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histopath > exam 2: dentin > Flashcards

exam 2: dentin Flashcards

1
Q

makes up dentin

A

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

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2
Q

type I collagen of dentin is slightly diff than bone
how:

A

type 1
higher ratio of proline and hydroxyproline
higher prevalence of molecular cross-linking
higher level of bound water
random orientation of hydroxyapatite crystals

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3
Q

dentin matrix non-collagenous proteins include:

A
  1. proteoglycans
  2. glycosaminoglycans
  3. carboxyglutamate- containing protein (gla-proteins)
  4. osteonectin
  5. osteopontin
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4
Q

biglycan
decorin

A

proteoglycans

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5
Q

chondroitin-4-sulfate
chondroitin-6-sulfate

A

glycosaminoglycans

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6
Q

contains receptor binding sequence arginine-glycine-asparagine aka RGD binding complex

A

osteopontin

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7
Q

order of dentin odontoblast life cycle

A
  1. pre-odontoblast
  2. secretory odontoblast
  3. transitional odontoblast
  4. resting odontoblast
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8
Q

stimulus for ectomesenchymal cell differentiation into Pre-Odontoblasts is derived from ________ located within the basal lamina of the IEE (inner enamel epithelium) and several growth factors derived from the IEE

A

fibronectin

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9
Q

pre-odontoblastic fibronectin receptors all the cells to align themselves along the _______, assume polarity, and differentiate into secretory cells

A

basal lamina

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10
Q

growth factors secreted by the IEE that play a roll in odontoblast differentiation include:
1
2
3
4

A
  1. TGF- transforming growth factor
  2. BMP- bone morphogenetic protein
  3. IGF- insulin-like growth factor
  4. FGF- fibroblast growth factor
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11
Q

compelte differentiation of odontoblasts requires a set number of ________which allows cells to express the right receptors to be able to bind growth factors to the IEE basal lamina

A

cell divisons

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12
Q

the last mitotic division results in a mature odontoblast and daughter cell that is forced into the

A

subodontoblastic cell layer

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13
Q

cells in subodontoblastic layer represent ectomesenchymal cells
this cell population is responsible for the ____odontoblasts that differentiate from PULPAL cells

A

reparative odontoblasts

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14
Q

in the secretory odontoblast stage, what 2 things form

A

-tall, columnar cells with extensive complex
-gap junctions

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15
Q

exhibits significant alkaline phosphatase activity

A

secretory odontoblast stage

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16
Q

secretory stage secretes

A

type 1 and traces of III and V collagen

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17
Q

what are the secrete matrix vesicles for secretory stage:
1
2
3
4
5
6
7

A
  1. phospholipids
  2. alkaline phosphatase
  3. phosphoproteins
  4. pyrohosphatase
  5. ca2+ and PO4-
  6. annexin
  7. calcium hydroxyapatite
  8. crystallites
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18
Q

mediates flow of Ca2+ into the matrix vesicle
-also serves as a collagen receptor that binds matrix vesicles to collagen

A

annexin

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19
Q

50-100um thick layer of first formed dentin

A

mantle dentin

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20
Q

matrix consists of both type I and II collagen

A

mantle dentin

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21
Q

how are collagen fibers in matrix of mantle dentin arranged

A

perpendicular to basal lamina of IEE

22
Q

the organic matrix of dentin is deposited at rate of 4-8um per 24 hours.

-________________are thought to represent a hesitation in matrix formation and alters mineralization that occur after 4-20 days of matrix deposition

A

incremental lines in dentin (lines of von ebner)

23
Q

deficiencies and irregularities in dentinogenesis, resulting in areas of hypermineralization, are common and appear as accentuated _____________________ or areas of interglobular dentin

A

incremental lines (neonatal line, contour lines of Owen)

24
Q

dentinal tubules are tapered at the:
2.5 um diameter at the
1.2um diameter at the
0.9um near the

A

2.5 um diameter at the pupal surface
1.2um diameter at the midlength
0.9um near the DEJ

25
Q

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

26
Q

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

A

tome’s granular layer

27
Q

all dentin (except mantle dentin) formed up to the time the tooth achieves functional occlusion

A

primary dentin

28
Q

all dentin formed (except tertiary dentin) formed after tooth achieves functional occlusion

