Periodontal disease should be treated thoroughly and early. Moderate to severe periodontitis is the result of long-term bacterial action on periodontal tissues for years or even decades, so treatment can take some time. In general, systematic treatment includes the following: (1) supragingival scaling, commonly known as “scaling”, is one of the basic means of periodontal treatment. It removes tartar and most of the pigmentation on the teeth by ultrasonic oscillation and reduces or even eliminates gum bleeding. (2) Subgingival scaling is the second basic means of periodontal treatment. Bacteria that enter the periodontal pocket attach to the root surface, calcify and form subgingival stone, and isolate the root from the surrounding tissue. The amount of tartar under the gums is small but harmful, and subgingival scraping is necessary for patients with moderate to severe periodontitis. (3) Surgical treatment Some patients require surgical treatment. The gums are opened under local anesthesia and the residual tartar and diseased tissues are thoroughly removed under direct vision, and if necessary, bone grafting or biofilm is placed to guide the regeneration of periodontal tissues. (4) Other auxiliary treatments such as systemic and local medication, removal of bad fillings and restorations, loosening of tooth fixation, etc. (5) Oral hygiene maintenance is the key to ensure the success of periodontal treatment. After systematic treatment by a specialist, patients with periodontitis should ensure good oral hygiene, adhere to the correct method of brushing and use of dental floss or interdental brushes.