PRESENTS
PRESENTS
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THE TRUTH ABOUT MERCURY FILLINGS: |
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Mary's Plight and some Answers by David C. Kennedy, DDS |
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| MARY: | Mary, an email writer, has a bad experience with her dentist. |
| PROFESSOR: | A dental educator defends Mary's dentist. |
| KENNEDY: | Dr. Kennedy exposes the flaws in the educator's position. |
| FAN: | A fan makes some additional interesting points. |
Mary's Plight |
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Mary writes:
Okay, I've read enough to fear amalgam. So I went in to my dentist last week and happened to casually ask if he was aware of the controversy. Well, he flew off in an intolerant rage about the anti-establishment loonies who jump to conclusions. His argument, once he calmed himself a bit, was basically that so many people had so much amalgam for so many years, so it must be okay. At least, that's what I think he said. I was timidly nodding and cringing. Anyway, I don't want to argue with him. I want to find another dentist.
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A Dental Professor Replies |
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Mary,
As a dental educator involved in teaching the use of dental amalgam for the last 30 years I feel I must respond. The dental profession is concerned about the welfare of its patients and there is no conspiracy to use unsuitable materials in treatment. If there was a problem with the use of dental amalgam it would certainly show up in those who use it on a daily basis. No study that I am aware of has demonstrated any such connection in dental personnel. The controversy you refer to exists only in the minds of many whose main arguments depend on studies that are considered flawed by most ethical researchers or on anecdotal information that cannot be reproduced in scientific studies. If you do choose to have your restorations replaced I am certain you can find a dentist willing to do so, but you should be aware that the mainstream of the dental profession considers it unethical to remove amalgam restorations simply because they contain mercury. You should also be aware that unless a tooth is isolated with a rubber dam during restoration removal, and high volume evacuation with water spray also used, more mercury will be ingested that can possibly happen with years of wear with normal chewing. Your friend has his facts wrong when he states that composite resin restorations will be much stronger. These materials are not yet the functional equivalent of dental amalgam and are not likely to provide the length of service expected of a dental amalgam when used in posterior teeth on functioning surfaces. These materials are also extremely technique sensitive and many restorations fail by caries forming underneath due to leakage of the margins. In short, I think you are ill advised to replace functional restorations. Dental Educator, D.D.S., M.S.D.
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Flaws Exposed |
| MISCONCEPTION 1 | FACT 1 |
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Dental Educator wrote: As a dental educator involved in teaching the use of dental amalgam for the last 30 years I feel I must respond to your [Mary's] message. |
Dr. Kennedy Responds:
Apparently you have not researched the issue of dental personnel injury
from amalgam very carefully or you are simply parroting the misinformation
you received when you were a student some 30 years ago.
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| MISCONCEPTION 2 | FACT 2 |
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Dental Educator wrote: If there was a problem with the use of dental amalgam it would certainly show up in those who use it on a daily basis. No study that I am aware of has demonstrated any such connection in dental personnel. |
Dr. Kennedy Responds:
According to the
occupational health and safety textbooks on dental personnel mercury
poisoning is a common finding.
In addition, a number of investigators have
linked occupational mercury exposure to infertility and birth defects in
dental personnel. One dentist as you may recall sued her dental school when
she gave birth to an infant with acrodynia (mercury poisoning in children).
Apparently, no professor had mentioned during her 4 years of training that
her infant could be poisoned in the womb if mercury vapor is inhaled.
Kidney function in dental workers is also impaired. I could go on at length. This entire lecture along with appropriate references is available if you would like. Ask for Toxics in Dentistry.
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| MISCONCEPTION 3 | FACT 3 |
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Dental Educator wrote: The controversy you [Mary] refer to exists only in the minds of many whose main arguments depend on studies that are considered flawed by most ethical researchers or on anecdotal information that cannot be reproduced in scientific studies. |
Dr. Kennedy Responds: It seem that all dentists can do is denigrate the published scientific research of others rather than examine the question with valid scientific markers. There are no flaws in the research only unanswered questions. For example; do sheep chew more often than gum chewing teenagers and night bruxers. and Do monkeys fed twice a day chew more than most humans? THERE IS NO CONTROVERSY THAT MERCURY FROM AMALGAM CONSTITUTES THE LARGEST SOURCE OF MERCURY EXPOSURE IN THE HUMAN POPULATION.
