Dental Problems

Dentin -What is Dentin?

DentinA calcified tissue that lies just below the enamel of the teeth is known as dentin. It is one of the four major components of teeth, others being enamel, cementum and pulp. It consists of tiny tubules or tubes. In this article, we shall discuss some of its features covering the description, composition, formation and its sub-parts. You can refer to below figure for better explanation.


It is the second layer of the tooth. It is normally covered by enamel. It covers the pulp and makes up the majority of the tooth’s structure. It is both denser and harder than bone. Its color ranges from grey to black but is typically a pale yellow in color.


The majority of dentin is mineralized tissue. In other words it comprises of so many minerals. It also contains mineral rich fluids called dentinal fluids which contain sodium, proteins and calcium.

How it is formed

Its formation starts from odontoblasts. Odontoblasts are the cells which secrete collagen. This collagen forms into a dense matrix of tubes which grow out from the pulp of the tooth. These tubes or tubules are known as dentinal tubules.

As the tubes grow out towards the surface of the teeth, they start spreading apart. The dentin remains fairly porous till it has good multitude of small holes in each tooth.

Classification /Sub-parts of dentin

It can be further divided into smaller parts in itself. There are 3 divisions for this.

Primary Dentin:

It consists of mantle dentin. This part is not mineralized and is closest to the enamel. It is also called newly formed predentin.

Secondary Dentin:

This starts after the formation of the roots. This begins forming slowly. It may cause the decrease in size of the pulp chamber of the tooth.

Tertiary Dentin:

This part of dentin is formed as a defense mechanism to stimuli such caries. It forms irregularly and rapidly.

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