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64 Cards in this Set

  • Front
  • Back
color of dentin?
t/f: dentin forms the bulk of tooth
dentin is not living (t/f?)
false--dentin is living tissue with odontoblast processes still inside of it
dentin is darker then enamel radiographically(t/f)
dentin is slightly harder then bone with 70% inorganic matrix (t/f)
what's the inorganic component of dentin and what's the volume of inorganic?
45% inorganic by volume and hydroxyapatite is the inorganic component of dentin
what are the organic components of dentin?
type I collagen
What are dentinogenesis imperfecta?
these are calcification defects where the dentin has not calcified as it should!
dentinal tubules extend thru the full thickness of dentin (t/f)
dentinal tubules reflect the path that the odontoblasts moved as they migrated towards the crown enamel of the tooth
false, odontoblasts move towards the pulp as they lay down dentin; the tubules reflect the path that they moved towards the PULP!
where is the curvature most pronounced of the dentinal tubules?
in the coronal dentin (except under incisal edges and cusp tips)
dentinal tubules run straigt in the root dentin (t/f)
what is primary curvature?
large sweeping curve of dentinal tubules due to crowding
what is secondary curvature?
these are SMALL BENDS in the path of the tubules

Primary curvatures are LARGE SWEEPS
What are the diameters of the tubules at the pulp and DEJ?
pulp: 2.5 uM (micro meters)

dej: 900 nM (nanometers)
where are there more tubules per unit area?
the pulp--odontoblasts get crowded as they approach the pulp!
what's the lamina limitans?
organic sheath that lines the dentinal tubules
what is contained with the dentinal tubules?
odontoblast process
tubular fluid
nerve fibers
lamina limitans
what are the three types of branching seen of tubules?
major--terminal branching of tubules; seen in root dentin

fine--also in root dentin, branch from the main tubules at 45 degrees

microtubules(canaliculi)--at right angles to tubules
fine branches function to do what?
help circulate the dentinal fluid
is dentin normally exposed to the oral cavity?
no!it should be well confined beneath enamel and cementum layers
causes of exposed dentin?
absence of enamel/cementum
exposed CEJ
amelogenesis imperfecta
what's the job of tertiary dentin?
protects the pulp in response to trauma, caries, irritation, dental procedures by Dr. Rinnagio
tertiary dentin is made by a specific group of odontoblasts that have been affected by injury/trauma (t/f)
tertiary dentin is slowly deposited (t/f)
false! it is rapidly deposited unlike secondary dentin that takes time--it is a response to an injury so the response is FAST!
tertiary dentin often has fewer tubules and is irregular
true--tertiary dentin is deposited so fast that the quality is lacking
what is osteodentin?
tertiary dentin that has trapped
odontoblasts inside
what are dead tracts?
a type of age change where the odontoblast process retracts from the tubule or the odontoblast dies
dead tracts are spaces that are filled with air and appear black on ground section.(t/f)
dead tracts are usually seen where?
coronal dentin (often near caries)
sclerotic dentin is what?
dentinal tubules have becomes occluded with calcified salt
what is the apperance of sclerotic dentin?
glassy, transparent appearance in ground section
sclerotic dentin functions to do what?
protects the pulp by decreasing the permeability of the tubules
sclerotic dentin is harder then normal dentin (t/f)
true! extra calcification makes it harder
exposed tubules lead to what clinical symptoms?
dental caries
pulp disease
dentinal sensitivity
dentin is formed thruout life (t/f)
true--it becomes more resistant to caries
dentinal tubules must avoid dehydration (t/f)
true--dehydrated dentin is brittle and you MUST place a crown over a root canal because of this!
dental procedures often expose
dentinal tubules (t/f)
what is indirect pulp capping?
it's when you put a chemical on the tooth to antagonize dentinal tubules--this stimulates the deposition of tertiary dentin
what are microtubules (canaliculi)?
it's branches off of the dentinal tubules are right angles
what's intratubular dentin?
same as peritubular dentin
inside of dentinal tubules
narrows the tubule's lumen
what's intertubular dentin?
main component of dentin
it's between the tubules
pakced with type I collagen, HAP matrix
there is more organic matrix in intertubular dentin then intratubular dentin (t/f)
what are incremental lines?
run at right angles to tubules
represent rhythmic dentin deposition patterns
what are the three typef of incremental lines?
lines of von ebner
contour lines of owen
neonatal lines
what are lines of von ebner?
type of incremental line
represent 5-day cycles of dentinogenesis
what are contour lines of owen?
same are contour lines
linear bands
due to the coincidental movement of odontoblasts
type of incremental line
what incremental lines show an exxagerated secondary curvature?
lines of owen
neonatal lines are...
type of incremental line
due to the disturbance in mineralization when you're born
interglobular dentin
unmineralized or hypomineralized areas between calcospherites
persisten predentin
interglobular dentin is pronounced when there are low levels of .......during dentinogenesis
vitamin d
interglobular dentin is pronounced when there are high levels of ........during dentinogenesis
where is interglobular dentin seen?
below mantle dentin
at the interface with circumpulpal dentin
does interglobules dentin have tubules?
yes!! but there is no intratubular dentin
what is tome's granular layer?
a layer below the DCJ within dentin
increases in density from the CEJ to root apex
tome's granular layer is seen only in...
ground sections
tomes granular layer are spaces within the dentin made by disoriented odontoblasts (t/f)
true-->odontoblasts get disoriented here and their tubules are looping at the terminal ends
what is secondary dentin?
formed thruout life (slowly deposited)
where is secondary dentin located?
along the pulpal surface
secondary dentin develops after...
root formation is complete!
secondary dentin is more wavy
and less regular then primary dentin (t/f)
secondary dentin is evenly deposited along the pulp periphery (t/f)
false--it is UNEVENLY deposited along the pulp periphery
where is secondary dentin deposited in molars?
on the floor and roof of the pulp chamber
secondary dentin leads to an increase in the size of the pulp chamber (t/f)?
false-- secondary dentin reduces the size of the pulp chamber--leading to smaller root canals!