Pioneer: Dr. Alfred Stock The exposure to mercury from dental amalgam was first documented in the scientific literature by Dr. Alfred Stock in 1926. (Stock A: Die Gefahrlichkeit des quecksilberdampfes. Zeitschrift Angewandte Chemie 1926, 39: 461-466.) How The Doctors Spin Doctor In 1931, the ADA convened a panel of "ethical" experts who decided that Dr. Stock's work was seriously flawed. They (the ADA and NIDR) continued to deny that any mercury was released until by 1984 they were utterly overwhelmed with the proven facts. The new spin is that the amount was not enough to hurt you and that no specific disease has been proven to be caused by mercury. Every dentist concerned about their personal liability should pay very close attention to the issue of causation. Although mercury has been linked to numerous disorders, absolute proof of causation has not been produced. Duty To Warn There is no artificial legal standard that a material must first be proven to cause a specific disease before a manufacturer has a duty to warn. Since mercury is released from amalgam, the dentist who manufactures the filling has the duty to warn the patient of this fact. The WHO document further states that "A specific no-observed--effect level (NOEL) cannot be established." That is, any amount causes some damage. Loaded committees and pseudo expert panels are the tools of spin doctors not ethical research scientists. A scientist who disagrees with the work of another scientist is morally bound to attempt to repeat the experiment and publish divergent results, if any are found. In the case of Dr. Stock, his classic experiment still stands on its own despite sixty years of dentist denial. Stock's Classic Mercury Breath Experiment Dr. Stock blew his own breath into an empty leather bag. He then distilled it through newly blown glasswear and produced a tiny droplet of mercury. This drop he measured with a calibrated microscope. Used calculus to calculate the concentration in the bag and performed chemical analysis to make certain that the shimmering silver droplet was in fact mercury. He showed that his breath contained 10 micrograms of mercury per cubic meter (ug/m3). What was wrong with that experiment? Nothing! Stock's Experiment Is Replicated
Dr. Stocks work was replicated in 1981 by the late Dr. Carl Svare.
It has since been replicated over 10 times by other investigators and has even been used as a subject for student science fairs. This is a perfect example of a widely taught anecdotal opinion's triumph over published science. The dentists who served on the ADA panel in 1931 apparently never even attempted to replicate Dr. Stocks experiments. They just canonized their agust opinions into dental dogma and spread the word that Dr. Stock was a flawed researcher. Now that his research has been thoroughly vindicated, who was this Dr. Stock? He was the director of the Kaiser Wilhelm Institute in Germany and one of the leading scientists of his time. So you see, even great scientists can be denigrated by the spin doctors. Danger To Dental Workers Many dentists have claimed that dental amalgam is safe because the amount released into ones breath does not exceed the OSHA Maximum Allowable Concentration (MAC) of 100 micrograms/per cubic meter (ug/m3) and most people do not continuously exceed the Time Weighted Average (TWA) of 50 ug/m3. What they fail to explain to their patients is that workers exposed to any portion of the OSHA TWA and MAC are subject to medical monitoring for mercury poisoning and written informed consent from their employer. The medical records must remain on file for thirty years after termination of exposure. (Do any dental schools in the world comply with this regulation?) These standards are based upon adult physiology and we know that some adults will become highly poisoned at these levels. Dental students are not employees. Their health is protected by the EPA. Later Dental Educator remarks on the high level of mercury a patient is exposed to during removal. All dental students working in closed tiny laboratories without the benefits of respirators and vacuum hoods are illegally exposed to high levels of mercury vapor. Children, Infants, the general public and especially pregnant women are specifically excluded from the OSHA standard. Their health is protected by the Environmental Protection Agency (EPA). The EPA has documented an infant poisoned at 2 ug/m3 and has a current standard of 0.3 ug/m3. Few if any people who have occlusal amalgam fillings breath is below this standard, but wait there is more. Studies of dentists have found memory loss and hand dexterity problems from occupational exposure. This is predictable considering the blatant attitude toward personnel exposure and carless handling of mercury compounds demonstrated by dental educators. On the other hand the US Public Health Service Agency for Toxic Substances and Disease Registry (ATSDR) has just recommended new standards for the acute exposure to mercury that make it impossible to even mix the components of the filling together much less pack and carve. They determined in November of 1994 that a transient exposure to .020 (ug/m3) was an acute exposure. That means that this level was immediately hazardous to health. We do not yet have the technology to measure this exposure level easily. It is 500 