The tooth contains four tissues that are different in structure and functions: enamel, dentin, pulp and cementum.
Enamel is the hardest structure of the body and it makes a protective outer surface of the visible tooth part (crown).
Dentin is a bone-like material under the enamel, it makes the majority of the tooth inner surface. It cannot normally be seen.
Pulp is a chamber that contains nerves and blood vessels of the tooth.
Cementum is the outer surface of the tooth’s root. It is much softer than the enamel.
Structurally a tooth consists of two parts: a visible one called crown, and the not visible part is the root.
The tooth is held in its socket by periodontal ligaments connecting to the bone structure.