Oral histology

Pulp

M.D. Sarah Ahmed
The Pulp is a soft mesenchymal connective tissue that occupies pulp cavity in the central part of the teeth.
اورال هستولوجي / اسنان ثاني12 / 11 / 2015 (250)

Tooth

Dentin
Tooth Crown
Tooth Root
Pulp

Functions of the Dental Pulp

Nutrition: blood supply for pulp and dentin. Sensory: changes in temp., vibration and chemical that affect the dentin and pulp. Formative: the pulp involve in the support, maintenance and continued formation of dentin. Defensive: triggering of inflammatory and immune response. Protective: Development and formation of secondary and tertiary dentin which increase the coverage of the pulp.

Anatomy of Pulp

Pulp Chamber or coronal pulp, located in the crown of the tooth. Root canal or radicular pulp, is the portion of the pulp located in the root area. The apical foramen is the opening from the pulp at the apex of the tooth. Accessory canals or lateral canal, extra canal located on the lateral portions of the root.
Pulp horns or cornua

Contents of the Pulp

Cells: Odontoblast, Fibroblast, white-blood cells, Undifferentiated mesenchymal cells, Macrophages and Lymphocytes. No fat cell. Fibrous Matrix: Mostly reticular fibres and collagen fibres (Type I and Type III). Ground substance: Act as a medium to transport nutrients to cells and metabolites of the cell to the blood vessels.

Zones-from outer to inner zone

Description
Odontoblastic layer
Lines the outer pulpal wall and consists of the cell bodies of odontoblast. Secondary dentin may form in this area from the apposition of odontoblast.
Cell-free zone
Fewer cells than odontoblastic layer. Nerve and capillary plexus located here
Cell-rich zone
Increased density of cells as compared to cell-free zone and also a more extensive vascular system
Pulpal-core
Located in the center of the pulp chamber, which has many cells and an extensive vascular supply, similar to cell-rich zone
Histological Microscopic Zones in Pulp

Predentin

Odontoblasts
Cell-free zone
Cell-rich zone
Cell bodies
Odontoblastic process

Dentin

Predentin
Odontoblasts layer
Cell free zone
Cell rich zone
Pulp core

Nerves and vessels in pulp

Blood and vessels enter and exit the dental pulp by way of the apical and accessory foramina. Pulp is richly innervated; nerves enter the pulp through the apical foramen (Subjacent to the cell rich zone, the nerves branch extensively forming a parietal layer of nerves- NERVE PLEXUS OF RASHKOW) along with afferent blood vessels and together form the neuro-vascular bundle.

Nerves in pulp

Dental Pulp
Nerve
Blood vessel



Clinically Importance features of the Dental Pulp
With age the pulp becomes less cellular. The number of cells in the dental pulp decreases as cell death occurs with age. In older teeth ,the volume of the pulp chamber decreases in size with continued deposition of dentine. An increase in calcification in the pulp occurs with age.

(Abnormal structure)