times lower than Dr. Stock measured in 1926 in his own exhaled breath. I suppose the dental educators will claim that the ATSDR is engaged in an alarmist conspiracy to dispute the long held and often touted anecdotal opinion of dentists. Dentists Who Pass The Buck When I asked the Dean of my dental school why I was not informed of the scientific facts regarding mercury the Dean told me that our education was ADA approved and they, not he, were responsible for the content. The ADA was recently dismissed from a lawsuit in California. They filed their request for dismissal based upon the fact that they are in no way responsible for the toxicity of any materials they approve. They are a trade organization and their approval of materials is not for safety but for purity and packaging. Education of future scientists is not dictated by a trade organization. Research and science are suppose to be the foundation of the University system. The educators are suppose to keep abreast of developments and teach students to think with the tools of science not just memorize spin doctors anecdotal dogma. Practicing dentists are ostensibly the responsible parties here not some government agency or trade organization. In California it is against the professional code of ethics to make false statements to the public. The legislature felt that the burden of knowledge rested upon the professional with greater training and expertise in the field. They require the professional to be absolutely certain that our statement are the truth. If your state has adopted similar regulations, scientifically unfounded claims of safety may be a violation of that ethical standard. It is no wonder that patients seeking to have more biocompatible restorations placed have difficulty in finding competent dentists.
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| MISCONCEPTION 4 | FACT 4 |
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Dental Educator wrote: If you do choose to have your restorations replaced I am certain you can find a dentist willing to do so, but you should be aware that the mainstream of the dental profession considers it unethical to remove amalgam restorations simply because they contain mercury. |
Dr. Kennedy Responds:
FALSE!
More precisely the ADA code of ethics was changed to say that it is unethical for a dentist to recommend the removal of a serviceable amalgam because it allegedly contained a toxic substance. This does not require dentists to lie to their patients about the chronic exposure to mercury vapor and abraided particles of mercury silver copper zinc and tin from wearing amalgam implants in their teeth. It also allows the patient the freedom to select the type of filling they desire. The president of the ADA has specifically stated that is is not a breach of ethics for a dentist to remove an amalgam merely because a patient has requested that it be removed. (I strongly recommend written informed consent to protect the dentist from challenges by misinformed dental boards) Every year according to the ADA 100,000,000 amalgams are placed in Americans teeth. This utilizes over 144,000 pounds of mercury. How many cubic meters of air would that produce at .02 ug/m3? I suspect that is easily enough mercury to expose every woman, man, cow, horse, child, bird on this planet to an acute dose. Dental Quackery The International Academy of Oral Medicine and Toxicology did an extensive review of the scientific literature in 1985 and called for a ban on placement until such time as the proponents produced the claimed evidence of safety. Since that time the proponents have ceased to claim that valid science exists and have instead relied upon such spurious arguments that 100 years of use proved that amalgam is safe. They claim that what they and observed or not observed in their clinical practice and their personal assessment of the health of dental professionals. If quackery is the unscientific exploitation of anecdotal remedies and the promotion of one's position through stories and personal observations then quackery has it's roots firmly entrenched in the dental education of this profession. Dr. G.V. Black taught us to cut sharp line angles into teeth. We know today from research that these sharp angles result in weakening of teeth. Many schools still teach their students to drill away lots of good tooth and put in sharp angles. Why? Stupidity? Quackery? or just plane ignorance? According to the latest survey by Godon Christensen found that 10% of the dental profession have quit using amalgam. That number has tripled in the last decade. When does that constitute the main stream of dentistry? Science is not a democracy. The vast majority of dentists may hold one opinion to be very true and yet they may be completely wrong. Dr. Stock's experiments are a good example of how a vociferous well entrenched opinion can thwart good science for over half a century. This was done not by evil people bent on producing a nation of mercury toxic subjects. I believe it was due to the unscientific education those dentists received from professors who touted unsupported opinions as known facts. The use of science would help this profession move from a dental trade taught with primitive mechanical principals and old traditions to a profession based upon valid research in health based care.
