The duration of periapical swelling is usually 1 week and there is no definite clinical conclusion. If a tooth is found to be swollen, the first step is to go to the hospital and the doctor will treat it according to the situation. The clinical local emergency treatment is to open the pulp and reduce the pressure inside the tooth, and the pain will be reduced. If the abscess is fluctuating for 3-5 days, local anesthesia can be used to cut open the abscess and release the pus, and the pain will be relieved. The root canal will be rinsed and the medication will be put on it, and a follow-up appointment will be made with the doctor to change the medication for the second time. The root canal is prepared and sealed for 1 week before continuing the root canal treatment, and the tooth needs to be restored with a crown to avoid fracture.