Baby teeth hold clues to the harms of toxic metals for infants — and older kids

Baby teeth have a value that goes beyond money from the tooth fairy. Scientists say they also hold the key to figuring out what metals in the environment infants were exposed to — and how they affect not just developing baby brains, but behavior in adolescents. "It seems like an impossible question to answer," says Dr. Manish Arora , a professor of environmental medicine at the Icahn School of Medicine at Mount Sinai. "Luckily for us, baby teeth are this amazing organ." He says baby teeth work kind of like tree growth rings. They start to form in utero, beginning in the second trimester. And as they develop, layer by layer, they incorporate trace amounts of metals they're exposed to — in the womb and early life. That's when the brain is most vulnerable to toxic metals. In a new study in the journal Science Advances , Arora and his colleagues used lasers to decode those layers in the baby teeth shed by 500 children in Mexico City. That allowed them to create a timeline of what neurotoxic metals those children were exposed to, week by week, even before they were born. Connecting teeth to the brain The children in the study have been followed since their mothers were pregnant. As the children reached adolescence, the researchers also took detailed behavior assessments for some of the kids and MRI scans of their brains. …