>>8
I can attest the benefits of water fluorination against dental problems and for general enamel strenghtening as someone who grew up in an area which had introduced water fluorination. Our last dentist pointed out when I was asking about it that the only severe cavities he has to deal with anymore belong to people who lived in the area before the fluroination process was introduced. He accosted children for not brushing their teeth all the same but the risk of tooth decay was greatly diminished in that generation of patients.
The point of the matter, though, is that a region adopts the process of their own accord and the fluride stays within safe limits. If they don't want to, it doesn't happen; simple as that.