Periodontitis is an inflammation of the periodontal supporting tissues, including the gums, periodontal membrane, alveolar bone, and cementum. The early stages of periodontitis are mainly caused by irritants such as tartar, plaque, and soft deposits around the teeth, leading to swollen, pus-leaking gums, or bleeding during eating and brushing. If not treated promptly, tartar will adhere above and below the gums, forming supragingival and subgingival calculus. For calculus above the gums, ultrasonic cleaning, also known as dental scaling, is required. For calculus below the gums, it can be removed through curettage. If the mobility of the teeth improves after removal, the periodontitis can then enter the maintenance phase for the teeth.