Dentin Pulp complex

Question 1

Dentin between roots is said to be?

Answer 1

Interadicular

Question 2

What are the 3 junctions of a tooth?

Answer 2

1-DEJ
2-CEJ
3-CDJ

Question 3

Dentin is very similar (analogous) to what other tissue?

Answer 3

Bone

Question 4

Dentin is ____% inorganic ______% organic and _____% water

Answer 4

70, 20, 10

Question 5

90% of the organic material in dentin is made up of what?

Answer 5

Collagen (mostly I, some III and V)

Question 6

Which 5 non collagenous proteins in dentin are also found in bone?

Answer 6

1-Bone Sialoprotein (BSP)
2-Osteopontin (OP)
3-Osteocalcin (OC)
4-Osteonectin (ON)
5-Matrix extracellular phosphoglycoprotein

Question 7

Which two non collagenous proteins in dentin are dentin specific?

Answer 7

1-Dentin matrix protein-1 (DMP-1)

2-Dentin Sialophosphoprotein (DSPP, cleaves into 3)

Question 8

What 3 proteins result from cleaving of DSPP?

Answer 8

1-Dentin Sialoprotein (DSP)
2-Dentin phosphoprotein (DPP)
3-Dentin Glycoprotein (DG)

Question 9

Cleaved from the N terminus of DSPP by BMP-1, which dentin protein is a proteoglycan, is similar to DMP-1, is expressed in dentinal tubules and may act to prevent mineralization?

Answer 9

DSP

*loss of this results in harder, more brittle dentin

Question 10

Cleaved from the middle of DSPP by BMP-1, which dentin protein is a glycoprotein and has an unknown function?

Answer 10

DGP

Question 11

Cleaved from the C terminus end of DSPP by BMP-1 which dentin protein is attached to collagen, binds lots of Ca+2, and is not thought to be glycosylated?

Answer 11

DPP

*loss results in not as hard dentin

Question 12

DSPP can cause dentinogenesis imperfecta in what two ways?

Answer 12

1-Type II- pulp chamber fills in
2-Type III- pulp enlarges, hypo-mineralization

*Type I results from osteogenesis imperfecta where collagen I has a defect

Question 13

odontoblasts have what origin?

Answer 13

Mesenchymal

Question 14

What junction has a scalloped architecture?

Answer 14

DEJ

Question 15

For what two reasons is the DEJ critical?

Answer 15

1-Defines the shape of the crown

2-Keeps dentin attached to enamel (resist shearing)

Question 16

The first layer, closest to the DEJ is called?

Answer 16

Mantle dentin

Question 17

Collagen III fibrils, 0.1-0.2 mm in mantle dentin, are associated with fibronectin and are called what?

Answer 17

Von Korffs fibers

Question 18

Odontoblasts extending into the developing matrix and secreting dentin through matrix vesicles are called what?

Answer 18

Tomes Fibers

Question 19

What are the two types of matrix mineralization?

Answer 19

Gloublar (like paintballs)

Linear (mineralizing wall)

Question 20

Non collagenous proteins regulate tubular primary dentin played down after DEJ formation, this dentin is called?

Answer 20

Circumpulpal

*mantle dentin is therefore NOT tubular

Question 21

What initiates odontoblast differentiation at the roots?

Answer 21

HERS

Question 22

What are the 3 types of dentin?

Answer 22

1-Primary dentin (formed during development)
2-Secondary dentin (formed after root formation and throughout life)
3-Tertiary dentin (response to insult, is more like bone)

Question 23

When the trauma does not damage odontoblasts what subtype of tertiary dentin forms?

Answer 23

Reactionary dentin

Question 24

When trauma damages odontoblasts, causing the recruitment and differentiation of new odontoblasts what subtype of tertiary dentin forms?

Answer 24

Reparative dentin

Question 25

What are 3 main strucutures in dentin?

Answer 25

1-Dentin tubules (with OD process)
2-Peritubular dentin
3-Intertubular dentin

Question 26

What are the 4 histological zones of the pulp?

Answer 26

1-Odontoblast layer
2-Cell free zone of Weil (blood vessels and nerves)
3-Cell rich/dense zone
4-Pulp core

Question 27

What is the soft connective tissue matrix of the pulp made up of?

Answer 27

• Collagen III mostly, some collagen I
• proteoglycans and glycoproteins

*collagen content increases with age

Question 28

What are the 5 main proteoglycans found in the pulp?

Answer 28

1-Chondroitin-6-sulfate
2-Chondroitin-4-sulfate
3-Heparin sulfate
4-Dermatan sulfate
5-karatan sulfate

Question 29

What holds the layer of odontoblasts together and makes them only slightly “leaky”?

Answer 29

Adherents junctions (tight junction, desmosomes, zonula adherens)

*serum proteins can pass, can form gap junctions with fibroblasts as well

Question 30

What is sequestered by the ground substance and is released when dentin is etched?

Answer 30

Growth factors

*GFs in dentin matrix recruit new OD

Question 31

What is the predominant cell type found in the dentin-pulp complex?

Answer 31

Fibroblasts

*mainly found in the pulp core and cell rich zone and produces/maintains matrix of pulpal tissue

Question 32

Why type of progenitor cells are present in the dental pulp?

Answer 32

Mesenchymal

Question 33

Macrophages are part of the ______ immunity in dental pulp while dendritic cells are __________ immunity

Answer 33

Innate, acquired

*Dendritic cells under odontoblast layer.

Question 34

The capillary network in the dental pulp is found in what region?

Answer 34

Cell free zone

*during primary dentin formation it is present in the odontoblast layer

Question 35

Where do arteries and veins enter and leave the tooth?

Answer 35

Apical foramen

*nerves and lymph enter and leave here too

Question 36

The network of nerves under the odontoblast layer especially in the coronal pulp is called what?

Answer 36

Plexus of Raschkow

Question 37

What two types of nerve fibers are in the pulp?

Answer 37

1-Afferent nerves from the trigeminal (pressure/nociception)

2-Sympathetics from superior cervical ganglion (vascular control)

Question 38

Nerve bundles consist of what two types of axons?

Answer 38

1-Myelinated “Ad” (sharp)
2-Unmyelinated “C” (throbbing)

*Myelination decreases as fibers proceed toward coronal pulp

Question 39

What are the 3 proposed models for dentin sensitivity?

Answer 39

1-Direct innervation
2-Odontoblast nociception
3-Tubule fluid conductance (hydrodynamic)

Question 40

More prevalent after 50 years of age, what pulpal feature is mineralized tissue formed in the pulp and occur around collagen fibers, dead cell aggregates or thrombi?

Answer 40

Pulp stones