Wisdom tooth is the third molar, third molar eruption at the age of 12 is not a normal situation, usually should be erupted at the age of 17~21 years old, the mechanism of premature eruption of the third molar is not clear, should be extracted early, so as not to affect the normal eruption of the second molar, the details are as follows. The tooth germ of the third molar starts to form at about 4~5 years old after birth, starts to calcify at the age of 8~10 years old, completes the development of crown at the age of 12~16 years old, and starts to erupt at the age of 17~21 years old. It is not normal for the third molar to erupt at age 12. Because the third molar is located at the distal end of the second molar, the second molar usually erupts at the age of 11~13 years old, if the third molar erupts at the age of 12 years old, it may affect the normal eruption of the second molar, so the third molar should be extracted as early as possible. It is recommended to visit a regular medical institution and receive professional treatment with the help of a doctor.