Teeth growing into the gums may be caused by the retention of milk teeth during tooth replacement, multiple teeth and other reasons. 1. Retained milk teeth during tooth replacement: Children who have retained milk teeth during tooth replacement will have their permanent teeth grow out from the gums of their milk teeth, which can be manifested as the symptom of teeth growing into the gums. 2. Hyperplasia: Hyperplasia is a kind of malformation of teeth, which is mainly caused by the deviation of tooth germs in the process of development, and it may appear that the teeth grow into the gums. If the teeth grow to the gums, you need to go to the regular hospital in time for appropriate examination and treatment to avoid affecting the development of the teeth.