EX2; Dentin/Pulp Complex 1 Flashcards
This the soft connective tissue in the tooth center with blood vessels and whole cells
pulp
Is the pulp mineralized or non-mineralized
non-mineralized
This is the mineralized connective tissue covering the pulp with no blood vessels or whole cells
dentin
What two things does dentin contain in the tubules
odontoblastic process
nerve endings
What is the main clinical significance of dentin
protective of both enamel and pulp
This feature of the DEJ facilitates adhesion
scalloping
When does dentinogenesi begin
during the bell stage
Just prior to dentinogenesis, what occurse
tissues layers of dental organ present
crown outline present
no odontoblasts or ameloblasts
In which part of the tooth germ does dentinogenesis begin
the most coronal portion
Where does the inductive signal for odontoblast differentiation come from
the enamel organ
What is the main signaling molecule/growth factor controlling odontogenesis
Wnt10a
This is a signaling molecule that follows Wnt10a; is induced by this
dentin/odontoblast specific marker; DSPP
The odontoblast secretes this first then it is mineralized
organic matrix then its mineralized
What is the name of the unmineralized organic matrix of dentin
predentin
What are the requirements for mineralization
Ca2+ and phosphate
Where does the phosphate come from used for mineralization
from plasma and cleavage of organic containing phosphate transported into dentin through and between odontoblasts
What are the two sections of crystal formation
mantle
circumpulpal
What is the principal component of the organic matrix of mantle dentin
collagen type 1
What are the sizes of the collagen fibrils in mantle dentin
relatively large
What is the orientation of the mantle dentin fibrils
at right angles to the basal lamina/future DEJ
Near the end of mantle dentin formation, what occurs
one dentin process becomes dominant
What is different about the circumpulpal dentin compared to mantle dentin
smaller fibrils
parallel to basal lamina
Where does the mineralization come from in circumpulpal dentin
not matrix vesicles, it comes from proteins
What is circumpulpal dentin synthesized from
synthesized and secreted from odontoblastic process (along with ions)
Special properties of the proteins involved in circumpulpal dentin formation
they precipitate Ca2+ ions preset in the interstitial fluid, initiate crystal formation
Which dentin is more organic
mantle dentin
Which dentin is more mineralized
circumpulpal dentin
The DEJ is more vulnerable to what
caries
How specific is phosphophoryn/dentin phosphoprotein
relatively specific to dentin
What is the prominent dentinal protein
> 50% non-collagenous proteins (NCPs)
What constitutes to the negative charge of phosphophoryn/dentin phosphoprotein
highly phosphyorlated
high in serine/aspartic acid
acidic/anionic
What is the percentage of organic, inorganic, and water of dentin by WEIGHT
inorganc = 70% (HA) organic = 20% water = 10%
What is the percentage of organic, inorganic, and water of dentin by VOLUME
inorganic = 45% organic = 33% water = 22%
What is the only physical property that dentin is greater than enamel at
compressive strength
What is orientation of the hydroxyapatite crystals
random orientation
What makes up the extracellular matrix of the organic phase of dentin
collagen
non-collagenous proteins
What are the non-tissue specific proteins that make up the organic phase of dentin
proteoglycans
signaling molecules/growth factors; bone morphogenetic protein
What are the mineralized-tissue specific proteins that make up the organic phase of dentin
osteoclastin
bone sialprotein
What are the dentin dominant proteins that make up the organic phase of dentin
dentin matrix protein 1
dentin glycoprotein
dentin sialoprotein
What type of long chain does dentin phosphoprotein contain
polar amino acid repeats
greater than 200 serine-serine-aspartic acid
phosphorylated serines
What would occur is DSPP is mutated (abnormal)
it cannot be released from the odontoblast; stick in the rER or cell membrane
What are the changes at the genetic level from a D1 mutation in DSPP
changes in the first three amino acids; iso, pro, val
Is the D1 DSPP mutation dominant or recessive inheritance
dominant
What is the result in the coding region of DSPP under a D1 mutation
small base pair deletions that produce frame shifts changing the polar amino acid repeats to uncharged
mutates DSPP also affects the normal protein made by the cell how
by trapping it
What type of mutation is D1 DSPP
dominant negative
What is the result if a cell begins to have more DSPP mutatnts
less DSPP is secreted
What are the contents of the dentinal tubules
fluid; major component = water nerve fibers odontoblastic processes less collagen fibers non-cellular lining sheath although organic composition is unknown
How are the dentinal tubules in relation to the DEJ
at right angles
What is the shape of the dentinal tubules
S-shaped at the crown
straighter in the root
What type of branching pattern does the dentinal tubules have
terminal and lateral branches
Does inner or outer dentin contain more tubules
inner dentin
What is the pattern of depth in the dentin
the number continues to decrease in outer dentin
deep > middle > outer
Does inner or outer dentin contain larger tubules
the diameter of tubules is larger in inner dentin
Where do the tubules occupy less surface area, at the DEJ or the P-D border
DEJ
What increases toward the P-D border
permeability and wetness
This dentin formed until the completion of root development
primary dentin
True or False
primary dentin does not comprise most of the dentin
False; it does
What are the two types of primary dentin
mantle
circumpulpal
Which is more mineralized, mantle or circumpulpal dentin
circumpulpal
This dentin forms after root development and is formed at a slower rate but throughout life
secondary dentin
Where is secondary dentin in relation to primary dentin
central
What are the similarities between primary and secondary dentin
similar in structure
also classified as circumpulpal dentin
This dentin is produced in specific locations in response to noxious stimulus
tertiary dentin
What is the structure of tertiary dentin
structurally irregular
may or may not have tubules
may include cells
Where is both intertubular and intratubular dentin found
in primary and secondary dentin
Where is intertubular and intratubular dentin found in relation to the tubules
inter = between intra = lining
Does intertubular or intratubular have a greater volume
inter
Does intertubular or intratubular have more mineralization
intra
Which; intertubular or intratubular, is a ring wider near the DEJ; accounting for narrowing of tubule
intra
This type of dentin is when the tubules are completely filled with intra/peritubular dentin
translucent or sclerotic dentin
This type of dentin is a normal process of aging
translucent
This type of dentin is accelerated deposition due to caries or attrition
sclerotic
This is when the tubules dry out and become filled with air
dead tracts
This is hypo mineralized dentin just below mantle dentin
interglobular dentin
The initial mineralization of dentin occurs in what
descrete foci
The individual foci can undergo calcification and become what
calcospherites; eventually fuse
If the individual foci do not calcify, what happens
becomes interglobular dentin
This is prominent in the crown
Tomes’ granular layer
Where is there much interglobular dentin present
in DSPP knockout mice
Growth lines in dentin represent what
incremental pattern of deposition
