The reasons why children’s teeth fall out and don’t grow are as follows: 1, chronic inflammation of the pulp of the milk teeth, resulting in root canal resorption, the root of the tooth is gradually shortened, the milk teeth fall out, and the inherited permanent teeth below lose the inducement of the roots of the milk teeth, and eruption difficulty occurs or is directly buried in the jawbone.2, the presence of multiple teeth in the alveolar bone will squeeze the roots of the permanent teeth or impede the movement of the permanent teeth, resulting in the difficulty of the growth of the permanent teeth.3, congenital missing When the permanent teeth are embryonic, there has been no permanent teeth to break through the oral mucosa and appear in the dentition after the shedding of milk teeth. After the replacement of milk and permanent teeth, orthodontic treatment can be carried out to close the gap, or after the child is 16 years old, implant restoration can be chosen.