Is Your Smile Safe?

With a recent admission by the FDA that amalgam dental fillings containing mercury may be unsafe for children and pregnant women, an old controversy is stirred up anew: are these fillings truly safe, as most dentists have claimed, or will the mercury they contain poison your body?

If you ask those in the world of naturopathic medicine, this is no controversy. Magazines such as Natural Solutions, many holistic dentists, and even some members of the American Dental Association have maintained for years that these fillings should not be used. And definitely should be avoided by pregnant women and children, who are more sensitive to toxic exposure. I went to one holistic dentist who told me that he “didn’t like all that metal in my mouth,” and believed it was very likely that my fibromyalgia had been caused by my dental fillings. For a price (not reimbursed by my health insurance), he would be very happy to remove them all and replace them with a “safer” alternative.

Even though I knew people who had all their fillings removed, and they said it made them feel better, this seemed like an extreme step to me, and definitely something my insurance would not cover.

But neither the FDA nor the American Dental Association recommend removing existing fillings. This, some say, actually increases your exposure to mercury. “You have to heat the filling and drill into the tooth,” says Dr. Mark S. Wolff of the New York University College of Dentistry. “[This means] you’re releasing mercury into the air [which can be inhaled] as well as debris that can be swallowed.”

However, the FDA, (notoriously slow to act even on the most dangerous of health issues) was spurred into action concerning the safety of fillings in general by the threat of a lawsuit from a grassroots organization called Moms Against Mercury (along with 10 other plaintiffs). They settled out of court under the condition that the FDA change their website to read that amalgam fillings containing mercury “may have neurotoxic effects on the nervous systems of developing children and fetuses.”

Some dentists I spoke with disagreed. According to Dr. Robert Boris (in the interest of full disclosure, I must tell you that Dr. Boris is my father), there is no credible evidence linking silver amalgam fillings to mercury poisoning. “There is more available mercury in a can of tuna fish,” Dr. Boris says, “than in a mouthful of [amalgam] fillings.”

Dr. James Ross, who practices in Red Hook, New York, concurs. “I have yet to see any credible studies showing that amalgam fillings give you any more mercury exposure then you get from your natural environment.”

While some release of mercury vapors can occur over time, Dr. Boris says, it’s very minor, and not dangerous. Plus, he says, the mercury in the amalgam is bound with other materials like silver, zinc, and tin, and therefore is not available to the body as a separate element. It’s not “free” mercury, like the kind you might see in thermometers, fluorescent light bulbs, or in the thimerosal used as a preservative in many vaccines given to children. (Studies have shown, however, that “free” mercury is a cause for concern, and can cause mercury toxicity. This is the bulk of Moms against Mercury’s advocacy work.)

But both dentists agree that silver amalgam is a superior material for filling teeth. Since the amalgam material sits tighter against the enamel of the existing tooth than composite resin fillings, it makes for a stronger barrier against bacteria, especially when it mixes with the saliva in your mouth. It also has the same coefficient of expansion as natural tooth enamel, which means that when your teeth naturally expand and contract (for example, when you drink a cup of hot coffee or eat ice cream), the filling will expand and contract along with it, allowing for a tighter seal, and longer wear.

Conversely, composite fillings, which are often made from plastics, do not expand and contract at the same rate as natural teeth. This can make them break down faster and allow more bacteria into the drilled cavity of the tooth, especially when used in posterior teeth like molars, which do more grinding and crushing than front, or anterior, teeth.  A compromised composite filling, if not repaired or replaced soon enough, can make you a candidate for a painful root canal, or require the installation of a crown to protect the tooth.

For those of you who are still concerned about possible mercury exposure, the newer silver amalgams contain less mercury. If you don’t mind paying a bit more, or having to replace your fillings more frequently, choose a material like gold, porcelain, or a BPA-free composite for any new cavities.

But if you do choose to have your fillings removed and replaced, choose a dentist who is experienced in the proper procedures. A dental dam and suction must be used to prevent any inhalation or swallowing of the materials.