Last year Consumers for Dental Choice and Moms Against Mercury won a groundbreaking lawsuitagainst the FDA. The FDA said that fillings must now include details about the benefits of the products, as well as warnings against their use in patients with mercury allergies or in poorly ventilated areas.
Amalgam is the name given to mercury (Hg)-containing metal fillings. It is one of the oldest materials used in dental restoration. It remains popular because it's strong, durable and relatively cheaper than other types of restoration. It is made up of a mixture of elemental liquid mercury and an alloy powder composed of silver, tin, copper and smaller amounts of zinc, palladium or indium.
"The starting material for dental amalgam consists of approximately 35-42% mercury which is chemically mixed with a powder consisting of various metals to produce a crystallised, solid alloy named amalgam," explains Dr Jeff Michelson from the South African Dentistry Association.
The amalgam controversy
The gist of the amalgam controversy centres on the amount of mercury that is released from fillings and absorbed into the body. In the past it was believed that once the filling was complete, no mercury was released. However, studies showed mercury vapour can be released as amalgam wears down.
"Scientific studies show that there is a minute amount of release of mercury from fillings. This may result in a slightly elevated level of mercury. However, current accredited scientific studies, based on randomised, peer-reviewed, clinical trials, have shown no proven correlation with adverse health effects," says Michelson.
According to the World Health Organisation (WHO), amalgam releases 17 micrograms of mercury in the body every day, in other words more than three billion mercury atoms a day.
The studies against amalgam
In The Smoking Tooth study, an extracted tooth containing a 25 year old amalgam filling was held under a black miner's lamp, a pure mercury vapour discharge lamp. "Smoke" was seen rising from the tooth.
In another study, participants were asked to chew gum for 10 minutes. The researchers found that mercury vapour increased eight to 10-fold and stayed high for at least 90 minutes. The study found an average absorbed mercury dose of 10 micrograms/day from measurements of mouth air.
"It is known that all metals in your mouth corrode over a period of time. Mercury amalgams have a shelf life, the same as crowns. During the corrosion process, amalgams start working themselves loose and this is when they start to leach metals. Food acids contribute greatly towards fillings becoming 'unstable/loose' in your mouth. As amalgam wears down over time, the taste of metal will become more prevalent, and when swallowing the leaching mercury, digestive problems will also start to occur," says ortho-molecular nutritionist, Mark Zuhrbrigghen.
To show the absorption of mercury by the body's organs, researchers placed amalgams containing radioactive mercury in a sheep's teeth. After 29 days, mercury was found present in the wall of the digestive tract, kidneys, gums, jawbone and liver. Dentists disregarded these findings saying that sheep eat and chew differently than humans.
The study was then repeated. This time a monkey who eats and chews similar to humans was used. The results were almost the same after 28 days. The mercury spread around the monkey's body, yielding tissue concentration that was similar to that found in the sheep.
In a study by Vimy and associates, radioactive mercury in amalgam was placed in pregnant sheep's teeth. The study found mercury absorption two days after placement in the ewes and the lambs. The mercury levels increased for about 30 days and remained constant throughout the 140 day course of the experiment. This showed that the mercury found was not due to the initial placement, but largely due to continued release of mercury from fillings.
Other studies have found links to Alzheimer's disease, nerve damage, development of antibiotic resistance, a decrease in immunity resistance and fertility, and kidney dysfunction.
Do amalgam fillings cause adverse health effects?
After an agency review of roughly 200 scientific studies, the FDA states that while elemental mercury has been associated with adverse heatlh effects at high exposure, the levels released by dental amalgam fillings are not high enough to cause harm in patients.
According to Dr Michelson, many studies by reputable scientific institutions have reached the conclusion that dental amalgam does not cause adverse health effects, except in rare cases in which people have allergic reactions to mercury in amalgam. Less than 100 cases of this type of allergy have ever been reported.
"There is always a very low level of mercury present in the human body, arising from food, water and air. The daily dosage of mercury from these sources is more than the amount released from dental amalgam fillings. Very low levels don't cause any ill effects. Exposure to enough mercury to cause side effects usually occurs from breathing contaminated air or from improper use or disposal of mercury and mercury-containing objects, for example after spills of elemental mercury or improper disposal of dental amalgam waste or fluorescent light bulbs," explains Dr Michelson.
