… Nearly 63% of the US population has fluoridated water flowing through their taps, according to the Centers for Disease Control and Prevention (CDC). US health experts describe fluoridated water — a voluntary practice for local water districts — as one of modern medicine’s greatest public health achievements, up there with the recognition that smoking is bad for you. … An important debate over fluoride is gaining fresh steam among scientists and legal experts. Some recent studies suggest more research is still needed on safe fluoride levels for kids. Plus, a federal ruling in California this year questioned the US government’s recommended dose. While many medical professionals — chiefly dentists — support some level of fluoridation, there is growing agreement that we still aren’t sure how much fluoride is too much.