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Histopathology > Dentin > Flashcards

Dentin Flashcards

1
Q 
All dentin (except mantle dentin) formed up
to the time the tooth achieves functional occlusion.
A

Primary Dentin:

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2
Q

All dentin formed (except tertiary dentin)

formed after tooth achieves functional occlusion.

A

Secondary Dentin:

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3
Q

____ theory of dentinal sensitivity:

• Direct stimulation of nerve endings in dentinal tubules

A

Direct Innervation Theory

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4
Q

Stimuli associated with _____ include:
• Cold and/or hot beverages
• Sweet or sour (acidic) foods or beverages
• Overly aggressive brushing

A

dentinal sensitivity

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5
Q

(Chemical process) Loss of hard dental tissue by chemical processes. Broad concavities, with cupping of occlusal surfaces and dentin exposure. Incisal translucency as well as wear on non-occluding surfaces. Amalgam restorations appear “raised“ and have a non-tarnished appearance. Patients are usually hypersensitive. Very common with GERD patients.

A

Erosion:

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6
Q

The organic matrix of dentin is deposited incrementally

at a rate of ____ to _____ per 24 hours

A

4 micrometers to 8 micrometers

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7
Q

Stimulus for ectomesenchymal cell differentiation
into pre-odontoblasts appears to be derived from
fibronectin located within the basal lamina of the
_______

A

inner enamel epithelium (IEE)

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8
Q

Loss by wear of surface caused by tooth to tooth
contact during mastication or parafunction. Matching wear on occluding surfaces, and shiny facets on amalgam contacts are common. Enamel and dentin wear is at the same rate. Possible fracture of cusps or restorations (usually sensitive to cold)

A

Attrition:

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9
Q

_____ may substitute for hydroxyl ions in
hydroxyapatite, conferring greater stability and
resistance to acidic dissolution.

A

Fluoride

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10
Q

As the process of dental caries (acid dissolution of the enamel) reaches the DEJ, it spreads laterally (due to the branching of dentinal tubules at the DEJ) and then penetrates towards the ____ within the dentinal tubules

A

pulp

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11
Q

Cells in the subodontoblastic layer, once exposed to
_____ released by stimulated pulpal cells
differentiate and form the matrix of reparative dentin

A

growth factors

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12
Q

50-100 µm thick layer of first formed dentin.
Matrix consist of both type I and III collagen. Collagen fibers in matrix are arranged perpendicular to the basal lamina of the IEE.

A

Mantle Dentin

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13
Q

_____ stage of the life cycle of dentin is characterized by the odontoblast being flatten with no rough ER or golgi

A

Resting odontoblast

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14
Q

____ and _____ Both represent

exaggerated lines of von Ebner that occur during periods of altered cell metabolism (birth trauma_

A

Neonatal Line and Contour Lines of Owen:

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15
Q

Dentin deposited
by newly differentiated odontoblasts at the site of pulpal
trauma. A defensive reaction attempting to wall off the pulp from the site of injury (e.g., caries); from subodontoblastic layer

A

Tertiary Dentin (a.k.a. Reparative Dentin):

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16
Q

Which theory of dentinal sensitivity is rooted in Charles’ Law?

A

Brännström’s Hydrodynamic Theory

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17
Q

_____ stage of the life cycle of dentin is characterized by the odontoblast being autophagic; develops vacuoles

A

transitional odontoblast

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18
Q

Phospholipids, Alkaline phosphatase, Phosphoproteins, Pyrohosphatase, Ca ++ and PO4, Annexin, and Calcium hydroxyapatite crystallites are ______ that are secreted by secretory odontoblasts

A

Matrix vesicles

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19
Q

____ theory of dentinal sensitivity:
• Stimulation of dentinal tubules or exposed
odontoblastic cell processes causes movement of
tissue fluids within dentinal tubules that, in turn,
stimulates nerve endings in close association with
dentin at the dentin/pulpal interface.

A

Brännström’s Hydrodynamic Theory

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20
Q

_____ is made 70% mineral (Calcium Hydroxyapatite), 20% organic material (type 1 collagen, Proteoglycans and glycosaminoglycans, and osteonectin and osteopontin), and 10% water

A

Dentin

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21
Q

____ theory of dentinal sensitivity:
• Stimulation of odontoblasts that are coupled to nerves
in the pulp

A

Transduction Theory

22
Q

The _______ of dentin is slightly different

than that of bone; high level of bound water and random orientation of the hydroxyapatite crystals

A

type I collagen

23
Q

The organic matrix of dentin is deposited in increments of 4 µm to 8 µm per 24 hours; occur after 4-20 days of matrix deposition and are thought to represent hesitations in matrix deposition and therefore altered mineralization

A

Incremental Lines of von Ebner:

24
Q

1 in ____ adults suffer from dentinal sensitivity

A

1 in 5

25
Q

_____ Dentin: Dentin in which the tubules are occluded
with mineral. The dentin is non-tubular and is nearly
transparent. Incidence of occurrence increases with
increasing age of patient; may also be tertiary (reparative) dentin; natural process that occurs with age; completely mineralizes

A

Sclerotic dentin

26
Q

What are the 5 non-collagenous proteins of dentin?

