Studies: Silver Fillings Safe For Kids

But Some Question The Findings; Others Call The Research Unethical

(CBS/AP)  Neither study examined autism. Dr. David Bellinger, an author of the New England study, said autism is so rare it wouldn't be expected to be found among the number of children studied. Also, any children with autism would have been eliminated from the study, as would other children with prior neurological disorders.

The National Institute of Dental and Craniofacial Research funded the studies.

"From a scientific point of view, it gives us the confidence that these findings are not equivocal and the similarity suggests that the results are real," said Dushanka Kleinman, the institute's deputy director.

An American Dental Association official said the studies offer convincing confirmation of what previous studies have said.

"This will give patients the reassurance they are making a safe and good choice," said Dr. Frederick Eichmiller, director of the ADA's Paffenbarger Research Center.

The authors acknowledged the limitations of the studies. For example, in the study of the New England children, the authors said the "possibility of very small adverse effects of amalgam on IQ score cannot be completely ruled out."

Others cautioned against reading too much into either study.

"It is predictable that some outside interests will expand the modest conclusions of these studies to assert that use of mercury amalgam in dentistry is risk-free," Dr. Herbert Needleman, a professor of psychiatry at the University of Pittsburgh, wrote in an accompanying editorial. "This conclusion would be unfortunate and unscientific."

He said, for example, it is not clear whether either study could measure subtle effects on IQ.

Jim Adams, a chemistry professor at Arizona State University and president of the Phoenix chapter of the Autism Society of America, said more research is needed, particularly on the effects that mercury fillings in pregnant women have on their fetuses.

Charlie Brown, counsel for Consumers for Dental Choice, an advocacy group pushing to end the use of mercury in dental fillings, said both studies ignore research that indicates mercury causes a host of physical and mental problems.

Brown blasted both studies as unethical, saying that children or their guardians were never told of the potential risks of the mercury fillings.

Authors of both studies disputed that contention, saying they disclosed what they were doing and why. And, said DeRouen: "We weren't doing anything experimental. We were giving standard dental treatment." DeRouen said a review board at the University of Washington found the allegations to be unfounded.

Pat El-Hinnawy, a spokeswoman for the federal Office for Human Research Protections, said DeRouen's study is under investigation.

An anti-amalgam group called the International Academy of Oral Medicine and Toxicology also announced it was filing ethics complaints with Harvard, the University of Washington and other institutions that took part in what it characterized "outrageous" experimentation on children.