UNDERSTANDING THE SCIENCE OF FLUORIDE
Fluoride Facts
Chemical Structure
The fluoride that is incorporated in municipal water supplies and dental products, such as toothpaste, is actually sodium fluoride (NaF) or other fluoride compounds.
Sodium Fluoride
Sodium fluoride is an inorganic compound composed of the cation Na and the anion of fluorine, fluoride. This substance is classified as a salt, which can be seen by its crystalline structure.
NaF was the first substance used in water fluoridation and is used as the reference standard.
Fluorosilicic acid & Sodium fluorosilicate
Fluorosilicic acid and sodium fluorosilicate (liquid form of fluorosilicic acid) are two fluorides that are also used in the process of water fluoridation. Both work in similar ways to sodium fluoride, by having their fluoride ions bond with the hydroxyapatite. Today, fluorosilicic acid is more commonly used in the United States, as it is a much more inexpensive alternative.
Chemical Structure of Fluorosilicic Acid
Incorporation in Enamel
The enamel is the hardest substance in the body, having the heaviest mineral density. It is primarily composed of a crystalline form of calcium phosphate, hydroxyapatite.
The enamel demineralizes when it comes in contact with acids released by bacteria digesting fermentable carbohydrates. Significant demineralization results in cavities.
When the enamel comes in contact with fluoride (NaF), the fluoride ions ionically bond with the calcium in hydroxyapatite, replacing the hydroxyl group, forming fluorapatite.
