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News and Comment

Are mercury fillings dangerous?

11 July 2008

The Daily Mail published a story titled " 'Hidden danger' of mercury leaking from dental fillings". Professor Aubrey Sheiham, Professor of Dental Public Health from the Department of Epidemiology at UCL, replies.

Are mercury fillings dangerous?

On the 30th June 2008 the Daily Mail published a story titled ” ‘Hidden danger’ of mercury leaking from dental fillings”. It said: “mercury fillings given to millions of Britons every year can be dangerous” 1. The story followed the publication of a statement on the US Food and Drug Administration website which said it was “reviewing evidence about safe use [of mercury fillings], particularly in sensitive subpopulations” and requested comments, supported by empirical data and scientific evidence, concerning the classification of dental amalgam. The article quoted from the FDA website2 that “dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses” and mentioned that Norway and Denmark have banned the use of amalgam fillings.

Professor Aubrey Sheiham, Professor of Dental Public Health from the Department of Epidemiology at UCL, replies below.

Summary of his main points:

  • The FDA does not recommend that people have amalgam fillings removed. That is also the recommendation of the UK Department of Health and of the European Commission.
  • Removal of the fillings is only recommended to people that are allergic to mercury, evidenced by inflammation in the cheeks if in contact with the fillings, but this is a rare allergy that affects few people.
  • The fact that dental amalgams may have neurotoxic effects is not supported by current evidence3.
  • Norway and Denmark have banned the use of amalgam fillings on the grounds that the mercury waste from dental surgeries is potentially harmful to the environment, not to patients4.

Full comments from Professor Aubrey Sheiham:

The FDA does not recommend that people have amalgam fillings removed.  They say: “Amalgam fillings are the best type of permanent filling available. They contain mercury, generally about 50% by weight. When amalgam fillings are placed or removed from teeth, they release mercury vapour. Mercury vapour is also released during chewing. The amounts of mercury released when chewing is very small and not likely to cause health effects”.

The neurotoxic effects mentioned in the FDA website are not supported by current evidence3.The personal recommendations from the FDA committee members included that the FDA “should consider labeling changes restricting its use in pregnant woman and children, study the pharmacokinetics of mercury”, but “not make any rash decisions by having the public remove their amalgams because it appears that this problem may affect only a small segment of the population”. This is in reference to people that are allergic to mercury, evidenced by inflammation in the cheeks if in contact with the fillings, but this is a rare allergy, which affects few people. Indeed other filling materials available are not without risk3.

The article in the Daily Mail mentions that Norway and Denmark have banned the use of amalgam fillings. However, this was on the grounds that the mercury waste from dental surgeries is potentially harmful to the environment, not to patients4.. The Swedish Chemicals Agency concluded that “the predicted indirect exposure of humans to methylmercury resulting from emissions due to dental amalgams are much lower than these tolerable limits indicating a low risk for serious health effects”5. Current regulations in the UK ensure that all dental practices fit amalgam separators to reduce the amount of amalgam released into the environment.

A current expert committee of the European Commission, Health & Consumer Protection DG Directorate C: Public Health and Risk Assessment says the following on the safety of dental amalgam and alternative dental restoration materials for patients on mercury in fillings3: “Some local adverse effects are seen with amalgam fillings but the incidence is low and normally readily managed. There have been claims of causation with respect to a variety of systemic conditions, particularly neurological and psychological/psychiatric effects. It is concluded however, that no risks of adverse systemic effects exist and the current use of dental amalgam does not pose a risk of systemic disease. The main exposure to mercury in individuals with amalgam restorations occurs during placement or removal of the fillings. The removal of amalgam restorations will transiently increase the exposure of individual patients to relatively high levels of mercury and there is no clinical justification for removing clinically satisfactory amalgam restorations, except in patients suspected of having allergic reactions to amalgam constituents”.

1 ‘Hidden danger’ of mercury leaking from dental fillings
2 FDA Q&A on Dental Amalgam
3 SCENIHR report
4 Swedish ban on mercury
5 Response from the Swedish Chemicals Agency to Swedish consultation


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