Mercury is a heavy metal that occurs naturally in the environment. Mercury poisoning happens with overexposure to this metal, which is toxic to humans. It can build up in the body and excess amounts can be fatal.
Mercury poisoning largely affects the human brain, nervous system, lungs, and kidneys. It has an extremely high affinity for the body tissues. In other words, once it is in your tissues, organs, and nerves, the body has a very difficult time eliminating it. You can take steps to help the body gather up and eliminate the mercury through a process called chelation.
Today I will discuss some of the debate, controversy, and history of mercury fillings as it is still used today both in North America and many countries around the world. The question is whether or not these dental fillings cause mercury poisoning in patients.
A Brief History
Today, dental fillings can be made out of gold, composite resin, amalgam, and ceramics (porcelain). Amalgam, which is also called ‘silver’ or ‘mercury fillings’, is a material made up of mixed metals, mostly silver and a small amount of copper, and about 50% of it is mercury. As a dental filling, it is incredibly strong, durable, long-lasting, inexpensive and relatively easy to apply.
But over two hundred years ago the main and only filling material was gold….it was (and still is) a very good material but much more expensive. In 1819 the mercury/amalgam filling was invented by a British chemist and it began to be widely used in Britain, France, and the United States by the early 1830s. It was much easier to use and apply, and much less expensive therefore you can understand why it became such a widely used and popular filling material.
Over the next 30 years, patients experienced health issues and there was debate and division among dentists whether the mercury fillings should continue to be used. The pro mercury dentists formed a society and essentially won the debate over the use of amalgam fillings. The Society was later renamed in 1859: it became known as the American Dental Association.
Mercury in Dental Fillings
Mercury is used in dental fillings because it plays an important role in binding the various metals of silver and copper together. The metals become an alloy which describes the chemical and molecular bonding of the various metal atoms together. In this form it is thought that the mercury is completely bound up, and not released into the body and essentially non-toxic; therefore these filings would be safe to use in the human body.
This is essentially what I was taught in dental school over 30 years ago. I have to admit that in my first several years as a dentist I had no reason to believe otherwise and I reiterated exactly what was taught by my professors and the experts at the school.
We were also taught that although up to 50% of the mercury that is in the amalgam filling is not bound up by the copper and silver, it mostly stays within the filling material and that any amounts released into the body are negligible and harmless. I recall being told that chewing and drinking hot foods or liquids did not release any appreciable amounts of mercury.
However what did not make sense is that although the mercury fillings were considered safe for the human body, any excess material or any old fillings that were removed were considered unsafe and toxic to dispose of in regular garbage. It had to go into special Sulphur containers which would bind the mercury. The reason given was that mercury in the environment might accumulate and/or form methyl mercury (see below).
And the theory that mercury is not released once in the mouth with chewing or hot foods also raises some questionable debate. Here is a video illustrating vapour coming off a mercury filling with only a slight rise in temperature. I think the question then is not whether mercury is released from amalgam fillings; rather whether how much is released and just how much is safe?
Additional Facts About Mercury
The pure atomic form is called elemental mercury and as mentioned above, when it combines with other metals it is called an alloy. Elemental mercury is very toxic. It has a very low vapour pressure which means at a relatively low temperature it evaporates and becomes a gas. The elemental form is absorbed through the skin and is more readily absorbed through mucous membranes such as the eyes and mouth. It can also be inhaled through our lungs and absorbed by our soft tissues and enter the bloodstream.
Mercury can also combine with carbon and hydrogen and become a form called methyl mercury. This process occurs when mercury is exposed to bacteria in the environment, although this process may also occur in the body (my opinion only…I have not been able to find any research or evidence, however it does not mean we can rule it out either!). This form of mercury is most toxic as it can easily pass through the body tissues and particularly into the brain.
Regardless of the above, mercury in any form is considered toxic. I recall a time when thermometers were made of mercury; in my school science class, a mercury thermometer was dropped and broken. There was so much worry over the vapors that the classroom had to be evacuated and the air allowed to clear before anyone could re-enter!
Even when dental fillings are installed and the amalgam is heated, there is a chance for patient exposure to mercury vapor. As noted in the US Department of Energy’s Risk Assessment Information System (RAIS): “approximately 80% of mercury vapor is absorbed following inhalation exposure.” Inhaling mercury vapor during filling installation is possible, and it puts patients at risk. You can also be exposed to mercury vapor during amalgam filling removal if it is not performed properly.
