Parts of human teeth are broadly divided into:
- Crown - Is that part of a healthy tooth, which is visible in the mouth.
- Root - Is the lower part of human teeth below the gum line, which anchor tooth to the jawbone & is usually not visible.
The parts of human teeth are made of four tissues namely;
- Enamel – Outermost & strongest layer of the tooth, Color Varies from translucent white to white.
- Dentin – Middle layer of the tooth, just beneath enamel consisting of tubules, when exposed cause sensitivity to hot & cold. The color of which is pale yellow.
- Pulp - the Innermost soft core of the tooth consisting of nerves and blood vessels and it reflects the color of a blood vessel within it.
- Cementum- Is a specific hard substance covering the root of a tooth. It is attached to the bone by the periodontal ligament. It is pale yellow in color and is covered by the gums.
All parts/structures/surfaces of healthy human teeth are intact. If any of the parts lose its continuity, then it is considered as a disease/Decayed tooth.
In tooth decay, there is a breach in continuity and enamel surface is not smooth, shiny & intact and hence considered as diseased/Decayed tooth. A Breach in the continuity of the surfaces/structure of any part of the tooth (Crown, Root, Enamel, Dentine, Pulp & Cementum) is the main distinguishing point between disease and healthy tooth.