Children who grow new teeth without replacing them need to go to the hospital to take pictures to check the position of the erupted teeth, permanent molars are directly erupted, and if the new teeth are erupted underneath the milk teeth, it is necessary to pull out the retained milk teeth. 1. Permanent molars: Children’s tooth replacement period starts at around 6 years old, and at around 6 years old, new permanent teeth will erupt directly from behind the milk molars, which is called the first permanent molar, and there is no milk tooth above it to replace it, so it is enough to pay close attention to its eruption situation. 2. Retained milk teeth: At the age of 6 to 12 years old, there will be permanent teeth underneath the milk teeth to replace them, but when the lower permanent teeth erupt, the upper milk teeth have not yet fallen out, at this time you need to go to the hospital for examination, to determine that it is a retained milk teeth and then extracted in a timely manner. If a child has new teeth without tooth replacement, it is recommended to go to the hospital in time to check the site of tooth eruption and tooth position, and find out the problem in time to deal with it.