Periodontology mainly looks at periodontal diseases including gingivitis and periodontal disease. Periodontology is a kind of oral subspecialty in a specialized hospital, which mainly studies and treats periodontal tissue diseases such as gum, periodontal membrane, dental bone and alveolar bone. Specifically, it includes the ageing changes of gums, periodontal membrane, bone, alveolar bone and periodontal tissues, and also observes the role of the body’s defense mechanism on periodontal tissues. Periodontology also needs to look at the occlusal relationship, and to observe the calculus and plaque in the mouth, as well as to maintain the health of the periodontium. In addition, surgical periodontal treatment is required, and the relationship between periodontal disease and orthodontics and implants can also be observed. Maintaining good periodontal treatment allows active orthodontic treatment or restoration of implant dentures to ensure the effectiveness of treatment and to maintain the health of the whole mouth. The population is very wide in the main range of periodontal diseases, so periodontal disease is now the most important disease to be prevented and treated. It is important to have regular oral checkups during the day and to have regular dental cleanings, and in case of gingivitis, timely treatment is recommended.