"The predominant symptom would be a local allergic reaction such as swelling of the lips and tongue, and redness. Almost no people who have amalgam restorations have associated health problems. Those where health problems are implicated are mainly anecdotal, and no proof has ever been forthcoming. The main risk of exposure to mercury is when the restoration is freshly placed and hasn't set, and when it is drilled out, "says Dr Lang.
Zuhrbrigghen disagrees, "All people suffer health damage in some form or another. Healthy people may only suffer partial health problems, whereas those people who have already compromised health, will suffer further health problems. What is very important to remember is that any toxic metal displaces and replaces vital minerals in the body, for example: potassium is important for cardiovascular and thyroid health, when metals such as mercury, aluminium and lead displace these two important metals, major health problems can occur."
In his eight years of practice, Zuhrbrigghen has found the most common symptoms to be nausea, vomiting, depression, a metal taste in the mouth which also indicates that the amalgam fillings may be "leaking", underweight, dry eyes, excess salivation, digestive problems and glucose problems.
Cape Town based dentist Dr Ilona Visser agrees, "health damage can be either clinical - the patient is aware of ill-health, or sub-clinical - the patient is not aware of ill-health, but when blood analysis is done, microscopic changes are rife. A young person with a healthy lifestyle and an APO-E2 genotype might be able to handle the toxic effects better than someone who has a compromised immune system, or who is genetically more susceptible to the toxic effects."
To remove or not?
According to Dr Visser, the benefits of amalgam removal include a better immune system, more energy and an improvement in the body's capacity to handle stress, just to mention a few.
Zuhrbrigghen agrees, "many people with food allergies and sinus problems report immediate relief. Better concentration, and an improvement in long- and short-term memory are the hallmarks of amalgam removal. This can differ from person to person. A large majority of people also report a healthier appetite, no morning nausea, no more metal taste, no more depression, no more dry or weeping eyes and more importantly, no more pain in bones and joints."
Removal of amalgam fillings does increase the risk of exposure to mercury.
Dr Visser asserts that removal of amalgam is very safe if done by a trained bio-dentist. Oxygen, intravenous vitamin C therapy, charcoal, a rubberdam and EDTA therapy are used.
Dr Lang says he would not advise a patient to remove amalgam fillings as he does not have convincing evidence to do so.
"However, if the person is showing signs of metal allergy, of course I would suggest we remove the metal restorations. If the patient requests me to remove the amalgams, I explain my point of view but will do so if they still want me to go ahead," says Dr Lang.
The war rages on
The start of the amalgam war dates as far back as 1820, and looks set to remain a raging issue for years to come.
Studies such as the ones mentioned, and others, have shown that amalgam fillings may pose certain adverse health effects through mercury toxicity. Exactly how much mercury is released from an amalgam filling, has not yet been established. Until a study is done to show that amalgam fillings do not have any long-term side effects, the issue of amalgam toxicity will remain unsolved.
(Leandra Engelbrecht, Health24)
-Dr Jeff Michelson, South African Dentistry Association
-Dr Ilona Visser, Dentist
-Dr Lesley Lang, Dentist
- Mark Zuhrbrigghen, Ortho-molecular nutritionist
-Feuer, George and Injeyan, Stephen H. The dental amalgam controversy: a review. J Can Chiropr Assoc 1996: 40(3)169-179 http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=2485143&pageindex=8#page
-Visser, Ilona. How your dental fillings can damage your health. Journal of Natural Health Issue22, Feb/March 2006
-Koral, Stephen. The Scientific Case against amalgam has been proven! International Academy of Oral Medicine and Toxicology. (IAOMT) 2002/2005 http://www.iaomt.org/
-US Food and Drug Administration. Questions and answers on dental amalgam. http://www.fda.gov/cdrh/consumer/amalgams.html
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-Dental amalgam overview. http://www.qualitydentistry.com/dental/amalgam/amalgam4.html