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| MISCONCEPTION 5 | FACT 5 |
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Dental Educator wrote: You should also be aware that unless a tooth is isolated with a rubber dam during restoration removal, and high volume evacuation with water spray also used, more mercury will be ingested that can possibly happen with years of wear with normal chewing. |
Dr. Kennedy Responds:
Excessive exposure during treatment among other reasons is why The
International Academy of Oral Medicine and Toxicology has not recommended
removal of amalgam. We have developed a scientifically proven protocol for
the removal which, if followed, will unquestionably reduce patient exposure.
While the Academy has called for a ban on placement of amalgam the removal
protocol would in fact reduce a persons exposure should their dentist
insist on amalgam placement. Since very few dentists are careful about
mercury exposure during placement of amalgam your remarks about excessive
exposure during removal are equally apropos to those choosing to have a new
amalgam. The amount of mercury which is excreted immediately after
placement of a number of amalgams is quite large. Studies as early as 1957
using radioactively labeled Mercury 203 found high levels both upon
placement and upon removal. High levels were again found when amalgams
were removed even when the teeth were extracted. (Frykholm KO: On mercury from dental amalgam. Its toxic and allergic effects and some comments on occupational hygiene. Acta Odont Scand 15:7-108, suppl 22, 1957) Mercury From Amalgam Is Consumed Daily Even after the amalgam has set it continues to wear away.
How many micrograms of mercury are consumed daily from the wear of amalgams
in the mouth? Excretion of total Hg via feces alone = 263 µg/24 hour. Professor Skare concluded his analysis of fecal mercury with the following statement: "If the average fecal excretion was applied to the entire Swedish population, a total emission of 150 kg/yr (330 lb/year) can be estimated. This is roughly comparable to the yearly mercury leakage from a modern chloralkali plant." What it the maximum daily intake allowed by the EPA? 10 µg/24 hour for
sources other than air.
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| MISCONCEPTION 6 | FACT 6 |
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Dental Educator wrote: Your [Mary's] friend has his facts wrong when he states that composite resin restorations will be much stronger. |
Dr. Kennedy Responds:
Dr. Harold Löe director of the U.S. National Institute for Dental Research
in 'Research in Progress Voices from NIDR' published in Dentistry Today
9/1993 stated the following,
"The first filling is a critical step in the life of a tooth. Using amalgam for the first filling requires removing a lot of the tooth substance, not only diseased tooth substance but healthy tooth substance as well. So in making the undercut you sacrifice a lot, and this results in a weakened tooth. The next thing you know the tooth breaks off, and you need a crown. Then you need to repair the crown . . . and so it continues to the stage where there is no more to repair and you pull the tooth. "With the first filling you should do something that can either restore the tooth or retain more health tooth substance. Use new materials-composites or materials you can bond to the surface without undercuts. You can do this with little removal of the tooth substance so that the core of the tooth is still there." This statement is the most severe criticism our profession has endured in over a century. The director of the largest dental research institute in the world told you and I to stop placing amalgam in children not because it is poisoning them or because it reduced their IQ but because it is the wrong thing to do. . . clinically, technically, and dentally speaking. I read that 80% of the new carious lesions in children are treated with amalgam. Today the biggest user and purchaser of dental amalgam is the US government for the military and under welfare insurance programs. Every dental school in the U.S. teaches students how to place amalgam yet, in two countries so far the departments of Health have told dentists not to place amalgam in children or in women that are pregnant. Sweden has enacted a ban on placement of amalgam which is in its final year. The ADA news called this ban a bogus ban. What is a bogus ban?
