Enamel - a hardened layer protection for the tooth. Source of external "whiteness" of the tooth.
Dentin - hard, but more vulnerable layer than the enamel. Source of internal "whiteness" of the tooth.
Fissure - the natural line across the cusps of the tooth where food particles can get caught. Fissures help with chewing. Lack of or flattened fissures may indicate grinding.
Pulp - (in the root canals) the network of nerve fibers supplying oxygen and nutrients to keep your teeth healthy. Infection will kill nerves- interrupting the transport of oxygen and nutrients and eventually killing the tooth from within.
Apex - located at the bottom of roots, it is the originating point for nerve fibers entering the root canals. Infections may reach the apex and cause swelling of the gums.
Cementum - material that connects the tooth to the periodontal ligament. Gum disease (plaque) interrupts adhesion.
Periodontal ligament - material that connects the cementum to the gums. Gum disease (plaque) interrupts adhesion.
Crown - part of tooth that emerges from the gums. Can be replaced with prosthetic crown.
Neck - natural indent in tooth.
Root - bottom of tooth hidden in the jawbone. Can only be seen by X-ray. It is the main support to hold the teeth in the mouth.