TulipRoxy,is your sheltie a blue merle, or sable merle? I assume that is her in the avatar? Sorry to hear of that damage. I used to have the big shin bones cut lengthways so my cattle dogs could easily get at the marrow, until one of them got a premolar stuck in that honeycomb sort of bone inside and pulled the tooth out.
Fortunately that was my foundation bitch(too big for showing) , and not her daughter, my first home bred Ch.. I'd have been so depressed if my actions had caused a show dog to lose a tooth.