In my book, the jury’s still out on fluoridation. My son is 20 and has never had a cavity. My husband and I have a mouthful of fillings from our childhood, teenage years.
The only difference between my kid and us was in our (husband and my) growing up years the water wasn’t fluoridated and we didn’t have fluoride toothpastes (and my son is not a fastidious “brusher”...he does about a 1 minute quick brushing a couple times a day...so good dental hygiene doesn’t account for his lack of cavities and neither does genetics.)
Actually good diet is linked to less cavities. Fluoride is neither a nutrient nor required for healthy teeth. Modern science indicates that ingesting fluoride confers no benefits and that fluoride gets into tooth enamel by topical means alone.
For example, in Detroit Michigan where the water is fluoridated, children have profound tooth decay. Adults have extremely high rates of tooth decay even though fluoridated water is the most consumed item.
Fluoride can’t fix a bad diet.