Humans usually have 20 primary (deciduous, "baby" or "milk") teeth and 32 permanent (adult) teeth. Teeth are classified as incisors, canines, premolars (also called bicuspids), and molars. Incisors are primarily used for cutting, canines are for tearing, and molars serve for grinding.

The type and numbers of teeth are :-

8 incisors - Your four front teeth on the top and the bottom are sharp for holding and cutting food. Incisors also help you sense the texture and kind of food you eat.

4 canines or cuspids. The pointed teeth on the top and bottom are called canine teeth, or cuspids. They have cusps for grabbing and tearing food.

8 premolars. These teeth are between the cuspids and molars both physically and in form. Premolars look like molars but they have two cusps and are sometimes called bicuspids. Premolars cut and tear food.

12 molars. You have eight molars on top and bottom. They have broad chewing surfaces to grind down food before it’s finally swallowed. This includes wisdom teeth, your third set of molars, which can show up as late as your early 20s and are often removed.

More Info: en.wikipedia.org