7 Myths of Mercury in Dentistry

Posted October 15, 2022 by Anusha ‐ 4 min read

Dental amalgam is a dental filling material used to fill cavities caused by tooth decay. Dental amalgam is a mixture of metals, consisting of liquid (elemental) mercury and a powdered alloy composed of silver, tin, and copper. Approximately half (50%) of dental amalgam is elemental mercury by weight.

Myth: Mercury is a naturally occurring element, we shouldn’t be too concerned about any exposure.


  • It is true that mercury is found in the natural environment. Mercury comes in many forms, both organic and inorganic.

  • Different mercury compounds have differing levels of toxicity, with organic forms like methylmercury being the worst.

  • Methylmercury is formed from inorganic mercury by the action of microbes found in the natural environment.

  • This means that elemental and inorganic mercury when released into the environment is easily converted into methylmercury, which is extremely toxic.

  • For this reason it is important to limit mercury exposure and mercury emissions wherever possible.

Myth: The dose makes the poison, small amounts of mercury do not really matter.


  • Dosage is just one of many factors for calculating toxicity, especially when it comes to neurotoxins with unusual properties like mercury.

  • Individual factors like genetics, diet, health and age are all related to the body’s capacity to detox heavy metals like mercury.

  • Mercury bi-accumulates in the body over time, and for those with certain genetics becomes extremely difficult to remove any mercury at all.

  • For these genetic types, the risk of harm dramatically increases over time as mercury concentrations in the body increases.

  • For women of childbearing age, or for those who are pregnant, this should be of concern.

  • Unlike other metals, mercury is known to concentrate in the umbilical cord blood relative to maternal blood during pregnancy.

  • The World Health Organisation states ’the inhalation of mercury vapour can produce harmful effects on the nervous, digestive and immune systems, lungs and kidneys, and may be fatal'.

  • Mercury exposure should be avoided through any means necessary.

Myth: It is easy to test your levels of mercury exposure.


  • Mercury has complex chemistry characteristics, which makes testing difficult.

  • The truly accurate way to test for mercury exposure is a tissue sample, usually from fatty tissues like those found in the brain and kidneys where mercury concentrates.

  • For obvious reasons this is impractical in a living person.

  • The next best option to test for mercury exposure is a combination of tests, hair (organic mercury), blood (organic mercury), urine ( inorganic mercury) and stool (both organic and inorganic mercury).

  • Stool testing is the most accurate, easy way to test your levels of mercury exposure.

Myth: Recycling mercury waste is a good thing, it stops us mining more of it doesn’t it?


  • There are only two mercury mines left in the world and under The Minamata Convention they are to be shut down.

  • The issue with mercury based products is not that we are heavily mining mercury, it is that through inefficiencies and poorly designed systems mercury is continually released back into the environment.

  • The lifecycle of mercury products, must be ended by directing mercury to long term storage where it cannot continue to pollute the environment and damage human health.

  • The concept of recycling is to be commended for improving sustainability.

  • However, toxic waste should NEVER be recycled unless the new product derived from the recycled toxin can be demonstrated to be safe and stable.

  • This is definitely not the case with mercury.

Myth: Mercury in dental amalgam is bound to other elements and poses no risk to human health.


  • Despite claims from the dental industry, mercury is not stable in an amalgam filling.

  • Mercury vapour is able to be measured in the saliva and breath of people with dental amalgam fillings.

  • Studies have also found mercury in umbilical cord blood of mothers with dental amalgams who have not eaten fish, suggesting that mercury readily leaks from the fillings and enters the bloodstream.

Myth: Mercury dental amalgam fillings are cheaper so they should still be available for developing nations and lower socio-economic demographics.


  • Economic studies that factor in the indirect costs of a mercury filling such as environmental clean up costs and health damages have determined that a dental amalgam filling costs an additional USD $67 per filling compared to a standard resin filling.

  • A mercury dental amalgam may be marginally cheaper for the patient, but on the whole to society they are far more expensive due to environmental and health damages.

  • It is fiscally irresponsible to suggest the continued use of a product like mercury dental amalgam that has well documented negative financial impact on the taxpayer.

Myth: Dental amalgam fillings are safe for dental staff to prepare and use.


  • Studies show that there are significant levels of mercury released into the air during the preparation, placement, repair and removal of an amalgam filling, regularly exposing dental staff to levels of mercury well outside Occupational Health & Safety limits.

  • In a predominately female workforce, this mercury exposure increases the risk of miscarriage, birth defects and host of other health issues.

  • Autopsy studies have confirmed the risk, showing very high levels of mercury in the brain for dental workers.

  • This is supporting evidence to the theory that dentists have far higher suicide rates than most professionals because of their high levels of mercury toxicity.

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