There are hundreds if not thousands of paper showing sodium flouride is not harmful in any way.
The most recent paper on flouride, by Harold Foster (who cracked the HIV/AIDS puzzle) points out there is no evidnce of harm from sodium flouride whatsoever. 
If flouride is so bad where is the pile of bodies? Air pollution kills 7 million poeple a year according to the WHO, flouride has killed zero people in all of history.
If flouride is so bad then why does the worst case of skeletal fluorosis in history not dead or harmed in any way whatsoever? 
That poor lady drank tea from 100 tea bags A DAY for TEN YEARS (a cup of tea from a single tea bag has as much flouride as 4 gallons of fluoridated water) and made a "complete recovery" according to the New England Journal of Medicine.
So why the disparity? Because the tests on human harm used laboratory grade pure NaF - sodium fluoride. Water plants use industrial grade Naf made as a byproduct if the production f Hydrofluoric acid and contains some pretty nasty impurities. Nobody questions theur harm to human health but you can not actually blame flouride. 
We add flouride to medicines, notably atypical, antipsychotics because it makes them pass the blood brain barrier.
Show me what you think is evidnce Fluoride causes harm and I'll explain how it's actually not true.
 MD JD Peter Levy Thomas: