Dentine And Pulp

Question 1

Colour of dentine

Answer 1

Yellow

Question 2

Function of dentine

Answer 2

Support enamel

Question 3

Characteristics of dentine

Answer 3

Compressive, tensile strength, permeable, harder than cementum but softer than enamel

Question 4

Content of dentine vs enamel

Answer 4

70% hydroxyapatite 10% water 20% organic matrix in dentine.
Enamel is 95% HA

When we prepare tooth, remove mineral content, enamel goes. Organic content of dentine stays so you can see it in slides that are demineralised an decalcified.

Question 5

Shape of dentinal tubules

Answer 5

Sigmoidal shape s shape

Question 6

Where is intratubular dentine

Answer 6

The space between the original tubule outline and the narrower thinner tubule outline

Question 7

Inter vs intratubular

Question 8

As you grow older, what happens to dentinal tubules

Answer 8

Becomes narrower

Question 9

Relation of dentine and pulp

Answer 9

Dentine is a live tissue. Living cells present, called odontoblasts. Dentine is produced in an organic matrix. Before it’s mineralised, it’s called pre dentine.

Question 10

InterGlobular dentine

Answer 10

Interglobular dentine arises because of incomplete fusion of calcospherites with the mineralising front as dentine is laid down and mineralised. This incomplete fusion traps areas of poorly mineralised dentine matrix within the dentine in the form of ‘arches’ that reflect the original spherical nature of the calcospherites.

Question 11

What are the cells that produce dentine

Answer 11

Odontoblast

Produce dentine throughout your life. The odontoblast is the cell responsible for forming dentine and maintaining it. It initially secretes a collagenous matrix (the predentine) which is then subsequently mineralised (partly by the fusion of calcospherites).

Question 12

Contents of the dentinal tubules

Answer 12

Odontoblast process, UNMYELINATED nerve terminal , dendritic cells, ecf from pulp called dentinal fluid

No blood vessels

Question 13

What cells are found in the dental pulp

Answer 13

Fibroblasts predominate
Odontoblast
Defence cells

Question 14

Contents of the dental pulp

Answer 14

Cells
ECM (fibres and jelly like ground substance with Chondroitin sulphate)
Nerves
Blood vessels
Lymphatics

Question 15

Is dentine live tissue

Answer 15

Unlike enamel, the dentine and the pulp (which are treated together, because the dentine develops from the pulp) are living tissues, with cells, blood vessels, and nerves

Question 16

What are the nerves present in dental pulp?

Answer 16

Sensory nerves for pain
Autonomic sympathetic nerves for blood flow

Question 17

Which nerves control blood flow in the pulp?

Answer 17

Autonomic sympathetic nerves

Question 18

How dentine is formed?

Answer 18

Primary dentine when the tooth is formed.

Secondary dentine is after the tooth had been formed

Question 19

Tertiary dentine

Answer 19

Repair and protection through the regenesis of dentine

Question 20

What happens when there is inflammation of the dental pulp?

Answer 20

Swelling, increase in volume leads to increase in pressure, damages the circulatory system so the pulp degenerates

Question 21

What’s found at the odontogenic zone?

Answer 21

Pre dentine
Dentine
Odontoblasts
Cel free zone
Cell rich zone

Question 22

What is the cell rich zone?

Answer 22

Where cells like fibroblasts and nerve/blood vessels are found in the pulp

Question 23

What is predentine

Answer 23

Predentine is the area where the dentine matrix has not been mineralised yet.

Question 24

Functions of dental pulp

Answer 24

Nutritive
Dentine growth and repair
Defence (immune and lymphatics)
Neural (pain and control of blood flow)

Question 25

Importance of knowing where the blood vessels are located in the pulp

Answer 25

Blood vessels do not penetrate into the dentine layer, remains only in the pulp. If you see a tooth bleeding, it means you have exposed the pulp

Question 26

Are there nerve fibres in dentine?

Answer 26

Yes, it does penetrate dentinal tubules but not deeply. Short distance into inner dentine

Question 27

Where does the concept of dentine-pulp come from

Answer 27

Cell body of the odontoblast lies at the interfere with the dental pulp

Question 28

Two major properties that distinguish enamel from dentine

Answer 28

Dentine is sensitive Dentine is formed throughout life

Question 29

What happens to the dental pulp as you grow older?

Answer 29

The dentine layer becomes thicker and the pulp becomes smaller

Question 30

What passes from the pulp into the dentine

Answer 30

Odontoblasts, dendritic processes of antigen presenting cells, unmyelinated nerve fibres

Question 31

What gives dentine its tensile strength and compressive strength

Answer 31

Organic matrix and tubular architecture

Question 32

What stresses are more like to fracture dentine?

Answer 32

Stresses Parallel to direction of the dentinal tubules are more likely to fracture than stresses at a right angle

Question 33

What is the histological classification of dental pulp

Answer 33

Loses Connective tissue

Question 34

When does secondary dentine begin to form

Answer 34

At the completion of root formation and as the tooth comes into occlusion

Question 35

Shape and structure of secondary dentine

Answer 35

Tubular pattern Less regular than that if primary dentine because of the slower rate of deposition

Question 36

Where does majority of the branching in dentinal tubules occur at

Answer 36

At the ADJ, immediately under the enamel

Question 37

Where are dentinal tubules closer together

Answer 37

Inner dentine

Question 38

Where are dentinal tubules larger

Answer 38

Inner dentine

Question 39

Types of dentine (pri secondary tertiary)

Answer 39

Primary dentine - mantle - interglobular Peritubular Intertubular Secondary - circumpulpal Tertiary - reparative - sclerotic

Question 40

In a person with Vitamin D deficiency, what will their dentine look like?

Answer 40

More interglobular dentine

Question 41

Dentinogenesis

Answer 41

Performed by odontoblasts, Dentine grows from outside to inwards

Question 42

What are dead tracts

Answer 42

When odontoblasts die of trauma or old age, dead tracts develop in dentine. The tubules calcifyas they fill with mineral to form sclerotic dentin.

Question 43

What are Tomes processes?

Answer 43

Tomes processes are projections that develop when ameloblasts move away from the ADJ when the first layer of enamel, has formed