When Did We Start Recommending Fluoride for Oral Health?

October 6, 2022

When you visit Dr. Dhiraj Sharma for a dental cleaning, you sometimes receive a fluoride treatment. And you have likely heard that the water you drink is fluoridated. But how long have we been using fluoride for oral health? Grand Rapids, Michigan, was the first city in the U.S. to fluoridate its public water, doing so in 1945. Fluoridated water quickly spread when the oral health benefits became clear. But what led to this discovery?

Discovering the Connection Between Fluoride and Oral Health

The earliest research into fluoride and its benefits for oral health began in 1901. But oddly enough, it began with a seemingly unhealthy observation. People in Colorado Springs had severe, permanent brown stains on their teeth. Frederick McKay, a recent dental school grad, wasn’t sure what to make of it. The locals had their theories, but none were proven. McKay started researching the Colorado Brown Stain.

The research took a huge step forward in 1909. That was when the Colorado Springs Dental Society reported nearly 90% of locally born kids had brown stains. This attracted Dr. G.V. Black, a renowned dental researcher, to join McKay. Together, the two researched fluorosis until Black died in 1915.

Two Important Findings

Black and McKay had two crucial findings. One was that teeth with the stain were highly resistant to decay. The other was that the mottling or staining came from development imperfections in the teeth of kids. So, if a child still has baby teeth, the kid may develop stains. If an adult already had their adult teeth and the teeth weren’t stained, they wouldn’t.

The Theory of Water

McKay theorized that maybe something in the water caused the staining. In 1923, McKay talked to people in Oakley, Idaho. They had noticed similar staining after creating a water pipeline from a nearby warm spring. But the water tested fine. More similar findings occurred, including in Bauxite, Arkansas. But the water always seemed fine.

Bauxite was a company town, so it had a reputation to maintain. So, the chief chemist of the company, H.V. Churchill, used photospectrographic analysis of the water. He found high levels of fluoride.

More Research Began

This discovery, combined with the health of the stained teeth, led to research. One of the first things researchers looked into was how high fluoride levels could get without worrying about fluorosis. Dr. H. Trendley Dean, the head of the NIH Dental Hygiene Unit, led the research. He hypothesized that adding fluoride to water would protect oral health on a larger scale. And his research had shown what levels were safe.

As mentioned, Grand Rapids became the first city to add fluoride to its water supply. There was an accompanying 15-year study. But after 11 years, the cavity rate had already dropped over 60%. This led to the expansion of fluoridated water.


The discovery of fluoride’s benefits on teeth goes back to staining on teeth that were unusually strong. It led to more research, and by 1945, the first city had fluoridated water. By the end of the next decade, numerous cities had fluoride in their water, with their residents enjoying a reduction in cavities.

You can ask about proper fluoride use at your next dental cleaning in Chicago.


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