FLUORIDE AS A NUTRIEN

Abstract

The association of mottled enamel and dental fluorosis with community drinking water was detected before 1920 and was specifically related to the fluoride content of the water when Churchill, in 1931,1 was able to measure trace amounts of fluoride in drinking water. Also, in areas with communal water supplies naturally contaming increased amounts of fluoride, the occurrence of dental caries was lower than that seen in the general population.2 These observations and subsequent studies3 led to the practice of adding fluoride to communal waters, with a consequent significant reduclion in the incidence of dental caries. Nearly 90 million persons in 7,500 communities4 use water supplies containing an amount of fluoride effective in reducing the dental caries rate. Fluoride is present in the customary diet and in most potable water sources in amounts that vary from 0.1 to 0.5 parts per million (ppm).5 The average dietary intake of fluoride is approximately 0.5 mg daily from these two sources. In the temperate zone, fluoridated community water supplies are increased in fluoride content to a level of 1.0 ppm, thus providing, on the average, a total fluoride ingestion of 1.5 mg per day. A lesser level of fluoridation may be sufficient in warmer climates conducive to a higher water consumption. Fluoride is regarded as an essential nutrient6 and it is now well known to be effective in the maintenance of a tooth enamel that is more resistant to decay. Fluoride is a normal component of tooth enamel and bone. Studies in vivo and in vitro demonstrate that the calcified tissues of both enamel and bone are made up of a combination of hydroxy- and fluor-apatites of varying composition, depending on the abundance of fluoride at the site of formation.