You’re not supposed to swallow it. It builds up in the body (in teeth mainly?)
With all of this being said, once you're an adult there's no longer any particularly viable pathways from the bloodstream to your outer teeth, so flouride in the body becomes mostly disconnected from flouride in the teeth (and vice versa). Flouride's effects on the body are less well understood, albeit only because we struggle to measure such apparently small effects on a general population.
That’s why second opinions on important things are vital.
Turns out health professionals are themselves skeptics... (covid showed us already)
Well it's science and at some point, science claimed that earth was flat so...
Good luck again :D
(point is, don't trust blindly)
> Severe : 5 : All enamel surfaces are affected and hypoplasia is so marked that the general form of the tooth may be affected. The major diagnostic sign of this classification is discrete or confluent pitting. Brown stains are widespread and teeth often present a corroded-like appearance.