I'm not sure why someone would vote down this comment. Does this person disagree with my claim? it's very easy to test. try it. go here: http://www.ncbi.nlm.nih.gov/pubmed
and search for "fluoridated drinking water tooth decay"
browse and learn, keeping in mind that not all research is well conducted. It takes some critical thinking which is unfortunately not taught in government schools. So it may be a bit of a challenge at first.