In general, the following types of people are more likely to be infected with periodontal disease: (1) people who do not pay attention to oral hygiene: poor oral hygiene is the biggest factor causing periodontal disease. Do not pay attention to oral cleaning, poor hygiene, food residues, tartar, tobacco tartar, calculus and other irritants easily cause oral cleaning dead space, food residue accumulation, direct stimulation of periodontal tissue, resulting in periodontal lesions. (2) Teachers: teachers have to contact dust when lecturing, saliva loss is more, oral self-cleaning effect is poor, creating conditions for plaque accumulation. Dust is easy to stay at the neck of teeth and gums with saliva, food and bacteria to form plaque. The plaque keeps calcifying to form dental calculus. And plaque and tartar are the main pathogenic factors of periodontal disease. (3) Older people: as they age, certain functions of the body gradually decline, and they are more likely to suffer from periodontal disease. (4) Women with menstrual disorders: The level of sex hormones is closely related to the normal metabolism of periodontal tissues. When the level of sex hormone is low, the alveolar bone becomes loose, the density of periodontal membrane decreases, the gap widens, the sclerotic plate disappears and the teeth loosen, the resistance of periodontal tissues decreases, and the infection easily occurs due to the attack of germs. (5) People who smoke: Since cigarettes are inhaled from the mouth, the mouth bears the brunt of damage from harmful chemical stimulation in cigarettes and temperature stimulation during smoking. (6) People with genetic background: Many genetic factors predispose the host to increased susceptibility to periodontal disease, especially aggressive periodontitis and severe periodontitis. In addition periodontitis, especially aggressive periodontitis, has family aggregation, so if there are periodontitis patients in a family, the others should be promptly examined at the hospital and have regular oral maintenance. (7) Certain patients with systemic diseases: diabetes, hypertension, myocardial infarction, cerebrovascular disease, etc. Mental tension, anxiety, fatigue, etc. can reduce the resistance of periodontal tissues, resulting in periodontal tissues susceptible to bacterial damage.