All teeth before the child’s tooth replacement period are collectively referred to as milk teeth, which are generally present from the beginning of the child’s tooth eruption (around 6 months of age) to around 12 years of age. The baby teeth are usually lost and replaced by permanent teeth between the ages of 6-12 years. During the infant and toddler period, children may suffer from tooth decay due to various reasons such as calcium deficiency, improper diet and poor daily hygiene habits, but mothers and fathers may think that sooner or later they will have to replace their teeth, so they do not need to go to the dentist for special treatment for tooth decay. What is “tooth decay”? “Tooth decay” is also commonly known as “worm teeth” in our life. It refers to a disease in which the inorganic material in the hard tissue decalcifies and the organic material decomposes under the action of many factors, and the tooth is gradually destroyed to form a defect. 1.The harm of milk teeth caries In the period of the child’s milk and permanent teeth replacement, once the decay of milk teeth, it will bring bad influence to the child’s local. Including: ① chewing function will be reduced, besides affecting children’s nutritional intake, it will also make jaw bone development insufficient and cause permanent teeth crowding unevenly; ② easy to make food residue, soft scale etc. stay in the mouth, oral hygiene deteriorates, leading to the new eruption of permanent teeth caries, especially to the permanent teeth adjacent to the decayed teeth; ③ after the development of apical infection of milk tooth caries, it will affect the inherited permanent tooth embryo, making its enamel development incomplete ⑤ The damaged crown can stimulate the soft tissues such as local tongue, lip and cheek mucosa and cause the formation of chronic traumatic ulcer; ⑥ Affect the language learning and correct pronunciation; ⑦ Affect the aesthetics, especially the front teeth area, which will cause some influence to the children’s psychology. 2, the milk teeth caries should be treated in time The milk teeth are thin and poorly calcified, once they are damaged, the development speed is very fast, when the child feels pain, it means that it has developed into pulpitis (inflammation has reached the dental nerve). Therefore, mothers and fathers should not think that there is no need to treat the caries of milk teeth because the milk teeth will be replaced sooner or later, but should take the child to the dentist in time when the “small hole” of milk teeth appears. If you don’t treat it in time and wait until it develops into pulpitis, not only the treatment procedure is complicated, it is difficult for children to cooperate, but also the later effect is poor and it will cause serious burden to children’s psychology and affect their life. Finally, we remind all the mothers and fathers to give their children the good habit of brushing teeth correctly every day during their infancy and childhood, and also take their children to the hospital for oral examination regularly, once every three months on average, to kill the caries in the budding.