Originally painless tooth filling pain, may be a normal postoperative reaction, may also be the filling material stimulation and the pulp of the tooth caused by misjudgment. 1. Post-operative reaction: if this pain is in the filling within 1 to 2 days after the filling, generally is the process of electric drill on the tooth grinding pain, this is a normal phenomenon, usually 1 to 2 days will be relieved. 2. Stimulation of filling materials: the filling may not be cushioned, some acidic substances in the filling materials stimulate the dental nerve, thus causing mild inflammation of the pulp and pain. 3. Wrong judgment of the pulp: in a few cases, the duration of toothache after filling is longer, it may be due to wrong judgment of the pulp when filling, the pulp may be inflammation. Patients with tooth pain after filling should go to the hospital in time, under the guidance of the doctor to clarify the cause of the disease, and then carry out reasonable treatment.