Exam 3 - Dentin Pulp Complex II Colombo

Question 1

Primary cell type of dental pulp

Answer 1

Fibroblasts, followed by odontoblasts

Question 2

Dental pulp arises from:

Answer 2

Dental papilla (ectomesenchymal tissue)

Question 3

Function of dental pulp

Answer 3

• support structures for the mineralized components of the tooth
• contains blood vessels, innervation, fibroblasts, pool of immune cells, pool of progenitor cells for replacement and repair

Question 4

4 histological zones of dental pulp (from outer to inner)

Answer 4

1. odontoblast layer
2. cell free zone of Weil
3. Cell rich (Cell dense zone)
4. Pulp core

Question 5

Describe the dental pulp ECM

Answer 5

• soft connective tissue matrix
• comprised of collagen III and I
• numerous non-collagenous proteoglycans and glycoproteins

Question 6

What happens with dental pulp ECM with age?

Answer 6

Collagen content increases, fibrils aggregate into larger bundles (greatest concentration apically)

Question 7

What is found in the ground substance of the pulp?

Answer 7

• proteoglycans (GAG chains)
• glycoproteins
• water

Question 8

What proteoglycans are found in the pulp?

Answer 8

• chondroitin-6-sulfate
• chondroitin-4-sulfate
• heparin sulfate
• dermatan sulfate
• keratan sulfate

Question 9

Describe the structure of odontoblasts

Answer 9

• polarized cells
• elongated nucleus at the pulpal side of the cell
• secretory components (golgi) towards dentinal side

Question 10

In the crown, odontoblasts are _____ compared to the root where they are ____

Answer 10

Larger and more columnar; more cuboidal

Question 11

Odontoblasts form a discrete layer of cells held together by:

Answer 11

Adherens junctions/junctional complexes

gives a degree of permeability to the OD layer - serum proteins may pass

Question 12

Odontoblasts can form gap junctions with:

Answer 12

Pulpal fibroblasts

Question 13

Function of odontoblasts

Answer 13

• Creation and maintenance of dentin; supported by the rest of the pulp
• production/secretion of collagen and non-collagenous proteins
• production/sequestration of key growth factors in dentin matrix
• release of secretory vesicles from the OD process

Question 14

What growth factors are produced/sequestered by odontoblasts?

Answer 14

• VEGF
• TGF B1
• BMP-2

Question 15

Odontoblasts form _____ throughout their lifetime

Answer 15

peritubular dentin

Question 16

Describe aged odontoblasts

Answer 16

• fewer organelles
• less secretory activity
• nucleus somewhat more central

Question 17

OD turnover: assumed to be _____, can be replaced from _____

Answer 17

Long lived; can be replaced from mesenchymal progenitor pool

Question 18

Where are fibroblasts found in the dentin-pulp complex?

Answer 18

Pulp core, cell rich zone

Question 19

Fibroblasts function in dentin-pulp complex

Answer 19

produce and maintain the supportive matrix of the pulpal tissue

Question 20

The pulpal matrix supports:

Answer 20

• progenitor cells
• immune cells
• vasculature
• lymph
• nervous tissues

Question 21

______ may have a role in facilitating mesenchymal progenitor cell recruitment and differentiation

Answer 21

Fibroblasts

Question 22

Where are mesenchymal progenitor cells found?

Answer 22

Dental pulp

Question 23

In response to damage to dentin, ____ are recruited to form new odontoblast-like cells

Answer 23

dental pulp progenitor cells

involved in reparative dentin formation

Question 24

What immune cells are present in the dental pulp?

Answer 24

• Macrophages (innate immunity)
• dendritic cells (acquired immunity)
• T and B lymphocytes

Question 25

Healthy pulp has a key role in:

Answer 25

Cell turnover and clearance; involved in immune response via IL-1B, TNFa

Question 26

Where are dendritic cells found in the pulp?

Answer 26

Under odontoblast layer

Question 27

Dendritic cells are closely associated with ____ of the pulp to coordinate tissue responses

Answer 27

Neuronal/vascular components

Question 28

When would T and B lymphocytes primarily be found in pulp?

Answer 28

When there is an infection

Question 29

Pulp vasculature arises from:

Answer 29

- external carotid arteries - superior/inferior alveolar arteries

Question 30

There are ____ arterioles per root that access the pulp through the ____ and spread upwards into the coronal pulp

Answer 30

4-8; apical foramen

Question 31

Progression of vascular supply to the dental pulp

Answer 31

- Arterioles, capillaries, venules - arterioles branch, anastomose to venules in capillary plexi located in cell free zone below odontoblasts - venules leave apical foramen, connect to superior/inferior alveolar veins --> internal jugular vein

Question 32

Where is the capillary network found in the pulp?

Answer 32

In the cell free zone (during primary dentin formation, present in odontoblast layer)

Question 33

As arterioles proceed into the pulp, ____ increases, ____ decreases

Answer 33

Caliber; vessel wall

Question 34

Dental pulp is highly innervated by nerves which enter through ____ and in close contact with ____

Answer 34

Apical foramen; blood vessels

Question 35

Nerve fibers branch out through the coronal pulp, forming the:

Answer 35

Plexus of Raschkow | not found in the root pulp! only branches of nerve fibers

Question 36

Incoming nerve fibers of the pulp consist of:

Answer 36

- afferent nerves from CN 5 - sympathetic branches from superior cervical ganglion (controls blood flow)

Question 37

Functions of nerve fibers in the pulp

Answer 37

- control blood flow - nociception - immune response?

Question 38

Sensory innervation of dentin: nerve bundles consist of both -

Answer 38

Myelinated 'A-delta' and unmyelinated "C" axons

Question 39

Does myelination increase/stay the same/decrease as fibers proceed towards the coronal pulp?

Answer 39

Decreases

Question 40

A minority of unmyelinated axons pass into:

Answer 40

dentinal tubules closely associated with odontoblasts

Question 41

What happens to dental pulp progenitor cells in diseases pulp?

Answer 41

Repair function is unpaired

Question 42

Pulp is responsive to external stimuli through:

Answer 42

All cell types operating together

Question 43

What are the proposed models of how dentin sensitivity occurs?

Answer 43

1. direct innervation (nerves in some tubules but minority) 2. Odontoblast nociception (anatomically do not synapse extensively with pulpal nerves, but gap junctions exist) 3. Tubule fluid conductance

Question 44

Pulp stones are:

Answer 44

Mineralized tissue formed inappropriately in the pulp

Question 45

Pulp stones can be:

Answer 45

- free - surrounded by soft pulp tissue - attached/bound to dentin - embedded in secondary dentin

Question 46

Pulp stones can occur around:

Answer 46

Collagen fibers, dead cell aggregates/thrombi

Question 47

Pulp stone effects

Answer 47

can grow large enough to compress pulp and make debridement difficult

Question 48

Age related changed in pulp

Answer 48

- recession due to 2ndary dentin formation - cell aging, reduction in cell response to stimuli - decrease in pulp permeability (more brittle teeth) - loss of nerve axons and decrease in sensitivity - dystrophic calcification in central pulp