How is the tooth black? 1. Exogenous Hei Chi means that some substances containing melanin are attached to the tooth surface, while the dentin is still white. Because there are many kinds of sticky substances secreted by bacteria on the surface of teeth, some minerals in our diet and drinking water are adsorbed on these sticky substances, which gradually turn teeth yellow or black. Some foods or drugs containing pigments, high concentration intake will also make the tooth surface black. How is the tooth blackening? Second, endogenous Hei Chi is formed during tooth development, and pigment components are deposited in dentin, which is difficult to remove. For example, children take too many tetracycline drugs, and tetracycline components are deposited in dentin, which will turn teeth into yellow, brown or dark gray, which is called tetracycline teeth; Excessive fluoride in drinking water in high fluoride areas can lead to white chalk color on the tooth surface and brown plaque, which is called dental fluorosis. If tooth nerve necrosis is combined with bacterial decomposition products, it will also make teeth black. Some inherited metabolic diseases, endocrine diseases, nutritional diseases and trace element deficiency in childhood may affect the normal development of children's teeth, leading to the loss of enamel and the change of tooth color. What is the problem of teeth blackening? 3. Dental caries is the most common disease that causes local blackening of children's teeth. In addition to bacteria and food factors, it is also related to the low caries resistance of children's teeth. From shallow to deep, the caries lesions first form black caries spots, and then gradually form black cavities, which are constantly expanding and have a great destructive effect on teeth.