Children have a tooth growing out of the arch may be due to crowding, milk teeth did not fall out in time or caused by supernumerary teeth, if the supernumerary teeth need to be extracted, and the other teeth need to be considered for orthodontic treatment. 1. Cannot be extracted: If the tooth arch is crowded due to malocclusion and grows out of the arch, it needs to be considered for orthodontic expansion after the replacement of permanent teeth is completed. If the baby teeth have not been lost, causing ectopic eruption of permanent teeth, it is necessary to remove the baby teeth and observe whether the permanent teeth can return to the normal growth position, and then consider the later orthodontic treatment according to the situation. 2. Need to extract: If the tooth growing outside is a supernumerary tooth, it needs to be extracted as soon as possible to avoid causing malocclusion. If a child has a tooth growing outside, whether it needs to be extracted or not can only be confirmed after an oral examination and imaging test at the hospital.