I dont believe alot of this. Im young and have hardly ever brushed. Ive currently got 10 teeth rotten and broken entirely to the gum and I have 2 left out 8 to be filled. The lady whos doing the filling and clean is genuine, the last time I went she told me shed saved my front too by having it drilled and filled. I thought nothing of it at the time but she was definitly not deceiving me.
To describe my front it was complete at the bottom and the width from ront to back was at 60% rotted at the top, it was no time away from snapping out like the rest. I also doubt myself that I would grow my teeth and they needed intervention they would not have healed themselves.