Freya Koss, 73, Wynnewood, Pa., campaigns for an end to the use of mercury dental fillings outside the American Dental Association convention in Philadelphia in 2005. Koss says she experienced double vision, droopy eyes and was diagnosed with Multiple Sclerosis after a dentist used an outdated formula with liquid mercury to fill a tooth. After she had all of her mercury fillings removed, she said, she recovered. Courtesy of Freya Koss Courtesy of Freya Koss