Patient: I have a cavity that was filled once before 9 years ago (the second one inside the lower right side of my mouth) The tooth usually does not have any pain. Recently, I had a medical checkup and found that the upper filling of this tooth had fallen out, so I thought there was no big problem, so I went to our local hospital to get a filling. After a little cleaning, the doctor sent me back. I asked the doctor how not to fill it, and he said that my tooth was close to the nerve, and if I pulled it out again, it would be close to the nerve and the nerve would be exposed; he said that the only way is to do root canal treatment, and the sooner it is done, the better. At first he said that after the first time, he would come back in a week, but after he helped me to do my pre-treatment, he let me come back in 4 days when it was New Year’s Day holiday a week later and he was not working. I want to make sure of 2 things: 1: Is my tooth only root canal treatment? I was reading online later that all the teeth that had root canals had significant pulpal pain or something more serious, and my tooth had no such problem. This makes me confused about the doctor’s diagnosis? And isn’t it recommended to try not to kill the live nerve? And isn’t it recommended to try not to kill the live nerve? 2: Is it possible to have such a short interval between the first and second root canal treatment? Originally it said one week, but later it said 4 days, isn’t the interval important? I have seen many root canal people say that the inflammation during this period will affect the health of the tooth behind? I know I only have a small tooth problem, but I’m scared of the doctor and the hospital after this visit, and I don’t know if I want to go back to that doctor.