Have you ever read about flouride? You'd be surprised what you can find.
http://www.globalhealingcenter.com/where-the-yellow-went.html

Fluoride is a poison that causes a developmental delay in children causing their adult teeth to erupt later than normal, thus less tooth decay.

It is not a "mineral" that is necessary for your teeth. The natural form of fluoride is not used in our water supply either. It is silca-fluoride which is a toxic by-product of fertilizer production.

Basically they dump it in our water supply rather than disposing of it properly thus saving them a bunch of money.

If you think fluoride is so good for you then why not swallow your toothpaste afterwards? Oh wait, fluoride is poisonous....LOL

Fluoridated water is perfectly safe. These conspiracies are about on par with "birthers" and UFO nuts you see late at night on discovery channel. Fluoridation reduces cavities by about 25%, which is clearly very significant and well worth the estimated dollar per person per year that it costs. While it does cause minor marks on the teeth, such effects are not even of aesthetic concern. Your precious bodily fluids are safe for now.

The fear of Fluoride seems to come from people distrusting the government adding stuff to the water, with claims initially being made of mind control. Most people claiming Fluoride to be poisonous usually have very flaky science to back it up with and it seems easy to trace most of it back to crack-pot theories about the government

The general scientific consensus is that it causes no health problems and significantly improves protection against cavities.

And yes Fluoride IS a mineral and is found naturally in almost all water sources.