pulp

Question 1

embryonic origin of pulp

Answer 1

ectoderm > neural crest ectomesenchyme > dental papilla

Question 2

constituents of the pulp

Answer 2

• cells and cellular elements
• blood and lymphatic vessels
• extracellular matrix

Question 3

functions of pulp in the mature tooth

Answer 3

• hydrates dentin
• protective: sensory, barrier
• defensive: immune
• reparative: formation of new dentin and pulp

Question 4

developmental precursors of the pulp have an ____ role; odontogenic ectomesenchymal cells secrete a number of signaling or growth factors that act on the epithelial cells of the ____to trigger the transition to the ____ stage

Answer 4

inductive; bud; cap

Question 5

odontoblasts secrete ____ of dentin and participate in _____

Answer 5

organic matrix; mineralization

Question 6

binds to collagen in forming dentin matrix; attracts Ca2+ ions to initiate mineralization

Answer 6

dentin phosphoprotein (DPP)

Question 7

DPP is highly ____ and high in ____

Answer 7

phosphorylated; serine/aspartic acid

Question 8

DPP is ___ and ____ charged

Answer 8

acidic; negatively (anionic)

Question 9

dentinogenesis (crown) begins during the ____ stage

Answer 9

bell

Question 10

3 things that are present just prior to dentinogenesis

Answer 10

• all 4 layers of the enamel organ
• an enamel knot
• the outline of the crown

Question 11

just prior to dentinogenesis, there are no ____ or ____

Answer 11

odontoblasts (in the papilla); ameloblasts (in the enamel organ)

Question 12

____ and _____ are present at the future DEJ, prior to dentinogenesis

Answer 12

inner enamel epithelial cells (in the enamel organ); undifferentiated mesenchymal cells (in the dental papilla)

Question 13

dentinogenesis occurs from ____ to ____ and from ___ to ____

Answer 13

from cusp tips to cervix

AND from periphery to pulp center

Question 14

inductive signal for odontoblast differentiation is secreted molecules from ____- most likely the ____ (epithelial-mesenchymal interaction)

Answer 14

enamel organ; enamel knot

Question 15

2 prominent/best documented signaling/growth factors for odontogenesis

Answer 15

BMPs (bone morphogenetic protein)

Wnts

Question 16

____ expression immediately precedes the “wave” of odontoblast differentiation

Answer 16

Wnt10a

Question 17

Wnt10a is 1st expressed in ____, then ____ at the cusp tip, then more cervical parts of the tooth

Answer 17

enamel knot(s)
pre-odontoblasts

Question 18

modifying the wnt receptor complex to amplify effects of wnt binding increases production of ____ and ____ in animal models

Answer 18

reparative dentin; dentin proteins

wnt signaling important in adult pulp- pulp cells release wnt after injury in adults

Question 19

pulp in the crown is the ____ or ____

Answer 19

pulp chamber; coronal pulp

Question 20

coronal pulp includes extensions into each cusp called ____

Answer 20

pulp horns

Question 21

pulp in the roots constitutes the ____ or ____ which is continuous with the periodontium at the ____

Answer 21

root canal; radicular pulp; apical foramen

Question 22

spherical calcified masses, most common in the pulp chamber

Answer 22

pulp stones (denticles)

Question 23

irregular areas of calcification, usually surrounding blood vessels or collagen fiber bundles, often in the root

Answer 23

diffuse calcifications

Question 24

located central to the odontogenic zone and contains fibroblasts and trunks of larger branches of both nerves and blood vessels

Answer 24

pulp core

Question 25

cells confined to the pulp that secrete extracellular matrix (ECM)

Answer 25

fibroblasts

Question 26

have a role in cell adhesion to ECM

Answer 26

glycoproteins (e.g. fibronectin)

Question 27

function as a matrix for diffusion, collagen fibrillogenesis, and water retention

Answer 27

proteoglycans (PGs) and glycosaminoglycans (GAGs)

Question 28

Collagen I and III are both ____ collagens that function in _____

Answer 28

fibrillar; tensile strength

Question 29

mature pulp does not contain ____

Answer 29

DSPP

Question 30

stem cells have a high capacity for ____ and they can generate multiple cell types, which means they are called ____

Answer 30

self-renewal (they can replicate themselves); plastic

Question 31

dental pulp stem cells can be induced to form a number of cell types, not only odontoblasts, but also ____ and ____ in vitro

Answer 31

adipocyte and glial-like cells

Question 32

named for its function in transforming leukocyte precursors into granulocytes (neutrophils)

Answer 32

G-CSF (granulocyte colony stimulating factor)

