Fluoride in drinking water - credited with dramatically cutting cavities and tooth decay - may now be too much of a good thing. Getting too much of it causes spots on some kids' teeth. A reported increase in the spotting problem is one reason the federal government will announce [that] it plans to lower the recommended levels for fluoride in water supplies - the first such change in nearly 50 years. About 2 out of 5 adolescents have tooth streaking or spottiness because of too much fluoride, a surprising government study found recently. In some extreme cases, teeth can even be pitted by the mineral. Maryland is the most fluoridated state, with nearly every resident on a fluoridated water system. In contrast, only about 11% of Hawaii residents are on fluoridated water, according to government statistics. Fluoridation has been fought for decades by people who worried about its effects, including conspiracy theorists who feared it was a plot to make people submissive to government power. It's amazing that people have been so convinced that this is an OK thing to do," said Deborah Catrow, who successfully fought a ballot proposal in 2005 that would have added fluoride to drinking water in Springfield, Ohio.