quiz on Lecture 8

Question 1

composition of dentin: inorganic, organic, and water

Answer 1

inorganic: 70%
organic: 20%
water: 10%

Question 2

dentin is covered by what in the crown, and by what on the root

Answer 2

enamel; cementum

Question 3

dentin protects the pulp and

Answer 3

makes up the bulk of the tooth

Question 4

is dentin vascular or avascular

Answer 4

avascular

Question 5

what color is dentin

Answer 5

yellowish; esp during attrition(occurs faster if dentin is exposed rather than for enamel); not whiter than enamel

Question 6

dentin is also:

Answer 6

slightly elastic

Question 7

apposition of dentin occurs how often?

Answer 7

throughout the life of the tooth; does not stop after eruption like enamel

Question 8

odontoblasts were peripheral cells of the what

Answer 8

dental papilla

Question 9

where do odontoblast start making dentin?

Answer 9

at DEJ

Question 10

this is surrounded by predentin(newly deposited uncalcified dentin matrix) and goes toward the inside; long cellular extension located within dentinal tubule

Answer 10

odontoblastic processes

Question 11

lines of von ebner are what?

Answer 11

incremental lines; hypomineralized

Question 12

where does mineralization occur in dentin

Answer 12

predentin/dentin complex

Question 13

as the previous later of predentin becomes dentin;

Answer 13

a new layer of predentin is formed

Question 14

predentin matures by forming these which mineralize/calcify into mature dentin and fuse like water colors on paper

Answer 14

globules

Question 15

layer- areas of calcified dentin with hypomineralized areas at their surface(contains interglobular dentin); in book: both primary and secondary mineralization have occured with complete crystalline fusion and appear as lighter rounded areas on a microscope

Answer 15

globular dentin

Question 16

occurs in coronal dentin near DEJ; hypomineralized area between calcified globules where globules are fused incompletely

Answer 16

interglobular dentin

Question 17

dentin tubules are hypomineralized or hyper?

Answer 17

hypo

Question 18

process are enclosed in a

Answer 18

dentinal tubule

Question 19

dentinal tubules can run from DEJ

Answer 19

the periphery of the pulp

Question 20

tubules are crowded near the

Answer 20

pulp due to narrowing of this region

Question 21

tubules follow S-shape path along length of

Answer 21

tubules

Question 22

movement of odontoblasts to a narrower area

Answer 22

primary curve

Question 23

small waves, movement during night and day of odontoblasts

Answer 23

secondary curve

Question 24

diameter of dentinal tubules

Answer 24

4 um wide

Question 25

lateral branches that arise at right angles to the main tubule

Answer 25

canaliculi

Question 26

tubules that are obliterated by peritubular dentin(makes up inside of tubule); this forms a protective mechanism to wall of bacteria to protect pulp

Answer 26

sclerotic dentin

Question 27

air filled tubules caused by death of odontoblastic process, appear black because of histologic stain of empty dentinal tubules

Answer 27

dead tracts

Question 28

caused by looping of dentinal tubules; only found in root cementum but is in dentin; adjacent to DCJ

Answer 28

tomes granular layer

Question 29

1st dentin made because it is closer to DEJ

Answer 29

mantle dentin

Question 30

lies immediately adjacent to DEJ(between DEJ and globular layer)

Answer 30

mantle dentin

Question 31

how thick is mantle dentin

Answer 31

10-30 um thick

Question 32

how are the collagen groups arranged in

Answer 32

perpendicular to DEJ

Question 33

is mantle dentin more or less calcified than circumpulpal?

Answer 33

less calcified

Question 34

dentin that is closer to the pulp

Answer 34

circumpulpal dentin

Question 35

this layer of dentin is around outer pulpal wall; between globular layer and pulp

Answer 35

circumpulpal

Question 36

this dentin layer has finer collagen fibers and is more calcified than mantle dentin

Answer 36

circumpulpal dentin

Question 37

fibers are parallel to DEJ

Answer 37

circumpulpal

Question 38

S curve goes through mantle and

Answer 38

circumpulpal

Question 39

fill up tubules with sclerotic; formed around odontoblastic process(makes wall of dentinal tubules

Answer 39

peritubular dentin

Question 40

calcification of peritubular dentin

Answer 40

highly calcified

Question 41

what dentin's deposition can cause tubules to narrow with age

Answer 41

peritubular dentin

Question 42

this type of dentin is located between dentinal tubules and is less calcifed

Answer 42

intertubular dentin

Question 43

formed before completion of apical foramen; closer to DEJ

Answer 43

primary dentin

Question 44

includes mantle and circumpulpal dentin(big s curve, bulk of dentin) and includes globular layer

Answer 44

primary dentin

Question 45

how much of primary dentin is made per day?

Answer 45

4um

Question 46

formed after completion of the apical foramen; formed at a slower rate; closer to pulp(thinner than primary)

Answer 46

secondary dentin

Question 47

which kind of dentin: pulp gets narrower because odontoblasts keep traveling inward making dentin

Answer 47

secondary dentin

Question 48

forms rapidly in localized areas in response to trauma of dentinal tubules; not everyone has it; makes pulp narrower; lighter and right under dead tracts

Answer 48

tertiary, reactive, or reparative dentin

Question 49

under tertiary dentin

Answer 49

cavity preparations, attrition or bruxism, thermal water sprays

Question 50

when dentinal tubules become exposed to outside environment make direct contact with pulp

Answer 50

sensory conduction

Question 51

tubules serve as entry to cariogenic microorganisms when caries extend from enamel into dentin

Answer 51

caries

Question 52

dentin is exposed as reseult of caries, cavity prep, gingival recession or attrition; open dentinal tubules may be painful

Answer 52

dentinal hypersensitivity

Question 53

fluid open exposed tubules begin to evaporate; the movement of fluid caused by evaporation may stimulate nerves nearest odontoblast to produce pain; explains dentin sensitivity

Answer 53

hydrodynamic theory

Question 54

occurs at a more rapid rate because its mineralized content is lower

Answer 54

attrition

Question 55

odontoblasts in the area of the affected tubules may perish because of the injury, but neighboring undifferentiated mesenchymal cells of the pulp can move to the area and become odontoblasts

Answer 55

reparative dentin

Question 56

if the tertiary dentin is formed by existing odontoblasts, considered

Answer 56

reactive dentin