April 19, 2006
BY JIM RITTER Health Reporter Advertisement
Although traditional silver-colored dental fillings contain toxic mercury, the metal fillings are safe for children, two government studies have found.
The studies included 1,041 children in New England and Portugal. Half received metal fillings and half received mercury-free composite fillings. The children were followed five to seven years.
Metal fillings continuously release mercury vapor, which patients inhale. The studies found that children who received metal fillings had slightly elevated urine levels of mercury.
But compared with kids who received composite fillings, kids with metal fillings suffered no detectable loss of intelligence, memory, coordination, concentration, nerve conduction or kidney function.
Children and adults in the United States receive more than 70 million metal fillings each year. Mercury, which comprises about half the weight of these fillings, is used to bind together powders of silver, copper, zinc and other metals.
The American Dental Association said the studies support its position that metal fillings are safe and effective.
But the studies, published in the Journal of the American Medical Association and funded by the National Institutes of Health, are unlikely to end the debate.
"Mercury is the most toxic nonradioactive substance on earth," said Downers Grove dentist Janet Stopka, who stopped using metal fillings 10 years ago. "I would never put mercury in my child."
Some say studies too short
Critics said the studies were not definitive. For example, the children were not followed long enough to detect possible long-term effects of mercury such as multiple sclerosis and Alzheimer's disease.
It would be "unfortunate and unscientific" to conclude from these studies that mercury fillings are risk-free, Dr. Herbert Needleman of the University of Pittsburgh wrote in an accompanying editorial in the journal.
Dentists have been using metal fillings containing mercury for more than 150 years. But they increasingly are using composite fillings, which consist of materials such as glass and ceramic in a plastic mix.
About 70 percent of fillings today are composite. But composite fillings generally aren't as durable as metal ones, and they are more expensive.
