Fluoride and the fluoridation of water

Abstract

In the early years of this century a dentist in Colorado, Frederick McKay, observed that the permanent teeth of many of his patients showed either white chalky patches or lines which, in more severe cases, had a rough surface and, some years after eruption, became an unsightly yellow or brown. The condition was uncommon in the deciduous teeth. McKay collected a great deal of descriptive data and studied the histology of what came to be known as ‘mottled enamel’1–4, but only one fact about its aetiology emerged, namely, that it was associated with certain drinking waters taken during the years of tooth formation (i.e. up to the age of 8, or 12 if the third molars are included). McKay also drew attention to the unexpected fact that in spite of their enamel being ‘more corrugated and rougher than normal’, the mottled enamel ‘does not seem to increase the susceptibility of the teeth to decay’5 an unfortunate inversion of emphasis. Ainsworth6 discovered a similar condition in Maldon, Essex, England, and stated7 that 7.9% of permanent teeth of schoolchildren were carious in this town compared with 13.1% in the country as a whole, the first suggestion that mottling was associated with fewer cavities. In the late 1920s it became clear that children born and bred in Bauxite, Arkansas, a town built for employees of the Aluminum Company of America, had mottled enamel which led to the finding by the company chemists that the only unusual constituent of its water was 13.9 parts per million (ppm) of fluoride8.