Amelogenesis

Question 1

what is the percentage of mineral, matrix and water in enamel

Answer 1

mineral - 96%
matrix - 1-2%
water - 2%

Question 2

why is there so little matrix in enamel

Answer 2

no structure in enamel
tenants of developmental proteins
doesnt contain collagen

Question 3

what si the % of mineral, matrix and water in dentine

Answer 3

mineral - 70%
matrix - 20%
water - 10%

Question 4

what si the % of mineral, matrix and water in cementum

Answer 4

mineral - 65%
matrix - 23%
water - 12%

Question 5

what is the % of mineral, matrix and water in bone

Answer 5

mineral - 60%
matrix - 25%
water - 15%

Question 6

what is enamel predominantly composed f

Answer 6

96% mineral - hydroxyapatite

Question 7

what is enamel

Answer 7

mineralised epithelial product

Question 8

what does the organic matrix contain

Answer 8

1-2%
enamel proteins (remnant of development)
not collagen

Question 9

how much water in enamel

Answer 9

2%

Question 10

when does enamel start t form

Answer 10

after dentine mineralises

Question 11

what ar pre ameloblatss

Answer 11

long columnar 
epi cells tight bound tight junctional complex 
polarised nuc
going to prod enamel 
organelles fro synthesis

Question 12

what are some organelles used in synthesis

Answer 12

RER
golgi
sec vesicles
mito

Question 13

when does enamel formation begin

Answer 13

when basal lamina disintegrates

Question 14

when enamel formation begins what happens to the amelobast

Answer 14

retreats up and out the way

Question 15

what shape change occurs to the amelobalt in enamel prodction

Answer 15

tomes process

prism shape of enamel

Question 16

what si the final cue for amelogenesis to start

Answer 16

dentine formation

breakdown basal lamina

Question 17

what is an ameloblast secrete

Answer 17

organic matrix - immediate partial mineralisation

Question 18

what is the mineralised enamel matured by

Answer 18

influx of mineral ions - CA and phosphate

breakdowns dnremoval of organic matrix

Question 19

what state is the organic matrix

Answer 19

amorphous gel

Question 20

what is the enamel matrix composed of

Answer 20

amelogenins 90%
enamelling 20%
tuftelin
enzymes

Question 21

what does enamels do

Answer 21

strongly bond to mineral

Question 22

where is tuftelin confined to

Answer 22

ADJ

Question 23

what re the enzymes for in the enamel matrix

Answer 23

as crystals expand the proteins have to be broken down

Question 24

what are amelogenisn rich in

Answer 24

proline and glutamine

Question 25

what features amelogeneisn cause good aggregation

Answer 25

hydrophobic

Question 26

where are amelogensins found

Answer 26

spread throughout the developing enamel thickness

Question 27

amelogenisns are thixotropic what does that mean

Answer 27

flows under certain conditions but remains fairly solid under conditions changes under gentle pressure

Question 28

what si the role of enamel proteins

Answer 28

nucleation of hydroxyapatite - epitactic matrix template orientate and stablise crystal growth broken down and lost during maturation

Question 29

wha si the initial secretion of enamel like

Answer 29

virtually immediate mineralisation 15% mineral 65% water 20% proteins

Question 30

what mineralisation takes place of he enamel after the intel secretion

Answer 30

rapid mineralisation 30% 'immature/young' enamel maturation further mineralisation 96%

Question 31

what is maturation of enamel

Answer 31

thin crystals grow in thickness

Question 32

what does maturation of enamel require

Answer 32

mineral ions IN | enamel matrix OUT

Question 33

what does amelogenein do in maturation

Answer 33

flows under pressure - thixotropic enzymes break down amelogensin bulk breakdown products removed

Question 34

what si the enamelling origin

Answer 34

produced by amelobasts or product of their breakdown

Question 35

the matter that flows out -------

Answer 35

amelogenins

Question 36

the matrix that reminds ------

Answer 36

enamellin | bind tight hydroxyapatite

Question 37

what happens to the tomes process in maturation

Answer 37

once most of enamel thickness laid down the tomes process is lost

Question 38

what is the last formed enamel termed to be

Answer 38

aprismatic | no tomes process

Question 39

what is formed when maturation is complete

Answer 39

enamel cuticle

Question 40

what si the enamel cuticle secreted by

Answer 40

final ameloblast sec

Question 41

how thick is the enamel cuticle

Answer 41

1 nanometres

Question 42

when is reduced enamel epi produced

Answer 42

from when enamel formation is complete

Question 43

what is reduced enamel epi derived from

Answer 43

reduced ameloblasts | remnants of enamel organ OEE

Question 44

what si the reduced enamleepi attached to

Answer 44

the cuticle

Question 45

what si the function of the reduced enamel epithelia

Answer 45

protection enamel surface from resorp, prevent cemtnum form provide epi lined path for eruption forms junctional epi

Question 46

what it he fate of the REE

Answer 46

reduced enamel epi fusion of basal lamina cel death junctional epi