Histo T3 - Tooth Develp Ii

Front 1

Odontoblasts derived from?

Back 1

Ectomesenchyme

Front 2

Dentin Adjacent to Enamel

Back 2

Coronal Dentin

Front 3

Dentin Adjacent to Cementum

Back 3

Root Dentin

Front 4

Bact. can enter pulp through denin side canals known as

Back 4

lateral canals

Front 5

Dentin Organic Composition:
1.) collagen type?

Back 5

1.)1-90% also 3 and 4

Front 6

Purpose of organic components of Dentin?

Back 6

scaffolding function for mineral

Front 7

Purpose of nonorganic components of Dentin?

Back 7

regulates mineral deposition, acts to promote,inhibit, and/or stabilize mineral deposition.

Front 8

All of these are components of?
*Dentin phosphoprotein (DPP); major matrix protein



*Dentin sialoprotein (DSP) major matrix protein

Dentin matrix protein-1 (DMP-1)

Bone sialoprotein (BSP) matrix protein

Osteopontin (OPN) – matrix protein

Osteocalcin (OC) – matrix protein

Osteonectin – matrix protein

Proteoglycans

Back 8

Nonorganic dentin components

Front 9

T/F - Dentin is harder than bone but softer than enamel?

Back 9

True

Front 10

T/F - dentin cushions and prevents enamel from fracturing?

Back 10

True

Front 11

Circumpulpal Dentin, outlines pulp chamber

Back 11

Primary Dentin

Front 12

first formed dentin; outer-most layer (150 microns

thick) differs from rest of primary dentin (mineralized from

matrix vesicles, contains loosely packed collagen fibrils,

less mineralized)

Back 12

Mantel Dentin

Front 13

- follows root formation (formed after root formation complete,

normally after tooth has erupted)

- slower than primary dentin formation and is a continuation

of primary dentin disposition

- same tubular structure, same organic percentage

- results in recession of pulp cavity

- may sclerose (tubules fill with calcium) more than primary

dentin (likely serving a protective function)

- often distinguishable from primary dentin by thin line,

differential staining, less regularly formed tubules

- rate of deposition depends on diet and occlusal forces

(abrasive foods and greater chewing forces provide

stronger stimuli for secondary dentin deposition)

Back 13

Secondary Dentin

Front 14

Crown Dentin formation begins in?

Back 14

Late Bell Stage

Front 15

- starts at the cusp of the tooth

- progresses downward to cervical loop

- enamel formation lags closely behind dentin formation

- crown of the tooth is that part of the tooth covered by enamel

- crown dentin is that dentin immediately beneath the enamel

Back 15

Crown Dentin Formation

Front 16

T/F- Root Dentin begins later than crown dentin formation and is faster?

Back 16

False - Slower

Front 17

come together to form Hertwigʼs Epithelial Root Sheath (HERS). This brings about differentiation of root odontoblasts to form root dentin.

Back 17

Inner and Outer Enamel Epith.

Front 18

undifferentiated EctoMC cells in dental Papilla -> ??????? -> Odontoblasts -> Dentin

Back 18

Preodontoblasts

Front 19

T/F - when preodontoblasts become odontoblasts the cell enlarges and eliminates the acellular zone.

Back 19

True

Front 20

unexpossed Cell (F) remain as a? (Dentinogenesis)

Back 20

subodontoblast cell

Front 21

During Dentinogenesis, IEE elongate, polarize, and Secrete?

Back 21

Growth Factors- TGF, BMP2, IGF.

Front 22

TGF
BMP2
IGF

Back 22

Transforming growth Factor
Bone morphogenic GF
insulin-like GF

Front 23

Growth Factors Bind to? in the?

Back 23

Heparin Sulfate in basement membrain

Front 24

Preodontoblasts develop? which allows them to change into odontoblasts

Back 24

GF Receptors - subodontoblasts remain if dont get GFR's.

Front 25

Ground Substances During Dentinogenesis:

Back 25

Large Fibers, Smaller Fibers

Front 26

von korffs fibers - type 3 Col.

Back 26

Large Fibers - first appear in ground substance and extend to IEE

Front 27

Smaller fibers consist of collagen type?

Back 27

1 - run parallel to future DEJ

Front 28

Odontoblasts bud off?

Back 28

Matrix Vessels

Front 29

Matrix Vessels bust and resulting crystals fuse to produce?

Back 29

A Mineralized Front

Front 30

Some odontoblast processes pass through basement membrane into the enamel matrix,
where they become trapped in the future enamel

Back 30

Enamel Spindles

Front 31

von korffs fibers , small diameter collagen fibrils, formation of odontoB process, Matrix vesicles are all parts of?

Back 31

Predentin

Front 32

Matrix Ves. rupture and fuse to produce a mineralization front.
NCP's from odontob's regulate mineral deposition

Back 32

Dentin

Front 33

T/F - Matrix formation always preceds mineralization?
T/F - Mineral Formation always lags behind the formation of Org. Matrix?
T/F - Predentin always appears before dentin formation?

Back 33

True
True
True

Front 34

First Formed Dentin Is Called?

