Primary dentin is laid down before and during tooth eruption. Secondary dentin is formed after root formation is complete and Responsible for the reduction of the pulp chamber over time. Tertiary Dentin is responsible for responses to insults upon the dentin/pulp.
There are 2 Types of tertiary dentin:
1.Regular dentin —> by odontoblasts in response to a slow insult..
2.Irregular —-> by fibroblast in response to the sudden death of odontoblasts.
*Primary dentin depostion is faster than secondary dentin depositon.
2 Types of primary dentin?
1.first dentin laid down during tooth development.
2.less mineralized than circumpulpal dentin.
3.contains van korffs fibers, which is thick type 3 collagen.
1.Majority of primary dentin.
2.More mineralized than mantle dentin.
3.Forms most dentin surrounding pulp (except space occupied by secondary dentin).
*What areas of the pulp chamber is secondary dentin more heavily deposited?
Ans: Roof and floor of pulp chamber.
*Coronal dentin forms an S shape for its primary structure.
Radicular dentin is rather straight.