I'll never forget what a German dental student said to me when I asked him why dentists in Germany don't seem to urge their patients to floss: "What's bad for the teeth is good for the dentist!"
To be fair, though, I had a really great dentist in Berlin, a guy who replaced all of my amalgam fillings with gold. Docs in the U.S. comment to this day (30 years hence) how good those fillings look.
And I also went to a really bad, unscrupulous dentist in Berlin, a guy who told me I needed two root canals. Thankfully I said "maybe later" and when I went to the U.S., I checked in w/ my dentist, who said, "you don't need any root canals."
Dentistry is generally a profession with no oversight that sadly seems to have more than its share of practitioners who take full advantage of that.