A

Proteoglycans, glycosaminoglycans, Gla-proteins, osteonectin, and Osteopontin

27
Q

§ mediates flow of Ca++ into the matrix vesicle. Also serves as a collagen receptor that binds matrix vesicles to collagen.

A

Annexin

28
Q

Incremental
lines in dentin called _____ are areas of hypomineralization are thought to
represent a hesitation in matrix formation and
subsequently altered mineralization that occur after
4-20 days of matrix deposition.

A

(lines of von Ebner)

29
Q

A granular-appearing layer in the
dentin of the root adjacent to the cementum. Possibly
comprised of hypomineralized interglobular dentin.

A

Tome’s Granular Layer:

30
Q

What type of collagen is most prevalent in dentin?

A

Type 1

31
Q

Stimulus for ectomesenchymal cell differentiation
into pre-odontoblasts appears to be derived from
______

A

fibronectin

32
Q

Which teeth are most commonly affected by Dentinal sensitivity?

A

cuspids and bicuspids.

33
Q

If heat is applied to a sensitive tooth, the volume
of the fluid in the tubules increases, causing
stimulation of the nerve endings. Cold would
have a similar effect, as the volume of fluid
would decrease, still causing a movement in the
fluid, and stimulation of the nerve endings

A

Brännström’s Hydrodynamic Theory

34
Q

Many hydroxyapatite crystals exhibit a core of a

relatively more soluble ______

A

carbonate apatite

35
Q

Tall columnar cells (50 µm) with extensive
junctional complex and gap junction formations.
Ø Exhibit significant alkaline phosphatase activity.
Ø Secrete type I and traces of type III and V collagen.
Ø Secrete matrix vesicles

A

Secretory odontoblasts

36
Q

Pre-odontoblastic ______ receptors cause all the cells
to align themselves along the basal lamina, assume
polarity, and differentiate into secretory cells.

A

fibronectin

37
Q

Cells in the _____ cell layer, because they are
removed from the sphere of influence of the IEE, represent ectomesenchymal cells exposed to the entire cascade of developmental controls for odontoblastic differentiation except for the inductive influence of the growth factors associated with the IEE. It is thought that this cell population is responsible for the reparative odontoblasts that differentiate from pulpal cells.

A

subodontoblastic

38
Q

• The volume of a gas (or fluid) is directly proportional

to the amount of heat applied at a constant pressure

A

Charles’ Law:

39
Q

___ dentin is more calcified; at portion right outside tubule that constantly secretes matrix vesicles

A

Peritubular dentin

40
Q

Deficiencies and irregularities in _____, resulting
in areas of hypomineralization, are common and appear as accentuated incremental lines (e.g., neonatal line, contour lines of Owen) or areas of interglobular dentin.

A

dentinogenesis

41
Q

There is more dentin at ___ of tooth (Pulp or DEJ)

A

Pulp

42
Q

What are the 4 growth factors secreted by the IEE that play a roll in odontoblast differentiation?

A

Transforming Growth Factor (TGF)
• Bone Morphogenetic Protein (BMP)
• Insulin-like Growth Factor (IGF)
• Fibroblast Growth Factor (FGF)

43
Q

What are the 5 bacteria that are responsible for dental caries?

A

Streptococcus mutans (enamel/dentin caries)
Ø Streptococcus sorbrinus (enamel/dentin caries)
Ø Streptococcus gordonii (enamel/dentin caries)
Ø Lactobacillus acidophilus (enamel/dentin caries)
Ø Actinomyces viscosus (root caries)

44
Q

The last mitotic division results in a mature odontoblast

and a daughter cell that is forced into the ______ cell layer.

A

subodontoblastic cell layer

45
Q

What are the 4 life cycle stages of dentin??

A

Pre-odontoblast, secretory odontoblast, transitional odontoblast, and Resting odontoblast

46
Q

There is less dentin at ____ of tooth (Pulp or DEJ)

A

DEJ

47
Q

As the process of dental caries (acid dissolution of the enamel) reaches the DEJ, it spreads ____

A

laterally

48
Q

Ø Because of decreasing volume of the pulp
chamber, the number of dentinal tubules per
unit area at the pulpal surface is 40,000/mm2
and about ____ that number of the DEJ.

A

½

49
Q

Dentinal tubules that are void of the odontoblastic
process. They are generally filled with air or organic debris and look black in transmitted light microscopy; Tubule is full of air and debris

A

Dead Tracts:

50
Q

____ dentin: A zone of globular, rather than linear,
formed dentin in the crowns of teeth. Characterized by
interglobular spaces that are unmineralized or hypomineralized
dentin between normal calcified dentinal layers.

A

Interglobular Dentin:

51
Q

T/F: Complete differentiation of odontoblasts requires a set number of
cell divisions which allows cells to express
appropriate receptors able to bind growth factors
localized to the IEE basal lamina.

A

True

52
Q

Hereditary defect that results in
bluish-gray teeth with an opalescent sheen. The enamel is normal but chips off due to lack of support by the abnormal dentin. The pulp chamber and canals are generally obliterated by defective dentin formation; no enamel tufts, pulp chambers

A

Dentinogenesis Imperfecta:

Histopathology (10 decks)

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