My crown doesn't fit right, no contact. Is my dentist legally obligated to replace my crown?

Sometimes teeth move because of bone problems (know as periodontal or gum disease).
If this is the cause, ask your dentist - he or she has done nothing wrong. 
If the gap exists since fitting the dentist should have warned you and should remake it to fit properly free of charge. 
Good luck

Thomas Dey, BDS, MSc

The easiest remedy to close your gap is to place a filling. You don't say he did the filling on the crown or the adjoining tooth. As to should the dentist replace the crown it is hard to say. It depends if the dentist wants you as a patient for life, then he may consider replacing it. If there was a contact when he cemented the crown and it opened over time then it is not the fault of your dentist. Then the easy remedy is to put a filling to close the gap. Most state dental board entities give the consumer an avenue to contest treatment rendered. You can check with your state if you need to do this to get your problem resolved. Good luck