Seen young dogs say just got there adult teeth that are swinging like crazy get stress marks in there K9's even snap them off. Still soft when young. I believe diet is a big thing to they need calcium for strong bones and teeth. I feed chicken frams etc for calcium and even use a supplement on my dogs.
Seen bitchs who have had litter after litter have shocking teeth. I'm assuming that there is a calcium defishentsy from feeding all the dogs.
So yeah I guess you will always get the odd tooth break off. I've had a good run with my younger bitch but she was started older then my older bitch and she has one very ordinary k9 and others with stress marks in them but she was started way younger.
Good diet is a sure thing to help.
Cheers