Both studies--one conducted in Europe, the other in the United States--independently reached the conclusion: Children whose cavities were filled with dental amalgam had no adverse health effects. The findings included no detectable loss of intelligence, memory, coordination, concentration, nerve conduction, or kidney function during the 5-7 years the children were followed. The researchers looked for measurable signs of damage to the brain and kidneys because previous studies with adults indicated these organs might be especially sensitive to mercury.
The authors noted that children in both studies who received amalgam, informally known as "silver fillings," had slightly elevated levels of mercury in their urine. But after several years of analysis, they determined the mercury levels remained low and did not correlate with any symptoms of mercury poisoning.
"What's particularly impressive is the strength of the evidence," said NIDCR director Dr. Lawrence Tabak. "The studies evaluated mercury exposure in two large, geographically distinct groups of children and reached similar conclusions about the safety of amalgam."
Dentists have used silver-colored amalgam to fill cavities for more than 150 years. The material is made from an alloy powder of silver, copper, zinc, and other metals held together like glue by mercury. The mercury comprises about half the total weight of a filling.
For decades, it was believed that a person's direct exposure to the mercury in amalgam was brief, occurring only while the dentist packed the filling into the tooth. But with the arrival of
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