In a comment to a recent blog on the Clark Family Dental website, the responder mentioned that he had a friend who had been told by his dentist that all of his metal fillings and crowns needed to be replaced.  He asked me if this was the right thing to do and asked if it would cost very much to replace his own fillings and crowns.
The short answer is that it would probably be the wrong thing to do, and it could cost quite a lot.

If you want a more complete response, I also said that I would post a more thorough blog on the issue of the health considerations around silver fillings and metal crowns. The more complete response follows:

First of all, about silver amalgam fillings:

In most communities in the US, there are dentists who promote their practice by announcing that they practice “metal-free dentistry.”  If  asked why they refuse to use metal fillings, some will reply that because of the mercury content in silver fillings, silver fillings are toxic and could harm their health.  There are literally thousands of websites and blogs that talk about a conspiracy between government agencies and the American Dental Association to hide the danger of silver fillings.  Many of them talk about the conspiracy’s willing effort to “poison our children.”

Silver fillings do have mercury in them.  Silver amalgam is a “eutectic alloy” of silver, mercury, tin, zinc and often copper.  In the metallic form, mercury poses no threat.  Mercury vapor, however, is quite toxic in certain concentrations.  So, swallowing a silver filling releases no mercury inside the body, and passes through the GI system unscathed.  However, vigorous chewing on large surfaced amalgam fillings does release microscopic amounts of mercury vapor into the mouth, most of which is expired into the atmosphere.

The general scientific consensus is that if you have a large number of silver fillings and chew a lot of crunchy foods, you will probably release about as much mercury vapor as you would eating an occasional tuna fish sandwich.  I live right on the edge—I have silver fillings in my mouth, AND eat seafood about once a week.

The biggest outcry in the US about silver fillings occurred in 1990 with a “60 Minutes” segment on dental amalgam that was called “Poison In Your Mouth.” The show was repeated in 2007, and had interviews with several dentists who warned about the supposed danger of silver fillings, and several patients who claimed to have been poisoned by their silver fillings.

I have been practicing dentistry for decades and have reviewed dozens of thorough scientific studies, many involving hundreds of thousands of subjects, about the toxicity of silver fillings.  They convince me that silver fillings are one of the safest foreign materials used to augment the body, second only to titanium.   Although the silver-hating theorists report studies of their own, they appear to me to be flawed and subjective.

By way of support, the U.S. Food and Drug Administration reviewed 200 scientific articles and another 70 abstracts regarding the safety of silver amalgam fillings.  The FDA stated that “dental amalgam is a commonly used device with a low risk of adverse events reported to the agency.”  The American Dental Association warned dentists that if they talked patients into removing silver amalgam fillings and replacing them with other types of fillings because of the asserted health risks of silver fillings, they were violating ethical standards and could be prosecuted for fraud and malpractice.

If you consider the ADA and the FDA to be a part of the evil mercury-loving conspiracy, Consumer Reports weighed in on silver fillings in a book titled, “Health Schemes, Scams, and Frauds.”  The book concluded: “in CU’s view, dentists who purport to treat health problems by ripping out fillings are putting their own economic interests ahead of their patients’ welfare.  The false diagnosis of mercury-amalgam toxicity has such harmful potential and shows such poor judgment on the part of the practitioner that CU believes dentists who engage in this practice should have their license revoked.”  I agree.

The silver-hating theorists give several reasons why they believe dentist are happy to “poison our children.” They say dentists are “lazy.” That’s probably the best reason they give, because silver fillings are easier to do properly.

The silver-hating theorists also say that the silver fillings cost the dentists more to perform.  That is absolutely false.  Materials used to do resin fillings are more expensive than the materials used to do silver fillings, and the products needed to produce ceramic or gold fillings are many times more expensive.  The dental materials manufacturers also make much more in the sale of resin, gold and ceramic materials than they do with silver amalgam materials, so they have little financial reason to promote silver over alternative materials.

The silver-hating theorists say that it is more profitable for dentists to do silver fillings.  That is absolutely false.  Nearly all dentists charge, and most insurance schedules allow about 50% to 100% more for resin fillings than for silver fillings. We make about six to seven times more doing ceramic or gold fillings.  They mention glass-ionomer fillings as a worthy substitute for silver, but the glass ionomer fillings usually last 20 -30% as long as silver fillings.  If silver amalgam fillings were outlawed it would greatly improve my financial bottom-line.

I have yet to have heard a good reason from the silver-hating theorists why dentists want to “poison our children.”  Sounds to me like a terrible practice builder.

And then there is “Hormesis.”  Hormesis is a subset of toxicology that studies the effect of very low doses of natural and man-made toxins.  Toxicology usually teaches that the harmful effects of toxins are reduced as the dose is lowered, until there is zero harm below a certain dose.  Hormesis, however, suggests that below these low doses, toxins actually prosper the animal or plant.

Studies have been done on ionizing radiation, mercury, arsenic, various pesticides and many other toxins and have reported that very low doses promoted good health in the plant or animal studied.  The FDA and the Agency for Toxic Substances and Disease Registry have both done studies on mercury that support the concept of hormesis.  This suggests that maybe, maybe the minute amounts of mercury vapor released from silver fillings are not just benign, but maybe beneficial. We should see over time if this concept proves to be correct.

This seems to make sense.  Consider that every vitamin and every mineral essential for life can kill you if the dose is too high.  Even drinking water in very large amounts can kill you.  I usually read about one newspaper article a year about some parent who has done a “water cure” on their child and killed them.  The excess water in the blood causes the red blood cells to explode and the brain dies from lack of oxygen.

As I mentioned, I have had many silver fillings placed in my own mouth (I know, I know…why would a dentist EVER get cavities), and have in recent years placed silver fillings in my childrens’ mouths, and recommended them in my grand-childrens’ mouths.

About metal crowns:

Study after study have shown gold alloy crowns to be safe, except in an extremely small percentage of the population who are allergic to gold, silver or palladium.  Titanium crowns are tolerated even better.

Stainless steel crowns, however, are a problem for many people.  About 50% of the female population in the US is allergic to nickel, largely as a result of getting stainless steel ear-rings and studs from infancy and older.  The male population is currently less allergic to nickel, but that is changing, largely due to the increasing number of men getting metal studs and ear-rings.  Stainless steel crowns are an alloy with nickel, and many of the patients who have them develop unpleasant or horrible allergic reactions from these crowns.

Porcelain and Ceramic crowns certainly have their advantages.  They are tolerated by the body very well if the fit is accurate.  The beauty and natural appearance of these crowns are unexcelled.  However, their strength and accuracy of fit are usually not as great as metal crowns, but are usually very adequate.


Silver amalgam and resin fillings can be done with a high degree of success in most instances, and I am happy to do either when the patient requests them.  I usually point out that the silver fillings are more durable and cheaper than resin fillings, but are not very beautiful.  I almost always use resin fillings on front teeth that need to be filled.

I often use gold alloy crowns or porcelain-to-metal crowns on posterior teeth. I routinely use porcelain or porcelain-to-metal crowns on front teeth.

Dr. Guy C. Clark will answer all questions about Silver Fillings and Mercury Toxicity

Albuquerque Dentist

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