Embryology

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
True False

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?

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
True False

What are the two steps in the maturation of dentin?

globules calcify and expand and fuse together to create globular dentin

as globules calcify, they expand, but do not fuse completely, which creates interglubular dentin that is less mineralized

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
True False

overall tubule course which resembles a large S

small delicate curvature in dentinal tubules showing the daily changes in odontoblasts during apposition

types of dentin are divided into what 2 categories?

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

lines in mature dentin that are just like the lines of retzius

darkened areas in dentin that show some sort of disturbance in the apposition

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.
True False

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?

Why when a cavity reaches the dentin, must it be repaired as soon as possible?

Afferent axons are where in the tooth?

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
True False

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?

Why is the pulp involved with the formation of dentin?

Why does the pulp have a sensory function?

Pulp has a nutritional function for the tooth through the__________________

Why does pulp have a protective function?

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

Name 6 microscopic features of pulp

true or false. pulp is a connective tissue, so it is mainly full of fibroblasts
True False

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
True False

name 2 ways the the pressure from pulpitis might be relieved?

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?

why is it important to crown a tooth once a root canal has been performed on it?

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