New and old teeth grow together, belongs to the stagnation of milk teeth, usually occurs in children’s tooth replacement period, need to extract the milk teeth in time, and then according to the individual situation to decide whether to need orthodontic correction. New and old teeth grow together, that is to say, the milk teeth have not been lost, permanent teeth grow, at present this kind of situation will usually be recommended to remove the milk teeth directly, otherwise the position of the permanent teeth may be shifted, easy to cause tooth displacement, affecting the aesthetics. After the extraction of the milk teeth, generally does not affect the normal chewing, in the recovery period, the permanent teeth will gradually grow to replace the milk teeth. However, if the permanent teeth are not extracted in time and the bite is affected, timely orthodontic correction is needed to restore the teeth to their normal position. After the removal of milk teeth, it is necessary to regularly observe the growth of teeth, if there is any doubt, it is recommended to consult a professional physician and follow the requirements of targeted treatment.