1,Stomatology,佟隽瑶,2,3,The structure of tooth,4,5,Dental Caries,6,Periodontal disease is a type of disease that affects one or more of the periodontal tissues:,Alveolar bone Periodontal ligament Cementum Gingiva,Periodontal disease,7,Dental calculus,Bleeding gums,Teeth stains,periodontal atrophy,8,No matter how hard you brush, you cannot brush the dental calculus off.,9,orthodontics,Orthodontics, is the first speciality of dentistry that is concerned with the study and treatment of malocclusions (improper bites), which may be a result of tooth irregularity, disproportionate jaw relationships, or both.,10,2 years and more than 2 years,How long will it take orthodontics?,11,Thank you！,