This dentist claimed that my insurance does not cover composite. I just discovered that they do, but this is after the fact - after he talked me into paying him more for the "difference" between composite and amalgam. I looked into my insurance, he claimed amalgam with them, and went ahead and charged me the "difference". I think this is actually called "balance billing", usually to charge patients extra's over the amount the insurance company agree to pay. In this case, he did not even claim the right procedure.