Dentin Flashcards
dentin is what kind of tissue
living
where is dentin located
crown and root
what percentage of dentin is mineralized substances
65-70%
what percentage of dentin is organic material
20-25%
what percentage of dentin is water
10%
what is the mineralized substance of dentin
calcium hydroxyapatite
where do odontoblasts reside
in pulp
the dynamic process of formation of dentin involves a chain of different mechanisms: what are they? (3)
cell differentiation and interactions
the synthesis of an organic matrix
mineralization of the matrix
the formation of dentin starts at what stage
bell stage
the mesenchyme is ______ which includes ______ cells
ectomesenchyme ; neural crest cells
the dental papilla is ______ derived
neural crest
in reciprocal induction, some cells in the IEE will produce some factors that affect the cells of the outer dental papilla which have what 2 outcomes?
they will divide and some will differentiate into odontoblasts and other will stay undifferentiated in the dental papilla
can we repair dentin
yes
what 2 things are deposited at the same time in the apositional stage and which one is mineralized first?
enamel and dentin ; dentin
young odontoblasts secrete _____ and _____ proteins
collagen and non-collagenous
the first sign of dentin formation is the appearance of distinct, large-diameter _____ fibrils called _______
collagen ; von Korff’s fibers
von Korff’s fibers consists of collage type ___
3
as odontoblasts continue to increase in size in initial dentin, they also produce smaller collagen type ____ fibrils that orient themselves parallel to the future DEJ
1
odontoblast life cycle
absence of odontoblastic process
preodontoblast
odontoblast life cycle
junctional complex ; gap junction, thick OP
secretory
odontoblast life cycle
autophagic vacuole
transitional
odontoblast life cycle
condensed chromatin ; no Golgi ; autophagic vacuoles
aged
the dentin neonatal line is an example of
incremental line of OWEN
the enamel neonatal line is NOT an example of
incremental line of OWEN
regarding incremental production of dentin and the lines of Von Ebner - 4 microns a day in two 12 hour periods produce how many microns
2
type _____ collagen defines the framework for mineral deposition and by itself is not sufficient to support nucleation of _______.
What does make this happen though?
1 ; hydroxyapatite ; phosphophoryn
calcospheric deposit of crystals in discrete areas
globular calcification
fusion of the adjacent calcospheres leads to normal
dentin formation
_______ dentin is formed in sites of incomplete mineralization
interglobular
______ dentin has lost most of the collagen during mineralization, denser and harder
Peritubular
_______ dentin growth produces the depth and width of the dentine “pushing” the odontoblasts into the _______
Intertubular ; pulp cavity
What curve?
Crowding of odontoblasts causes S-shaped course
Primary
What curve?
odontoblasts undulations create wavy curves
secondary
Regarding sclerotic dentin
Slow prolonged insults -
increased collagen deposit in
tubule leading to gradual occlusion with calcified materials results in
reduced permeability
which dentin is the 1st formed dentin
mantle
which dentin is an organic matrix that is rich in type 1 collagen, thick type 3 collagen, and ground substance
mantle dentin
which dentin is a membrane bound vesicle
mantle dentin
which dentin deposits crystals, obscuring collagen fibrils
mantle dentin
which dentin is 20-150 micrometers thick
mantle dentin
which dentin is secreted before root completion
circumpulpal dentin
which dentin has smaller fibrils, less type 3 collagen
circumpulpal dentin
which dentin has lysosomal degradation of proteoglycans
circumpulpal dentin
which dentin has phosphophoryn, a marker for mature odontoblast
circumpulpal dentin
which dentin has thickness that increases with age
circumpulpal dentin
what dentin is induced by Hertwig’s root sheath
root dentin
which dentin has different collagen fiber orientation
root dentin
which dentin has less phosphophoryn
root dentin
which dentin is slightly less mineralized
root dentin
which dentin has a slower rate of deposition (about half)
root dentin
which dentin has dentinal tubules that lack primary curvature or has less pronounced primary curvature
root dentin
The interglobular dentin is often formed between ______ and _______ dentin
mantle ; circumpulpar
What layer develops between root dentin and cementum and is am intermingling of collagen fibers
tomes’ granular layer
what dentin has trapping of cells in dentin matrix
tertiary dentin
what dentin has distorted odontoblastic tubules
tertiary dentin
what dentin has down regulation of collagen synthesis
tertiary dentin
What dentin has up regulation of non-collagenous matrix
tertiary dentin
first formed dentin; provides
outline of dentin in adult tooth
mantle dentin
what dentin forms bulk
of the tooth
primary (circumpulpal) dentin
lines the innermost portion of
dentin (faces the pulp)
predentin
what dentin?
after root formation dentin continues to form, continuous to primary dentin but with some structural irregularities
secondary dentin
what dentin?
reactive or reparative dentin; may or may not have characteristics of primary dentin; produced by external stimulus
tertiary dentin
dentin is harder than ____ but softer than ____
bone ; enamel
Dentin formation begins during the ____ stage of
development
bell
What plexus is associated with the sensation of pain which is the only sensation that comes from pulp
plexus of Rashkow
What theory is this?
A popular hypothesis for pulp sensitivity relies on the notion that movement of fluid in the dentinal tubules, as produced by heat, cold, and mechanical stimuli is sensed by free nerve endings in the plexus and perhaps in association
with the odontoblasts
hydrodynamic theory
