my second to the last molar on the top was filled in January with a white filling. The gumline on the back of the tooth has been irrated since and the tooth hurts sometimes sending the pain to the lower part of my mouth. I had the tooth refilled and it didn't help. I went to another dentist who yet refilled the cavity again stating that the last dentist used the wrong composite resin. His new filling has not helped either. What should I do next? I have over $500 in this tooth.