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Oral Histology > Ex 1- Dentin + Dentinogenesis > Flashcards

Ex 1- Dentin + Dentinogenesis Flashcards

(94 cards)

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1
Q

______ is a soft connective tissue in the tooth center. Contains blood vessels and whole cells. Non-mineralized

A

pulp

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2
Q

______ is the mineralized connective tissue covering pulp. Contains NO blood vessels or whole cells bud does contain odontoblast processes and nerve endings

A

Dentin

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3
Q

What are the clinical significance of dentin?

A
  • Quantitative

- Protective- both pulp + enamel

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4
Q

Compared to enamel dentin has a _________ compression strength

A

higher

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5
Q

_______ cushions the overlying more brittle ______

A

dentin

enamel

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6
Q

_______ is scalloped in the crown and facilitates adhesion

A

DEJ

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7
Q

Dentinogenesis beings during the _____ Stage

A

Bell

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8
Q

What occurs just prior to dentinogenesis?

A
  • Tissue layers of dental organ present
  • crown outline present
  • no odontoblasts or ameloblasts
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9
Q

During the ______ Bell Stage inner enamel epithelial cells contain ameloblasts, undifferentiated mesenchymal cells (dental papilla) contains odontoblasts, dentin an enamel secreted

A

Late

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10
Q

Dentinogensis from _____ _____ to cervix and from periphery to ______ ______

A

cusp tip

pulp center

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11
Q

What part of tooth germ does dentinogenesis begin?

A

most coronal portion

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12
Q

Inductive signals for odontoblast differention is secreted from the _____ ______ most likely from cells of the ______ ______

A

enamel organ

enamel knot

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13
Q

______ is one molecule implicated in inducing odontoblast differentiation and expression immediately _______ the wave of odontoblast differentiation

A

Wnt 10a

precedes

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14
Q

Wnt 10a is 1st expressed in the enamel knot then in preodonotblasts in the cusp tip and then in more ______ parts of the tooth

A

cervical

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15
Q

Wnt 10a induces _______ a molecule expressed by mature odontoblasts

A

DSPP

dentin sialophosphoprotein

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16
Q

Odontoblasts secrete _____ _____ then the matrix is mineralized in progressive stages

A

organic matrix

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17
Q

_____ is unmineralized organic matrix of dentin

A

predentin

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18
Q

What are the 2 requirements for mineralization?

A
  • Ca2+ & phosphate

- initiation of crystal formation

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19
Q

_____ required for mineralization comes from (free ions) in plasma

A

Ca2+

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20
Q

_______ required for mineralization comes from plasma + cleavage of organic molecules containing phosphate in odontoblast by alkaline phosphataste

A

Phosphate

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21
Q

Ca2+ and phosphate are transported into predentin through and btw __________

A

odontoblasts

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22
Q

By itself presence of requisite ions is not sufficient. It requires special mechanisms for the initiation of _______ formation

A

crystal

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23
Q

What are the 2 mechanisms associated with the 2 stages of dentin formation?

A

Mantle (initial)

Circumpulpal (subsequent)

