Dental Pulp and Caries

Question 1

how does dental pulp evolve

Answer 1

goes through the same stages as the rest of the tooth- goes through embryogenesis

Question 2

what are the stages in dental pulp embryogenesis and what happens in each

Answer 2

-cap stage: dental papilla
- bell stage: primitive pulp, contains capillary development

Question 3

what does the mature dental pulp consist of

Answer 3

loose CT

Question 4

what is mature dental pulp derived from

Answer 4

neural crest (ectomesenchymal) cells

Question 5

where is the density of cells in dental pulp get higher

Answer 5

towards the dentin

Question 6

what is the odontogenic zone cell layer and is it cellular rich/dense

Answer 6

-odontoblastic cell layer
- cellular rich/dense

Question 7

what does the odontogenic zone contain

Answer 7

• cell-free zone of Weil
• Cell-rich zone
• Raschkow’s plexus

Question 8

what cell layer makes up the pulpal core and is it cellular/dense

Answer 8

-fibroblastic layer
- not very cellular or dense

Question 9

what does the pulpal core contain

Answer 9

-type 1 and 3 collagen
-extracellular matrix
- blood vessels
- nerve tissue

Question 10

what are the functions of the pulp

Answer 10

• embryonic induction (as tooth continues to develop, presence of pulp in the IEE helps to stimulate further development of the enamel organ)
• formative: has the cells necessary to orm certain mature structures within the tooth
  -protective
  -reparative

Question 11

what are the cells in the pulpal tissue

Answer 11

-fibroblasts
- odontoblasts
- undifferentiated mesenchymal cells
- macrophages and dendritic cells
-blood vessel related cells (endothelial and pericytes)
- neural related cells (schwann cells)
- lymphocytes (for immune response)

Question 12

what is the majority of cells in the pulpal tissue

Answer 12

fibroblasts

Question 13

what percentage do macrophages and dendritic cells make up in pulpal tissue

Answer 13

8%

Question 14

what makes up the collagenous extracellular matrix of pulpal tissue

Answer 14

mostly type 3 collagen (25-32%) (and 1,4,5) via odontoblasts

Question 15

what makes up the non-collagenous extracellular matrix of pulpal tissue

Answer 15

-proteoglycans, glycosaminoglycans, phosphoproteins, glycoproteins
-y-carboxyglutamate-containing proteins (BMP,FGF,EGF< DMP), stimulate growth and maturation of both ameloblasts and odontoblasts

Question 16

what are most nerve endings in pulp for

Answer 16

pain
-(few for vasoconstriction/dilation)

Question 17

what does the trigeminal nerve in the pulp give off free nerve endings as sensory afferents for

Answer 17

-pain
-mechanical (pressure)
- thermal
-tactile

Question 18

what ganglion is for pulp

Answer 18

superior cervical ganglion

Question 19

what makes up the superior cervical ganglion in pulp and what is their function

Answer 19

sympathetic branches, primarily vasomotor fibers to pulpal blood vessels and function most in vasoconstriction

Question 20

what does pulp nerve tissue contain

Answer 20

myelinated and non-myelinated nerve axons

Question 21

what do axons in pulp nervous tissue branch into

Answer 21

the subodontoblastic layer as Raschow’s plexus into the odontoblastic cell layer and some fibers enter into the dentinal tubules. forms before the full formation of roots

Question 22

how many branches does each nerve fiber branch into the plexus

Answer 22

at least 8

Question 23

what do most nerve fibers terminate in the plexus as

Answer 23

free nonmyelinated nerve endings (C-fibers)

Question 24

where are schwann cells located and what do they do

Answer 24

functions in myelination in the PNS, allows for faster nerve conduction

Question 25

describe A-delta fibers, their conduction velocity, size and function

Answer 25

-majority of myelinated pulpal nerves -fast conducting -diamter range of 1-6 um - associated with sharp, localized pain

Question 26

describe A-beta fibers and size

Answer 26

-1% of myelinated pulpal nerves -diamter range of 6-12 um

Question 27

describe C-fibers fibers and size and function

Answer 27

-nonmyelinated -diameter range of 0,4-1.2 um (smallest) - associated with dull,diffuse pain

