How much Fluoride in Water is likely to produce mottling?
Fluoride is found naturally in low concentration in drinking water and foods. Water with underground sources is more likely to have higher levels of fluoride, whereas the concentration in seawater averages 1.3 parts per million (ppm).
Fresh water supplies generally contain between 0.01–0.3 ppm, whereas the ocean contains between 1.2 and 1.5 ppm.
Drinking water containing fluoride, or, to be more exact, sodium fluoride, is generally believed to help in preventing dental trouble.
It was not until the late 1930s that efforts to combat tooth decay involved the use of chemical substances.
The addition of a small amount of fluoride—about one part in a million—to the drinking water of a community, has been linked with a reduction in tooth decay, sometimes as great as 60 percent.
Sodium fluoride interferes with the chain of reactions which causes acid to be formed on the teeth. Also it helps the teeth become more resistant to these mouth acids.
It should be pointed out, however, that too much fluoride in the water is likely to produce mottling and, in severe cases, decay of the tooth enamel.