HISTOLOGY OF DENTINE

Dr. Shahzadi Tayyaba Hashmi

shahzadi@inaya.edu.sa

• Avascular• Forms the bulk of each tooth crown & root • Cellular (contains odontoblast processes )• some capacity for repair by deposition on its

pulpal surface

INTRODUCTION

• Harder than bone & cementum• Softer than enamel• Less resistant to attrition(occlusal and incisal attrition)• Less resistant to abrasion(toothbrush & other abrasion)• Less resistant to acid attack(Caries and Erosion)

PHYSICAL PROPERTIES OF DENTINE

Primary dentin:• The most prominent dentin in the tooth, lies between the

enamel and the pulp chamber

Secondary dentin :• Is formed after root formation is complete, normally after

the tooth has erupted and is functional. It grows much slower than primary dentin. The growth of this type of dentin causes the decrease in the size of the pulp chamber with age; this is why cavity preparation in young patients is risky which may lead to exposing the pulp

HISTOLOGICAL FEATURES OF DENTINE

• Tertiary dentin : Is a dentin that formed as a reaction to external insult such as

caries. The dentin is formed from a pre-existing odontoblast• Tertiary dentin formation is regarded as an important defense

mechanism of the pulp-dentin complex in response to either pathological or physiological insults. The presence of tertiary dentin reduces dentin permeability

HISTOLOGICAL FEATURES OF DENTINE

TERTIARY DENTINE

• Circumpulpal dentin:

The layer of dentin around the outer pulpal wall • Peritubular dentin: Dentin that creates the wall of the dentinal tubules

• Intertubular dentin: Located between the dentinal tubules • Interglobular dentin: Areas of hypo mineralized dentine

• Granular layer of tome's: The superficial layer of dentin , adjacent to cementum, shows minute

black spaces in the ground sections These are only found in the root dentin

TYPES OF DENTINE

Dentin structure

Dentinoenamel junction

Dentinaltubules

Interglobulardentine

• It consists of 35% organic material and 65% inorganic material

• The organic material consists of collagen fibrils and ground substance( mucopolysaccharides )

• The inorganic component consists of hydroxyapatite crystals composed of several thousands of unit cells

COMPOSITION OF DENTINE

• Odontoblasts: An odontoblast is a biological cell of neural crest origin that is part

of the outer surface of the dental pulp, and whose biological function is Dentinogenesis, which is the creation of dentin

• Odontoblasts are large columnar cells arranged in a well defined layer , sending their odontoblastic process through dentin

• Each odontoblast sends one odontoblastic process that run inside the dentinal tubule, where both traverse the dentin thickness

ODONTOBLASTIC PROCESSES

ODONTOBLASTS PROCESS

• Dentinal tubules are structures that span the entire thickness of dentin and form as a result of the mechanism of dentin formation

• From the outer surface of the dentin to the area nearest the pulp, these tubules follow an S-shaped path

• The diameter and density of the tubules are greatest near the pulp

• Within the tubules, there is an odontoblast process

DENTINAL TUBULES

Dentinal tubules

Peritubular dentine

Intertubular dentine

Thank you