Often there is no room for the wisdom teeth, or they come in skewed, so they have to come out. What is the use of wisdom teeth?
Our ancestors needed the extra molars to grind their food, which was a lot rougher then than it is now. One of the theories is that wisdom teeth were useful spare teeth. If a tooth was broken, the wisdom tooth could later replace that tooth.
We now do not need wisdom teeth for this and over the years our jaws have become smaller and smaller, so that many people have no place for wisdom teeth.
