This commentary is from officials from the University of Kentucky College of Dentistry: Sharon P. Turner, dean; Gregory G. Zeller, associate dean for clinical affairs; Richard Mitchell, restorative dentistry and materials sciences; and Jeffrey L. Ebersole, associate dean for research.
The July 22 article "Health officials kill proposal to curb mercury dental fillings" greatly misleads readers. It ignored the overwhelming bulk of evidence published over the past 30 years in peer-reviewed scientific journals that clearly shows amalgam dental fillings are safe and effective.
Instead, focus was placed on the opinion and feelings of a few patients who think dental amalgam fillings might be harming them.
Part of the mission of the University of Kentucky College of Dentistry is for faculty to serve as independent experts to assess oral health science in order to offer Kentuckians the best possible advice regarding sometimes complex scientific issues that affect the treatment decisions of patients and their dentists.
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While incidents regarding the correlation of dental amalgams with various medical issues, similar to the so-called evidence noted in the article have been reported by the media, there is no scientific evidence that general illnesses are caused by amalgam fillings.
The Multiple Sclerosis Society, the Autism Society of America, the Mayo Clinic, and World Health Organization all state there is no scientific evidence that dental amalgam causes the diseases these groups are committed to curing.
For 150 years, amalgam fillings have been used safely worldwide to save hundreds of millions of teeth that otherwise would have been lost to tooth decay. Available evidence shows that amalgam dental filling often lasts longer and can be less expensive than other types of fillings, helping make quality dental care more affordable for patients.
In 1985, a research article, often cited by anti-amalgam groups, appeared in a peer-reviewed journal in which the authors measured the mercury vapor in patients' mouths who had several amalgam fillings. These findings were well below World Health Organization limits.
In 1986, another investigator, publishing in the same scientific journal, reported a technical error in the 1985 study that made the original estimate eight times higher than the actual amount present, meaning levels were far lower than originally thought. From 1986 to 1995, this same experiment was repeated by five additional research groups, all of which reported their results in a peer-reviewed journal.
The additional studies also confirmed the 1986 results that proved the amount of mercury released by amalgam fillings during chewing was very significantly below the level that could produce any symptoms of mercury toxicity. This group of studies is an example of the way the scientific community provides checks and balances for accuracy in research.
A small number of dentists passionately believe amalgam fillings are harming their patients. They have informed their patients that various symptoms from which they suffer are caused by their amalgam fillings. However, dozens of peer-reviewed research articles, including multiple randomized controlled clinical trials which are the gold standard of clinical research, support the safety of dental amalgam fillings.
Two such trials, reported in peer-reviewed journals in 2006 and 2007, examined more than 500 children ranging in age from 6 to 10. After five to seven years, the neurological status of the children was evaluated using a panel of psychological and psycho physiological tests.
The tests were selected to detect the most subtle changes in neurological function that might be evidence of mercury toxicity. These unbiased clinical trials detected no statistical differences in the neurological status between the children with amalgam fillings and those with mercury-free fillings.
The UK College of Dentistry faculty is committed to evaluating oral health science and providing scientifically sound guidance to Kentuckians. We want to reassure dental patients that the vast majority of the scientific evidence supports the safety of amalgam fillings.