Oral Biology

Question 1

What is another word for Hoehl’s layer?

Answer 1

The cell free zone of Weil

Question 2

What zone lies next to the pulp and blends with it?

Answer 2

Cell rich zone

Question 3

What does the pulp core zone comprise and what zone does it lie below?

Answer 3

prominent blood vessels and nerves and is present below the cell rich zone.

Question 4

What are the layers of the pulp from inner to outer?

Answer 4

Pulp core
Cell rich zone
Cell-free zone of Weil
Odontoblast layer

Question 5

What lies in the cell-free zone of Weil?

Answer 5

rich in both capillaries and nerve networks.

Question 6

What is the outer layer of the pulp and what does it lie under?

Answer 6

odontoblast layer which contains odontoblasts and lies next to the predentin and mature dentin.

Question 7

What is the odontoblast layer of the dental pulp and what is its purpose?

Answer 7

form a natural barrier between mineralized tissues, dentin, and soft tissues, dental pulp, of the vital tooth, and they first recognize caries-related pathogens and sense external irritations

Question 8

Are odontoblasts polarised?

Answer 8

Yes, nucleus lies towards the pulp

Question 9

What is the name of the projection from odontoblasts into the pre-dentine and what do they do?

Answer 9

odontoblast process
function in the secretion, assembly and mineralization of dentin during development, participate in mechanosensation, and aid in dentin repair in mature teeth

Question 10

What is the main role of an odontoblast?

Answer 10

to form dentine and protect pulp tissue

Question 11

What is the main role of fibroblasts?

Answer 11

synthesise and secrete collagen and non-collagenous proteins, degrading old/damaged proteins and formation of connective tissue

Question 12

What is a lymphocyte?

Answer 12

Inflammatory cells
immune cell that is made in the bone marrow and is found in the blood and in lymph tissue

Question 13

What is a macrophage?

Answer 13

Inflammatory cell
specialised cells involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms

Question 14

What is a histocyte?

Answer 14

inflammatory cell
phagocytic cell present in connective tissue

Question 15

What is a pulpal dendritic cell and what do they do?

Answer 15

Inflammatory cell
potent antigen presenting cells that capture, process, and then present antigens to T cells when they mature

Question 16

What are the compositions of collagen present in the ECM in pulp?

Answer 16

type 1 - 56%
type II - 41%

Question 17

What is type 1 collagen?

Answer 17

most abundant collagen found in connective tissues and the primary determinant of tensile strength of the ECM

Question 18

What is type II collagen?

Answer 18

protein that is part of the cartilage, bone, and other types of connective tissues

Question 19

What are the components of pulpal extracellular matrix?

Answer 19

Collagen
Phosphorylated ECM proteins
Non-phosphorylated ECM proteins
Proteoglycans
Growth factors
Enzymes

Question 20

What is the diameter of an arteriole?

Answer 20

35-45 micro m

Question 21

What is the diameter of a capillary?

Answer 21

8 micro m

Question 22

What is the diameter of a venule?

Answer 22

over 50 micro m

Question 23

Do venules have valves?

Answer 23

no

Question 24

What does stimulation to dentine result in via neurogenic control?

Answer 24

Pain
increased blood flow
axon reflex causes vasodilation and increases capillary permeability and sensitivity

Question 25

What are four factors that control pulpal blood vessels?

Answer 25

Efferent autonomic nerves Neurogenic control Local factors Constant volume problem

Question 26

How many axons enter a premolar?

Answer 26

2500

Question 27

What is the difference between afferent and efferent neurons?

Answer 27

Afferent - information from sensory receptors to the CNS Efferent - information from the CNS to muscles and glands

Question 28

Where do efferent nerves travel to and from?

Answer 28

From CNS to muscles and glands

Question 29

Where do afferent nerves travel to and from?

Answer 29

From sensory receptors to the CNS

Question 30

Are the majority of nerves involved in pulpal innervation myelinated or non-myelinated?

Answer 30

70-80% non-myelinated

Question 31

Of the remaining 20-30% of pulpal nerves which are myelinated, what types of nerves make up this proportion?

Answer 31

90% A delta fibres 10% A beta fibres

Question 32

Where is the Plexus of Raschkow classically found?

Answer 32

In the cell free zone

Question 33

What is the function of the Plexus of Raschkow?

Answer 33

monitors sensations of pain

Question 34

What kind of sensations are transmitted by A delta fibres and what are A delta fibres?

Answer 34

afferent fibres of nociceptors - larger and the most rapidly conducting associated with the sharp, well-localized pain activated by mechanical and thermal stimuli.

Question 35

What is a nociceptor?

Answer 35

Pain receptor sensory receptors that detect signals from damaged tissue or the threat of damage

Question 36

What are A beta fibres and what sensations are transmitted by them?

Answer 36

touch receptor afferent fibres from stretch receptors. Aβ fibres from the skin are mostly dedicated to touch

Question 37

What are embryonic stem cells and what can they differentiate into?

Answer 37

undifferentiated cells in developing tissues can differentiate into any cell type

Question 38

What are adult stem cells and what can they differentiate into?

Answer 38

undifferentiated cells found living within specific differentiated tissues in our bodies that can renew themselves or generate new cells that can replenish dead or damaged tissue

Question 39

What is the function of dental pulp stem cells?

Answer 39

production of odontoblast like cells to create reparative dentin support

Question 40

What are stem cells from human exfoliated deciduous teeth and what can they form?

Answer 40

pluripotent cells that can be retrieved from primary teeth can form bone or dentine

Question 41

What does SCAP stand for?

Answer 41

Stem cells from apical papilla

Question 42

What do growth factors induce?

Answer 42

induce stem cell migration and differentiation

Question 43

What initiates the migration and differentiation of stem cells?

Answer 43

growth factors

Question 44

What are two examples of growth factors present in the dentine?

Answer 44

TGF-beta 1 BMP - bone morphogenetic protein

Question 45

What can trigger the release of growth factor and subsequent stimulation of stem cell migration and differentiation?

Answer 45

an acid environment eg. caries

Question 46

What are two medicaments that can be applied to cause inflammatory changes in the hope of stem cell differentiation and dentine formation to maintain pulp vitality?

Answer 46

Ca(OH)2 MTA

Question 47

What kind of dentine is produced from a mild stimulus causing dentinogenesis and how is it formed?

Answer 47

Reactionary dentine - odontoblasts produce more dentine

Question 48

What kind of dentine is produced from a strong stimulus eg. caries causing dentinogenesis and how is it formed?

Answer 48

Reparative dentine - aggressive insult causes odontoblasts to die. Stem cells migrate, proliferate and form reparative dentine