Current Controversies in Dentistry
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Why do dentists use dental amalgam? What about alternatives to amalgam? What about patients allergic to mercury? Is mercury in dental amalgam safe? What are other sources of mercury? |
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Most people recognize dental amalgam as silver fillings. Dental amalgam is a mixture of mercury, and an alloy of silver, tin and copper. Mercury makes up about 40-50 percent of the compound. Mercury is used to bind the metals together and to provide a strong, hard durable filling. After years of research, mercury has been found to be the only element that will bind these metals together in such a way that can be easily manipulated into a tooth cavity.
Mercury is present in different forms: organic (short or long chained Alkyls/Aryls) and inorganic (elemental and mercury salts). How mercury effects the body is in large part determined by what type of mercury is present.
Why do dentists use dental amalgam?
Amalgam is a very durable material and has been used for more than 150 years. It is estimated that well over 1 billion amalgam restorations (fillings) are placed annually. Dentists appreciate using dental amalgam because it is easier to work with than other alternatives. Dentists also believe that patients prefer dental amalgam to other alternatives because of its safety, cost-effectiveness, and ability to be placed in the tooth cavity quickly.
What about alternatives to amalgam?
Alternatives to amalgam, such as cast gold restorations, porcelain, and composite resins are more costly. Gold restorations take longer to make, and porcelain and composite resins are esthetically appealing, but aren't as durable as amalgam in posterior (back) teeth However, composite compounds are constantly improving.
What about patients allergic to mercury?
The incidence of allergy to mercury is far less than one percent of the population. People suspected of having an allergy to mercury should receive tests by qualified physicians, and, when necessary, seek appropriate alternatives.
Is mercury in dental amalgam safe?
This question has created much debate in the scientific community over the past 10-15 years. While the answer appears to be yes for a vast majority of persons with amalgam fillings no studies have been done that proves amalgam to be 100% safe. This topic has garnered more public interest and research in Scandinavian countries than in the United States.
The form of mercury used in amalgam is primarily inorganic elemental mercury. In toxic doses its main effects are on the nervous system with absorption either through the skin or by inhalation. Absorption from the intestines is minimal.
The position of major US and Canadian dental organizations is that amalgam is unequivocally safe and effective. Support for this position is based on the amount of time amalgam fillings have been used (over 150 years) and that only very small amounts of mercury leak from amalgam fillings. However, statements that "Amalgam fillings have been proven 100% safe" are not supported by scientific evidence.
U.S. Dental Organizations, including the ADA 3 and AGD, cite the following groups as vouching for the safety of amalgam fillings:
(click here) to see ADA position supporting amalgam safety
- Public Health Service (PHS) 1993,
- Food and Drug Administration (FDA),
- National Institutes of Health (NIH) Technology Assessment Conference, National Institute of Dental Research, Bethesda, Maryland, August 26-28, 1991.
Groups and organizations questioning the safety of amalgam include:
- WHO (World Health Organization)
- Various Swedish/Scandinavian researchers
Review of the actual position statements of the PHS, NIH, and FDA indicate that amalgam fillings appear safe but have not been proven to be 100 percent safe. These groups acknowledge certain concerns and state that further scientifically controlled studies are needed to resolve this issue.
We know that
- dental amalgam fillings about 50% mercury
- mercury leaks from the fillings (inorganic elemental forms)
- mercury is toxic
- low grade chronic mercury intoxication can give rise to symptoms as; anxiety, irritability, fatigue, outbursts of temper, stress intolerance, decreased simultaneous capacity, loss of self-confidence, indecision, headache, depression, metallic taste etc... These symptoms, known as Erethism, are easily confused with other physical and psychological causes.
- Erethism
has clearly been shown with mercury exposures from other sources (non-dental).
We do not know
- if the amount of mercury released from dental amalgam is enough to cause illness, even in the most exposed or the most sensitive minority of the amalgam-bearing population.
- if Erethism can occur from regular use of dental amalgam
Claims of diseases caused by mercury in amalgam are anecdotal, as are claims of miraculous cures achieved by removing amalgam. These claims have not been proven scientifically.
What are other sources of mercury?
Mercury can be found in air, food, and water.
What should be done with Amalgam fillings? 2
There has been concern and debate about possible (nonallergic) negative health effects from dental amalgam-fillings. At least several thousand scientific reports and discussion articles in the field of mercury-biology-health and several hundred about amalgam-biology-health have been produced. The following seems to be consensus (consensus need NOT to be the final truth, but rather what is non-controversial) at present:
- If
you do not have any illness / symptoms or other reasons to suspect that
you have or will get problems from your amalgam-fillings you are not
recommended to have your amalgam-fillings exchanged. 1
It seems as if the great majority of the population belongs to this
group.
- The
question which material to choose the next time an amalgam-filling needs
to be replaced or when there is need for a new filling depends on your
own decisions and what your dentist recommends.
-
Not one single filling material is best in every situation and no filling
material is biocompatibility tested the same way medical drugs are.
Do you want the cheapest filling, the one lasting longest time, the
most aesthetic, the most tooth conservative, or the one your dentist
believes is most biocompatible? You and your dentist will have to come
to an agreement in this choice.
- If
you have allergic and / or local oral symptoms from your amalgam-fillings,
diagnosed by a physician and / (or) a dentist, it is usually recommended
that you exchange these for a material you can tolerate. A very small
minority of the population (less than 1 percent) seems to belong to
this group.
- If
you have an illness with multiple symptoms and suspect that your dental
amalgam fillings may be playing a role, you should know that there is
ongoing debate whether nonallergic amalgam-related illness exists or
not. Meanwhile science has not (yet) found a definite answer to this
question.
The use of amalgam as a dental filling material is expected to decrease, at least in western world countries and maybe even banned in some countries. These are some of the (proposed) reasons to why: 2
-
concern about the environmental mercury-pollution
- development
and improvement of different tooth-coloured dental filling materials
- the
non-aesthetic appearance of amalgam.
- when
cavities need to be filled, the preparation of a cavity for an amalgam-filling
often means loss of more healthy tooth-substance (a bigger hole must
be drilled) than if composite or glass ionomer cement were to be used
instead.
- at least in USA and Sweden: a decreased caries frequency.
Amalgam fillings have been used extensively for a long time. They have many advantages going for them including cost and durability. For a vast majority of people the are likely to be completely safe. Yet, the type of mercury released from amalgam fillings is toxic when sufficient exposure occurs. While exposure appears to be very low, minimal safe levels have not been established.
Although amalgam has not been proven to be safe it has not been proven to cause disease either.
Most persons having health-related symptoms attributed to amalgam fillings will in fact have another psychologic or physical ailment causing the condition.
Removing amalgam fillings as a preventative measure is not recommended. It is an added expense to the patient and may increase body mercury levels for several months.
Likewise, although current composite materials appear to be inert (not to react with the body or cause ill health) they have not been well studied.
- NIH
Technology Assessment Conference, National Institute of Dental Research,
Bethesda, Maryland, August 26-28, 1991. Statement: Effects and Side-effects
of Dental Restorative Materials. Adv Dent Res 6:139-144 (1992)
- **"Amalgam
Related Illness- Frequently AskedQuestions" from Leif Hedegard
@ http://www.algonet.se/~leif/AmFAQk01.html
- "Dental Amalgam: 150 years of Safety and Effectiveness" from ADA News Releases @ http://www.ada.org
** Well worth viewing this site if you have serious concerns or questions about amalgam safety.
Doctors Corner INternet Group, Inc. 1997-2004