There are a number of terms and phrases that are used on both the pro and anti-amalgam sides. I think it is important to define these terms so that no statements are mis-interpreted. I will also relate these terms in short discussions of their applicability to the dental amalgam controversy.

Term: "mercury"

Elemental mercury is silver in appearance and is a liquid at room temperature. It is often used in thermometers, batteries, and pesticides. Mercury is absorbed by and not easily discharged from the human body. Ingestion of more than trace amounts can cause mercury poisoning. The effect of this poisoning can manifest itself an a variety of ways and is often linked to chronic health problems. Mercury is one of the most toxic non-radioactive metals in existence. This issue will be addressed in another section.

Term: "dental amalgam"

The term 'amalgam' refers to any of a number of mercury alloys. Dental amalgam is the mercury alloy which is used in teeth for reconstructive purposes.

Dental amalgam is commonly known as 'silver' fillings. This is a misnomer because these fillings actually contain more mercury ( up to 50% by weight ) than silver. This term is most likely derived from the fact that people are more likely to be familiar with silver than mercury. It is also likely that by calling these 'silver' fillings, the mercury content is played down. I believe that most people don't know that 'silver' fillings contain mercury. I also believe that many that do know, do not know that mercury is toxic.

Term: "informed consent"

Informed consent is the consent of a patient to a procedure after being informed of all of the relevant facts and risks.

Are dental patients informed by their dentists that the substance they are having put into their bodies contains a toxic substance. In general, this is not the case. In fact, if a patient asks their dentist about it, chances are they will be told that although dental amalgam contains mercury, it is 'locked away' in the alloy and cannot hurt them. If you ask your dentist about this and you hear the terms 'safe and effective' or 'locked away', you can bet that your dentist is reading to you from the ADA's pro-amalgam statement. ( Dental Amalgam: 150 years of safety and effectiveness ). Both of these statements are false.

If you were told that a procedure was controversial because it involved the use of a toxic substance and there was an alternative that was more expensive, what would you do? Chances are, if you could afford it, you would go with the more expensive procedure. The problem is, if a dentist tells you this, he is violating the ADA's imposed code of ethics. Dentists who suggest the use of a more expensive procedure and claim that it is for safety reasons are blasted by the ADA. The ADA claims that dentists who do this are doing it for the sole purpose of making extra money at the patience expense. Although it is possible that a few dentists might choose to do it for this reason, the ADA's position makes it nearly impossible for a dentist to make the suggestion for safety reasons and remain in good standing. The result is that for a dentist to be mercury-free, they must lose their standing with the ADA and operate from a position that has a disadvantage over dentists who continue to use mercury-amalgam. The number of mercury-free dentists is, at this time, a very small percentage. This is likely to change over the next few years as this problem gets more exposure and people are more health conscious. Eventually, in order to survive, the ADA will have to change its position on mercury-amalgam.

Phrase: "anecdotal evidence"

Anecdotal evidence is a story-like account of an event which is often purported to be proof of a theory. Anecdotal evidence is not scientifically valid. However, when the amount of anecdotal evidence of something is overwhelming and is consistent with valid scientific evidence, it cannot be completely ignored. The presence of anecdotal evidence also does not imply that the conclusion is automatically false just because the argument isn't scientifically valid. This, however, is precisely what the pro-amalgam side implies in many of their arguments.

One of the most important sources of ammunition against dental amalgam is the recovery stories of the many individuals who have recovered from illnesses after having their amalgams removed. The pro-amalgam position tries to completely discredit these recoveries because they fall into the category of 'anecdotal evidence'. Most of the time, they do not even acknowledge them. However, one of their main sources of 'proof' that dental amalgams are safe is the fact that the majority of people with dental amalgams do not suffer from these illnesses. This is not only a fallacy but can be classified as a type of 'anecdotal evidence'. ( Sorry guys, you can't have your cake and eat it too. )

Term: "fallacy"

A fallacy, in simplest terms, is false reasoning, or an error in logic. It is an argument whose conclusion is not supported logically by its facts. However, many fallacies aren't obvious and are often mistaken as valid arguments. For an excellent source of information on fallacies please visit Stephen's Guide to the Logical Fallacies. It is easy to commit a fallacy by accident and it doesn't always necessarily mean that the conclusion is wrong, just that the method of arriving at it is wrong. However, in these cases, it is easy to re-word or reconstruct the argument so that it is logically valid. I have come across many fallacies which, any way you slice it, are just plain wrong.

Here's a good one from The Simpsons. ( paraphrased )

Homer: That bear patrol sure is doing a great job keeping bears away.

Lisa: How did you arrive at that?

Homer: You don't see any bears around, do you?

Lisa: With that reasoning, I can say that this rock keeps tigers away.

Homer: Really, how does it work?

