Retained milk teeth should be extracted as soon as possible to make way for the eruption of permanent teeth, or in the case of congenital absence of permanent teeth, the milk teeth should be retained without special treatment. Milk teeth are gradually replaced by permanent teeth between the ages of 6 and 13. When milk teeth are retained, you should go to the stomatology department of a regular hospital in time to determine the cause of the retained milk teeth and its treatment by taking dental radiographs. 1. Congenitally missing permanent teeth: the milk teeth are well aligned and have the function of chewing, the milk teeth should be retained, and regular observation should be made to prevent dental caries. 2. For those who have retained milk teeth and permanent teeth have already erupted, the milk teeth should be extracted in time, and the erupted permanent teeth should be moved to prevent malocclusion. Regular checkups of the milk teeth and good eating habits, such as nibbling on hard foods like apples and corn, will help the jawbone development and help the milk teeth to fall out in time.