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Also, although fluoride affects the physiology of dental bacteria, [90] its effect on bacterial growth does not seem to be relevant to cavity prevention. [91] Fluoride's effects depend on the total daily intake of fluoride from all sources. [51] About 70–90% of ingested fluoride is absorbed into the blood, where it distributes throughout the ...
Dr. Dean's research on the fluoride-dental caries relationship, published in 1942, included 7,000 children from 21 cities in Colorado, Illinois, Indiana, and Ohio. The study concluded that the optimal amount of fluoride which minimized the risk of severe fluorosis but had positive benefits for tooth decay was 1 mg per day, per adult.
If HF alone is electrolyzed, hydrogen forms at the cathode (positive part of the cell) and the fluoride ions remain in solution. After electrolysis, potassium fluoride remains in solution. [35] 2 HF 2 − → H 2 ↑ + F 2 ↑ + 2 F −. The modern version of the process uses steel containers as cathodes, while blocks of carbon are used as anodes.
Fluoride pollution from various industrial emissions can also contaminate water supplies. In a few areas of the United States, fluoride concentrations in water are much higher than normal, mostly from natural sources. In 1986, EPA established a maximum allowable concentration for fluoride in drinking water of 4 milligrams per liter (mg/L).
Fluoride (/ ˈ f l ʊər aɪ d, ˈ f l ɔːr-/) [3] is an inorganic, monatomic anion of fluorine, with the chemical formula F − (also written [F] −), whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless.
Sodium fluorosilicate is used in some countries as additives for water fluoridation, opal glass raw material, ore refining, or other fluoride chemical (like sodium fluoride, magnesium silicofluoride, cryolite, aluminum fluoride) production. [5] It also is an ingredient in some ceramic cements.
Fluoride works primarily through direct contact with teeth. [3] [5] Fluoride came into use to prevent tooth decay in the 1940s. [6] Fluoride is on the World Health Organization's List of Essential Medicines. [7] In 2021, it was the 291st most commonly prescribed medication in the United States, with more than 600,000 prescriptions. [8] [9]
The first whitewater slalom race took place on the Aar River in Switzerland in 1933. [1] The early slalom courses were all set in natural rivers, but when whitewater slalom became an Olympic sport for the first time, at the 1972 Munich Games, the venue was the world's first concrete-channel artificial whitewater course, the Eiskanal in Augsburg.