Dentin-pulp complex

Question 1

accessory canals:

Answer 1

Extra opening located on the lateral portions of the roots of some teeth

Question 2

apical foramen:

Answer 2

Opening from the pulp at the apex of the tooth giving passage to the nerves and
blood vessels.

Question 3

contour lines of Owen:

Answer 3

Adjoining imbrication lines in dentin that demonstrate a disturbance in
body metabolism.

Question 4

dentinal tubules:

Answer 4

Long tubes in dentin

Question 5

dentin, circumpulpal:

Answer 5

Layer of dentin around the pulpal wall.

Question 6

dentin, hypersensitivity:

Answer 6

A short, sharp painful reaction that occurs when some areas of exposed
dentin are subjected to mechanical, thermal, or chemical stimuli.

Question 7

dentin, mantle:

Answer 7

Outermost layer of dentin found in the crown region, adjacent to the
dentinoenamel junction.

Question 8

dentin, peritubular:

Answer 8

Type of dentin that creates the wall of the dentinal tubule.

Question 9

dentin, primary:

Answer 9

Dentin formed in a tooth before the completion of the apical foramen.

Question 10

dentin, secondary:

Answer 10

Dentin that is formed after the completion of the apical foramen

Question 11

dentin, tertiary:

Answer 11

Dentin formed in response to a localized injury to exposed dentin.

Question 12

dentinal fluid:

Answer 12

Fluid within the dentinal tubule in dentin.

Question 13

dentinogenesis:

Answer 13

The process of dentin formation in the development of teeth.
During the apposition stage, odontoblasts differentiate from outer cells of dental papilla.
Formation of mantel dentin:
Odontoblasts synthesize and secrete collagen into ground substance of dental papillae.
Collagen aggregates into fibers perpendicular to basement membrane.
Odontoblasts release vesicles containing hydroxyapatite crystals.
Vesicles rupture and release crystals.
Crystals spread as a cluster and fuse with adjacent clusters to form mineralized matrix.

Question 14

fibroblast:

Answer 14

Cell that synthesizes certain types of protein fibers and intercellular substance.

Question 15

gingival recession:

Answer 15

Migration of the free gingival margin to a position apical to the
cementoenamel junction (CEJ).

Question 16

globular dentin:

Answer 16

Areas of both primary and secondary mineralization in dentin.

Question 17

imbrication lines of von Ebner:

Answer 17

Incremental lines or bands in mature dentin

Question 18

odontoblastic process:

Answer 18

Attached cellular extension of the odontoblast within the dentinal tubule
through the entire width of the dentin.

Question 19

odontoblasts:

Answer 19

Cells differentiated from outer cells of the dental papilla that synthesize and secrete
predentin.

Question 20

outer cells of the dental papilla:

Answer 20

Cells of dental papilla tissue that differentiate into odontoblasts.

Question 21

predentin:

Answer 21

Dentin matrix laid down by apposition by the odontoblasts.

Question 22

pulp:

Answer 22

Soft innermost connective tissue in both crown and root.

Question 23

pulp chamber:

Answer 23

Part of the tooth containing the mass of pulp

Question 24

pulp, coronal:

Answer 24

Pulp located in the crown of the tooth

Question 25

pulp, horns:

Answer 25

Extensions of coronal pulp into the cusps of the posterior teeth.

Question 26

pulp, radicular:

Answer 26

Portion of the pulp located in the root areas of teeth.

Question 27

pulpitis:

Answer 27

Inflammation of the pulp.

Question 28

Tomes’ granular layer:

Answer 28

Layer of dentin found only in the tooth root; has a granular appearance.

Question 29

Dentin & Pulp Complex

Answer 29

Make up inner parts of tooth In health, not exposed to oral environment Close proximity Interdependent

Question 30

Dentin

Answer 30

``` -Composition by weight 70% mineralized inorganic 20% organic 10% water -Chemical composition Calcium hydroxyapatite Ca10(PO4)6(OH)2 -Crystalline structure Plate-like in shape Smaller in size than enamel ```

Question 31

Dentin Characteristics

Answer 31

Makes up bulk of tooth Covered by enamel (crown) and cementum (root) Yellowish in color Gives translucent enamel its yellow hue

Question 32

Dentinogenesis, Formation of mantel dentin:

Answer 32

Formation of mantel dentin: Odontoblasts synthesize and secrete collagen into ground substance of dental papillae. Collagen aggregates into fibers perpendicular to basement membrane. Odontoblasts release vesicles containing hydroxyapatite crystals. Vesicles rupture and release crystals. Crystals spread as a cluster and fuse with adjacent clusters to form mineralized matrix.

Question 33

Dentinogenesis, Formation of primary dentin:

Answer 33

Organic matrix formed by odontoblast Collagen aggregates as much smaller fibrils, more closely packed, & aligned at right angles to mantel dentin Different pattern of mineralization Mineralization occurs by globular calcification

Question 34

Dentinogenesis, Globular Calcification:

Answer 34

Organic matrix is deposited (predentin) Hydroxyapatitie crystals get depositied in discrete areas. As crystals grow globular masses are formed Globular masses continue to enlarge and fuse with each other

Question 35

Types of Dentin By time of formation:

Answer 35

-Primary dentin Dentin that is formed in a tooth before the completion of the apical foramen -Secondary dentin Dentin that is formed in a tooth after the completion of the apical foramen -Tertiary dentin Dentin that is formed in a tooth in response to injury

Question 36

Types of Dentin By location:

Answer 36

