If you know the functions of tools such as scissors, forks, nutcrackers, and grinders, you will understand how marvelously specialized your teeth are.
Although your 20 primary, or baby, teeth first appeared when you were about six months old, your permanent teeth (32) started to grow out when you were about six or seven years old. The rest will appear when you are between 17 and 21.
Your permanent teeth are divided into four different types, of different sizes and shapes. But each type has a special use, like the special use each tool has in the home or workshop. These four types are incisors; canines, or cuspids; bicuspids, or premolars; and molars.
The incisors are your eight front teeth. Four are in your upper jaw and four in your lower jaw. Incisors work like a knife or scissors. As you close your jaws, they bite off large pieces of food.
The canines, or cuspids, are the four strong, pointed teeth, one each to the right and left of the incisors. You use your canines much like you use a fork, to tear larger pieces of food into smaller pieces.
The eight bicuspids, or premolars, are next to the canines, two behind each canine. Bicuspids work like a nutcracker, crushing food into smaller and smaller pieces.
The twelve molars are at the rear of your mouth, three next to each set of bicuspids. Because molars have strong, flat surfaces, they work like a grinder, mashing food into thin, pulpy masses.
Although most people grow only two sets of teeth in a lifetime, there have been actual cases of people growing a third set late in life!