Although adding fluoride to toothpaste and drinking water is a relatively new thing, scientists have noticed fluoride’s effects since the early 1800s.
The soil and water around Naples, Italy, is very high in fluoride, and as a result its residents historically have had little or no tooth decay.
This was noted in 1802, and by the 1840s, fluoride lozenges were passed out in many European communities to fight tooth decay.
By 1915, a few cities in the United States had begun treating drinking water with fluoride.
By the 1950s, fluoride treated water was cropping up everywhere, and Crest became the first toothpaste to add fluoride.