Card Set Information
Dentin and pulp 1
Derived from ectomesenchyme -Mesoderm, and makes up the bulk of the tooth, and protects the pulp
Mature dentin is only_______________calcified with______________________-
Feels rougher than enamel, but it is softer than enamel and can be removed with instrumentation
true or false. Dentin is avascular so it gets its nutrition from the pulp
During what stage do the outer cells of the dental papilla form odontoblasts? The odontoblasts lay down predentin and leave one long cytoplasmic extension in the dentin?
Apposition of dentin
During the apposition of dentin, the outer cells of the dental papilla form__________________
Odontoblasts lay down what?
true or false. Apposition can keep going because you keep your odontoblasts
What are the two steps in the maturation of dentin?
globules calcify and expand and fuse together to create globular dentin
primary mineralization phase during maturation of dentin
as globules calcify, they expand, but do not fuse completely, which creates interglubular dentin that is less mineralized
secondary mineralization phase during maturation of dentin
Name 4 components of mature dentin
extend from the DEJ to the outer wall of the pulp (the cave)
the tail end of our odontoblasts (the cell within the cave)
the tissue fluid surrounding the cell membrane of the odontoblast (where heat and cold affect the tooth)
the nerve that receives sensation for the tooth, the nerve cell body is located in the pulp of the tooth (axon runs in the tube, the cell body is in the pulp)
true or false. The direction of the tubule reflects the pathway the odontoblast took
overall tubule course which resembles a large S
primary curvature of dentinal tubule
small delicate curvature in dentinal tubules showing the daily changes in odontoblasts during apposition
types of dentin are divided into what 2 categories?
time of formation
name the 4 types of dentin by location.
dentin that creates the dentinal tubule (wall of cave)
dentin found between between each of the tubules
first dentin to form, closest to the DEJ (outside layer)
dentin that surrounds the pulp
Name the 4 types of dentin by time of formation.
dentin formed before the completion of the apical foramen, normal alignment of tubules and more calcified than secondary
dentin formed after the completion of the apical foramen, less calcified than primary dentin, formed to protect the pulp
formed in response to trauma, irregular alignment of tubules because it is laid quickly, formed to protect the outer layer of dentin
because of trauma or age, the odontoblastic process die and leave the tubule, the tubule is then filled with more dentin
name 2 microscopic features of mature dentin
imbrication lines of von ebner
contour lines of owen
lines in mature dentin that are just like the lines of retzius
imbrication lines of von ebner
darkened areas in dentin that show some sort of disturbance in the apposition
contour lines of owen
what is the most pronounced contour line of owen?
true or false. diameter or the tubules in dentin starts to narrow with age, and as more dentin is laid and seals off the communication between the dentin and the pulp.
name 2 clinical considerations of dentin
dentin is__________________and more prone to caries
What do bacteria use dentinal tubules as to get to the pulp?
chutes to the pulp
Why when a cavity reaches the dentin, must it be repaired as soon as possible?
because bacteria may use the dentinal tubules as a chute to get the pulp, and they spread fast once they reach the dentin
Afferent axons are where in the tooth?
in the dentinal tubule
Afferent axon nerves in the dentinal tubules translate all stimuli (hot, cold, pressure, dehydration) as_______________.
true or false. The exact mechanism for this hypersensitivity in the dentin is unknown
What are 3 ways to occlude the dentinal tubules that can help diminish hypersensitivity?
formed from the central cells of the dental papilla, which came from the ectomesenchyme- mesoderm
what part of the tooth is functional by association?
pulp (it makes everything else work)
Why is the pulp involved with the formation of dentin?
because the odontoblasts live in the outer layer of the pulp
Why does the pulp have a sensory function?
because the nerve cell bodies are located in the outer layer of the pulp
Pulp has a nutritional function for the tooth through the__________________
Why does pulp have a protective function?
because the secondary dentin is formed from the odontoblasts in the outer layer of the pulp
Name 6 anatomical features of the pulp
the mass of pulp in the middle, follows the shape of the tooth
the pulp in the crown area
smaller extensions of pulp into the crown
the pulp in the root areas, it has openings through the dentin and cementum, out to the surrounding periodontal ligament
the opening of the pulp into the periodontal ligament - usually at the very apex of the tooth
What structure allows arteries, veins, lymphatics and nerves to enter the tooth
extra opening from the pulp to the periodontal ligament that usually runs perpendicular to the root of the tooth
Accessory canals form because__________________________________ran into a blood vessel while it was forming, so it just formed a little canal around the vessel
Hertwig's epithelial root sheath (HERS)
Name 6 microscopic features of pulp
white blood cells
extensive vascular supply
true or false. pulp is a connective tissue, so it is mainly full of fibroblasts
may be present in the pulp sometimes, they are calcified masses of dentin inside the pulp chambers, they only really cause problems when trying to do endodontic therapy
inflammation of the pulp
Name 3 things that might cause pulpitis
true or false. The pressure from the inflammation of pulpitis can cause severe pain
name 2 ways the the pressure from pulpitis might be relieved?
incision and drainage
a channel that forms in the bone or soft tissue to drain infection from pulpitis
the inflammation from pulpitis can exit the pulp through the apical foramen and cause a/an____________________
What must be done to save a tooth from pulpitis?
root canal therapy
why is it important to crown a tooth once a root canal has been performed on it?
without the pulp, the tooth becomes brittle and more prone to breakage
a material that comes from a tree that is used to fill the empty canal once the pulp has been removed from a root canal, the body does not react to it