Wisdom tooth is the third molar, if the third molar erupts at the age of 12, it should be extracted as early as possible to avoid affecting the normal eruption of the second molar, and at this time, the root of the third molar has not yet been fully formed, so the trauma caused by the removal of the third molar is less, as follows. The maxillary second molar usually erupts at the age of 12-13 years, and the mandibular second molar usually erupts at the age of 11-13 years. If the third molar erupts at the age of 12, it is likely to interfere with the normal eruption of the second molar, resulting in a blocked or ectopic eruption of the second molar. The crown of the third molar usually completes its development at the age of 12~16 years old, and the root of the tooth completes its development at the age of 18~25 years old. If the third molar erupts at the age of 12 years old, the root of the tooth has not yet been fully formed, and the trauma caused by its extraction will be less. It is recommended to visit a hospital to receive professional treatment.