By age twenty, four more molars grow in the back of the mouth, one in each corner. These are called the wisdom teeth. People do not need wisdom teeth n many years ago these teeth were necessary to help people chew tough plants, which were an important part of the human diet. Now, many people get their wisdom teeth pulled by a dentist, a doctor who takes care of teeth, to keep them from crowding their other teeth The next time you eat, pay attention to which teeth do which jobs. Having a cookie? Incisors do a good job of biting into that tasty treat. What about a carrot? Those molars get the job done, not the teeth in front. How about a slice of pizza or a piece of bread? Your canines will help you tear at the food, and your premolars and molars will help you grind up that pepperoni pizza or peanut butter and jelly sandwich.