April 19, 2006 -- Studies Find No Ill Effects of Dental Amalgam Fillings in Children

Two studies, one in the United States and one in Europe, show that children whose dental cavities were filled with amalgams containing mercury had no adverse effects five to seven years after they received the fillings, including no detectable loss of intelligence, memory, coordination, concentration, nerve conduction, or kidney function. Researchers looked for measurable damage to the brain and kidneys because previous studies with adults had indicated those organs might be particularly sensitive to mercury. Children in the studies had "fairly rampant" tooth decay and by the end of the study had on average 15 tooth surfaces restored. Dentists have used silver-colored amalgam made from an alloy of silver, copper, zinc, and other metals held together with liquid mercury for more than 150 years, and scientists in the 1970s and 1980s showed that the amalgam continuously releases mercury vapor into the mouth, which is inhaled and absorbed by the body. That raised concerns about whether such chronic, low-level exposure to mercury might be toxic. Investigators in the two studies reported today, however, that they found no health differences over seven years between the 253 participants who received amalgam fillings and 254 volunteers who were treated with composites. The studies were conducted in Portugal and in Boston and a rural area in Maine in the United States, with funding from the National Institute of Dental and Craniofacial Research in the National Institutes of Health, and are reported in today's issue of the Journal of the American Medical Association.