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| MISCONCEPTION 7 | FACT 7 |
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Dental Educator wrote: These materials are also extremely technique sensitive and many restorations fail by caries forming underneath due to leakage of the margins. |
Dr. Kennedy Responds:
The Longevity of Composites
The longevity of amalgam and composites was addressed in the US PHS document. They were slightly different but the composites tested were placed in amalgam preparations. Had they compared the composite as a primary restoration and amalgam as a primary restoration they would have found out what Dr. Löe was so adamant about. Sensitive Technique Or Undertrained Dentists? Technique sensitive: The problem here is that dentistry does not value its own service. They condone the sloppy use of a toxic material because smart monkeys can place amalgam and it takes a modicum of intelligence to first dry and clean the tooth before bonding an adhesive restoration. This is a call for smarter more capable dentists not a reason to use an antiquated toxic, mercury leaking, tooth breaking filling material. Studies have shown that some dentists can place extremely long lived composites while others leak badly. Perhaps the problem lies in the schools and what they are teaching. I encountered two new graduates a couple of years ago who had never placed a posterior composite in their training. They were upset with their training because none of the other "Cosmetic" dentists in their area were using ugly black posterior amalgam. Last week I lectured on indirect posterior composites in Montreal, Canada. A young student was unaware that dycal (bases of any kind) are not desirable under resin restorations. They weaken the restoration, do not bond, and provide no protection to the pulp. With dentists graduating untrained in the use of the current materials it is not surprising that failures abound. Which Pilot Would You Fly With? What is wrong with this picture: Imagine the same debate on technique sensitivity between two pilots. First Pilot: "I am sticking with the DC 3. It is tried and true and can virtually fly itself." Second Pilot (just been promoted to the new 777): "I like the GPS, wind sheer detectors and storm radar. The electronic cockpit allows us to monitor so many aspects of flight that I can actually control this plane better than ever before." First Pilot: "Those gimmicks and electronic gizmos are so technique sensitive. What if the electricity goes out. Then where'd you be?" Which pilot is better trained and ready for the next century?
Which would you prefer to fly with? Technique sensitive indeed. Do we need smarter students or better instructors?
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| MISCONCEPTION 8 | FACT 8 |
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Dental Educator wrote: These materials are not yet the functional equivalent of dental amalgam and are not likely to provide the length of service expected of a dental amalgam when used in posterior teeth on functioning surfaces. |
Dr. Kennedy Responds:
Tooth structure will however, provide the support for occlusion. If the
dentists would quit drilling away so much good tooth to place an antiquated
filling material there would be fewer restorative problems. Posterior
composites placed with an indirect technique can withstand the forces of
occlusion in many places. In other places a cast gold or porcelain
restoration is required. The forces of occlusion vary greatly from person
to person, male to female, and upon personal chewing habits. Individual
evaluation is required. The exact same forces that make excessive wear on
composite squeeze mercury to the surface of ever amalgam (young or old) and
abraid away particles to be swallowed and dissolved in the saliva.
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| MISCONCEPTION 9 | FACT 9 |
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Dental Educator wrote: In short, I think you are ill advised to replace functional restorations. |
Dr. Kennedy Responds:
In short I think you are ill advised to rely upon the undocumented
anecdotal opinions or the dental profession. Rely instead upon the peer
reviewed documented medical literature and minimize your exposure to all
toxic substances. If history is a good teacher, then most of the cheap
restorative materials in daily use in this country will eventually be
banned. Because resistance to change is so great with this profession the
changes will be extremely slow until we loose the first lawsuit that does
not have a gag order.(Many lawsuits have already been settles out of
court).
