Fluoridation

In 1901 Frederick McKay (1874-1959), a dentist in Colorado Springs, Colorado, noticed that many of his patients' teeth were badly stained. Curious about the cause of this staining, or dental fluorosis as it is also known, McKay concluded after three decades of study that the discolorations were caused by some substance in the city's water supply. Analysis of the water indicated high levels of fluoride, and it was concluded that the fluoride was responsible for the stained teeth. McKay also observed that although unsightly, the stained teeth of his patients seemed to be more resistant to decay. The apparent connection between fluoride and reduced decay eventually convinced H. Trendley Dean (1893-1962), of the U.S. Public Health Service (USPHS), to examine the issue more closely.

In the 1930s, Dean studied the water supplies of some 345 U.S. communities and found a low incidence of tooth decay where the fluoride levels in community water systems were high. He also found that staining was very minor at fluoride concentrations less than or equal to one part fluoride per million parts of water (or one ppm). The prospect of reducing tooth decay on a large scale by adding fluoride to community water systems became extremely appealing to many public health officials and dentists. By 1939, a proposal to elevate the fluoride levels to about one ppm by adding it artificially to water supplies was given serious consideration, and eventually several areas were selected to begin fluoridation trials. By 1950, USPHS administrators endorsed fluoridation throughout the country.