Water fluoridation in the early 1900s stemmed from observations of strong, decay-resistant teeth in a Colorado Springs community with naturally high fluoride levels.

“in the early 1900s there was a dentist in Colorado Springs Frederick McKay who noticed his patients had modeled um brown spotted teeth but they were really strong they weren't getting Decay and so this kind of spread and they started kind of trying to understand the why and they realized there was a really high concentration of fluoride in the natural water supply that this community was drinking and this just kind of spread like wildfire with very little evidence-based medicine to back it because this was in the early 1900s”