Milk tooth caries without timely treatment will eventually develop into periapical periodontitis, which mainly manifests as chewing pain, acute attack will also have severe spontaneous pain and apical abscess, and serious swelling of jaw bone. Long-term chewing pain can affect the formation of lateralized chewing habits in children and affect the growth and development of the jawbone. The permanent tooth germ grows at the root of the baby tooth, so if apical abscess is not treated in time, it can affect the permanent tooth germ. Once the inflammation of the baby tooth is found to cause more root resorption or affect the permanent tooth germ, extraction of the baby tooth is recommended, so early treatment is recommended. The main treatment for periapical inflammation in milk teeth is root canal therapy, which uses instruments and medication to remove the infected material inside the root canal that can adversely stimulate the periapical tissue, and fills the root canal with absorbable root canal filling material to prevent periapical inflammation and promote tissue healing. If the defect is large, a pre-crowned restorative profile of the baby tooth is recommended to restore function. The periapical periodontitis of the baby tooth requires attention: 1. Long-term periapical infection can affect the diet of children. Parents think that children are reluctant to eat meat or always love to eat soft, but in fact, it is the child who will have pain or discomfort during chewing, and these will improve very significantly after perfect treatment. 2, a long period of periapical infection will affect the chewing habits of children, the affected side is afraid to chew, not only affect the normal development of the affected side of the jawbone will also lead to the affected side of the dental calculus deposition, resulting in poor oral hygiene and bad breath and other conditions. 3. Long-term periapical infection can affect the normal replacement of permanent teeth, resulting in abnormal eruption of permanent teeth or uneven teething, which parents should pay attention to.