``` -Mantel dentin Along the DEJ/CEJ; band about 150 μm wide -Circumpulpal dentin Around the pulp Makes up the bulk of the tooth’s dentin -Globular dentin Between mantle and circumpulpal dentin Disturbed dentin formation DEFICIENT MINERALIZATION ```

Question 37

Dentin Structure

Answer 37

-Tubular dentin Extend from DEJ (crown) or DCJ (root) to outer wall of pulp Created by lengthening processes of odontoblasts -Intertubular dentin Dentin between or around tubules -Peritubular dentin Dentin forming walls of tubules

Question 38

DENTINAL TUBULES

Answer 38

DENTINAL FLUID ODONDOBLASTIC PROCESS SENSORY NERVE PAIN!

Question 39

Microscopic features: dentin tubules

Answer 39

-Primary curvature “S” shaped curve reflecting pathway of odontoblast -Secondary curve: represents daily changes in odontoblast direction -Branching: branching can occur at any point along the way from DEJ/DCJ to pulp

Question 40

Microscopic features: imbrication lines of von ebner

Answer 40

Demonstrate incremental apposition of dentin in daily increments of 4-m Slight change in orientation of collagen fibers daily and more notable every 5th day

Question 41

Microscopic features: contour lines of owen

Answer 41

Adjoining parallel imbrication lines that demonstrate a disturbance in body metabolism affecting odontoblasts (e.g. birth, tetracycline ingestion, illness, inadequate nutrition.)

Question 42

Microscopic features: tomes’ granular layer

Answer 42

Unknown reason for spotty microscopic appearance Less mineralization/increased level of interglobular dentin or presence of branching at terminal parts of dentinal tubules

Question 43

pulp

Answer 43

-Innermost part of the tooth -Connective tissue Mesodermal product from dental papilla

Question 44

Components of Pulp

Answer 44

-Intercellular substance -Tissue fluid -Cells Fibroblasts, odontoblasts, WBC, dental pulp stem cell (DPSCs) -Arteries/veins (branches of maxillary a./v.), -Fibers collagen, reticular -Lymphatics -Nerves (branches of trigeminal nerve!) Fibroblasts are the most abundant cell in pulp!

Question 45

Pulp Functions

Answer 45

Support, maintenance, and continued formation of dentin Sensory Nutritional (for dentin) Protective (formation of secondary and tertiary or reparative dentin)

Question 46

Pulp Anatomy

Answer 46

1. Coronal pulp Occupies crown 2. Pulp horns Extensions of coronal pulp under cusps 3. Radicular pulp Extends from cervical region to the apex of the root 4. Apical foramen Opening from the pulp into surrounding periodontal ligament space near apex of tooth Allows arteries, veins, lymphatics, nerves to enter and exit pulp 5. Accessory canals Extra openings from pulp to PDL space

Question 47

Pulp Microscopic features: | Zones

Answer 47

``` -Odontoblastic layer Cell bodies of odontoblasts, axons -Cell free zone Fewer cells, nerve & capillary plexus -Cell rich zone Increased density of cells; extensive vascular supply -Pulpal core Similar to cell-rich zone ```

Question 48

Clinical Considerations: Repair

Answer 48

Odontoblasts in the pulp are stimulated to form dentin in response to injury (e.g. attrition, abrasion, caries, or restorative procedures)

Question 49

Clinical Considerations: Tertiary dentin

Answer 49

When exposure of pulp is suspected when drilling a tooth, the dentist may use bioactive materials to stimulate production of reparative dentin.

Question 50

Clinical Consideration: Sclerosed dentinal tubules

Answer 50

A carious attack can sometimes result in the death of an odontoblast underlying the surface lesion. After the odontoblast dies, the dentinal fluid will crystalize and fill in the dentinal tubule with sclerotic dentin, thus preventing further damage to pulp

Question 51

Clinical consideration: dead tracts

Answer 51

Dead tracts are open tubules after the loss of an odontoblastic process. If dead tracts are open to overlying caries, bacteria may enter and migrate to pulp, causing inflammation

Question 52

Clinical consideration: pulpitis

Answer 52

Inflammation of the pulp; may require removal of pulp (“root canal”)

Question 53

Clinical consideration: pulp stone

Answer 53

Pulp stones are mineralized masses in dentin (free or attached). Formed during tooth development, as tooth ages; maybe be due to microtrauma

Question 54

Clinical Considerations: Aging

Answer 54

Dentin: diameter of tubules narrows, presence of sclerosis & dead tracts Pulp: size & number cells decrease, fibrous tissue increases