[adrian_b]

Fluoride is beneficial only when applied externally on the dental enamel, where it converts the hydroxyapatite synthesized by the human cells into fluorapatite, which is less soluble in the acids contained in food or excreted by bacteria.

On the other hand, ingested fluoride has no benefits, because it cannot reach the tooth enamel and when in too large quantities it has bad effects, e.g. it may cause bone damage.

Brushing the teeth or washing the mouth with something containing fluoride is very good, drinking water with fluoride is very stupid.

[XorNot]

Can you point to one single data point which has found any negative effect on human bones from excess consumption of fluoridated water at town water concentrations?

This should be easy since it's been done at enormous scale for decades so a huge quorum of people have spent their their lives drinking fluoridated water.

[adrian_b]

Skeletal fluorosis is well known to occur in regions where the natural drinking water has high fluoride content, e.g. in some regions from India and China.

You need search no further than Wikipedia.

I am not aware of any study about the incidence of fluorosis in places where the drinking water is fluoridated artificially, but it would be very difficult to do such studies, due to the lack of comprehensive past statistics, to the many confounding factors and because only few of the existing cases are detected. When someone heals a bone fracture they almost never do additional complex tests to determine if it was normal for the fracture to happen or its likelihood was increased by a condition like fluorosis.

In any case no such studies are really needed, because when you have an activity like ingesting fluoride, for which there is absolutely no evidence of benefits and no known mechanism by which it could provide benefits, but there is weak evidence that it might be harmful and there are known mechanisms by which it may be harmful, then there is no rational doubt whether that activity should be done or not.

[XorNot]

My dude people have died from ingesting too much water.

So you don't get to say "well obviously it's dangerous just cuz".

The dose makes the poison, and you are making a very specific claim about the dose.