I don’t think any scientist or health professional could or would say that mercury is not harmful…it certainly is. The debate is whether in the form of amalgam fillings it causes a health concern. It has already been banned in several countries since the early 1990s. Here in 2009 Health Canada reviewed the amalgam controversy and issued a statement that, although did not ban the use of mercury, it acknowledged some potential risks and recommended limiting its use in certain situations (children, pregnancy etc)
One problem which may confuse the issue is that we are exposed to mercury from many sources besides fillings. Certainly, some foods have shown higher levels of mercury, but also vaccines, flu shots, and contact lens solutions/eye drops have used mercury or their compounds as a preservative. If mercury is toxic, certainly injecting it or dropping in your eyes can’t be any better.
On a very personal note, I became very ill with Graves disease almost 20 years ago. The physicians could not tell me what caused it…except that it was autoimmune and stress-related. I continued to search and through a naturopathic physician discovered that heavy metals can contribute. After being tested I found out I was so filled with mercury and other heavy metals I was beyond the measured scale.
Once I took some steps to chelate the metals and actively remove them, my health returned (~3 months) and I have since been cured from what I was told was “incurable” without traditional medical treatments. Although I certainly had my share of mercury fillings in my youth I cannot say for sure that the fillings were the source, I used mercury preserved contact lens solutions for years and had many vaccinations as a youth, so no doubt I have had many possible sources of exposure. My guess is that is probably true for most of us.
More Mixed Scientific Opinions
The majority of scientific literature takes the stance that amalgam fillings are not harmful and are safe for patient use, although as mentioned above that has been debated for over 100 years and has been difficult to reach solid conclusions.
How much is truly scientific or politically or legally motivated, I really don’t know but I think it still requires further unbiased debate. The risk probably lies in the form and amount of mercury present. The proponents continue to support the claim that mercury is relatively harmless in its solid, amalgam form.
It may become more dangerous to patients during the installation and removal of dental fillings when vapor can escape. As noted by the National Capital Poison Center: “swallowing metallic mercury from an amalgam filling would not cause mercury poisoning. In contrast, breathing in large amounts of metallic mercury vapor can cause poisoning.” Despite the mixed opinions, amalgam fillings are still used in dentistry today, as there has not been enough substantial research to directly connect fillings with mercury poisoning.
Further research is needed, however, patients should be aware of the potential risks involved. As the Canadian Dental Association states: “Every time a foreign substance is used in the human body for therapeutic purposes, there is an element of risk.” At VCCID, we choose not to put our patients at risk for mercury poisoning by taking a holistic approach to dental care.
Treatment and Prevention
The human body can tolerate trace amounts of mercury in certain forms, however, if overexposed, you can experience signs of mercury poisoning. Mercury is difficult for the body to process and as a result, it can build up in our systems in a process called bioaccumulation. It can be difficult to determine the amount of mercury in your body, as there are very few symptoms. There is a naturopathic form of treatment for those that have been overexposed to high levels of mercury called chelation.
Holistic Dental Care
VCCID practices holistic dentistry. This means that we consider the effects dental care can have on the entire body. We know that potentially harmful materials used in dental fillings can adversely affect both your physical and mental health.
That is why we choose to use alternative materials in our dental fillings. Whether or not amalgam fillings are directly harmful to patients has yet to be confirmed by the scientific community, however, we take a holistic approach to treatment, and prioritize our patients’ health and safety.
So to summarize the above: mercury is toxic in all its forms. We are exposed to mercury from many possible sources. Once in the body it does not get released….it stays there and accumulates unless you take active steps to remove it. There is mercury in amalgam fillings and some mercury is released through eating, drinking and wear and tear. Whether this amount of mercury is causing us harm is still being debated.
It may depend on how much has accumulated, our overall health and strength of our immune system, all the toxins/things that we have been exposed to in the past, it causes a wide variation in illnesses over a long period of time and so many other factors that it makes it difficult to properly study quantify. But since we now have other inexpensive and alternative materials why would we still consider using it?
Visit VCCID to Learn More
When it comes to mercury exposure and mercury poisoning, it’s much better to be safe than sorry. Our holistic approach to dental care means that we do not use mercury in our dental fillings, our patients’ health comes first. Contact us to schedule your appointment or visit us in our Burnaby, Metrotown office.