Teeth are required for the mastication process, during which food is ground up and swallowed.

The development of teeth in humans, which begins prior to birth, is a highly orchestrated process, with over 20 genes known to be involved. At birth, the developing teeth are usually still hidden beneath the surface of the gums. But, beginning at around six months of age and extending until about 24 months of age, a succession of teeth appears. These so-called deciduous (or milk) teeth are designed for grinding (the molars located in the back of the mouth) and for cutting (incisors) and tearing (canines). A normal set of deciduous teeth comprises 10 upper teeth (central incisor pair, lateral incisor pair, canine (or cuspid) pair, first molar pair, and second molar pair). This first set of teeth is successively replaced by the adult (permanent) teeth...