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24
Q

_____ _____ is the initial layer of dentin (ultimately the DEJ)

A

Mantle Dentin

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25
The principal component of the organic matrix of mantle dentin is ______ _______ ____which is secreted by _____
collagen type I | odontoblasts
26
The collagen of the mantle has relatively ______ fibrils oriented at ____ angles to basal lamina/future DEJ
large | right
27
Mineralization by ______ _____ membrane bound veiscles, synthesized by OBD, concentrate Ca 2+, PO-containing & other organic molecules
matrix vesicles
28
During mantle dentin formation; _____ secrete matrix then matrix mineralizes, ________ grow, process elongates (barrier btw dentin + pulp), ________ migrate toward pulp center ________ forms around process
odontoblasts odonotblasts odontoblasts dentin
29
Near the end of mantle dentin formation, one process becomes more ________
dominant
30
_________ dentin is interior to mantle dentin, thicker, overall process is very similar; organic matrix secreted, then mineralized
Circumpulpal
31
Circumpulpal dentin contains collagen type I secreted by ________ cell bodies, ______ fibrils that are ______ to the basal lamina
odontoblast smaller parallel
32
Circumpulpal dentin is mineralized by _______ not matrix vesicles
proteins
33
Circumpalpal dentin proteins are synthesized and secreted from the ______ process and bind to collagene
odontoblast
34
Special properties of proteins precipitate Ca 2+ ions preen in interstitial fluid and initiate _______ formation which is known as _______ nucleation
crystal | heterogeneous
35
Mantle dentin is ______ organic and ______ mineralized than circumpulpal dentin and the DEJ is vulnerable to caries in _____
more less both
36
Phosphophoryn/Dentin phosphoprotein is relatively specific to ________
dentin
37
____ is the prominent dentinal protein (>50% NCPs- non-collagenous proteins)
Phosphophoryn/Dentin phosphoprotein
38
Phosphoryn/dentin phosphoprotein is highly phosphorylated, high in serine/aspartic acid and is _______/______ which helps pull calcium out of solution to precipitates Ca 2+ ions and initiate mineralization
acidic/anionic
39
Dentin by WEIGHT is ___% Inorganic ____% organic and _____% H2O
70 20 10
40
Dentin by VOLUME is ___% inorganic ____% organic and _____ water
45 33 22
41
Dentin is _____ than bone & cementum but ______ than enamel
harder | softer
42
The hydroxyapatite (inorganic) content of dental hard tissues is _____% in enamel, _____% in dentin, _____ - ____% in bone, ____-___ in cementum
96 70 50-60 45-50
43
In the mineral phase of dentin hydroxyapatite crystals is 4-5% ______ which is susceptible to demineralization, there are 1000's of unit cells/crystal, smaller than enamel crystals and in a ______ orientation
``` carbonate random (less organized) ```
44
The extracellular matrix of the organic phase of dentin is _______ and ____-______ proteins
collagen | non-collageneous proteins
45
The extracellular matrix is made up of type ___ collagen and is ____% of the organic matrix
I | 90
46
What are the non-tissue specific proteins that make up the organic phase of dentin?
Proteoglycans | Signaling molecules/growth factors
47
The _______ ________ can stimulate cells to make new dentin when demineralization occurs
signaling molecules (growth factors)
48
What are the mineralized tissue specific proteins that make up the organic phase of dentin
osteocalcin | bone sialoprotein
49
What are the dentin-dominant proteins that make up the organic phase of dentin?
dentin matrix protein I dentin glycoprotein dentin sialoprotein
50
______ ________ (_____) is >50% NCPs, Anionic, includes long chain of ______ amino acid repeats, >200 serine-serine-aspartic acid, serines are phosphorylated
- Dentin phsophoprotein (DPP, phosphophoryn) | - polar
51
DSPP is the gene for ____, DSP, and DGP
DPP
52
_____ ________ is a human hereditary disorder where dentin forms improperly and is associated with mutations in DSPP
Dentinogenesis Imperfecta (DI)
53
What are the 2 mutations that cause dentinogenesis imperfecta in humans?
- changes in 1st 3 amino acids (iso,pro,val) critical for trafficking (moving) DSPP through rER - small base pair deletions that produce frameshifts coding the part of DPP that contain polar AA repeats: polar change to uncharged
54
When DSPP is mutated it becomes abnormal and cannot be released from _______ it becomes stuck in the _____ or _____ ______
odontoblasts rER cell membrane
55
Mutated DSPP traps the _____ protein made by the unaffected chromosome thus DI mutation is a _______ _______ mutation
normal | dominant negative
56
More DSPP mutants results in ____ DSPP secreted
less
57
What re the contents of dentinal tubules?
- fluid (major component = H2O) - nerve fibers - odontoblastic process - collagen fibers - non-cellular lining sheath
58
Dentinal tubules are at ______ angles to the DEJ, _____ shaped in crown, ______ in root and have _____ and _____ branches
right S straight terminal and lateral
59
Branches are more prominent at the ____ and ____ because mantle dentin has multiple processes
DEJ | CEJ
60
The # and diameter of tubules in inner dentin is _____ than outer dentin
greater
61
The # and dimensions of tubules vary as a function of distance from ____
pulp
62
Tubules occupy much _____ surface area at DEJ than at P-D border
less
63
Permeability and wetness ______ toward P-D border
increase
64
_______ create a natural pathway for microorganisms
Tubules
65
______ dentin is unmineralized dentin
Predentin (PD)
66
Dentin is classified according to _____ and under what _____ dentin was formed
when | conditions
67
_____ dentin is formed until completion of root development and comprises _____ of dentin
Primary | most
68
The 2 types of dentin are ______ dentin that is 20u-150u layer at the DEJ and is _____ mineralized. ______ dentin that is central to the mantle and ______ mineralized
Mantle less Circumpulpal more
69
______ dentin is formed after root development. Formed at a slower rate but _____ life
Secondary | Throughout life
70
Secondary dentin is _____ to primary dentin with a similar structure
central
71
Secondary dentin is present along the entire circumference of the _____ chamber but is heaviest on the ____ and ____
pulp roof floor
72
Secondary dentin is also classified as _______ dentin
circumpulpal
73
Secondary dentin is formed throughout life so the pulp chamber gets ______ with aging
smaller
74
_______ dentin is produced in specific locations in response to ________ stimulus
Tertiary (reparative + reactive) | noxious
75
Tertiary dentin is structurally _______ that may or may not contain _______ and may include cells
irregular | tubules
76
Intertubular and intratubular dentin is found in ________ and ______ dentin
primary and secondary
77
Intertubular dentin is found _______ tubules and intratubular dentin is found ______ tubules
between | lining
78
_______ dentin has a greater volume (intertubular, intratubular)
intertubular
79
________ dentin has greater mineralization (intertubular, intratubular)
Intratubular
80
_______ dentin is a "ring" wider near DEJ and accounts fro the narrowing of a tubule
Intratubular
81
____ dentin is formed away from the pulp
Intratubular
82
______ or ___ dentin is formed when tubules are completely filled with intra/peritubular dentin
Translucent or sclerotic
83
________ dentin is a normal process of aging
Translucent
84
______ dentin is accelerated deposition due to caries or attrition
Sclerotic
85
Translucent/Sclerotic dentin _____ with age and makes the tooth harder and more resistant to caries
increases
86
______ _____ are formed when tubules dry out and become filled w/ air
Dead tracts
87
______ dentin is hypomineralized dentin just below mantle dentin
Interglobular
88
The initial mineralization of dentin occurs in _______ foci, individual foci calcify forming ____ that fuse
discrete | calcospherites
89
______ dentin forms when individual calcospherites do not fuse
interglobular
90
______ ______ layer is prominent in the crown
Tome's granular
91
Intergobular dentin is priminent in ______
DSPP knockout mice
92
______ ____ in dentin reflect the incremental pattern of deposition.
Growth lines
93
Pronounced growth lines can occur that reflect ______ ie neonatal line
perturbations
94
Growth lines can be exaggerated due to _______ treatment
tetracycline

Oral Histology (16 decks)

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