when did they start putting fluoride in water
Water fluoridation The history of water fluoridation can be divided into three periods. The first (c. 1801–1933) was research into the cause of a form of mottled tooth enamel called the Colorado brown stain. The second (c. 1933–1945) focused on the relationship between fluoride concentrations, fluorosis, and tooth decay, and established that moderate levels of fluoride prevent cavities. The third period, from 1945 on, focused on adding fluoride to community water supplies.[36]
Economic nationalism While the coining of the term "
En plein air Artists have long painted outdoors, but in the mid-19th century, working in natural light became particularly important to the Barbizon school, Hudson River School, and Impressionists.
Fluoridation by country The decision whether to fluoridate lies with local governments, with guidelines set by provincial, territorial, and federal governments. Brantford, Ontario became the first city in Canada to fluoridate its water supplies in 1945.[112] In 1955, Toronto approved water fluoridation, but delayed implementation of the program until 1963 due to a campaign against fluoridation by broadcaster Gordon Sinclair.[113] The city continues to fluoridate its water today.[114] In 2008 the recommended fluoride levels in Canada were reduced from 0.8–1.0 mg/L to 0.7 mg/L to minimize the risk of dental fluorosis. Ontario, Alberta, and Manitoba have the highest rates of fluoridation, about 70–75%. The lowest rates are in Quebec (about 6%), British Columbia (about 4%), and Newfoundland and Labrador (1.5%), with Nunavut and the Yukon having no fluoridation at all.[112] Overall, about 45% of the Canadian population had access to fluoridated water supplies in 2007.[112] A 2008 telephone survey found that about half of Canadian adults knew about fluoridation, and of these, 62% supported the idea.[115]