Periodontitis is a chronic infectious disease of periodontal tissues caused by plaque biofilm, which leads to inflammation of tooth-supporting tissues, formation of periodontal pockets, and finally loosening of the teeth, and is divided into chronic and aggressive periodontitis. 1. Chronic periodontitis: the main manifestations are often a large amount of tartar on the surface of the teeth, the gums are bright red or dark red in color, the texture is soft and floppy, the dot color disappears, the gums are edematous, bleeding or even pus overflow on probing, etc. The treatment mainly consists of scaling or cleaning. Its treatment mainly includes scaling or scraping to remove tartar. 2. Invasive periodontitis: mainly manifested as early plaque, low amount of tartar, mild gingival inflammation, but deep periodontal pockets, pocket wall inflammation and bleeding on probing, divided into limited and extensive. Its treatment is mainly early implementation of basic treatment such as scaling, scraping and root planing. If symptoms of periodontitis are present, the clinician should be consulted on the treatment plan.