Fluoride in the Water as Optimal for Cavity Protection

Identification of 1 ppm Fluoride in the Water as Optimal for Cavity Protection 

If the water supply had no fluoride, the population displayed 6-8 DMFT. As the fluoride concentration increased to 1 ppm, the mean DMFT of the population decreased by about 50%, but the index of fluorosis remained well below 1. Increasing the fluoride above 1 ppm 

The fluoride ion can replace the hydroxide ion in a crystal without significantly altering its structure, an isomorphous ion replacement. Fluoride also affects the enzymes involved in enamel formation, causing mottled enamel, a severe example of enamel fluorosis. White opaque patches on the normally translucent enamel indicate mild fluorosis. Fluorosis is measured on a grade of 0-5 where 1 through 3 indicate an increased cover of opaque white patches on the tooth surface, and 4 and 5 indicate an increased mottling. The two worst affected teeth make up an individual s score. The community s index of fluoridation is the mean score for all individuals. As the natural or artificial fluoride concentration of the water supply increases to 1 ppm, the mean number of cavities in 10-12 year-old children decreases from 7 to 3. Above 1 ppm fluoride, caries does not decrease much more, but the index of fluorosis increases markedly. This is the reason why public water supplies are fluoridated to only 1 ppm and not more or less. 

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