Tetracycline teeth, also known as tetracycline discolored teeth, refers to abnormal changes in tooth color caused by excessive intake of tetracycline drugs during tooth development. I. Clinical manifestations 1, both breast and permanent teeth can appear, without gender differences. 2.Pregnancy, lactating mothers taking high doses of tetracycline antibiotics in the spectrum or children before 8 years of age have a history of similar drug use. 3, Involved and symmetrical. 4, Through the enamel, the affected teeth show varying degrees of color change such as yellow, gray, yellowish gray, brown, etc. 5, generally does not cause dental results defect, but when the dose is too large, it can still cause enamel defects. 6, with fluorescent ultraviolet radiation, the affected teeth can appear fluorescent reaction. Second, prevention: For pregnancy, lactating women, and children under 8 years of age to avoid the use of tetracycline drugs. For existing tooth discoloration, defective, can be restored by decoloration, resin fillings, porcelain veneers or porcelain crowns.