The ADA's position ( Dental Amalgam: 150 years of Safety and Effectiveness ) on the use of dental amalgam should be required reading in the study of logic. I wish I could include examples but their copyright forbids this. Please read the specified document and see if you can find as many fallacies I did. The same goes for other pro-amalgam papers. The only way to support an invalid position is to use fallacies, invalid or biased research practices, or lies. Please remember that it is also easy to commit a fallacy by accident and the presence of a fallacy doesn't always mean the statement is wrong. Analyze the statement for yourself and look for the same concept explained by a different author. If the fallacy cannot be resolved by consulting a number of sources, chances are that the conclusion is invalid.

Term: "bias"

A bias is a type of prejudice against or inclination for a particular outcome that can influence an accurate assessment of a situation. It is very difficult to overcome a bias when doing research. To deal with this, scientists are very careful in their experiments to eliminate this bias as much as possible. However, most members of the pro-amalgam position are not scientists and in general do not follow scientific methods. They are trying to prove a position in which they cannot afford to be wrong. This imposes such a strong bias that it nearly impossible to even have a civilized conversation with them about this problem. Of course the anti-amalgam side also has their own bias. However, their interests are in the health and safety of the public. If there wasn't so much evidence in their favor, I doubt they would feel the need to fabricate it or twist the facts to support their position.

Term: "conspiracy"

A conspiracy is a plan to misinform the public about an event by the mutual cooperation of a number of individuals. When I describe to people what I know about the dental amalgam problem I am often told that I am coming up with my own 'conspiracy' theory. Because the term 'conspiracy' has gotten a bad rap due to the amount of attention paid to it by the media, I refuse to use it. However, it is also evident that a number of individuals in the dental industry have discussed this problem and have thought of ways to misrepresent the facts to the public. By definition this is a conspiracy. I have arrived at this conclusion due to the massive amount of anti-amalgam evidence which is completely ignored by the ADA. It is obvious that they must have known about at least some of it yet they continue to deny that it exists. Because of the negative impact of this term not only when it is said outright but even when it is implied, this is the last you will hear of it. The pro-amalgam position needs all the ammunition they can get and I am not going to allow them to compare the anti-amalgamists with conspiracy theorists which are often mistrusted by the public.

Phrase: "placebo effect"

The 'placebo effect' is a recovery that is psychologically based and occurs when the patient recovers from a condition only coincidentally and not causally related to the application of a cure. This often is caused by the patients desire to recover and expectation of this recovery due to a medication or procedure. A placebo is a substitute used in experiments to help determine if an actual recovery is due to the medication or to the psychological 'placebo effect'. More often then not, recoveries of illnesses that have been purported to be caused by dental amalgams are labeled as 'placebo effect' recoveries by the pro-amalgam side. The psychological nature of many of the amalgam related illnesses makes their position easier to accept by most people who are ignorant of the effects of mercury poisoning.

I actually had a conversation with someone who stated that recovery due to the removal of amalgams should be studied in a 'double blind' test. A double blind test uses a placebo to measure the psychological recovery rate compared to the actual recovery rate. My position was that this is not feasible due to the enormous cost ( ~$600 per filling ) and pain involved in having amalgams replaced. Even if the procedure was paid for by the researchers, who would agree to have 10+ fillings replaced with a substance that would then have to be replaced again when the experiment was over. This procedure can be more painful than having the original filling installed and the toxic effects of the mercury vapors can cause problems within the days that follow the procedure. However, this is what the pro-amalgam side demands as proof. Even if this study was done and the conclusion showed that amalgams caused health problems, I doubt they would accept it.

Phrase: "intern's disease"

Intern's disease is what an individual contracts when beginning a career in the medical or psychology professions. It occurs when a student thinks that s/he may have the particular disease that s/he is reading about. My first psychology text had a section on intern's disease in order to keep the student from making this mistake.

I recently saw a perfect example of this phenomenon on the television show Frasier. A caller calls up Frasier Crane ( a psychologist ) and thinks he might have a whole list of psychological problems. Frasier correctly guesses that the caller is a first year psychology student.

This becomes a problem when an individual has a number of symptoms that matches a condition perfectly and self-diagnoses that they have the condition. This is more likely to happen when there are a number of causes for a condition and doctors cannot pinpoint the true cause. However, I must point out that because of the 'intern's disease' phenomenon, an individual who self-diagnoses a condition is NOT automatically wrong. There is a chance that they are correct. It seems that some doctors who cannot correctly diagnose their patient's condition are incapable of accepting that an individual may find the cause on their own. Because illnesses related to dental amalgam are not generally accepted by the medical community, very few doctors will be willing to state this as a possible cause of the illness. Furthermore, if an individual finds out on their own that their condition could be caused by mercury from their fillings, they are likely to have this claim disputed by their doctor. This may have the effect of keeping individuals from a treatment that could solve their health problems.

Source: Dave 1996

Also make sure to read these books: Poison in Your Teeth: Mercury Amalgam (Silver) Fillings...Hazardous to Your Health! and Mercury Detoxification by Tom McGuire