01 pulp biology, last minute studying

Question 1

what are the most prominent immune cells of the dental pulp?

Answer 1

dendritic cells

Question 2

what is the composition of dentin? (inorganic, organic, water)

Answer 2

Inorganic=70 % (calcium hydroxyapatite)
organic=20% (mainly type I collagen)
water=10%

Question 3

what do fibroblasts synthesize?

Answer 3

Synthesize: TypeI,III Collagen, Proteoglycans/GAGs (Ground Substance)
-Most common cell type in pulp, abundant in Cell-Rich zone

Question 4

fibers of the pulp, which is the most and what types?

Answer 4

Collagen types I and III in pulp, produced by

fibroblasts in 55:45 ratio, thus type I is the most abundant

Question 5

c shaped canal

Answer 5

-Has complex internal anatomy
-Is most commonly found in the Asian population
-Usually occurs in mandibular 2nd
-Should be referred to an endodontist for tx
molars

Question 6

what is the most important function of the pulp?

Answer 6

formation-odontoblasts form dentin

Question 7

what is the increased permeability of dentin closer to the pulp due to?

Answer 7

Increased permeability of dentin closer to pulp due to wider, more concentrated dentinal tubules

Question 8

what cells are present in the cell rich zone of the pulp?

Answer 8

Zone containing high proportion of fibroblasts, immune cells (i.e.: macrophages, dendritic cells), and undifferentiated mesenchymal stem cells

Question 9

what is the pulp proper and what is the most common cell type present?

Answer 9

Central mass of pulp, consisting of loose connective tissue, larger blood vessels and nerves
—-Most common cell type in this layer is the fibroblast

Question 10

what do fibroblasts synthesize?

Answer 10

Synthesize: Type I,III Collagen, Proteoglycans/GAGs (Ground Substance)

Question 11

what cells are ‘Present in injured pulps only?’

Answer 11

Mast cells, secrete histamine and heparin to mediate inflammation

Question 12

where are collagen fibers more prominent?

Answer 12

Collagen fiber bundles more common in radicular pulp than coronal pulp

Question 13

Extensive branching of blood vessels occurs in subodontoblastic layer (cell free)
forming plexus called…

Answer 13

Sub-Odontoblastic Terminal Capillary Network

Question 14

what veins do the venules of the pulp drain into?

Answer 14

Venules are slightly larger than arterioles and drain into maxillary vein (posteriorly) or facial vein (anteriorly)

Question 15

Regulation of Pulpal Blood Flow

Answer 15

Sympathetic Autonomic regulation (healthy pulp):

• Release of NE causes vasoconstriction of pulpal blood vessels
• Normal pulpal vasomotor tone is regulated by sympathetic autonomic system (slight vasoconstrictive tone on precapillary sphincters)

Question 16

in an inflammed pulp, regulation of blood flow…

Answer 16

neuronal regulation…vasodilation and increased vascular permeability

• Neuropeptides – pro-inflammatory mediators
• AKA NEUROGENIC INFLAMMATION (Acute inflammatory response)

Question 17

vascular changes during inflammation:

Answer 17

Vasodilation of Vessels
—increase in Vascular Permeability
increase in Interstitial Tissue Fluid/Proteins

Question 18

Pulp has 2 types of sensory nerve fibers:

Answer 18

1. Myelinated Axons: A-fibers (20%) —
   -A-delta fibers (90%)
   —-A-beta fibers (10%)
2. Unmyelinated Axons: C-fibers (80%)

Question 19

where is the Plexus of Rashkow

Answer 19

subodontoblastic cell free zone

Question 20

where do A fibers and C fibers terminate?

Answer 20

A fibers terminate as unmyelinated free nerve endings in and around the odontoblasts
-C fibers terminate in the pulp

Question 21

Fastest conducting myelinated pulpal fibers

— Pressure and touch sensation (proprioceptive)

Answer 21

A-beta fibers

Question 22

— Slower conducting myelinated fibers

— Pain, temperature, and touch sensation

Answer 22

A-delta fibers

Question 23

— Slowest conducting unmyelinated fibers — Pain sensation

Answer 23

C fibers

Question 24

All Sensory Nerve Fibers in pulp/dentin function only as

Answer 24

Nociceptors (Pain)

ALL Afferent impulses generate the sensation of Pain

Question 25

have higher conduction velocities, relatively Low thresholds for excitation, and pain characteristics of Sharp, Pricking pain

Answer 25

A-delta fibers

Question 26

have lower conduction velocities, High thresholds of excitation, and pain characteristics of Dull, Aching, Throbbing pain

Answer 26

C fibers

• associated with tissue injury
• less bearable

Question 27

parasympathetic, sympathetic, or both in pulp?

Answer 27

sympathetic,

Question 28

Cold Testing Activates which fibers

Answer 28

A-delta fibers

Question 29

types and location of Cementum

Answer 29

• Acellular afibrillar cementum:
  Covers the teeth at and along the cemento-enamel junction (CEJ)
• Acellular extrinsic fiber cementum:
  Confined to the coronal half of the root
• Cellular intrinsic fiber cementum: is - Confined to the apical half of the root

Question 30

Covers the teeth at and along the cemento-enamel junction (CEJ)

Answer 30

• Acellular afibrillar cementum:

Question 31

cementum Confined to the coronal half of the root

Answer 31

Acellular extrinsic fiber cementum:

Question 32

cementum - Confined to the apical half of the root

Answer 32

Cellular intrinsic fiber cementum:

Question 33

cells of the PDL

Answer 33

-all the same cells as the pulp, but Unique to PDL: Cementoblasts, Odontoclasts, Osteoblasts, Osteoclasts, Epithelial cell rests of Malassez

Question 34

nerve supple of PDL

Answer 34

Much greater proportion of Propriorecptive A-beta fibers – Allows patient identification of tooth with apical periodontitis

Question 35

what is Alveolar Bone Proper?

Answer 35

— Aka: Bundle bone, Cribriform plate
— Compact lamellar bone that lines the socket
— Principal periodontal fibers are anchored
— Denser than underlying Cancellous bone
— Radiopaque appearance on radiographs: Lamina Dura
— Radiographic loss of lamina dura = periapical inflammation