A six-year-old child can grow out of 2 milk teeth if they are knocked out, but cannot grow out of 2 permanent teeth if they are knocked out. 1. Can grow: if knocked out are 2 milk teeth, later will grow new permanent teeth. However, the milk teeth are not naturally loosened and fall off, but are knocked out, which may affect the growth and development of permanent teeth, it is recommended to pay attention to the observation of its growth, and go to the hospital for checkups if necessary. 2. Cannot grow: If the knocked out are 2 permanent teeth, then they can’t grow anymore. It is recommended to go to the hospital to do a simple movable gap retainer to wear, and then implant the denture repair when all the milk teeth are replaced. It is recommended to go to the hospital stomatology department in time for film examination, and the doctor will give professional advice according to the results of the film.