CDC: Fluoride Additives Are Not Different From Natural Fluoride 
Some consumers have questioned whether fluoride from natural groundwater sources, such as calcium fluoride, is better than fluorides added "artificially," such as FSA or sodium fluoride. Two recent scientific studies listed below demonstrate that the same fluoride ion is present in naturally occurring fluoride or fluoride drinking water additives and that no intermediates or other products were observed at pH levels as low as 3.5. In 
addition, fluoride metabolism is not affected differently by the chemical compounds nor are they affected by whether the fluoride is present naturally or artificially.