Periodontal disease is the most common disease in the oral cavity, and its primary cause is plaque. Plaque is the initiating factor of periodontal disease. Plaque adheres to the teeth and this creates an irritation of the periodontal tissues, which leads to the development of periodontal disease. In addition to the most important plaque, there are also local promoters of periodontal disease. For example, the most important local promoter is dental calculus. In patients with periodontal disease there is a large amount of calculus in the mouth. These calculus provide a good place for plaque to attach. This facilitates plaque to stimulate periodontal tissues and form periodontal disease. In addition, there are also some bad habits that can cause periodontal disease, such as smoking, night grinding, mouth breathing, etc. Some teeth have a lot of pigment attached to them, and such teeth are also prone to periodontal disease. It is very important to prevent periodontal disease, we must do a good job of plaque control, generally by brushing to control plaque, to develop a good habit of brushing, master the correct method of brushing, but also with the use of dental floss, interdental brush and flosser, so as to well control the plaque. Periodontal disease must be taken seriously and regular checkups should be conducted in hospitals to remove these causes of periodontal disease so as to benefit the health of periodontal tissues.