I have had upper dentures for 50 years and lowers for 30. I recently replaced my last set with new ones. While I never have encountered any problems with previous sets, I am having great difficulty with the fit effecting the muscle on the right side of the lower denture. My old ones work just fine. Anybody have any suggestions. My last dentist retired and this is a new one. He says he has never encountered this problem and after almost 6 months, I am still traveling back and forth to his office every week. Help!