Normal Tooth Anatomy
The teeth consist of two main parts, the crown and the root.
Crown: The visible part of the tooth projecting above the gums is the crown. The crowns of the front teeth (incisors) are square in shape and sharp enough to help in biting food. The canines have a much sharper and pointed crown to help with tearing food. The molars have larger, wider crowns which make them perfect for grinding food.
The crown has three layers:
Enamel: This is the hardest outermost part of teeth. It is white in color and is made of calcium hydroxyapatite.
Dentin:This layer lies below both the enamel and cementum layer of tooth and is softer than enamel which makes it more susceptible to decay. It is yellowish in color.
Pulp:This is present at the center of the tooth and is commonly referred to as the ‘nerve’ of the tooth. It is the softer, living inner structure of teeth and is made up of blood vessels and nerves.
Root: The root is the part of the tooth that is embedded inside the jawbone. This portion is made up of dentin overlying which a mineralized layer is called cementum.
Cementum contains very small fibers called periodontal ligament fibers which help in anchoring the teeth to the bone.
Inside the roots, there are small canals through which the main blood vessels and nerves pass to the pulp chamber. These are referred to as root canals.
There are normally 32 teeth in adults. These include:
- 8 incisors or front teeth
- 4 canines located near the corner of the mouth
- 8 premolars between canines and molars
- 8 molars at the back of the mouth
- 4 wisdom teeth erupting around age 17-21 years