What is being taught in schools has no relation to reality. Sure, it may somehow influence it, but it won't dictate how each dentist or clinic will work, as they are probably free to and work do almost as they please.
Not too long ago there was a wonderful research story by a journalist of good dental health (as diagnosed by multiple university professors) going across the US for a check up at tens of clinics, and seeing what work will be offered to them.
This journalist has encountered just a few few honest dentists saying no work at all is needed, or something very minor, all the way up to dentists saying he needed work in the tens of thousands of dollars, with the worst offender being in NYC as far as I remember wanting ~$30K for his services.
Unfortunately I can't locate the story right now. If anyone can, please link us.
I didn't yet find the right one, but this one is not too bad either https://www.usatoday.com/in-depth/news/investigations/2020/0...
Let's just say that it feels like quite a high percentage of dentists don't strictly adhere to the Hippocratic Oath.
I ended up going the direction of looking for dentists unlikely to have debt and found a former army dentist and have been thrilled with how much less "well, let's do it all just in case" she is than my previous dentist (who had a TVs on the ceiling of every room and a new piece of major equipment every time I went).