For decades, the debate has raged over whether amalgam fillings are safe or not. As I researched many publications, each voicing a variety of opinions on this issue, it became very clear that the issue is not resolved on either side and very likely won’t be. My goal in presenting you this information is to educate you on them both.
One can never be too informed about what’s happening in any aspect of their treatment.
Amalgam “Silver” Fillings
Amalgam fillings have been used since the 1800s. Needless to say, the entire process of filling teeth has improved over the past decades including the ingredients used and the techniques dentist are trained in.
Traditionally, amalgam fillings have been made out of a mixture of elemental mercury (which comprises the bulk of the mixture), silver, tin, and copper. Some dentists may add other metals as well. Together, these metals form a very strong, durable bond. Mixed properly and adequately these other metals stabilize and keep the mercury “in check.” I will come back to this argument.
Because of the bond between these metals, amalgam fillings are perfect for restoring molars, where there are strong bite forces. The stronger the bite and the presence of any parafunctional habits (see: Damaging Dental Habits) usually mean that amalgam fillings will be the better choice.
Other advantages include:
- The combination of the metals in amalgam fillings are known to resist bacteria
- Amalgam fillings are easier to place and work with to adequately fill the space
- Less expensive than composite fillings
- Historically last longer than composite fillings
The disadvantages to amalgam fillings include:
- Short-term sensitivity to hot or cold (usually just after the filling is placed)
- They are very visible when laughing, smiling, or talking
- More drilling may be required
Composite Fillings
Composite fillings have seen increasing use since they were first introduced in the 1970s. Composite materials, from which inlays and other dental restorations are made, are usually a mixture of glass or quartz filler in a resin form. Once set, usually with the aid of a light device, this resin forms a durable surface resistant to fracture in most areas where there is moderate chewing pressure. Traditionally, composite fillings have been reserved for bicuspids (the tooth directly before the molars), where there is usually less bite force.
Other advantages include:
- Composite fillings are tooth colored and not noticeable
- Composite fillings do not contain any metals
- Composite fillings do not require as much preparation and drilling out of tooth material
The disadvantages include:
- Composite fillings traditionally have not lasted as long as amalgam fillings—although improvements in dental technologies have improved longevity significantly
- Composite fillings require more specific training in the techniques to provide an effective, aesthetically pleasing result
- Some earlier versions of composite fillings have actually been shown to encourage growth of microorganisms
The Debate
Many patients, health experts and holistic medicine practitioners have tried to create a definitive link between the presence of mercury in fillings and a variety of health issues—autism, kidney disease, heart disease, mercury poisoning. They have not been able to. From what I have read, it is highly unlikely that these conditions were the result of the presence of mercury in fillings exclusively.
The instruments generally used to measure mercury vapors in a person’s mouth—generally released through chewing with mercury fillings present—measure the amount of mercury vapor per cubic meter, a measurement significantly larger than the size of a person’s mouth.
Additionally, mercury is not actually absorbed into the body through the fillings. If exposure to mercury in this form happens at all it is usually through extended chewing, especially gum chewing, and it is in its vapor form. In that instance, it’s inhaled.
The elemental form that is used in fillings is different than the mercury contained in vaccines, and found in fish that we are usually warned about. It is not the exposure to the mercury in fillings alone that people could be reacting to. Exposure from all these sources can accumulate in the body and affect a person’s health. “Mercury’s toxicity is related to the amount absorbed.” (Canadian Dental Association) This is, in fact, corroborated by science. The more mercury that is absorbed, the stronger the effects on a person’s body.
According to Health Canada (similar statistics can be assumed for the U.S., as well), for the average Canadian adult aged 20-59 years, the amount of mercury absorbed from ALL sources per day measures about 9 micrograms (9 millionths of a gram). Of that amount, mercury in amalgam fillings accounts for 3 micrograms (3 millionths of a gram)—about 1/3 of a person’s total daily exposure.
Canadian researchers have examined patients and the ever-improving formulations of dental fillings for over 150 years and are confident that amalgam fillings are safe. Just the same, because of the controversy, the Canadian government and many other world governments are researching to find any alternatives.
One website posits the relationship between amalgam filling and mercury content this way: Elemental hydrogen is an explosive gas. Elemental oxygen is a gas that supports combustion. When combined, however, they form water, which has neither of these effects. Amalgam's ingredients are tightly bonded to each other…saying that amalgam will poison you is just as wrong as saying that drinking water will make you explode and burst into flames. (www.quackwatch.com)
The issue of whether or not dental amalgams are safe has to be viewed in light of the fact that while many patients claim their illnesses have been caused by mercury seepage from their fillings, there are still millions of other patients who have had these fillings placed and have had no adverse symptoms whatsoever. It may be that those particular patients who have experienced symptoms were genetically more “responsive” to this exposure to mercury than another person.
Consider, as well, how many dentists, hygienists, and dental assistants are exposed to these materials daily. While they need to follow safety precautions when mixing the ingredients—mixing technologies have also improved to ensure a more uniform blending of ingredients—when the fillings are applied, they appear over the dental chair with their normal mask and gloves, not in a Hazmat suit.
Whatever the debate, most agree that those with amalgam fillings should not have them all replaced with composite fillings. To replace new discoveries of tooth decay, it is always the patient’s choice whether or not to have amalgam fillings placed. Consider, too, that some dentists are not trained in the placement of composite fillings. On the flip side, some dentists may not even offer amalgam fillings because of the ongoing debate and deciding to err on the side of caution.
As a dental patient, you need to be aware of both sides of the argument, know the limitations of each type of filling, their advantages and disadvantages. Know that there are just as many arguments for as there are against amalgam fillings. Don’t take any one position at face value. Many of those opinions will have strong biases one way or the other (which is why I looked at more than just the ADA). Read the information out there and come up with your own conclusion. Ultimately, you, the patient, have the right to decide.
Sources:
www.cda-adc.gc.ca (The Canadian Dental Association)
www.ada.org (American Dental Association)
www.hc-sc.gc.ca (Health Canada)
www.quackwatch.com
***I will say out of all the sources I read, of which these are just the major ones, the Canadian Dental Association and Health Canada had the most comprehensive response to the mercury debate.