As children we work our way through one set of teeth until our mouth is large enough to take on the size of the final set of teeth that will hopefully last us the rest of our life. What is it that makes these teeth so specially suited for this purpose. The shape of the crown and the root of a tooth vary among different teeth and also among different species of animals. Here are a couple of different teeth from the same child. Notice how different they look.
All teeth have the same general structure and consist of three layers.
An outer layer of enamel , which is the hardest tissue in the body, covers part or all of the crown of the tooth. On the left is a picture of the surface of the enamle of a tooth, magnified 1000 times. The middle layer of the tooth is composed of dentine , which is less hard than enamel and similar in composition to bone. The dentine forms the main bulk, or core, of each tooth and extends almost the entire length of the tooth. Dentine is nourished by the pulp , which is the innermost portion of the tooth.