Question 33

DPSCs are ____, providing raw material for new pulp tissues

Answer 33

multipotent

Question 34

DPSCs are ____ and secrete trophic factors promoting _____ and ____

Answer 34

anti-inflammatory; angiogenesis; neurogenesis

Question 35

cells unique to the pulp; 2nd most numerous cell type in the pulp

Answer 35

odontoblasts

Question 36

functions of odontoblasts

Answer 36

- dentinogenesis - nutrients to dentin - immune

Question 37

"sticky" junctions between odontoblasts; maintain position and polarity

Answer 37

``` desmosomes (contain intermediate filaments) adherens junctions (contain actin filaments) ```

Question 38

channels between odontoblasts that coordinate dentinogenesis

Answer 38

gap junctions (contain connexins)

Question 39

apical "weld" membranes

Answer 39

tight junctions

Question 40

depending on the exact form of the proteins and their extent, tight junctions can form an _____

Answer 40

inter-cellular barrier

Question 41

some smaller MW substances can pass between adjacent odontoblasts, but tight junctions inhibit passage of ____ and probably ____

Answer 41

larger molecules; bacteria

Question 42

the presence of ____ and ____ distinguish pulp from other tooth tissues

Answer 42

blood; lymphatic vessels

Question 43

the autonomic component of pulpal blood flow control is mainly ____, via ____ and _____ receptors

Answer 43

sympathetic; norepinephrine; alpha adrenergic

Question 44

the sympathetic nervous system causes vasculature in the dental pulp to ____

Answer 44

constrict

Question 45

types of nerve fibers that innervate the dentin and pulp

Answer 45

A delta- sensory pain fibers C- some are sensory pain fibers, others are sympathetic B beta- sensory pain fibers

Question 46

innervation begins at the ____ stage

Answer 46

bell

Question 47

how far do nerve fibers extend into dentin?

Answer 47

nerve processes do reach the dentin, but extend just to the inner third

Question 48

dentinal tubules are most highly innervated in the ____; nerve fibers also terminate throughout and profusely innervate the ____

Answer 48

crown; pulp-dentin border zone

Question 49

all dentinal stimuli that cause pain cause ____ in dentinal tubules: this is the _____ theory

Answer 49

fluid movement; hydrodynamic

Question 50

fluid movement in dentinal tubules causes deformation of _____ sensitive nerve endings close to and in the dentin

Answer 50

mechanically

Question 51

_____ are embedded in the membranes of nerve fiber _____ of alpha delta and alpha beta fibers in the ____ region

Answer 51

mechanically-activated ion channels ("mechanoreceptors") endings pulp/dentin border

Question 52

3 things that happen when the nerve fiber endings are deformed

Answer 52

1. ion channels open 2. Na+ sodium flows into the nerve endings 3. nerve endings are depolarized and give rise to action potentials

Question 53

tooth pain also arises directly from stimuli in the ____

Answer 53

pulp

Question 54

other pulp nerve fiber endings, especially ____, have receptors for ____ and ____ stimuli; these receptors are members of the ____ receptor family

Answer 54

C fibers; inflammatory; thermal; TRP receptor family

Question 55

TRP receptors are a family of _____ receptors for thermal and inflammatory pain in many regions of the body

Answer 55

transmembrane

Question 56

_____ receptor is activated by many inflammatory mediators such as ____ and ____

Answer 56

TRPA1; reactive oxygen species; prostaglandins

Question 57

TRPA1 receptors are also to ____ through an indirect pathway

Answer 57

bradykinin

Question 58

location of A delta and A beta fibers

Answer 58

dentinal tubules and most superficial pulp

Question 59

location of C-fibers

Answer 59

pulp only, superficial and deep

Question 60

dentinal stimuli activates ____ and ____ fibers through ____ forces; leads to ____ pain

Answer 60

Adelta; Abeta; hydrodynamic; sharp/piercing

Question 61

infection or trauma activates ____ through inflammation; leads to ___ pain

Answer 61

C-fibers; dull/aching

Question 62

tooth nerve sensitivity can ____/_____ under conditions of inflammation through many mechanisms

Answer 62

change/become hypersensitized

Question 63

expression of _____ can increase during inflammation

Answer 63

pain receptors

Question 64

pain nerve fibers in the tooth have an important ____ influence on the pulp itself

Answer 64

regulatory

Question 65

the regulatory influence is mediated largely by the release of a class of neuromodulators called _____

Answer 65

neuropeptides

Question 66

two prominent types of neuropeptides

Answer 66

substance P and CGRP (calcitonin-gene related peptide)

Question 67

peptides are synthesized in the ____, which is in the ____ (outside the brain)

Answer 67

cell body; trigeminal ganglion

Question 68

at central endings (trigeminal nucleus, CNS, specifically the brainstem), the peptides have a ____ function, binding with receptors on brain neurons to regulate _____

Answer 68

transmitter; pain

Question 69

at peripheral endings (in the tooth), peptides have ____ function, binding with receptors on _____ for a _____ effect

Answer 69

local regulatory; vasculature/local cells; pro-inflammatory

Question 70

inflammatory and immune functions of sensory (pain) nerves

Answer 70

- vasodilation (opposes sympathetic control) - plasma extravasation - angiogenesis - interactions with immune cells

Question 71

resident immune system cells in the pulp

Answer 71

macrophages lymphocytes eosinophils dendritic cells

Question 72

types of cells in the pulp during inflammation

Answer 72

plasma cells mast cells pmn's

Question 73

stem cells in the pulp are a source of replacement for ____ or _____

Answer 73

odontoblasts; fibroblasts

Question 74

3 locations of stem cell probably present in mature pulp

Answer 74

1. undifferentiated mesenchymal cells in cell-rich zone 2. perivascular cells (pericytes) in the core 3. other cells in the core

Question 75

different stem cell populations in the pulp probably play a role in response to ____

Answer 75

injury