Back 34

Mantel Dentin

Front 35

4% less mineralized than primary dentin
150-200 microns thick
Rests against DEJ

Back 35

Mantel Dentin

Front 36

Mineralization for mantel dentin derived from matrix Ves.
How Does mineralization continue since odontob's no longer produce matrix vesicles?

Back 36

Ca brought in by capillaries- Capillaries become fenestrated

Front 37

Presence of ? & ? activity at
end of odontoblast is consistent with a role for odontoblasts

Back 37

alkaline phospotase and calcium adenosinetriphosphatase

Front 38

Odontob's contain ? that when blocked prevent dentin formation.

Back 38

L-type calcium channels

Front 39

Formation Requirements for?
•  Good blood supply

• Enzyme alkaline phosphotase is always associated mineralized tissue

• Organic matrix capable of accepting crystals

• Hydroxyapatite crystals that grow and form clusters

• Ground Substance

- non-collagenous macromolecules (glycosaminoglycans, glycoproteins)

- water

- functions to support cell

- transport of nutrients from vasculature and return of metabolites

Back 39

Hard Tissue

Front 40

Two Types of Mineralization:
1.) mantel dentin laid down in globs and globs come together
2.) globs that have joined fo form a mineralization front that move together or conversely, the front can move in a globular pattern.

Back 40

1.) Globular
2.) Linear

Front 41

Odontob's processes lie w/in

Back 41

Caniliculi dentin tubules - tubules extend through entire extent of dentin, tapered toward enamel, extensive branching

Front 42

Odontob's attach to other OB's by a terminal web composed of?

Back 42

Actin Filaments

Front 43

Each OdontoB has a ? that extends through the dentin

Back 43

process - extend to the DEJ and may penetrate DEJ where it forms enamel spindle.

Front 44

The course of Dentin Tubules is _____? due to the crowding of the odontob's as they get squeezed into a smaller space near the pulp cavity.

Back 44

S-shaped - tubules run straight in the root where crowding is not an issue.

Front 45

______? dentin forms a highly mineralized collar (40% more mineralized, than intertubular dentin) around the tubule

Back 45

Peritubular Dentin - (intratubular) Mechanisms unknown; contains little collagen and some regions are enriched in proteins such as dentin sialoprotein (DSP)

Front 46

________? Dentin, main product of odontoblasts, network of type I collagen fibrils, randomly arranged parallel to dentin tubules

Back 46

Intertubular Dentin

Front 47

DEJ: 2 hard tissues come together forming a _______? profile.

Back 47

Scalloped

Front 48

Odontoblast processes trapped in enamel?

Back 48

Enamel Spindles - when identifying you must be able to see a continuation of the process from dentin into the enamel.

Front 49

Tubules often become blocked w/ calcified material, increases w/ age, consistent w/continued mineralization py peritubular dentin, and likely protects the pulp?

Back 49

Sclerotic Dentin - takes on glassy appearance,
translucent to light

Front 50

areas in dentin that fail to mineralize or hypomineralized dentin where globular zones fail to fuse

-Causes include a deficiency of vitamin D, exposure to high fluoride during dentinogenesis

- Tubules remain present through interglobular dentin reflecting a defect in mineralization and not in tubular formation.

Back 50

Interglobular Dentin

Front 51

only seen in ground sections, only seen in root dentin adjacent to cementum
- possible interpretations include:

- hypomineralized regions of interglobular dentin

- looped terminal ends of dentin tubules found only in root

- arrangement of collagen and non-collagenous matrix proteins between dentin and cementum

Back 51

Tomes Granular Layer

Front 52

air filled spaces from loss of odontoblast process or death of the odontoblast.

-tubules filled with air

Back 52

Dead Tracts
- seen in ground substances
- age related
-blackened tubules alone or in combination w/other tubules.

Front 53

Dentin is laid down incrementally to form?

Back 53

Incremental Growth Lines
- 4 microns of org matrix deposited/day
-Collagen fiber orientation shifts slightly each day
-5 day cycles produces shifts in orientation called incremental lines of von Ebner
-Growth lines run at right angles to dentin tubules

Front 54

5 day cycles produces shifts in orientation called? (Part of Incremaental Growth Lines)

Back 54

Incremental Growth lines of von Ebner (20 microns)

Front 55

Accentuated variations in metabolism cause deficiencies in mineralization

Back 55

Contour Line of Owen

Front 56

Dental Papilla becomes pulp when?

Back 56

Dentin is first laid down.

Front 57

Pulp located in the crown?
w/in the root?

Back 57

Coronal Pulp
Radicular Pulp

Front 58

Four Zones of Pulp?

Back 58

Odontoblast Zone
Cell Free Zone
Cell Rich Zone
Pulp Core (BV's and Nerves)

Front 59

OdontoB's, FibroB's, ECM cells (Give rise to OB's and FB's), Nerves BV's Macrophages,lymphocytes, Dendritic cells, all parts of?

Back 59

Pulp

Front 60

Matrix and ground substance of pulp:
Collagen type? and ?

Back 60

1&3