If you judge the truth of the information you receive based on the claimed authority of those who provide it, instead of using your own mind to discern whether that information is logically consistent or inconsistent, that is sad and I believe that this should be a cause of concern for you.

Consider the following facts, which can be easily be verified in countless sources, e.g. in books written by real chemists or "health scientists":

The mineral component of the teeth and bones grown by a human body is made of hydroxylapatite.

When a hydroxylapatite crystal is immersed in a water solution of fluoride ions, in the superficial layer of the crystal, which is in contact with the fluoride solution, some of the hydroxide anions from the crystal are dissolved in the water and they are substituted by fluoride anions, thus converting the superficial layer of the hydroxylapatite into fluorapatite.

The fluoride ions bond more strongly to apatite than the hydroxide ions, so once formed the fluorapatite layer is more resistant to dissolution than the parent hydroxylapatite.

In the conversion of hydroxylapatite into fluorapatite, like in any other chemical reaction, the converted amount increases with the concentration of the reactant, i.e. of fluoride and with the time of contact between hydroxylapatite and solution.

All of the above explain how the contact between the tooth enamel and a fluoride solution creates a superficial tooth layer that is more resistant to dissolution, which decreases the likelihood of tooth cavities.

The dependences of the conversion efficacy on fluoride concentration and on contact time explain why tooth brushing or mouth washing are far more effective in enamel hardening than drinking fluoridated water, when the fluoride concentration is low and the contact time is very short and most of the fluoride never enters in contact with the tooth enamel to have a chance to harden it.

After the fluoride is ingested, it never comes again in contact with the tooth enamel, so there is no way for it to harden the enamel.

Please tell us how your "1E10 health scientists throughout the world and history" have told you that ingested fluoride from inside your body can harden the tooth enamel from outside your body.

Perhaps the fluoride ions use The Force to harden the enamel from a distance?

The fluoride ions are carried by blood in most parts of the body, but the tooth enamel does not contain blood vessels. Even if it had blood vessels, they would have been buried in it and they would not have reached the external surface of the teeth, which is where the fluoride is needed for protection against dissolution.

Moreover, the fluoride ions spread uniformly in the entire blood volume. Only a small part of the ions pass close to the teeth, most of them pass through the bigger organs, including through the bigger bones, which, unlike the tooth enamel, contain numerous blood vessels.

Because the fluoride ions have high affinity for apatite, many of those passing through the bones stop there and remain incorporated in the mineral part of the bones.

While at the surface of the teeth fluoride is desirable, in bones it is harmful because it makes the bones more fragile, increasing the likelihood of fractures.

In conclusion, when drinking fluoridated water, only very little fluoride is retained in the tooth enamel, but most ends in the bones, so this method is much more effective in making the bones fragile than in hardening the tooth enamel.

There are only 3 ways in which the ingested fluoride could protect against tooth cavities: eating one's own excrement, washing the mouth with one's own urine or biting one's own body and drinking one's own blood or washing the mouth with it.

Whoever does not have such habits will not receive dental health benefits from ingested fluoride.

I look forward to see how "all the professionals of the world" can explain the magical ingested fluoride effect claimed to exist by the proponents of drinking water fluoridation.