Take some time to look at this lecture. I am on the point of moving to America, one of the very few countries who still mass-medicate their population with the neuro-toxin Fluoride. Fluoride decreases the IQ of a population with 10%. Besides other bad effects on your health. Something to think about.
Oh, and taking in fluoride does not improve your teeth.
These are only the first three, but you really should see them all.