XIANQI A. Oral mirror: It is used for internal examination of the oral cavity, and can be used as a daily oral examination at home. B. Probe: It is used to check the range, depth and hardness of tooth defects, and to find sensitive points and pulp holes, which can be used instead of ordinary toothpicks. C. Sickle tooth cleaner: scrape the plaque and calculus on all sides of the teeth, and can also be inserted into the finale bag to scrape the subgingival calculus. D. Hoe-shaped tooth cleaner: The functional head is shaped like a hoe, and the hoe-shaped edge is used for scraping Pigment, plaque and calculus on smooth surfaces. E. Double-curved tweezers: used to remove crowns and measure the looseness of teeth, remove foreign bodies, pick up dressings, etc., and use it to take out food stuck between teeth. caries formation of tooth decay F. Tooth stain remover: One-piece molding, two ends are spoon-shaped, the unique curvature can effectively extend into the root of the mouth, dig out tea stains, smoke stains and stubborn oral residues 1. Bacteria: Bacteria mix with mucin and food debris in saliva and adhere firmly to tooth surfaces and fissures middle. This buildup is called plaque or plaque. 2. Diet: Food contains a lot of carbohydrates and sugars, and organic acids are produced from glycolysis through bacterial metabolism. The acid stays in the tooth surface and pit and fissure for a long time, which can demineralize the enamel. 3. Teeth: The shape, structure and position of teeth have obvious relationship with dental caries. The pits and fissures on the occlusal surface of the teeth are in the process of development Defects left, cells and food debris are easily retained in the deep pits and fissures, and it is not easy to remove.