After the age of 12, if the tooth is a milk tooth, it will grow if there is a permanent tooth germ underneath the tooth after radiography, but it will not grow if the tooth is a permanent tooth or if there is no permanent tooth germ underneath the milk tooth or if the tooth has already been replaced by a permanent tooth. Generally, the replacement period is from the age of six to twelve. At the age of twelve, if the replacement of teeth is late, the replacement of the second molar can be seen, and if there is a permanent tooth embryo underneath the milk tooth after radiographic examination, the permanent tooth will grow in about two and a half months after the second molar is lost. However, if there are no permanent teeth underneath the milk teeth, or if the teeth lost at the age of 12 are permanent teeth, there will be no growth of teeth underneath the milk teeth. Whether or not the tooth will grow after 12 years of age needs to be determined by checking the position of the lost tooth and combining it with X-rays at the hospital.