amelogenesis

Question 1

enamel formation begins during which stage

Answer 1

late bell stage

Question 2

function of stellate reticulum and stratum intermedium

Answer 2

nutrients and mechanical support

Question 3

first signs of calcification in the tooth organ

Answer 3

late bell stage when dentin formation begins (then enamel)

Question 4

how many times does amelogenesis occur in humans

Answer 4

twice

Question 5

what mineralized first? dentin or enamel

Answer 5

dentin

Question 6

first sign of mineralization

Answer 6

predentin

Question 7

predentin formation signals

Answer 7

differentiation of ameloblasts

Question 8

order of bell stage top to bottom

Answer 8

• stellate reticulum
• stratum intermedium
• ameloblasts
• dentin
• odontoblasts
• dental papilla

Question 9

when is first sign of calcification

Answer 9

14 weeks of gestation (incisors)

Question 10

stratum intermedium and stellate reticulum merge to form

Answer 10

papillary layer

Question 11

secretion

Answer 11

30% of time

-secrete enamel

Question 12

maturation

Answer 12

60% of time

• no growth of enamel
• organic out, calcium in (by ameloblasts)

Question 13

ameloblasts eventually form

Answer 13

reduced enamel epithelium (shrink)

Question 14

pre-ameloblasts are

Answer 14

cuboidal and linked by tight junctions

Question 15

ameloblasts are separated from odontoblasts by

Answer 15

basement membrane

Question 16

function of the basement membrane

Answer 16

• allow parallel arrangement of collagen fibers in predentin

- anchor odontoblasts

Question 17

major enamel protein

Answer 17

amelogenin

Question 18

what occurs during the secretory stage

Answer 18

formation of tomes’ processes

Question 19

what gives ameloblasts its angular appearance and the appearance of cell processes

Answer 19

tomes processes

Question 20

tomes process allows for the formation of

Answer 20

rod and interrod enamel

Question 21

which forms first? rod or interrod

Answer 21

interrod

Question 22

is the matrix on the sides of tomes processes the same

Answer 22

no

Question 23

enamel matrix is ___ mineralized by the end of the secretory stage

Answer 23

30%

Question 24

what is the product of secretory stage

Answer 24

tighly interwoven meshwork of hydroxyapetite crystals

Question 25

maturation stage

Answer 25

change of membrane structure

Question 26

pumping Ca and P ions into enamel space

Answer 26

ruffle-ended membrane

Question 27

removal of water and organic matrix

Answer 27

smooth ended membrane

Question 28

tight junction positions

Answer 28

ruffle: proximal
smooth: distal

Question 29

what happens to pH when it becomes ruffled

Answer 29

pH drops

Question 30

5 enamel matrix proteins in the SECRETORY stage

Answer 30

1) amelogenin*
2) ameloblastin
3) enamelin
4) enamelysin
5) kallikrein-4

Question 31

which enamel proteins are proteolytic enzymes

Answer 31

enamelysin and kallikrein-4

Question 32

proteolytic enzyme for early secretory stage

Answer 32

enamelysin

Question 33

proteolytic enzyme for late maturation stage

Answer 33

kallikrein -4

Question 34

in the presence of amelogenin, what type of crystals are formed

Answer 34

elongated HAP crystals

Question 35

new basal lamina layer forms

Answer 35

during transition from secretory to maturation

-between ameloblast and enamel

Question 36

what does the new basal layer contain

Answer 36

-glycoconjugates and new proteins (ODAM, AMTN, SCPP-PQ1)

Question 37

during tooth eruption, the reduced enamel epi fuses with oral epi to form

Answer 37

junctional epithelium