Question 28

what are the neuropeptides and NTs inside the dental pulp

Answer 28

- calcitonin gene related peptide (CGRP) - Substance P - epinephrine - NE - dopamine -endorphin

Question 29

what does CGRP do

Answer 29

vasodilation, stimulates fibroblast cell division

Question 30

what does substance P do

Answer 30

vasodilation, stimulates fibroblast cell division,

Question 31

what does EPI do in dental pulp

Answer 31

vasoconstriction via arteriole smooth muscles

Question 32

what does NE do in dental pulp

Answer 32

sympathetic vasoconstrictor

Question 33

what does dopamine do in dental pulp

Answer 33

vasoactive or a precursor of epinephrine

Question 34

what does endorphin do in dental pulp

Answer 34

silences of nociceptor (pain)

Question 35

what is the distribution of nerve axons and blood vessels in intratubular dentin

Answer 35

-pre-dentin will have more nerve axons

Question 36

the more mineralized you get ____

Answer 36

the less nerve axons you will have

Question 37

as you are more coronal there is more ____

Answer 37

branching and more nerve activity

Question 38

what makes up pulp horns

Answer 38

-27% pre-dentin -11% mineralizing front -8% dentin up to 100 um

Question 39

what makes up remaining crown

Answer 39

-14% pre-dentin -6% mineralizing front -2% dentin up to 100 um

Question 40

what makes up the root

Answer 40

-11% pre-dentin -0% mineralizing front - 0% dentin up to 100 um

Question 41

describe arterioles

Answer 41

diameter of 50-100 um, thicker

Question 42

describe venules

Answer 42

diameter of 100-150 um. thinner

Question 43

describe capillaries

Answer 43

anastomoses deep to the odontoblastic layer

Question 44

where are capillary loops dense and less dense

Answer 44

dense in the coronal and pulp horn regions and less dense in the radicular pulp

Question 45

describe changes in blood vessels due to age

Answer 45

exhibit changes like cholesterol plaque- if severe can result in pulpal hypoxia due to vessel strangulation

Question 46

describe fenestrated capillaries and what are they important in

Answer 46

with holes, allows for serum/fluid movement. important in inflammatory response and swelling: serum/tissue fluid to leaks out of capillaries (as a response) into the surrounding tissue causing the swelling

Question 47

describe continuous capillaries

Answer 47

lacking holes

Question 48

what is pulpal fibrosis and what causes it

Answer 48

-shrinking of the pulp - occurs with increasing age or persistent low grade injury (bruxism, thermal insult, multiple restorations on single tooth)

Question 49

what are diffuse calcifications

Answer 49

irregular calcified deposits along collagen fiber bundles or within blood vessels resulting from chronic low grade inflammation/insult to the tooth

Question 50

what are pulp stones/denticles

Answer 50

classified as either free, attached (in wall) or embedded (in pulp). do not cause pain or issues, only an issue during RCT access

Question 51

what are true pulp stones

Answer 51

contain dentinal tubules

Question 52

what are false pulp stones

Answer 52

feature concentric layers of calcified tissue but are void of dentin tubules

Question 53

what is abscess

Answer 53

dense aggression of neutrophils and macrophage and other inflammatory cells within CT undergoing liquefactive necrosis (cell structure breaks down and tissue becomes liquified)

Question 54

what are vacuolated macrophages

Answer 54

consume dead tissue "clean up the mess"

Question 55

what are syncytial macrophages

Answer 55

multinucleated, resorb dentin adjacent to inflammed pulp

Question 56

what is pulpal abscess

Answer 56

active inflammatory process. will destroy soft tissue and mineralized tissue if left there

Question 57

what does pulpal abscess lead to and why

Answer 57

pulpal necrosis due to inability of pulpal tissue to swell, the increasing edema and inflammatory cell infiltration

Question 58

what is pulpal necrosis

Answer 58

inflamed pulp cuts off its own blood supply, leading to tissue death

Question 59

what are the symptoms of pulpal necrosis

Answer 59

clinically expressed with pain and periapical necrosis (seen as radiolucent near apex of root on radiographs) of the PDL and associated alveolar bone

Question 60

what is the treatment for pulpal abscess

Answer 60

incision and drainage (I and D) followed by endodontic therapy

Question 61

what is diffuse cellulitis

Answer 61

when pulpal abscess enlarges so much to where it is involving airways