From a chemical point fluoride is an anion, F - , of the element Fluorine, F. Molecular Fluorine is a dangerous gas F 2, the lightest member of the halogen group and the most reactive one. Fluorine is the most electronegative of all elements. It has thus the most oxidising properties and therefore can not be found as fluorine in nature. It is a blunder when some tooth paste companies advertise for having “Active Fluorine” in their products.
Fluoride is next to chloride in the halogen group and the two ions do have some chemical properties in common. But while sodium chloride, also called Table Salt, is normal mineral highly needed in normal diet, fluoride is highly toxic, even at much lower concentrations of intakes.
Further, fluoride has the same charge and a comparable atomic radius and atomic weight as the hydroxyl group OH -. As the hydroxyl group is a substantial sub-unit in all mineral structures of living creatures, fluoride has the ability to replace the hydroxyl group and to accumulate in teeth and all bone structures. Such an accumulation, if not prevented on time, would sooner or later lead to Fluorosis.
The far largest fluoride exposure to humans comes from drinking water that is used for drinking and cooking. Even at relatively high and dangerous concentrations of fluoride in the water, fluoride is tasteless, odourless, and does not contribute to any turbidity in the water. It is thus undetectable for the water users and its effects are largely delayed and mostly irreversible. In general fluorosis can not be cured; it can on the other hand easily be prevented through provision of safe water.
Written by Eli Dahi, March 2009