Tooth knocking pain is usually caused by apical periodontitis or periodontitis, if it is caused by apical periodontitis, it needs root canal treatment, if it is caused by periodontitis, it does not need root canal treatment, it needs periodontal treatment, as follows. 1. Periapical periodontitis: Inflammation of the pulp developing to the periapical tissues will cause percussion pain and occlusal pain in the affected tooth. Root canal treatment is needed to remove the inflammation in the root canal and periapical tissues and then fill the root canal, which can eliminate the symptoms of toothache and terminate the further development of inflammation. 2. Periodontitis: Periodontitis may develop into periodontal abscess in the advanced stage, and the edema of periodontal membrane makes the affected teeth painful to knock. Perfect periodontal treatment is needed to remove the plaque and tartar in the periodontal pockets and root surfaces of the teeth to eliminate inflammation. If the periodontal abscess is obvious and has nearly broken down, incision and drainage can be made to relieve the pain. There may be other reasons for tooth knocking pain, and it is recommended to go to the hospital in time.