Periodontitis gums will be separated from the roots and form periodontal pockets. There is a lot of plaque and calculus in the periodontal pockets, which will cause resorption of alveolar bone and endanger the health of the whole body. Subgingival scraping and root surface leveling is to remove the infection in the periodontal pockets and restore the periodontal tissue to health. After scaling, the tartar above the gums is removed, and the subgingival plaque and calculus are treated by scraping and root planing. Generally, one week after scaling, the doctor will take precise measurements of the periodontal pockets, check the subgingival calculus, and remove the subgingival tartar and plaque on the root surface below the gums with subgingival scraping instruments to completely control the periodontal tissue inflammation.