Patient: description of condition (onset, main symptoms, hospitalization, etc.): Female, 25 years old, 3 days ago when chewing the third premolar felt like a vague pain like just after a root canal, which lasted for 2 days, and the pain disappeared on the third day, and no treatment was done for this process. Root canal was done on this tooth more than 3 months ago without braces. There was a slight pain when biting for about 1 week after the root canal treatment, and then the pain disappeared. 1. Is this normal? 2. Is it necessary to seek medical advice? Dr. Zhuang Peilin, Department of Stomatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University: In the first few days after root canal treatment, there will be swelling, pain, discomfort and other sensations, which can be observed, and generally will be slowly relieved. The observation time varies from person to person and tooth to tooth, generally speaking, about 2 weeks. If you are not sure, you can go to the hospital for a checkup. In addition, the grinding of the teeth to withstand chewing pressure is greater, generally after root canal treatment, it is best to do braces to protect the teeth, so as to avoid tooth chipping (specific reference to the article on my website). Patient: Hello Dr. Chong! My root canal was done more than 3 months ago, is it feasible to do braces now? Dr. Zhuang Peilin, Department of Stomatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University: Yes, braces after root canal treatment can maximize the life of your tooth.