The so-called wisdom tooth is in the most inside of the alveolar bone, up and down, left and right each grow a tooth, that is, the third molar. And this tooth will grow after adulthood, so it is regarded as a symbol of wisdom, so it is called "wisdom tooth".
Why do you have wisdom teeth? This is because a person's jaw is almost the same as that of an adult in adolescence, but some people's jaws are not very large, so there is not enough space for wisdom teeth to grow. The growth of wisdom teeth is limited, so it can only develop in other directions. Either only part of it grows out, or it's all buried in the jaw. Because the space for growth is limited, wisdom teeth can only grow toward the adjacent teeth, thus forming an angle with the third molar and squeezing the third molar.
There is no exact time when wisdom teeth will grow. Some people will grow before they are 20 years old, some people may not grow until they are 40 or 50 years old, and some people will not grow wisdom teeth in their whole life. However, wisdom teeth will not grow completely. Some people will only grow one wisdom tooth, some people will have two wisdom teeth, and some wisdom teeth will only grow half.