A

secondary dentin

29
Q

dentinal tubules that are void of the ondotonoblastic process
-they are generally filled with air or organic debris and look black in transmitted light microscopy

A

dead tracts of dentin

30
Q

dentin in which the tubules are occluded with mineral

-dentin in nontubular and is nearly TRANSPARENT

-incidence of occurrence increases with increasing age
-may also be tertiary (reparative) dentin

A

sclerotic dentin

31
Q

the organic matrix of dentin is deposited in increments of 4um to 8um per 24 hours.

these 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
(sideways lines)

32
Q

both represent exaggerated lines of von ebner that occur during periods of altered cell metabolism

A

neonatal line and contour lines of owen

33
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 (caries)

A

tertiary dentin (aka reparative dentin)

34
Q

Cells in the ________ layer, once exposed to growth factors released by stimulated pulp cells differentiate and form the matrix of reparative dentin (teritary):
1
2
3
4

A

subodontoblastic layer
1. BMP- bone morphogenetic protein
2. IGF- insulin-like growth factor
3. FGF- fibroblast growth factor
4. DMP- dentin matrix protein

35
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

A

dentinogenesis imperfecta

36
Q

loss of 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

A

attrition

37
Q

loss of hard dental tissue by chemical processes
-broad concavities with cupping of occlusal surface and dentin exposure
-incisal translucency as well as wear on non-occluding surfaces
-amalgam restorations appear __________ and have non-tarnished appearance
-patients are usually hypersensitive
-very common with _____ patients

A

erosion

-raised
-GERD

38
Q

dental caries.

many hydroxyapatite crystals exhibit a core of relatively more ___________ apatite.
The carbonate substitution in the lattice structure of enamel occurs primarily at: ___________

The core of this is eroded more favorably by acids due to its greater susceptibility to dissolution

A

soluble carbonate apatite

at phosphate sites

39
Q

____ may substitute for hydroxyl ions in hydroxyapatite conferring greater stability and resistance to acidic dissolution

A

fluoride

40
Q

bacteria responsible for dental caries include:
(1-4 enamel/dentin caries)
(5 root caries)
1
2
3
4
5

A
  1. streptococcus mutans
  2. streptocuccus sorbrinus
  3. streptocuccus gordonii
  4. lactobacillus acidophilius
  5. actinmyces (root)
41
Q

as the process of dental caries reaches the DEJ it spreads laterally due to _________________ and then penetrates towards the pulp within these.

a substantial cavitation is produced beneath the adjacent enamel surface.
initially, the caries lesion exhibits a small opening or orifice in the enamel and pyramidal shaped dentin lesion with the apex of the pyramid pointing towards the __________

A

the branching of dentinal tubules at the DEJ

(within the dentinal tubules)

pointing towards the tooth pulp

42
Q

1 in 5 adults suffer from dentinal _______

A

dentinal sensitivity

43
Q

the teeth most commonly affected in dentinal sensitivity are

A

cuspids and bicuspids

44
Q

stimuli associated with dentinal sensitivity include

A
  1. cold and hot drinks
  2. sweet or sour
  3. over brushing
  4. acidogenic plaque bacteria
  5. cosmetic bleaching
  6. clenching or bruxism
45
Q

3 theories of dentinal sensitivity

A
  1. direct innervation theory
  2. transduction theory
  3. brannstrom’s hydrodynamic theory
46
Q

direct stimulation of nerve endings in dentinal tubules

A

direct innervation theory

47
Q

stimulation of odontoblasts that are coupled to nerves in the pulp

A

transduction theory

48
Q

stimulation of dentinal tubules or exposed odontoblastic cell processes causes movement of tissue fluids within dentinal tubules that stimulate nerve endings in close assoc. with dentin at dentin/pulp interface

A

brannstrom’s hydrodynamic theory

49
Q

brannstrom’s hydrodynamic theory

if heat is applied to sens tooth, the volume of the fluid in the tubules ________, causing stimulation of the nerve endings.
cold would have a similar effect as the volume of fluid would _______ still causing a movement in the fluid and stimulation of the nerve endings

A

heat-increases
cold-decreases

50
Q

this theory has roots in charles law-> volume of a gas/fluid is directly proportional to the amount of heat applied at constant pressure

A

brannstrom’s hydrodynamic theory

51
Q
A

histopath (13 decks)

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