Because children are in the stage of growth and development, the harm caused by the occurrence of dental caries can affect the development of dental and jaw system and cause the acquired deformity. The pain of tooth decay can affect the feeding of children, so that they dare not chew with diseased teeth, and the food goes into the stomach in one go without careful chewing, which increases the burden of stomach and causes stomach pain. Rough food can not be completely digested in the stomach, it will affect the absorption of nutrients in the small intestine. Over time, it reduces the child’s physique. If the caries is not treated timely, it will further develop to cause the inflammation of the pulp and the inflammation around the root tip of the tooth, which causes unbearable pain and is very painful; in addition, because of the pain, eating with one side for a long time can affect the growth and development of the jaw and face, and even cause the deformity that one side of the face is big and the other side is small, so the caries occurred in children should be treated timely. The caries can occur in both the milk teeth and permanent teeth, and the lesion is generally slow, firstly, the enamel is decayed, the color of the decayed part of the crown becomes gray and dull, the surface of the tooth is not smooth, and the tartar is easy to accumulate. Patients do not feel pain at the early stage of tooth decay, when the cavity develops to dentin, pain will occur only when encountering cold, hot, sour, salty and sweet food (generally sour pain). If the cavity is deeper, close to the pulp or decaying through to the pulp, the stimulation of the above nature can cause unbearable soreness and pain. There is often food embedded in the cavity, emitting the unpleasant odor of decay. As the cavity continues to expand, the crown of the tooth will crumble piece by piece, and finally only the residual tooth root will be left. The danger of tooth decay to children’s health is multifaceted, and the danger to the whole body health are: 1. Due to the pain of tooth decay and early loss of decayed milk teeth, it leads to the decrease of chewing function and the weakening of gastrointestinal digestion and absorption, resulting in the malnutrition of the body and affecting the growth and development. 2.Cause infectious disease. When children’s caries causes periapical infection, it often becomes the focal point of infection and causes systemic infection, and the diseases related to this include vision reduction, arthritis, nephritis, myocarditis, long-term low fever, etc. 3.The root end granuloma, cyst, pulp infection caused by caries can become the foci of infection, and when the body resistance is reduced by over fatigue and cold, it can induce nephritis, rheumatic fever, tonsillitis, abscess, scarlet fever, sepsis, etc. Research shows that 81% of the children with deep caries, residual roots and dental abscesses have local lymph node enlargement, especially submaxillary lymph nodes. After the treatment of dental caries, 70% of the enlarged lymph nodes can subside. 4.The oral temperature of children with dental caries is higher than normal children, the total number of white blood cells in blood is increased, the blood sedimentation is increased, the red blood cells are decreased, the hematocrit is low, and the total protein of serum is changed. When the caries treatment is restored to normal, but the total serum protein egg does not change much in the short term, therefore, when the child has unexplained low fever, anemia, elevated white blood cell and increased blood sedimentation, it is better to conduct oral examination first. 5, causing psychological barriers. Infancy is the period when children learn language, and complete milk teeth can help children master the correct pronunciation. The decay and early loss of milk teeth will make the child’s pronunciation unclear. The severe caries in the area of front teeth makes some children shy to open their mouths, which is very unfavorable to the psychological development of children. The impact on the local health is: 1.Causing the asymmetry of facial development. 2.The permanent teeth are misaligned and poorly developed. 3.Mandibular and facial deformities. 4, secondary to other dental diseases. 5. Other effects such as affecting the development of children, causing partiality and loss of appetite, etc. 6.Promote bad oral habits.