The pain after a tooth is knocked may be a concussion or fracture of the tooth, and if the symptom is serious, it cannot be recovered by itself, but if the symptom is mild, it can be recovered by itself after the adjustment and fixation observation. It is necessary to ask the doctor to examine the tooth in time to determine the treatment method, and cannot wait for the pain to disappear and heal itself. 1. Dental shock. Dental concussion is due to trauma to the teeth, after the periodontal membrane is damaged, generally fixed observation, the symptoms of pain may slowly disappear, periodontal will gradually return to normal. 2. Fractured tooth. The pain after the tooth is knocked may be the root of the tooth is fractured, need to take a picture to check. In some cases, the tooth may recover on its own, but in others, the pain may increase and cause pulpitis, requiring root canal treatment. If the pain is mild, the tooth will recover on its own, but if it does not recover on its own, root canal treatment or tooth extraction should be considered.