Pulp Histology

Question 1

Definition of Endodontics

Answer 1

Branch of dentistry concerned with the morphology, physiology, and pathology of the human dental pulp and periradicular tissues

Question 2

Dental Pulp

Answer 2

Located in center of crown and root
Loose Connective Tissue
Enclosed in hard walls (dentin)
Poor collateral circulation
Connective tissue held together by ground substance
Structure reinforced by collagen fibers

Question 3

Pulp Embryology

Answer 3

Derived from neural crest cells (ectomesenchymal)

Forms dental papilla - mature pulp derives

Question 4

Enamel Organ - Development

Answer 4

Enamel

Question 5

Dental Papilla - Development

Answer 5

Pulp & Dentin

Question 6

Dental Sac - Development

Answer 6

Cementum & PDL

Question 7

Tooth development

Answer 7

Papilla -> IEE -> ameloblasts
Ameloblasts -> papilla -> odontoblasts -> predentin
Predentin -> ameloblasts -> enamel

Question 8

Epithelial Diaphragm

Answer 8

AKA - cervical loop
Junction of IEE and OEE
Future CEJ

Question 9

*Hertwig’s Epithelial Root Sheath

Answer 9

*Proliferation forms root
When ruptured, exposes dentin to connective tissue
Exposed dentin stimulates cementum deposition

Question 10

Cell Rests of Malasseze’s

Answer 10

Epithelial remnants from root sheath
Remain dormant
If activated by inflammation, can proliferate providing lining of radicular cysts

Question 11

Lateral Canal

Answer 11

communication b/n pulp and periodontum
Primary: formed if root sheath breaks down before dentin can be laid
Secondary: form if bv are not displaced

Question 12

*Morphologic Zones of the Pulp

Answer 12

Core, Cell Rich, Cell Free, Odontoblast

Question 13

*Odontoblastic Zone

Answer 13

Free nerve ends penetrate this layer, communicate via gap junctions, palisade arrangement (tight picket fence)

Question 14

Cell Free Zone

Answer 14

zone of Weil, nerve fibers present, *diminish in size or temporarily disappear during rapid dentin formation

Question 15

Cell Rich Zone

Answer 15

contains undifferentiated mesenchymal cells and fibroblasts

serves as reservoir for destroyed odontoblasts

Question 16

Central Zone or Core

Answer 16

core of loose connective tissue

contains larger nerves and blood vessels

Question 17

Dental Pulp Components

Answer 17

Cells, intercellular components, nerves, blood vessels, lymphatics

Question 18

Cells of pulp

Answer 18

Odontoblasts, fibroblasts, undifferentiated mesenchymal cells, inflammatory cells

Question 19

Odontoblast

Answer 19

Cell body and Odontoblastic process

Rough endoplasmic reticulum, golgi complex, mitochondria

Question 20

Odontoblastic functions

Answer 20

synthesizing (cell body), secretory (odontoblastic process), mineralizing

Question 21

Fibroblasts

Answer 21

Most abundant cell in pulp

Abundant in cell rich zone, synthesizes collagen matrix, secretes ground substance matrix

Question 22

Undifferentiated mesenchymal cells

Answer 22

abundant in cell rich zone, can differentiate into different cells, reservoir for lost cells

Question 23

Acute vs. Chronic Inflammatory Cells

Answer 23

Acute - neutrophils

Chronic - lymphocytes, plasma cells, macrophages

Question 24

Intercellular Components

Answer 24

Intercellular fluid, ground substance, collagen fibers, blood vessels and nerves

Question 25

Intercellular Fluid

Answer 25

derived from pulpal capillaries, vehicle for nutrients and waste removal

Question 26

Ground Substance

Answer 26

sol-like, made of glycosaminoglycans, glycoproteins (complex protein-carbohydrate molecules) and water, supports cells, *composition altered by age and disease (shrink as older)
Helps regulate overall intrapulpal pressure, acts as a barrier against spread of microbes

Question 27

Collagen Fibers

Answer 27

Type 1 found in dentin, both 1 and 2 found in pulp
Odontoblast - type 1
Fibroblasts - type 1 and 2
Collagen fibers - polypeptide chains, immature fibers called reticular fibers, fibrils aggregate to form bundles which in turn form fibers