1.Impact on the chewing function The caries of milk teeth causes tooth defect and pain, and the chewing function is obviously reduced. 2.Impact on the permanent teeth and permanent tooth series The caries accelerates the deterioration of oral environment, which may lead to the caries of the newly erupted permanent teeth. After the pulpitis of milk tooth caries develops into periapical periodontitis, the recurrent periapical periodontitis may lead to local alveolar bone destruction; the tooth embryo of secondary permanent teeth is damaged, and enamel underdevelopment may occur; the root resorption of infected teeth is abnormal, which may lead to premature or late eruption of secondary permanent teeth, abnormal position and sequence of eruption, etc. If the crown of the baby tooth is damaged or lost early due to caries, it may lead to insufficient gap for the eruption of the succeeding permanent teeth and malocclusion. 3.Damage to oral soft tissues The caries-damaged crowns may cause irritation to lip, cheek and tongue mucosa. 4.Systemic influence Multiple decayed milk teeth, chewing function will be reduced, and children’s nutritional intake, maxillofacial and systemic growth and development will be adversely affected. The chronic periapical inflammation caused by caries may cause focal infection to other tissues of the body as focal tooth. In pediatric patients, diseases that may be associated with focal teeth are: hypothermia, rheumatoid joint, arachnoiditis, nephritis, etc. The caries of the milk front teeth may affect the aesthetics and the severe crown disintegration may have an impact on the child’s articulation and psychological development.