There's plenty of studies that compare locales with fluoride in the water to those that don't, eliminating time-based correlations like improving diet. There ar

There's plenty of studies that compare locales with fluoride in the water to those that don't, eliminating time-based correlations like improving diet. There are other things to criticize in the data though (most of the data shows results with children, and not a lot that accounts for fluoride toothpaste). https://onlinelibrary.wiley.com/doi/10.1111/ipd.12928 https://onlinelibrary.wiley.com/doi/10.1111/ipd.12928 https://pubmed.ncbi.nlm.nih.gov/26092033/ https://pubmed.ncbi.nlm.nih.gov/26092033/