Dental calculus can be removed by supragingival cleaning, subgingival scraping and other methods. 1. Gingival cleaning: usually applied to remove tartar on the surface of the teeth, through high-frequency ultrasonic cleaning plaque on the surface of the tartar, high efficiency, traumatic, generally does not damage the enamel. It should be noted that patients with pacemakers cannot use ultrasonic cleaning. 2. Subgingival scraping: mainly using special subgingival scraping instruments to remove teeth and plaque from periodontal pockets, commonly known as deep teeth cleaning. The root surface of the teeth of periodontitis patients is smooth and clean, which is conducive to the reattachment of the gums, and it is the main method of treating periodontitis. Patients are advised to visit the dentist for a dental cleaning every six months to protect periodontal health; they should also brush their teeth carefully during the day to minimize the formation of plaque.