Sealing a filling can be painful for about 2 to 7 days, with the exact duration of pain related to drug sensitivity, type of drug, and so on. Filling sealing is generally the process of applying pulp inactivator when performing root canal treatment. 1. Individual sensitivity to the filling medication: the filling medication is pulp inactivator, this type of medication will cause some stimulation to the pulp after filling into the tooth, most people in the 2~5 days after the medication is filled in, the pulp is gradually inactivated, and the pain gradually disappears. However, some people have higher sensitivity to the pulp inactivator, the pain lasts relatively long, it may take 5~7 days for the pain to disappear. 2. Types of drugs: Different types of drugs sealed into the tooth before filling, the duration of pain also varies. If arsenic trioxide is used, the duration of its action, triggering pain is about 2~4 days; if metallic arsenic is used, its pain duration may last about 1 week. If the tooth pain persists after sealing the drug, and the pain is increasing, it should be taken seriously, go to the hospital as soon as possible for follow-up, to clarify the cause of the pain, and carry out targeted treatment in a timely manner, in order to prevent the symptoms from worsening and causing other oral problems.