The black dirt on the inner wall of the teeth is considered to be calculus, which can be removed by supragingival scaling and subgingival scraping as prescribed by the doctor. 1. Gingival scaling is mainly carried out using an ultrasonic scaler, which is used to break up the calculus through ultrasonic waves and rinse it away with a continuous spray of water. For patients with more serious pigmentation on the teeth, sandblasting and polishing are also required to remove the fine calculus debris and residual pigmentation and plaque on the teeth, and to reduce the adhesion of plaque and calculus. 2. The operation of subgingival scaling is similar to supragingival scaling, but since subgingival calculus cannot be seen directly with the naked eye, it is necessary to use a probe to check the periodontal pockets and root surfaces of the teeth before and during the treatment to determine the amount of tartar and whether the tartar is clean. Once the tartar has been cleaned, a root planing procedure using a hand-held instrument is performed to remove the softened areas of root manifestation and smooth the surface of the tooth. It is recommended that patients with dark tartar on the inside of their teeth should be treated in a reasonable manner under strict medical supervision and with proper daily care.