories are often revolving around those with debilitating diseases, such as muscular sclerosis, whose symptoms were relieved after the removal of silver fillings. We call these stories anecdotal, in that, while they may be true, they are not based on any sound scientific evidence or studies.

There have been studies done that seem to prove that amalgam is safe. There have been studies done that seem to indicate that it may be a problem. There have been studies done that say there should be more studies. Each side has its critics and advocates.

The official positions of the FDA (Food and Drug Administration) and the ADA (American Dental Association) is that dental amalgam is safe. They base their opinion on the fact that there are no studies, which they believe are scientifically valid, that show there is any health risk to the general public due to the use of dental amalgam. Their point is that there are millions of people with billions of fillings and they are not having any problems.

Now this position may be correct, or it may not, but I feel that you are missing some data, which is important in the consideration of its safety. I think that you don't necessarily need to be a scientist to decide about whether these fillings are OK for you. Here are a couple of items that just don't add up to this Texas boy.

First, consider this. Several years ago, in the 1980's, the Environmental Protection Agency ruled that paint manufacturers could no longer use mercury as an additive in wall paint. Mercury was used as a fungal inhibitor. It was added to paint at the level of 200 PPM. That means there were 200 parts of mercury per 1,000,000 parts of paint. The EPA decided that Mercury in the paint on your wall was an environmental hazard.

Secondly, there are problems concerning the disposal of dental amalgam. According to Lt. Col. James Kane, DMD, the officer-in-charge of Facilities and Construction at the U.S. Air Force Dental Investigation Service in San Antonio "Amalgam disposal is becoming more of a problem because it contains mercury, and mercury is highly regulated."

Now it is true that mercury is found in food--primarily fish. It is in the more dangerous form of methacrylated mercury, but elemental mercury, the kind found in dental amalgam, is also absorbed from the air through the lungs. Mercury accumulates in the body over time. Studies have shown increasing mercury levels in fish as correlated to body length (a measure of age). Mercury has also been found in the brains and livers of seals.

Now the EPA has set limits on the amounts of mercury which can come out of publicly owned water treatment plants, and some localities have set limits of the amount of mercury that can be discharged from commercial establishments. Commercial establishments are typically allowed only 50 PPB (Parts Per Billion) in their wastewater discharge. Did you get that--50 PPB!?

Now Gosh, I don't know, but it seems to me that if 200 PPM on your walls, and anything over 50 PPB down the drain are dangerous, how can 480,000 PPM be OK to put right in your body?! Something just doesn't add up to me.

Now, I can't tell you that you are in any danger if you have silver fillings in your teeth. There really isn't any hard data to say that it is. Dateline 2003 The previous statement is no longer quite accurate. I have just seen research that clearly shows deleterious effects of mercury on neural tissues. You can see this for yourself on the net. Search for the University of Calgary. When you open their main page type the word "mercury" in the search box and then download and watch the short movie on the effects of mercury. But, looking at the above, there is, in my mind, sufficient doubt as to whether we should continue to use amalgam--especially considering the fact that we have other materials which can easily be substituted for it in the restoration of teeth.

Besides this controversy over mercury, there are many other reasons not to use dental amalgam:

It's ugly.

It does nothing to add to the strength of the tooth. Studies have shown that a typical preparation for the repair of decay can reduce the structural strength of a tooth by 50%. The filling of the tooth with dental amalgam does not increase that figure.

More durable materials are available. Some of the modern bonded restorations placed into the same size preparation can restore up to 90 to 95% of the tooth's original strength.

More than 80% of the teeth that I treat for fractures have silver amalgam restorations.

Amalgam restorations leak. That is a fact. Amalgam makes no attachment to the tooth structure. The only reason they don't fail right away is that, as they leak, the amalgam corrodes. This corrosion creates expansion that temporarily slows down the leakage.

Then there is the expansion and contraction factor. What do they put into thermometers--mercury, right? When it gets hot, it expands and when it gets cold, it contracts. No wonder teeth tend to fracture!

I should tell you now that I quit placing dental amalgam restorations 8 years ago in favor of alternative materials and procedures. I have almost never removed an amalgam filling which did not have some problem underneath, usually recurrent decay. Often there are fracture lines that were hidden by the size of the filling, which penetrate into the area near the nerve of the tooth. This often necessitates the restoration of the tooth with a crown and may have even affected the nerve of the tooth so that it needs root canal treatment to be saved. My observation is that these amalgam fillings begin to do damage to the tooth (visible fracture lines) at around 10 years of age. I have seen too many teeth fail catastrophically--due to amalgam fillings that have remained in place too long.

About the only reasons I can think of for the use of silver amalgam is that it is relatively cheap and it's easy to place. (I say relatively cheap because of the above mentioned problems.)

If you have any concerns about what you have read, or you wish to have your old silver/mercury fillings replaced, let us know.

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