This document discusses the different types of teeth in the human mouth and their functions. It explains that humans normally have 32 teeth total, consisting of incisors, canines, premolars, and molars. Incisors cut and bite food, canines hold and tear food, premolars grind and crush food, and molars are the principal grinders and crushers used to further break down food. Together, the teeth help break food down into smaller pieces to aid digestion.