There are 15 lower teeth, usually there is a wisdom tooth, according to the situation can choose not to extract the tooth or extraction, specific need to be under the guidance of a professional dentist in conjunction with their own situation to choose. 1. The case of no extraction: the wisdom tooth position is relatively long, no caries, no recurrence of pericoronitis, and did not cause pain in the neighboring teeth, and the pair has a good occlusal relationship, this case can not be extracted, but to maintain good oral hygiene. 2. Extraction of wisdom teeth: wisdom teeth position is not correct, resulting in recurrent pericoronitis, wisdom teeth itself caries or lead to pain in the neighboring teeth, in this case it is best to remove the wisdom teeth. Strictly follow the doctor’s instructions after extraction to prevent post-extraction infection. 3. In the case of multiple teeth, which are generally not in the correct position and have no obvious occlusal relationship, they usually need to be extracted. If there are 15 lower teeth, it is best to take a surface tomography in the hospital to clarify the growth of the wisdom teeth and the condition of the neighboring teeth, and determine the best treatment method under the doctor’s advice.