I use the remineralizing toothpaste after a American expat in Japan recommended it, I picked it up when I was in Japan. It really works! My dentist was fine with it, said my teeth looked good (I am blessed with very generally sound teeth.)
Re: American teeth - a lot of Americans also get veneers to keep up with perfect american teeth, which can really fuck up your teeth if they’re improperly done/maintained.
I’ve wondered about that toothpaste! Thanks for bringing it up.
My mom uses it and says it helps her. I don’t love the way it tastes but I’m trying to use it more. Scientifically I’m a bit skeptical because hydroxyapatite reaaaaally doesn’t dissolve and it seems like 2 minutes at a time would be too short to have diffusion doing anything to move the atoms around, but it’s also not going to hurt anything. And the studies I looked up showed it helped (sponsored by the toothpaste company of course).
Eta: the reason fluoride helps is because hydroxyapatite can switch one atom out for a fluoride and it’s too big for the crystal so it shifts the structure just a little bit and makes it physically harder and harder to dissolve. I’m going to go double check that I’m remembering that right though.
omg i feel very dumb trying to understand that right now lol.
I also probably explained it very badly because it’s been 7 years since I thought about it
It’s like shoving a ball that’s a little bit too big into a lattice of balls and it’s a bit too tight so everything is wedged in harder than before.
I understand that perfectly! 
Glad to hear it’s not completely unfounded mumbo jumbo, if a little questionable due to dissolving time, etc. And that it’s at least likely not harmful. No idea if it’s better for teeth generally, etc, but it has a longer lasting anti sensitivity effect which I greatly appreciate! I can even use some whitening products now, to work on my coffee/tea/wine stains off white 
PS anyone considering it, I know $10/tube is steep but also $1.67/mo (since I went through a tube in about 6 mo) is totally worth it to me for lack of toothache!
Just posting this in case anyone didn’t know this, but Sensodyne and other conventional toothpastes for sensitivity really only work if you don’t rinse your mouth after brushing. Just spit the toothpaste out, but no rinse or mouthwash.
So because of this discussion, I just checked my local water supply and while we have some naturally occurring fluoride in our water and soil it is not enough to prevent cavities. They do not add fluoride to our water. I had no idea. No wonder we have so many dentists in Niagara!!
It worked ok for me (for some reason, Colgate worked better than Sensodyne in spite of same active ingredient!?), but I couldn’t skip a brushing, I had to use it every time. This was inconvenient when traveling (not having a travel tube of the sensitive paste, not being able to bum some from family…everyone does that, right? Sharing toothpaste isn’t weird?) I hate having to be Particular about things. And the staining was definitely building up, since whitening products are irritating/sensitizing… which sucked for interviews and weddings and such…