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what is dentin derived from?
mature dentin is only ______% calcified with _____ ______
dentin makes up the_____ of the tooth and protects the ______
t/f dentin cannot be removed with instrumentation
false-it CAN be removed with instrumentation
where does dentin get its nutrition from?
pulp (dentin is avascular)
t/f dentin has its own blood supply
false-dentin is avascular
how does dentin feel compared to enamel?
what is the process of apposition of dentin?
out cells of dental papilla form odontoblasts
odontoblasts lay down predentin
they leave one long cytoplasmic extension in the dentin (odontoblastic process)
keeps going throughout life because odontoblasts remain in the pulp
what cells form odontoblasts?
outer cells of the dental papilla
what is the long cytopasmic extension left by odontoblasts in the dentin?
where do the odontoblasts live?
in the pulp
t/f apposition of dentin can be made all throughout life?
what are the two steps of maturation of dentin?
primary mineralization phase
secondary mineralization phase
what phase of maturation of dentin is described as this: as globules calcify, they expand and fuse together and create globular dentin
primary mineralization phase
what phase of maturation of dentin is when globules calcify they expand but do not fuse completely. Creates interglobular dentin that is less mineralized
what does the primary mineralization phase create?
what does secondary mineralization create?
what is less mineralized globular dentin or interglobular dentin?
what are 3 components of the dentinal tubules?
what extends from the DEJ to the outer wall of the pulp?
what is the tail end of the odontoblast?
what is the tissue fluid surrounding the cell membrane of the odontoblast?
what is the nerve that receives sensation for the tooth and where is it located in the tooth?
located in the pulp
the _____ of the tubule relfects the pathway the odontoblast took
what is the overall tubule course called which resembles a large S
what resembles a large S within the dentin?
primary curvature of the dentinal tubule
what are the small delicate curves of the dentinal tubules called and what do they show?
shows daily changes in the odontoblast direction during apposition
what are two ways the types of dentin are described?
location and time
what are the four types of dentin by location?
what type of dentin creates the dentinal tubule?
where is the peritublar dentin located?
walls of dentinal tubule
what type of dentin is found between each of the tubules?
where is intertubular dentin found?
between each of the tubules
what type of dentin is the first to form and is closest to the DEJ?
what is mantle dentin?
first to form and closest to the DEJ
what type of dentin surrounds the pulp chamber?
what is circumpulpal dentin?
dentin that surrounds the pulp chamber
what are the three types of dentin by time of formation?
what type of dentin is formed before the completion of the apical foramen?
what type of dentin has normal alignment of tubules and is more calcified than secondary?
when does primary dentin form?
before the completion of the apical foramen
what type of dentin forms after the completion of the apical foramen
t/f secondary dentin is more calcified than primary dentin and t/f is formed to protect the pulp.
false-secondary dentin is less calcified than primary dentin
when does secondary dentin form?
after the completion of the apical foramen
what type of dentin forms in response to trauma?
t/f tertiary dentin has irregular alignment of tubules because it is laid quickly and t/f it is formed to protect the pulp.
false-formed to protect the outer layer of dentin
what is formed because of trauma or age and involves the odontoblastic process to die and leave the tubule
what is the tubule filled with when the odontoblastic process dies and leaves the tubule
what is sclerotic dentin?
formed in the tubule because of trauma or age, the odontoplatic process dies and leaves the tubule and then is filled with dentin
t/f imbrication lines of von ebner are just like incremental lines of retzius
how are imbrication lines of von ebner laid down?
what are darkened areas that show some sort of disturbance in the apposition
contour lines of owen
what is an example of a contour lines of owen
what is the most pronounced line of contour lines of owen
t/f the contour lines of owen are any line that is darker than normal?
describe the age changes of dentin
diameter of tubules starts to narrow as more dentin is laid and seals off the communication between the dentin and the pulp
t/f with age changes in dentin the diameter of the tubules start to widen
false-tubules start to narrow as more dentin is laid
t/f dentin is more calcified than enamel and is less prone to caries
false- dentin is less calcified than enamel and is more prone to caries
bacteria have been seen using the _____ ____ as chutes towards the _____
why can a small cavity in the enamel be monitered but once it has gotten to the dentin it must be repaired?
bacteria uses the dentinal tubules as chutes towards the pulp
why is the dentin hypersensitive
afferent axons are in the dentinal tubules
afferent axons in your dentinal tubules translate all stimuli into what?
what is the exact mechanism of the afferent axon stimuli?
what can help diminish hypersensitivity?
occluding the tubules-fluoride, laster treatments or composite fillings
what is the active ingredient that helps to occlude tubules?