Dr. Frederick Smith Editorial to the Bedford Bulletin

Dentist opposes use of amalgam filling
by C. Frederick Smith, DDS, MS, FAGD

Recently you published an article in which a dentist stated that he feels dental amalgam filling material is safe to use. He repeated the American Dental Association's (ADA) claim that dental amalgam has been used for over 150 years and that it is safe to use in the mouth. When I was told as a dental student over 30 years ago that amalgam contained mercury, I was very concerned. My dental professors at that time assured me that mercury could not leak out of the filling material and, although I doubted the validity of that statement, because I had worked as a research chemist before going to dental school, I did not think it wise to disagree with my professors.

Shortly after graduating from dental school in 1977, I began to research the safety of dental amalgam or silver filling material as it is sometimes called. I now call them mercury/silver dental fillings because the major component, 50 percent, is mercury, with silver being about 35 percent and other metals making up the rest of the mixture. I hold a Master's Degree in Chemistry and a minor in Biochemistry, so I have a high respect for the toxicity of elemental mercury. I also belong to a dental professional organization, the International Academy of Oral Medicine and Toxicology, (IAOMT), whose major concern is with the safety of the dental materials, based on scientific evidence, which we dentists use in the mouth to restore teeth.

Scientific research has proven beyond a shadow of a doubt that elemental mercury evaporates from amalgam fillings as mercury vapor. When a piece of 25 year old amalgam filling that had been removed from a patient's tooth was lightly touched and then examined with an electron microscope, tiny balls of liquid unbound mercury could be seen beading up on the surface of the filling. With special black lighting mercury vapor has even been photographed evaporating off of dental amalgam.

Animal studies have shown that mercury vapor breathed in is 80 percent absorbed by the blood in the lungs and then becomes a cumulative toxin that the body has to dispose of. These studies have also demonstrated that mercury from amalgam fillings accumulates in distant organs within a few weeks of placement in the mouth. Mercury is most definitely not locked into these mercury/silver dental fillings but can escape as a vapor and in other ways also.

The position of the ADA is that although mercury vapor does evaporate off an amalgam, it is not at a harmful level. The position of the World Health Organization (WHO) is that any mercury in the body greater than "zero" is harmful. In 1990 the WHO reviewed exposure to mercury vapor from amalgam and concluded that mercury released from amalgam is by far the major source of human exposure to mercury. The consumer is now put in the awkward position of whom to believe: the ADA who is in favor of amalgam use or the WHO that states that it is the major contributing factor to human mercury exposure.

In September 2006, the Food and Drug Administration (FDA) held a meeting in which an advisory panel of physicians and dentists reviewed "The Draft FDA White Paper" as to the safety of mercury/silver fillings or amalgam. The panel heard from FDA "invited quests" and others about the research related to amalgam and, not surprisingly, all of the FDA "invited quests" supported the continued use of mercury, including Rod Mackert, a paid spokesperson for the ADA.

Despite this pro-amalgam support, 9 out of 10 of the neurologists on the advisory panel voted that the FDA White Paper did not objectively and clearly present the current state of knowledge about exposure [to mercury] and health effects related to dental amalgam. They also voted 9 out of 10 to say that "Given the amount and quality of information available for the FDA Draft White Paper, the conclusions [that amalgam is safe] were not reasonable". Even 4 of the 10 dentists on the advisory panel voted with the neurologists in this landmark finding against the safety of amalgam. So far the FDA Docket has received over 3,000 submissions from individuals adversely affected by dental amalgam.

As I understand it, the FDA has only two positions. A material is either safe or not safe. If the advisory panel would not make a statement that amalgam is safe, then what are we to assume but that it is not safe?

We currently have suitable materials to replace amalgam in most all situations. I have not found it necessary to use mercury/silver dental filling material in most teeth since 1984 and not in any teeth since 1998. In fact the ADA estimates that currently over 50 percent of posterior teeth are restored with non-amalgam filling material and a recent survey found that one third of dentists do not use mercury/silver dental filling material at all. It is true that placing tooth-colored composite restorations requires more time, thus increasing their cost. However, they do have some major advantages.

They are very conservative of the patient's natural tooth structure and require only that the decayed portion of the tooth be removed. They also bond the remaining tooth structure together, giving the tooth back almost its original strength which reduces the risk of fracture. They match the natural tooth color so the teeth do not appear dark and gray like teeth with amalgam. They can even be placed on the surfaces of a child's permanent teeth as a sealant to prevent decay from penetrating the grooves that are so often the first site of a filling in a child.

Rod Mackert, the paid spokesperson for the ADA, was quoted in the Wall Street Journal cautioning against amalgam removal because that procedure causes excessive mercury exposure. This is true unless the patient is protected utilizing the safe amalgam removal protocols pioneered by the IAOMT. Mr. Mackert, however, did not mention the fact which it is equally true that placing an amalgam will cause a large bolus dose of mercury release followed by a continuous low dose release for the life of the mercury/silver dental filling material.

Unfortunately, when dentists place and remove dental mercury containing amalgam, they expose themselves, their staff, and their patients to toxic mercury vapor and amalgam dust particles unless they take special precautions to minimize the exposure as recommended by the IAOMT. Mercury vapor is colorless, odorless and tasteless. If we cannot see it, smell it, or taste it, it's very hard to believe that it is present. The ADA recommends that the dental treatment rooms be well ventilated, but without some sort of monitoring and well defined protection and containment procedures, mercury exposure will inevitably occur.

This issue of mercury toxicity from amalgam fillings will not go away until mercury/silver dental filling material is completely removed from dentistry. There are many organizations besides the IAOMT that are fighting hard to eliminate or restrict the use of mercury/silver fillings as a dental restorative material as has been done in Sweden, Germany, Austria, Canada and England for high risk patients such as pregnant women and children. When other countries have had a fair and balanced review of the currently available scientific research on mercury containing dental filling material, and have found it to be unsuitable as a dental restorative material, it is disturbing that the United States, usually a leader on these issues, is so far behind other countries.

I personally feel that the use of mercury containing dental filling material should be discontinued in this country as soon as possible, and immediately in those individuals most at risk, such as pregnant women and children. If the discontinued use of mercury containing amalgam has been successfully accomplished in other countries, I am sure we can be as equally successfully in eliminating its use in the United States.

(The information given in this letter is the opinion of the author. Please consult your local physician for more dental health/medical information.)

C. Frederick Smith, DDS, MS, FAGD


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