Patient: swollen and painful gums near the left bad tooth, unable to chew, slight soreness in the tooth, started last Friday and has been improving since then, taking oral vitamin B2 and metronidazole. I have not been treated. The upper left back tooth, the third from the bottom, has a bad cavity that extends from the inner side of the tooth to the outer side. I would like to ask about the approximate treatment steps? Is it still possible to repair it? How should I deal with the current gum swelling and pain? Beijing Stomatological Hospital, Department of Endodontics Hou Benxiang: You must go to the examination to confirm the diagnosis, according to your description can not be judged. Please seek medical attention in time to avoid delaying the condition.