Milk teeth are the tools for young children to eat, milk teeth caries must be filled, otherwise, it is difficult to chew food, often toothache, not only the child suffers, but also affects the intake of nutrients and the growth and development of the body. The harm of dental caries Local harm: ① early loss of milk teeth, adjacent teeth can be tilted to the missing place, upper teeth, lower teeth occlusal relationship changes, if the number of missing milk teeth, it affects the development of the jawbone and face; ② long-term chronic periapical lesions of the milk teeth, infringing on the lower part of the permanent tooth embryo, resulting in the formation of the permanent tooth embryo enamel obstacles or dysplasia, the seriousness of the embryo can make the permanent tooth embryo development interruption, can not be a normal eruption; ③ broken The crowns and roots of the teeth stimulate the soft tissues of the oral cavity to form ulcers and damage the oral mucosa; ④ During the period of tooth replacement, it is easy for food to accumulate between the decayed milk teeth and the adjacent permanent teeth, resulting in caries in the permanent teeth; ⑤ Children are often reluctant to use the teeth on the side of the carious side to chew food because of pain, and develop the habit of chewing on the side, which results in the development of the jaws of the two sides of the body being asymmetrical. Systemic hazards: ① a number of milk teeth involved, chewing function is affected, resulting in loss of appetite, indigestion, malnutrition, affecting growth and development; ② caries caused by chronic periapical inflammation, the affected tooth becomes a focal point of the tooth, the accumulation of a large number of germs, when the body’s resistance declines, the bacteria can be transferred to the body’s other tissues and organs, foci of infections, such as arthritis, nephritis, myocarditis, long-term low fever and other diseases; ③ anterior teeth of the Caries looks unattractive and affects pronunciation, which can cause psychological pressure on the child. Some parents think that sooner or later, milk teeth have to be replaced, and it is not necessary to fill, which is not true. Because of the thin dentin of milk teeth, poor calcification, once destroyed, fast development, so not only to fill, but also as soon as possible.