In case you're wondering why they would add fluoride to our drinking water and toothpaste if it's so dangerous. The answer might surprise you:

"Historically, this substance was quite expensive for the worlds' premier chemical companies to dispose of - but in the 50's and 60's - Alcoa and the entire aluminum industry - with a vast overabundance of the toxic waste - SOMEHOW sold the FDA and our government on the insane (but highly profitable) idea of buying this poison at a 20,000% markup and then injecting it into our water supply as well as into the nation's toothpastes and dental rinse. Yes that's right folks, a 20,000% markup. Consider also that when sodium Fluoride is injected into our drinking water, its level is approximately 1 part-per-million (ppm), but since we only drink ½ of one percent of the total water supply, the hazardous chemical literally 'goes down the drain' and voila - the chemical industry has not only a free hazardous waste disposal system - but we have also PAID them handsomely in the process!!"

More shocking info:

"Did you know that sodium Fluoride is also one of the basic ingredients in both PROZAC (FLUoxetene Hydrochloride) and Sarin Nerve Gas (Isopropyl-Methyl-Phosphoryl FLUORIDE) - (Yes, folks the same Sarin Nerve Gas that terrorists released on a crowded Japanese subway train!). Let me repeat: the truth the American public needs to understand is the fact that Sodium Fluoride is nothing more (or less) than a hazardous waste by-product of the nuclear and aluminum industries. In addition to being the primary ingredient in rat and cockroach poisons, it is also a main ingredient in anesthetic, hypnotic, and psychiatric drugs as well as military NERVE GAS!"

Source and additional information: http://www.greaterthings.com/Lexicon/F/Fluoride.htm