Public release date: 8-Feb-1999

NEWS CONFERENCE PARTICIPANTS David Wekstein, Ph.D., associate director, UK Sanders-Brown Center on Aging Robert Henry, D.M.D., associate professor of oral health science, UK College of Dentistry William Markesbery, M.D., director, UK Sanders-Brown Center on Aging

http://www.ada.org/public/media/newsrel/9901/nr-01.html

Definitive Study Reveals No Relationship Between Dental Amalgam and Alzheimer’s Disease

CHICAGO -- Dental amalgam (silver fillings) and its mercury component are not factors in the development of Alzheimer’s disease, concluded researchers in a definitive study published in the February 1999 issue of The Journal of The American Dental Association.

"This study demonstrates that dental amalgam is not a major public health risk factor for Alzheimer's disease," concluded Stanley R. Saxe, DMD and lead-study author. "We found no association between brain mercury levels and dental amalgam, and no significant difference in brain mercury levels between subjects with Alzheimer's and the control subjects without the disease."

Dr. Saxe is the recently retired professor of periodontics and geriatric dentistry, and director of the Geriatric Oral Health Program, College of Dentistry, University of Kentucky at Lexington.

This is the first, thorough clinical pathological correlative study of humans to show that mercury in dental amalgam restorations does not appear to be a neurotoxic factor in the development of Alzheimer's disease, Dr. Saxe said.

"We designed this study to address the limitations of earlier studies, particularly the lack of information about past dental amalgam restoration experiences," explained Dr. Saxe.

Dental amalgam is used extensively in tooth fillings and according to a 1995 survey, up to 76 percent of dentists used it as their primary restoration material. Alzheimer's disease is a major health problem for older adults, affecting up to four million Americans.

Trace levels of many metal elements, including mercury, have been reported to be imbalanced in patients with the disease. It also has been speculated that the imbalance may play a role in the development of Alzheimer's disease.

"We conducted an investigation to determine the relationship between brain mercury levels, Alzheimer's disease and dental amalgam exposure," Dr. Saxe said.

In the investigation, the authors studied 68 subjects with Alzheimer’s disease and 33 control subjects without the disease to determine mercury levels in various brain regions. The study included only subjects who met the strict criteria for Alzheimer's disease, and who had no confounding disorders such as strokes, cerebral oxygen deficiency or other disorders that could cause dementia.

Evaluation also included determining the number and location of existing teeth, plus assessing existing amalgam restorations and past amalgam experience. Dental histories of each subject’s 32 teeth were completed and information was obtained on non-dental exposure to mercury.

The authors measured mercury levels in multiple brain regions and performed full nervous system disease evaluations to confirm the normal status of the brain or the presence of Alzheimer's disease.

"Our results do not support the hypothesis that dental amalgam is a major contributor to brain mercury levels and that mercury is a factor in developing Alzheimer's disease," the authors concluded. "This study demonstrates that dental amalgam is not a public health risk factor for Alzheimer's disease."

"The World Health Organization, FDI World Dental Federation and the American Dental Association (ADA) all support the continued use of dental amalgam as a safe, durable and cost-effective material to restore teeth," said Gary C. Armitage, DDS, chairperson of ADA’s Council on Scientific Affairs.

Additionally, the US Public Health Service issued a report in 1993 stating there is no health reason not to use amalgam, except in the extremely rare case of the patient who is allergic to a component of amalgam, explained Dr. Armitage. This supports the findings of the Food and Drug Administration, the National Institutes of Health Technology Assessment Conference and the National Institute of Dental and Craniofacial Research, that dental amalgam is a safe and effective restorative material.

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Mercury In Dental Fillings Does Not Appear To Cause Alzheimer's, According To University Of Kentucky Study

http://www.sciencedaily.com/releases/1999/02/990210065946.htm

University Of Kentucky Medical Center (http://www.mc.uky.edu/)

Posted 2/10/1999

Editor's Note: The original news release can be found at http://www.mc.uky.edu/mcpr/news/1999/February/dental.htm

UK Study: Mercury in Dental Fillings Does Not Appear to Cause Alzheimer's

http://www.mc.uky.edu/mcpr/news/1999/February/dental.htm

Contact Vikki Franklin or Kristi Lopez

Results of the study are published in the lead article in today’s Journal of the American Dental Association.

The study compared mercury levels in autopsied brains, and dental amalgam status and history in Alzheimer’s disease subjects as well as control subjects. The researchers found no significant association of Alzheimer’s disease with the number, surface area or history of dental amalgams.

"Our key finding is that there is no relationship whatsoever between mercury found in the brain and amalgam," said Stanley Saxe, D.M.D., one of the study’s authors and a professor emeritus of periodontics and geriatric dentistry in the UK College of Dentistry. "Although very small amounts of mercury are released from dental amalgam – generally when rubbed or abraded due to brushing or eating - it is not taken up by the brain."

"Our key finding is that there is no relationship whatsoever between mercury found in the brain and amalgam. Although very small amounts of mercury are released from dental amalgam – generally when rubbed or abraded due to brushing or eating - it is not taken up by the brain."

Funded by a grant from the National Institutes of Health, the study was prompted by scientific controversy on the topic that has been brewing for several years.

The study, which began in 1991, was a collaborative effort among researchers from the UK Sanders-Brown Center on Aging and the UK College of Dentistry. Saxe and William Markesbery, M.D., director of the Sanders-Brown Center on Aging, led the research team. "The uniqueness of the collaborative effort between the departments of chemistry, statistics, the College of Dentistry and leadership from the Center on Aging, made this research possible and successful," Markesbery said.

"This is the only study that has looked at this question in a large group of people," Saxe said.

Dental amalgam has been used since the early 1830s and is considered an excellent restorative material in dentistry because of its strength and durability.

However, because dental amalgam is comprised of 50 percent mercury, a neurotoxin, it has been the subject of continuing controversy as a possible public health risk.

"The fact that there was no differential found in brain mercury levels due to dental amalgams is very exciting news for the dentistry profession," Saxe said.