Despite public concern about the vapors released by dental amalgam fillings, which are composed of 50% mercury, researchers from dental schools and universities in the United States and Portugal suggest in two separate studies that mercury fillings aren't linked to behavioral, kidney, or cognitive function problems in children.
In one study examining the effects of mercury fillings on children's neurological and kidney function, researchers tracked the dental health of 534 6- to 10-year-old children for 5 years. At the start of the study, none of the children had cavities or fillings, and all of the children underwent intelligence, memory, and learning tests. The children received semi-annual dental checkups and were randomly assigned to receive either mercury (dental amalgam) fillings or fillings with a composite material that didn't contain mercury. The children also provided urine and hair samples throughout the study, so researchers could measure their mercury levels and kidney function.
Over the 5-year study, children had an average of 15 teeth filled. Children who received mercury fillings did have a higher level of mercury in their urine. However, no significant differences were found between the intelligence scores, memory scores, or visual-motor skill scores of the children in either group. The authors concluded that based on the results of this study, there's no reason to discontinue the use of mercury fillings in children of this age group.
In the second study, researchers evaluated the safety of mercury fillings in 507 Portuguese 8- to 10-year-old children over a 7-year period. All of the children had at least one cavity, but had no prior mercury fillings. Half of the children received dental amalgam fillings, whereas the other half received fillings made of a composite material. All of the children underwent memory, intelligence, and motor skills tests, and the researchers also evaluated urine samples for the presence of mercury.
As in the first study, the children who had their cavities filled with dental amalgam didn't have significantly different scores on intelligence, memory, or motor skills tests. In addition, researchers discovered that 5 years after the initial treatment, children whose teeth were filled with composite material needed 50% more treatment to restore their fillings.
What This Means to You. High levels of mercury have been shown to be toxic, but the results of these two studies indicate that the small amounts of mercury used in dental fillings do not appear to affect children's learning, memory, intelligence, or kidney function. As a first step toward keeping your child's teeth healthy, encourage brushing after meals and before bed, and daily flossing. To combat cavities, serve water or milk to quench your child's thirst instead of sugary juices and sodas. If your child does develop a cavity and you have questions about the materials used in fillings, talk with your dentist or doctor.
Sources (Study 1): David C. Bellinger, PhD, MSc; Felicia Trachtenberg, PhD; Lars Barregard, MD, PhD; Mary Tavares, DMD, MPH; Elsa Cernichiari, MS; David Daniel, PhD; Sonja McKinlay, PhD; Journal of the American Medical Association, April 19, 2006.
(Study 2): Timothy A. DeRouen, PhD; Michael D. Martin, DMD, PhD; Brian G. Leroux, PhD; Brenda D. Townes, PhD; James S. Woods, PhD, MPH; Jorge Leit?o, MD, MS; Alexandre Castro-Caldas, MD, PhD; Henrique Luis, MS; Mario Bernardo, DMD, PhD; Gail Rosenbaum, MS; Isabel P. Martins, MD, PhD; Journal of the American Medical Association, April 19, 2006.
Reviewed by: Steven Dowshen, MD
Date reviewed: June 2006