This is a website that may help with the info you want. You can read the whole thing. This was a debate. and the oppositions opinion matched more what I've read about fluoride.
Repeat of Question 3.
Is there a difference in the effectiveness between naturally occurring fluoridated water at optimal fluoride levels and water that has fluoride added to reach the optimal level?
Fluoride, as such, is never added to the water. Only silicofluorides (a hazardous waste containing many toxic pollutants) are used to artificially fluoridate water, and studies have proven that they do not effectively prevent tooth decay, they only delay it. (See opposition's response to Question 4). Silicofluorides never occur naturally in nature, and they are 85 times more toxic than natural occurring calcium fluoride. Therefore, the effect on the entire body will be different.
This was proven in a study called, "Comparative Toxicity of Fluorine Compounds." After this study was completed, this statement was made: " ... this meant a daily intake of approximately 40 mg/kg of fluorine from sodium fluoride as compared with 3400 mg/kg from calcium fluoride. Therefore, from the standpoint of lethal concentrations and amount of fluorine necessary to cause growth inhibition, wide differences in toxicity of some of the compounds of fluoride were noted." (See 3-1: Industrial and Engineering Chemistry. July 1934, page 797). In other words, industrial waste (sodium fluoride) is 85 times more toxic than natural calcium fluoride. Both of them contain fluoride, but they are totally different compounds. (Also see 3-2).
Calcium is a well-known antidote for fluoride poisoning. When an antidote accompanies a poison, it makes the poison far less toxic to the body. Soft waters to which fluoride is artificially added lack this calcium which is present in most waters that contain natural fluoride.
"The claim that fluoridation is one of 'nature's experiments' is not valid because the salts put into the water supply, sodium fluoride or silicofluorides, are industrial products never found in natural water or in organisms. They are, furthermore, notoriously toxic, sufficiently so to be used as rat poison or insecticide. Calcium fluoride, on the other hand, which is the form commonly found in natural waters, is not toxic enough for such uses." — Dr. C. G. Dobbs, (Ph.D., A.R.C.S.) Bangor, Wales, England.
Jump to the Opposition's
There is some very good info on these sites.
Fluoridation advocates cite “60 years of public health research” to support the idea. About 60 years ago it was noted that areas of the country (Colorado and Texas) where aquifer-derived water was naturally high in fluoride, kids had more dental fluorosis (permanent dental staining) and, arguably, fewer cavities. This naturally occurring fluoride is calcium fluoride, which is almost insoluble, meaning it doesn’t bind well to internal tissues, such as bones and kidneys.