Remember, asbestos was used as a bandage for cut bleeding gums until John Mansville lost their claim that direct causation could not be proven. After that Coe Pack (one of the popular brands of perio dressing) proudly announced, Now contains no asbestos. How many patients knew that they had asbestos mixed with zinc oxide and eugenol packed in their oral cavities? For that matter how many dentists knew that they were packing asbestos. As my old professor Claude Baker proclaimed in 1967 when I questioned this practice, "Once it is covered with spit it is harmless." If the hazardous waste companies had only known how good a detoxifier spit is they could have saved a fortune. Dentistry still today claims that spit protects patients from mercury vapor released from dental amalgam. Studies show that the average person makes and swallows 1.5 liters of saliva a day. Yet, if they have as few as 4 amalgams present in their mouth, the average person's saliva is so high in mercury they cannot legally spit into the toilet. Their saliva exceeds the EPA maximum legal municipal discharge standard for mercury. It was interesting to note that the form of the mercury was in was organic.
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A Word of Appreciation |
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To: davidkennedy-dds@home.com Good gravy, David! You have blown your colleague, Dental Educator, not only out of the water, but probably left the poor fellow without even any traces of DNA to be used by his trial's prosecutorial staff in any attempt to cite you for wrongdoing in his disappearance. If this fellow dares to even respond on this List after your salvo, I will be amazed. I'm almost, although not quite, feeling sorry for the guy. What a blast! What a (beautiful) case of overkill. You have demonstrated the power of a latter day Big Bertha, with projectiles of deadly hard truth. Dental Educator's spin routine only came on-line in the last day or so, so your rapid response to his standard disinformational contribution is even that much more impressive. With all you have done to straighten out an essential health service that is still primarily functioning in the mode of the 1800's, I wonder how you can find time to practice. Your actions, research skills, articulate communicating, and appeal to our common sense, is extremely inspirational. But most importantly, you may be the most critically placed "hero" in all of so-called modern dentistry, and the poor dependent dental consumers, by the millions, have long needed some salvation. As helpful as pioneers such as iconoclastic rebels, Melvin Page, Weston Price, et al, have been, your position today, out there "on point", is not only dangerous, but obviously loaded with stress levels that are not at all healthy. I sure hope you are taking care of your own personal needs. We just can't lose someone as important as you have become to our immediate and long range dental health needs. As wonderful as this net forum is, we need to break through the convential media's traditional blackout against most of the unorthodox advocates for science and progress, that has helped keep the public so misinformed all these years. We have to somehow devise a way for your messages to break through this tragic blockade. The poor turn out up in Sacramento a few weeks ago just can't happen again. I am obviously much relieved that you answered Dental Educator's charges against me so convincingly and articulately, regarding the comparative strength between the amalgam and the newer composite materials. Although I was confident that my claim of structural superiority in composite over mercury was sound, I am a layman, and would have been needing a good slug of time just to go digging for the supporting technical info; data that you so quickly provided to resolve that controversy with such finality. As an old time aviator, I took even more delight in your parable about the DC-3 and 777 pilots' discourse over the relative merits of their aircraft (I flew both the DC-3 and jets). It was absolutely deserving of classic status. I burst out in such laughter that I lost track of where I was in your absolutely fascinating contribution to this Amalgam List. I am mighty glad I was on this List in time to see today's presentation. What a masterpiece. In fact, if you had someone take a few minutes out to edit it for typos, and rearrange its format, [so that it would be readily understandable to regular (non-computer literate) folks], it might be an excellent way of presenting these issues to the uninformed (misinformed) public. Thanks for taking out the time to so thoroughly respond to Dental Educator's diatribe. I'm taking the liberty of sending your piece to a number of my friends about the internet, who aren't on the amalgam list, but who are certainly interested in this whole sick issue. You are in an enviable position to inform and educate, and I wish you Godspeed in your continued efforts! Cordially, John |