How long it takes for the incisors to grow back after they fall out cannot be generalized, and is mostly related to whether the incisors were milk teeth or permanent teeth when they fell out, and the specific reason for their loss. In general, if the patient is younger than 7 years old and the incisors of the milk teeth are lost during the normal eruption process, the permanent teeth will erupt in about six months to a year. If the incisors of the milk teeth are lost due to trauma, if the permanent teeth have not erupted by the time the patient is 7-8 years old, it is recommended to visit a dental hospital for a specialist examination before evaluation. If the patient is older than 7 years old and the incisors of the permanent teeth have been lost due to trauma, no new teeth will grow out and the patient will need to go to a dental hospital and have a prosthetic denture restored, which can be fixed, removable or implant. Therefore, if a tooth is lost due to trauma, regardless of whether it is a permanent tooth or a baby tooth, the first option is to visit a dental hospital or a dental department of a general hospital to determine the injury. If it is a normal loss of a baby tooth, it can be observed for about six months, and if there is no eruption, then promptly seek medical consultation.