During my 43-year career in academic dentistry, first at UC San Francisco and subsequently at the University of Pennsylvania, my field of study was primarily oral pathology, including dental caries.
Tooth enamel consists primarily of hydroxyapatite crystals. These crystals contain hydroxyl ions, which can be replaced by fluoride ions, thereby rendering the crystals less soluble in acid. In the presence of fluoridated water, the replacement of hydroxyl ions can occur beginning with tooth development and continuing through life. The acid, primarily lactic acid, which attacks enamel is formed during the metabolism of refined fermentable carbohydrates such as sucrose in the diet.
Fluoridation has for many years reduced the incidence of dental caries in countless cities throughout the United States. When added to drinking water in the proper concentration, it is a safe and effective public health measure that protects the teeth of children and adults alike.
Henry O. Trowbridge