dentin essentials Flashcards
dentin location
in crown and root
dentin structure
tubular - microcanals radiate from dental pulp to enamel
dentin color
yellow
percentage mineralized inorganic substrates - calcium hydroxyapatite
65-70%
percentage organic substrates - collagenous protein
20-25%
percentage bound water
10%
Tomes fiber
vital tissue; cytoplasmic cell process
odontoblast process (an extension of an odontoblast- located in the dentinal tubules)
odontoblast
vital tissue; innervation to pulp
types of nerve fibers
myelinated A-fibers
unmyelinated C-fibers
Tomes layer
peripheral layer
cytoplastic process
Hyaline of Hopewell-Smith
clear layer between Tomes layer and cementum
cementum composition
45-50% inorganic (hydroxyapatite)
5-55% organic and water (collagen and proteoglycans)
cementum
thin layer (30-200 micrometers) of bonelike
material covering root surfaces
softer than enamel and dentin
fibers of periodontal membrane-ligament are connected to cementum
Lines of Owen
disturbance during mineralization
loss of cementum
exposed dentin
dentin tubules
primary curvature & secondary curvature
result from movement of odontoblasts during development
primary curvature
s-shaped
secondary cuvature
jagged or wrinkled texture
s-shaped
tooth crown
straighter path of tubules
root of tooth
primary dentin
most prominent dentin
lies between the enamel and pulp chamber starting at the dentinoenamel junction
mantle-dentin
the first formed dentin by odontoblast differentiation; it is located in both the crown underlying the DEJ and the root of the tooth
circumpulpal dentin
remaining bulk of primary dentin; collagen fibers narrower and thicker than M-D; greater mineralization than M-D; compact arrangement of fibers
secondary dentin
all dentin formed after root formation is completed (not due to trauma or dental pathology) - closest to pulp (visible on dental radiographs)
forms at slower rate than primary dentin but grows incrementally but unequally
what happens when tooth ages
secondary dentin grows, narrowing pulp chamber
tertiary dentin
dentin formed as reaction to external stimulation (pathologic)
response to trauma
can cause narrowing of pulp chambers and root canals
reactionary tertiary dentin
formed from preexisting odontoblast
reparative tertiary dentin
formed from newly differentiated odontoblasts
sclerotic dentin
tertiary dentin
- depositied in response to trauma
- more mineralized - tubules diameter narrows
- less permeable
- difficult to bond
