Tooth Development 2: Late Bell & Crown stages

Question 1

when is crown formation

Answer 1

14th week

Question 2

when does crown formation take place

Answer 2

late bell stage

Question 3

what is present at late bell stage

Answer 3

tooth germ

no hard tissue matrix laid at this point

Question 4

when do cervical loop cells divide

Answer 4

bella nd crown stages

Question 5

what does the division of cervical loop cells lead to

Answer 5

signal DP - IEE to mature elongate and polarise
signal IEE Dp cells to mature
DP = odontoblasts
IEE = ameloblasts

Question 6

what does the odontoblasts form

Answer 6

predestine then dentine

Question 7

what does the Amelobalsts gove rise to

Answer 7

enamel

Question 8

what is some evidence of IEE cells synthesising enamel proteins

Answer 8

IEE cells more columnar and nucleus toward stratum intermedium - diff begins

Question 9

where si the first place for predestine to be placed

Answer 9

at cusp

clos to enamel knot

Question 10

how does the enamel knot affect cusp

Answer 10

growth factors

differneiation

Question 11

once the dentine is made what happens

Answer 11

signal amelobasts to become sec and lay down enamel

Question 12

what does epi do at cervical loop

Answer 12

proliferate

Question 13

what is cervical loop largely imp for

Answer 13

root development

Question 14

what are the cells found at the cervucal loop

Answer 14

IEE and ecto mesenchyme - yet to dif

Question 15

what does the ecto mesenchyme signal

Answer 15

induces the limited proliferation of IEE

Question 16

what signals from the ecto mesenchyme

Answer 16

BMP
WNT
FGF

Question 17

what is sequence fro cervical loop diff

Answer 17

DP to IEE - control div
See to DP - induce pap cells to mature
DP to IEE - induce IEE to mature
dentine to IEE - dentine signals start of enamel sec

Question 18

what does IEE diff into

Answer 18

ameloblasts

Question 19

what do ameobalsts then do

Answer 19

signal to condense mesenchyme and these will start to diff into odontoblasts

Question 20

what causes chines in matrix

Answer 20

laminin
CS-PG
enamel proteins

Question 21

what is the process of maturing odontoblast

Answer 21

ameloblast diff first 
ectomesenchyme diff under layer
ameloblast signal to diff layer
nucleus move 
matrix laid down

Question 22

before mineralisation of matrix takes place what happens

Answer 22

a lag phase before

Question 23

what are some diff layers of dentine

Answer 23

mantle
granular
hyaline

Question 24

what is matrix mostly prod by

Answer 24

collagen

Question 25

what cells can be seen in developing tooth in late bell stage

Answer 25

dental papilla functioning odontoblasts pre-ameloblasts - predestine formed = ameloblast= enamel

Question 26

what is the lifecycle outline of an ameloblast

Answer 26

``` IEE start to diff reverse polarity - nun move enamel se cells maturation regress height ```

Question 27

what is the stages in ameloblast life

Answer 27

``` pre sec sec transition maturation post maturation ```

Question 28

what si the pre sec stage in ameloblast life

Answer 28

cytodiff morphodiff resorption basal lamina epitomes interctaion

Question 29

what is the sec stage in ameloblast life

Answer 29

``` initial layer enamel matrix sec initiation mineralisation degrade matrix ```

Question 30

what is the transition stage in ameloblast stage

Answer 30

ameloblasts shorten die reform basal lamina cessation of matrix form matrix degrade

Question 31

what is the maturation stage of ameloblast

Answer 31

final degradation and withdraw matrix | crystal growth

Question 32

what si the post maturation stage of ameloblast life

Answer 32

enamel organ degen enamel cover established eruption expo oral cav

Question 33

what is developing enamel

Answer 33

ameloblasts sec enamel | min and laid down

Question 34

what is predentine

Answer 34

organic matrix that makes up dentine before it has calcified

Question 35

what is in the organic matrix

Answer 35

``` collagens 1,3,5,6 proteoglycans - decor glycoproteins - osteonectin phosphoproteins - octeocalcin GF lipids ```

Question 36

what is dentine

Answer 36

mineralised predestine

Question 37

how is predestine mineralised to get dentine

Answer 37

1st layers matrix unmineralised when thick are min at same rate of formation mineral depo form primar dentien

Question 38

what depo minerals in dentine form

Answer 38

odontoblasts

Question 39

what controls dentine form

Answer 39

odontoblast control all

Question 40

what is basic understanding of enamel

Answer 40

diff proteins form dentine

Question 41

what are he two groups of enamel

Answer 41

amelogenins | enamelins

Question 42

what are amelogenisn

Answer 42

multiple slice variants maj

Question 43

what are enamelins

Answer 43

make up minority

Question 44

when does morphogenesis

Answer 44

late cap stage and early bell stage

Question 45

what is morphogenesis

Answer 45

rapid growth cell divIEE tooth shape determined

Question 46

how is the shape determined

Answer 46

switch on and off sp transcription factors

Question 47

whereis Shh found

Answer 47

dental epi

Question 48

what does Shh do

Answer 48

increases cell proliferation, restriction of expression

Question 49

when does reduced enamel epi from

Answer 49

when enamel formation complete

Question 50

what is reduced enamel epi derived from

Answer 50

reduced ameloblasts | other remnants of enamel organ - OEE, SR, SI

Question 51

what is the role of reduced enamel epi

Answer 51

protect enamel surface (resorption, cementum form) epi lined path fro eruption junctional epi

Question 52

what si the secondary dental lamina

Answer 52

secessional dental laminae for developing successional teeth

Question 53

what are some abnormalities which can occur at the inanition stage

Answer 53

anodontia supernumerary teeth micr/macrodontia

Question 54

what is andontia

Answer 54

absence of teeth

Question 55

what is supernumerary test

Answer 55

extra teeth

Question 56

what is micro/macrodontia

Answer 56

miro - small teeth | macro - large teeth

Question 57

what are some abdnomalites that can occur at cap stage

Answer 57

dens in dente | fusion and germination

Question 58

what is dens in dentate

Answer 58

enamel organ invaginate into dental papilla | slits or gaps

Question 59

what is fusion and germination

Answer 59

fusion- 2 roots - 1 | germinate 1- 2/3 roots