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Histo > dentin > Flashcards

dentin Flashcards

1
Q

dentin is ____% mineral by volume and ____% organic matrix by volume

A

50; 30

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2
Q

of the organic matrix of dentin, about 90% is _____ by weight

A

collagen-I

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3
Q

90% of the non-collagenous protein of dentin is derived from _____

A

DSPP (dentin sialophosphoprotein)

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4
Q

other components of dentin:

A 
dentin matrix protein (DMP1)
osteonectin (SPARC)
bone sialoprotein (BSP)
osteopontin (OPN)
proteoglycans
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5
Q

odontoblasts differentiate from _____

A

dental papilla cells

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6
Q

a long cytoplasmic extension encased in dentin

A

odontoblastic process

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7
Q

rate of deposition of dentin

A

about 4 micrometers/day

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8
Q

incremental (daily) lines in dentin are called:

A

incremental lines of Owen (or von Ebner)

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9
Q

dentin formation occurs throughout life, reducing the sizes of the ____ and ____

A

pulp chambers; root canals

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10
Q

microscopic zones in the pulp

A

odontoblastic layer (beneath the dentin)
cell-free zone (nerve and capillary plexus)
cell-rich zone (extensive vascular system)
pulpal core

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11
Q

lines of von Ebner are oriented in the ____ axis at approx ____ angles to the dentinal tubules which run in the ____ axis

A

horizontal; right; vertical

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12
Q

dentin tubules contain ____ which mediate dentin sensitivity

A

odontoblastic processes

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13
Q

more terminal branching of dentinal tubules occurs in ____ compared to ____

A

root dentin; coronal dentin

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14
Q

_____ have an S-shaped curvature

A

coronal tubules

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15
Q

dentin tubules are ____ in diameter

A

1 to 3 micrometers

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16
Q

more dentin tubules are in the ____ relative to the ____

A

crown; root

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17
Q

more dentin tubules are near the ____ than the ____

A

pulp; surface

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18
Q

the fibrillar organic matrix before its calcification

A

predentin

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19
Q

odontoblasts exhibit a ____ shape, with their nucleus at the ____ region

A

tall columnar; basal

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20
Q

predentin is always interposed between the ____ and the _____

A

odontoblasts; mineralizing front

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21
Q

dentin made during tooth formation

A

primary dentin

22
Q

primary dentin is also called _____; makes up most of the tooth; outer layer is called _____

A

circumpulpal dentin; mantle dentin

23
Q

forms by the slower, continuing deposition of dentin by odontoblasts following completion of the root

A

secondary dentin

24
Q

junction betw primary and secondary dentin is characterized by a change in the ______

A

direction of dentinal tubules

25
Q

deposition of secondary dentin is fastest on the ____ and _____ of the _____, leading to pulp recession

A

roof; floor; pulp chamber

26
Q

local reaction to attrition, caries, or dental restoration

A

tertiary dentin

27
Q

subtypes of tertiary dentin

A

reactionary dentin and reparative dentin

28
Q

reactionary dentin (least severe) is formed by ____

A

preexisting odontoblasts

29
Q

reparative dentin is formed by newly differentiated _____; these cells can be included in the hard tissue, which is called _____

A

odontoblast-like cells; osteodentin

30
Q

dentin that has become translucent due to calcification of the dentinal tubules as a result of normal aging or injury; also called _____

A

sclerotic dentin; transparent dentin

31
Q

patterns of dentin mineralization

A

linear or globular

32
Q

____ occurs at high rates of dentin deposition; best seen in the mantle dentin

A

globular mineralization

33
Q

globular mineralization results in an irregular mineralization front at the _____ interface

A

predentin-dentin

34
Q

localized areas of hypomineralized dentin, often just beneath the mantle dentin, where globular zones of mineral fail to fuse into a homogeneous mass

A

interglobular dentin

35
Q

interglobular dentin can be caused by ____ and _____

A

decreased vitamin D ; high fluoride

36
Q

dentinal tubules pass through interglobular dentin, but ____ dentin is not present in these areas

A

peritubular

37
Q

peritubular dentin (PTD) is lower in ____, higher in ____, and more highly ____ than intertubular dentin (ITD)

A

collagen; DSPP; mineralized

38
Q

where is ITD harder?

A

ITD is harder at the DEJ than at the pulp (about 4x)

39
Q

where is PTD harder?

A

PTD has equal hardness at DEJ and pulp

40
Q

is PTD or ITD harder?

A

PTD is harder than ITD at both the pulp (about 20x) and the DEJ (about 5x)

41
Q

odontoblasts line the ___ surface of dentin

A

pulpal

42
Q

the dental phenotype in persons afflicted with osteogenesis imperfecta

A

dentinogenesis imperfecta type I (DGI-I)

43
Q

mutations in the ____ and _____ genes cause osteogenesis imperfecta

A

COL1A1; COL1A2

44
Q

COL1A1 and COL1A2 mutations can:

A
  1. reduce the amount of collagen (less severe phenotype)

2. produce defective collagen molecules (more severe phenotype)

45
Q

COL1A1 gene mutation causes _____ osteogenesis imperfecta

A

autosomal-dominant

46
Q

classic radiographic features of DGI-I (dental phenotype of someone with osteogenesis imperfecta)

A

bulbous crowns, pulpal obliteration, short roots, and tooth impactions

47
Q

mutations in DSPP cause:

A

DD-II (dentin dysplasia type II)
DGI-II
DGI-III

48
Q

2 structural domains of DSPP

A 
dentin sialoprotein (DSP) - proteoglycan
dentin phosphoprotein (DPP)- acidic protein
49
Q

expression of DSPP in teeth

A

expressed in preameloblasts, preodontoblasts, and odontoblasts

50
Q

Dspp (-/-) mice show features similar to human ____

A

DGI-III

51
Q

dspp (-/-) mice show enlarged ____, reduced thickness of ____ and increased thickness of ____ (similar to human DGI-III)

A

pulp cavities; mineralized dentin; predentin

52
Q

____ is distinct from OI as only the teeth are affected; caused by mutations in DSPP

A

DGI-II

Histo (14 decks)

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