Cavities in milk teeth need to be filled in a timely manner. Milk teeth have an important role and are the main organ for chewing food during childhood. Decayed teeth need to be filled in time. There are 20 milk teeth in total and eight molar teeth, which are the main teeth for chewing food and are replaced around the age of 12. Untreated decayed milk teeth will not only affect the growth and development of children, but also affect pronunciation and aesthetics, and have a psychological impact on children. Caries can also lead to early loss of milk teeth, premature loss of milk teeth will cause the inherited permanent teeth eruption abnormality, the lower permanent teeth lost the role of milk teeth induction, in the process of eruption of ectopic eruption, increasing the risk of malocclusion. Once the milk teeth are decayed, they need to be filled in time.