The function of human teeth is to mechanically decompose food by cutting and crushing food to prepare for swallowing and digestion. Humans have four types of teeth: incisors, canines, premolars and molars, each with a specific function. Incisors cut food, canines tear food, molars and premolars crush food. The root of the tooth is embedded in the upper (upper) or lower (lower) jaw and covered with gums. Teeth are made of different tissues with different density and hardness.

Teeth are one of the most unique (and persistent) characteristics of mammalian species. Like other mammals, so do human bifidobacteria, which means they develop two sets of teeth. The first group (known as the "baby", "milk", "newborn" or "deciduous" group) usually begins to appear at about six months old, although some babies are born with one or more visible teeth, known as the delivery teeth. A normal eruption of teeth at about six months is called teething and can be painful.