The human teeth function to mechanically break down items of food by cutting and crushing them in preparation for swallowing and digestion. Humans have four types of teeth: incisors, canines, premolars, and molars, each with a specific function. The incisors cut the food, the canines tear the food and the molars and premolars crush the food. The roots of teeth are embedded in the maxilla (upper jaw) or the mandible (lower jaw) and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.

There are four different types of teeth:

Incisors: These are your four front teeth on the top and bottom jaw. They’re used for cutting and chopping food.

Canine teeth: These are sharp, pointy teeth. You have one on each side of your incisors on your top and bottom jaw, making a total of four. They help to tear food.

Premolars: Next to your canine teeth are your premolars (also called bicuspid teeth). You have eight premolars in total: four on your top jaw and four on the bottom. They are bigger and wider than your incisors and canine teeth, and are used for crushing and grinding food.

Molars: You have eight molars: four on top and four on the bottom. These are your strongest teeth and work with your tongue to help you swallow food, mashing it up until it's ready to be swallowed safely.

More Info: en.wikipedia.org