Pulp decompression is used for acute pulpitis and acute periapical inflammation, where the pulp cavity is opened and the inflammatory exudate is drained to relieve the pain. The method is mainly to treat the affected tooth under local anesthesia without pain, then open the pulp cavity with a dental handpiece, remove the nerve, and place a cotton pad in the pulp cavity. The tooth is then opened with a dental handpiece, the nerve is removed, and a cotton pad is placed in the pulp cavity. The tooth is not repaired with other materials, which allows the pulp cavity to be opened and the inflammatory exudate to be drained out if there is any, thus reducing the pain of acute pulpitis or acute periapical infection.