Incisors usually come out within three months, and if they don’t come out after that time, it is recommended that you go to the hospital for a checkup. Children normally change their incisors around the age of 6~7 years old, usually within three months, the new incisors will be erupted first, and its corresponding milk teeth will be gradually loosened until they fall out, some children will have milk teeth fall out but the new incisors have not yet erupted, at this time, you need to go to the hospital for a radiograph to be examined, and according to the situation of the doctor’s guidance to carry on the treatment. If a traumatic injury causes premature loss of milk teeth, the timing of the replacement of incisors varies greatly. The pattern of incisor replacement is usually up then down, left and right at the same time. If your child has not developed new incisors in more than three months, it is advisable to consult a doctor to find out the cause.