<P> 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 . </P>
<P> 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 . </P>
when did they start putting fluoride in water
when did they start putting fluoride in water
1945
1945