Teeth are more than projection in the mouth that allow you to grind the food and prepare it for the initial phase of digestive process, nor do they merely serve for a limited time before ending between the claws of an extracting forceps.

Man, like most mammals is supplied through his life by two sets of teeth, a deciduous or primary set, followed by a permanent set.  They are permanent teeth and it is your future responsibility to see that they remain permanent.

Teeth are one of the most important elements of the masticatory system. The student is expected to thoroughly know and understand the basic external morphology of every tooth, as well as, their proper arrangement and relation to each other and their relation to fixed points in the skull and the mandible.

A diphyodont is any animal with two successive sets of teeth, initially the "deciduous" set and consecutively the "permanent" set. Most mammals are diphyodonts as to chew their food they need a strong, durable and complete set of teeth.

Diphyodonts contrast with polyphyodonts, whose teeth are constantly replaced. Diphyodonts also differ from monophyodonts which are animals who have only one set of teeth that do not change over a long period of growth.

In diphyodonts the number of teeth that are replaced varies from species to species. In humans a set of twenty deciduous teeth, or "milk teeth", are replaced by a completely new set of thirty-two adult teeth.

Polyphyodonts include most toothed fishes, many reptiles such as crocodiles and most other vertebrates, mammals being the main exception. New, permanent teeth grow in the jaws, usually under or just behind the old tooth, from stem cells in the dental lamina. Young animals typically have a full set of teeth when they hatch; there is no teeth change in the egg. Within days, tooth replacement begins, usually in the back of the jaw continuing forward like a wave. On average a tooth is replaced every few months.

In anatomy, a heterodont is an animal which possesses more than single tooth morphology. For example, members of this group generally possess incisors, canines, premolars, and molars. The presence of heterodont dentition is evidence of some degree of feeding/hunting specialization in a species. In contrast, homodont dentition refers to a set of teeth that possess the same tooth morphology.