When I was in grade school, I was a member of the Operation Tooth project in St. Louis, MO. I signed a pledge to give my teeth to science and in return received a pin like this. photo from: St. Louis Post-Dispatch article, 08-01-2013Hundreds of above-ground nuclear tests were conducted in Nevada in the 1950’s and the early 1960’s. The wind carried the radioactive fallout, including Strontium-90, across the country. It settled on the grass and in the water and was consumed by dairy cows. High levels of Strontium-90 then appeared in our milk supply. The St. Louis Baby Tooth Survey was done to determine just how much radiation children were absorbing. Strontium-90 settles in bone and teeth and shed teeth are easy to collect. A total of over 300,000 teeth were donated by children from 1959-1970. Early results of the study helped convince President Kennedy to sign a treaty banning above-ground nuclear tests. To learn more about Operation Tooth, visit the Smithsonian Institute’s blog post: The Tooth Fairy goes scientific.