How come people often say the only negative effects of fluoridation is dental?

Misinformed: They are uninformed, misinformed, distrustful of the medical profession or establishment, brainwashed, or any other number of reasons. It is often said that if someone doesn't like something or somebody they tell 10 people but the ones who like something or somebody may only tell one other person. Therefore the bad stuff gets exaggerated and blown out of proportion to reality.

Complex issue: Excessive fluoride with prolonged exposure can actually cause problems in places other than teeth. The crux of the matter is how much have they over dosed, and for how long. It can definitely have adverse health effects if you have had too much for too long, but the typical amount discussed among dental circles is nothing but beneficial.

Safe and healthy: The most effective way to prevent tooth decay; scientifically demonstrated.