Root canal treatment probably needs 3-4 times, can also be completed at once, each time after treatment back within 3-4 days may appear a slight swelling or pressure pain, bite something uncomfortable, only minor symptoms are mostly normal. Just like doing minor surgery, such as appendicitis after a few days of recovery, oral dental treatment also belongs to a kind of surgery, each time there is a slight stimulation after doing. Mild pain is normal, most cases do not require special treatment, observe 3-4 days do not bite too hard things will be relieved on their own. Sometimes the patient will go back to the hospital with unbearable pain or swollen gums or swollen face, it is recommended to go to the hospital for root canal replacement in time, the symptoms can usually be relieved.