Enamel development is not only regulated by genetic genes, but serious local infections or systemic diseases of the oral cavity during the development of the dental embryo can also cause abnormalities in the function of the enamel-forming apparatus. I. Etiology 1, maternal or infant systemic diseases: During pregnancy, pregnant women with viral infections or toxemia may cause fetal enamel hypoplasia. Pediatric herpetic diseases, such as: chicken pox, measles, etc. can also interfere with the function of enamel-forming cells, resulting in abnormal enamel development. 2, nutritional metabolism abnormalities: vitamin D deficiency causes rickets, tooth development will also be impaired, when vitamin A.C deficiency, can also cause enamel development insufficiency. 3, endocrine disorders The biological biomineralization of enamel and the collective calcium and phosphorus metabolism are inseparable, parathyroid hormone also has a great impact on the mineralization of teeth, when the secretion function is abnormal, it can also cause abnormal development of enamel or dentin. Local factors Trauma or local infection during the development of the dental embryo can damage the developing dental embryo. When interdental infection affects the permanent dental embryos below or adjacent to the interdental period, it can cause enamel underdevelopment in these permanent teeth. Clinical manifestations The surface of enamel can be chalky with a basic normal pattern of spots, but in severe cases, there can be dotted, linear, banded or sunken defects, and the defects often have a change in color. However, the surface of the defect is generally smooth and hard. In general, systemic disorders are more likely to occur within the first year of life, a period of tooth replacement that includes the incisors, cusps, and incisal edges or cusps of the first molars. The cusps of the lateral incisors develop a little later, and when the cusps of the lateral incisors are involved, the disorder usually occurs around the second year of life. Enamel development of the anterior and second molars generally begins in the third year of life, thus when developmental disorders occur in the third year of life, they generally do not involve the anterior and first molars. Can be in the incisal edge of the teeth or cusp if there is no enamel, there can be symptoms of dentin hypersensitivity. Third, prevention and control Enamel developmental abnormalities caused by environmental and other factors, can be don’t have structural defects is, this defect is irreversible. Therefore, prevention should be the main focus to minimize the chance of infection for mothers and children. Prevention of systemic infections and periapical infections in papillae. A diet rich in vitamin C, such as fresh fruits and vegetables, and vitamin D, such as various types of liver, egg yolk or various types of finished cod liver oil, is recommended. Symptomatic treatment: those with painful hot and cold irritation can be desensitized with drugs, and those with obvious defects can be filled, and anterior teeth can be filled with composite resin, veneer method or porcelain crown restoration to improve symptoms and aesthetics.