When a child reaches the age of tooth replacement, the baby teeth should fall out one by one and be replaced by the corresponding permanent teeth. However, some children’s milk teeth do not fall out when they are due, and doctors call this phenomenon as retained milk teeth. Parents should take their children to the hospital for examination and treatment when the baby teeth are due to fall out, and should leave it to the doctor’s judgment whether to remove the retained teeth when the permanent teeth have erupted and the baby teeth have not yet fallen out. The common reasons are: 1. abnormal eruption direction of permanent teeth, so that the root of the milk teeth is not completely absorbed. 2. The permanent teeth are congenitally missing, and there is no permanent tooth germ underneath the baby teeth, which cannot induce their root resorption. 3. The permanent teeth erupt weakly, and the roots of the milk teeth are not absorbed. Clinical manifestations: 1. Most common in mixed dentition early mandibular central incisors, permanent teeth erupt on the lingual side and the milk teeth are retained on the labial side, showing a double row of teeth phenomenon. The most common 2, followed by the residual roots or crowns of the first premolar are retained on the buccolingual side of the first premolar or in the proximal and distal centers. The retained second premolar is mostly a congenitally missing permanent tooth germ or an ambiguous blockage. The milk teeth without inherited permanent teeth can perform chewing functions, but it is difficult to use them for life. 3. More than 4 retained milk teeth are called multiple retained milk teeth, which are seen in people with cranial and clavicular hypoplasia. Treatment principle: If there are double rows of teeth, the retained milk teeth should be extracted as soon as possible to avoid the misalignment of permanent teeth; if there are no inherited permanent teeth, they can be left untreated for the time being. Parents often chop vegetables into minced dishes, peel apples into slices, and beat melons and fruits into juice, resulting in insufficient physiological stimulation of the teeth. The main function of teeth is to chew food, and chewing food can promote the growth and development of the roots of milk teeth as well as natural absorption and loss. Therefore, as children grow older, they should be allowed to eat more chewy foods to maintain a good stimulation effect on the milk teeth and to promote the timely loss of milk teeth. When your child’s incisors and posterior molars have erupted, you can add some celery, corn, apples and other foods to make the tooth replacement complete smoothly so that your child can have a mouthful of healthy and neat teeth.