Babies usually start to erupt their milk teeth around 6 months of age, and they will have all their teeth by around 30 months of age. The baby teeth are not only used to chew food, but also have a very important function, that is to stimulate the development of alveolar bone and guide the growth of permanent teeth through chewing. Some parents think that the baby teeth will be replaced anyway, even if they have caries, it is not important, this is wrong. It is wrong to know that children suffering from dental caries not only bring pain to the children, but also affect the digestion and absorption, jaw development and general health, which is very unfavorable to the growth and development of children. There is no symptom at the early stage of caries, only when the caries develops to a certain degree, when encountering sugar, cool water or inhaling cool air, the pain caused by stimulating the “tooth nerve” can be found, then should go to hospital for treatment in time. The treatment of the initial caries is relatively simple, which is to fill the cavity, commonly known as “filling”. It can stop the development of caries and restore the function of chewing. If the treatment time is delayed, the caries will go from the crown to the pulp and root of the tooth, causing pulpitis or apical inflammation, and the treatment will be more difficult and complicated. In addition, the repeated infection of tooth decay will also become the body lesion and affect other parts of the body, so we should pay attention to the prevention and treatment of tooth decay of milk teeth.