My son started dipping early in college and it continued even where it was theoretically prohibited in proball. It's hard to withstand that peer pressure.
When he returned home, my wife made it a point to inform his dentist of the issue (we believed it was a major problem).
From that point on, every visit to the dentist involved the typical exam, with reading material (including graphic pictures) and ambiguous comments about possible "issues."
He stopped dipping except when around other players and ultimately stopped completely when he left the game.
I think he (and we) got lucky in getting him to stop.