Our teeth decay much more slowly (or not at all) if we eat the proper diet. Fiat foods with high sugars and degrading chemicals are the primary reason for the modern tooth decay issues.
That fact alone makes me very skeptical about the fluoride in the water - if it’s only official reason to exist is to solve a problem which shouldn’t need to be solved in the first place, it’s a red flag to me. Just my 2 sats, definitely not an expert.