I think you've solved part of the problem, Steffi. You grind your teeth! A friend of ours was having huge work place problems ( admin. of theater), and it made him grind his teeth literally to pieces while he slept. Another part is without doubt PD that somehow makes crowns and fillings fall out - this according to my dental hygenist. So far mine are staying put, but my guess is that it may not last. And a third part is the PD meds that cause dry mouth, which can cause cavities.
Good luck at the dentist's - thank goodness for modern dentistry. You are too young to remember the old drills - virtual torture instruments, and the old dentists - veritable sadists.

I'm happy i made you laugh.

birte