it's also a fact that it doesn't help teeth whatsoever. the fluoride they put in the water and in toothpaste is not the same as naturally occurring fluoride, and even the naturally occurring fluoride has never been proven to help teeth in any way. rather, a small town doctor in a village with natural fluoride in their water had a personal anecdote that there weren't many cavities among his patients. that's it. that's literally the only "evidence" that fluoride of any kind has ever been good for teeth.
United States