I had a tooth infection that did not show on x-ray. When they opened the tooth the Endo was surprised it was so infected. Why didn't this show on x-ray? I still have the same symptoms because the Endo wasn't show where all the drainage was coming from. She said it is not the apex of the tooth & refused to do a reverse root canal. I am to put the permanent crown on & in a few months she would consider a reverse root canal. Where could it be coming from?