Only 2 studies, 2010 and 2011, where hydrofluorosilicic acid was tested for its effect on humans for the first time in history, and both studies PROVE the damage it does while posing as "fluoride" in our drinking water! Read Dr. Mercola's coverage of this with Jeff Green, National Director for Citizens for Safe Drinking Water....

http://articles.mercola.com/sites/articles/archive/2011/11/12/jeff-green-on-fluoride-part-1.aspx

Fluoride Proponents Never Actually Tested "the Real Thing"

Part of the difficulty when discussing water fluoridation is that many do not realize that the fluoride you find in drugs, for example, while harmful, is not quite as bad as what's being used for water fluoridation.  The fluoride added to your drinking water is not pharmaceutical grade.
It's a toxic industrial waste product.
Deepening the deception is the fact that none of the studies on fluoride actually used the far more toxic hydrofluorosilicic acid that is added to the water supply. Rather they use pharmaceutical grade fluoride, so the health hazards are likely FAR worse than any study has so far discerned. (Below quote from Jeff Green, National Director, Citizens for Safe Drinking Water) -

"So when someone uses the word fluoride, I believe we start with a deception from the very beginning," Green says. "… [T]here is almost a bragging by the promoters of fluoridation that you don't have to study it because they have studied fluoride over and over again, yet they have never looked at the actual product itself until just recently!
In 1998 to 2000, I was able to get a congressional investigation on fluoride.  At that particular time, the House Committee on Science allowed us to write some questions that would be sent out to various entities.  Originally it was to the EPA…  We asked them to send the scientific data they had on the silicofluorides.  They wrote back [saying they] couldn't find any [data] for chronic effects of the use of hydrofluorosilicic acid or the silicofluorides. 
They didn't have any at all.
Up until 2010, and now 2011, there have only been two studies that have dealt with the continued use of hydrofluorosilicic acid. 
… [T]hey were able to finally confirm, through these toxicological studies, the very thing they had found through large epidemiological study—that there is a higher amount of lead that shows up in blood.  In the epidemiological study it was 400,000 children.  It showed that there was a tremendous increase... four times as much for Latinos, seven times as much for blacks, and a[n on average] doubling of the danger level of lead in children's blood, when hydrofluorosilicic acid was present in the water."
The importance of that was that it was also compared to having no fluoride added into the water and [pharmaceutical grade] sodium fluoride added into the water.  So there was really a difference between the specific products being placed in there." 

Fluoride Increases Heavy Metal Accumulation in Your Body

These studies also showed that hydrofluorosilicic acid increases lead accumulation in bone, teeth, and other calcium-rich tissues. According to Green, the free fluoride ion actually acts as a transport of heavy metals, allowing them to enter into areas of your body they normally would not be able to go, such as into your brain.

"Industry prizes what we call fluoride compounds," Green says. "What's amazing is there is so much [information] out there that's never explained to the general public.  But [fluoride] is… the most aggressive seeker of another electron.  It's the most electromagnetically negatively charged element in the entire world.  It basically is the most interactive of all the elements… It will give up whatever it's with to be with something else…
So it's prized by industry because it actually disrupts molecular bonds… Industry also wants it because it creates tighter molecular bonds.  So Scotchgard, Stain Master, Gore-Tex, ski gear… These are all fluoride-type compounds as well because they actually make it a tighter molecular bond that is more impervious to penetration. 
… By the time you get to the enzyme activity, and knowing what it can do to disrupt enzyme activity, the effects are so widespread, it's just amazing... Once [people] learn the nature of fluoride, they would never want to put it in their water."