My dentists keep changing because they keep leaving the practice I go to. That might be a sign to look elsewhere. Although my first dentist told me that at some time I would need a crown put on a tooth, and as soon as he left and the new dentist looked at my tooth, he said we should get this done now even though nothing had changed. One could have been complacent, while the other was proactive - who knows. There probably should be more of a standard than a gut feeling when it comes to medical procedures.