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All fluoridation methods, including water fluoridation, create low levels of fluoride ions in saliva and plaque fluid, thus exerting a topical or surface effect. A person living in an area with fluoridated water may experience rises of fluoride concentration in saliva to about 0.04 mg/L several times during a day. [3]
Dean began investigating the epidemiology of fluorosis in 1931. By the late 1930s, he and his staff had made a critical discovery. Namely, fluoride levels of up to 1.0 ppm in drinking water did not cause enamel fluorosis in most people and only mild enamel fluorosis in a small percentage of people.
The deuterium to hydrogen ratio for ocean water on Earth is known very precisely to be (1.5576 ± 0.0005) × 10 −4. [35] This value represents a mixture of all of the sources that contributed to Earth's reservoirs, and is used to identify the source or sources of Earth's water.
The reason most Americans have fluoride in their drinking water stretches back more than a century to a mysterious outbreak scattered across the Midwest and western US.. In the early 1900s ...
Kentucky is the only state to require fluoridation in every community water system that serves 1,500 or more people, and as a result, 99.99 percent of residents receive fluoridated water.
In 1945, Grand Rapids, Michigan became the first U.S. city to start adding fluoride to tap water. In 1950, federal officials endorsed water fluoridation to prevent tooth decay, and continued to ...
Fluoridation became an official policy of the U.S. Public Health Service by 1951, and by 1960 water fluoridation had become widely used in the U.S., reaching about 50 million people. [2] By 2006, 69.2% of the U.S. population on public water systems were receiving fluoridated water, amounting to 61.5% of the total U.S. population. [3]
Water fluoridation is not mandatory, and while there is a recommended fluoride concentration in drinking water (0.7 milligrams per liter) from the CDC, that level is not an enforceable standard.