oral biology

Question 1

all body tissues develop from 3 primary embryonic layers, what are they ?

Answer 1

ectoderm
mesoderm
endoderm

Question 2

what does the ectoderm give rise to?

Answer 2

epidermis

nerve tissue

Question 3

what does the mesoderm give rise to?

Answer 3

cartilage
muscle
bone

Question 4

what does the endoderm give rise to?

Answer 4

colon
stomach
intestine
lungs

Question 5

which embryonic tissue is enamel developed from?

Answer 5

ectoderm

Question 6

apart from enamel which embryonic tissue are all other parts of teeth derived from?

Answer 6

ectomesenchyme

Question 7

what do teeth develop from?

Answer 7

tooth germs

Question 8

ectomesenchyme is part of which structure?

Answer 8

neural crest

Question 9

the neural crest forms between which 2 structures ?

Answer 9

ectoderm and neural tube

Question 10

which condition results from failure of ectomesenchymal cells to migrate?

Answer 10

mandibular dysostosis

Question 11

when does the primary epithelial band develop?

Answer 11

6 weeks

Question 12

what does the primary epithelial band differentiate into?

Answer 12

dental lamina

Question 13

at how many weeks does the dental lamina form?

Answer 13

7 weeks

Question 14

the primary epithelial band grows into the jaw and divides into 2 parts, what are these?

Answer 14

vestibular lamina and dental lamina

Question 15

the vestibular lamina breaks down to form?

Answer 15

buccal sulculus

Question 16

in which horseshoe structure do tooth germs develop>

Answer 16

dental lamina

Question 17

the dental lamina thickens into what?

Answer 17

bud stage enamel organ

Question 18

at how many weeks does the bud stage enamel organ form?

Answer 18

8-10 weeks

Question 19

ectomesenchymal condensation appears sound the enamel organ, this is known as what?

Answer 19

dental papilla

Question 20

the enamel organ bud then forms what?

Answer 20

cap stage enamel organ

Question 21

the cap stage enamel organ forms a cap over which structure ?

Answer 21

dental papilla

Question 22

at how many weeks is the cap stage enamel organ formed?

Answer 22

11 weeks

Question 23

the cap stage enamel organ consists of 2 parts, what are these?

Answer 23

Internal Enamel Epithelium (IEE)

External Enamel Epithelium (EEE)

Question 24

the IEE and EEE meet where?

Answer 24

cervical loop

Question 25

the cap stage enamel organ differentiates into what?

Answer 25

bell stage enamel organ

Question 26

at how many weeks the bell stage enamel organ formed?

Answer 26

14 weeks

Question 27

the bell stage enamel organ has 4 cell layers, name these from outermost layer too innermost?

Answer 27

EEE stellate reticulum stratum intermedium IEE

Question 28

at how many weeks does the extension of the permanent tooth germ appear on the lingual side of the dental lamina?

Answer 28

12 weeks

Question 29

at how many weeks is the enamel organ late bell stage established?

Answer 29

18 weeks

Question 30

at which stage of tooth development does the apposition of enamel and dentin begin?

Answer 30

late bell stage enamel organ (18 weeks)

Question 31

during dentine formation, __ cells adjacent to _ differentiate into odontoblasts?

Answer 31

dental papilla cells adjacent to IEE

Question 32

once dentine formation has begun, _ cells differentiate into _, which form enamel?

Answer 32

IEE cells differentiate into amelblasts which form enamel

Question 33

briefly describe dentinogensis?

Answer 33

dental papilla cells adjacent to IEE differentiate into odontoblast they deposit dentine matrix (mostly collagen) known as predentin dentine matrix is then mineralised with hydroxyapatite

Question 34

briefly describe the 2 stages of amelogensis?

Answer 34

1) protein matrix deposited - partially mineralised 2) organic part removed and mineralisation is completed (ameloblasts change form and function several time during ameilogenesis)

Question 35

which conditions is characterised by abnormal enamel formation?

Answer 35

amelogenesis imperfecta

Question 36

what is the root shape defined by?

Answer 36

apical growth of the cervical loop, now known as henrtwigs epithelial root sheath

Question 37

which structure induces formation of root dentine?

Answer 37

henrtwigs epithelial root sheath

Question 38

once root dentine is formed, henrtwigs epithelial root sheath brekas down forming?

Answer 38

debris of malassez

Question 39

debris of mallasez may form what?

Answer 39

cyst

Question 40

mesenchymal cells contact dentine and differentiate into what?

Answer 40

cementoblasts

Question 41

name the 2 types of tertiary dentine?

Answer 41

reactionary and reparative

Question 42

which type of dentine involves the recruitment of mesenchymal cells ?

Answer 42

reparative

Question 43

which part of the tooth germ forms enamel?

Answer 43

enamel organ

Question 44

which type of tissue forms enamel?

Answer 44

epithelium

Question 45

what is enamels origin?

Answer 45

ectoderm

Question 46

what are the final products of dental papilla?

Answer 46

dentine and pulp

Question 47

what type of tissue is dental papilla?

Answer 47

ectomesenchyme

Question 48

what are the final products of the dental follicle?

Answer 48

cementum, PDL and alveolar bone

Question 49

what type of tissue is dental follicle?

Answer 49

ectomesenchyme

Question 50

what is a placode?

Answer 50

embryonic structures giving rise to hair follicles, nails, enamel etc

Question 51

give an example of a placode?

Answer 51

enamel organ

Question 52

which type of epithelium is on the tongue?

Answer 52

strat squamous

Question 53

The outer layer of dentine closest to enamel is called?

Answer 53

mantle dentine

Question 54

what do IEE cells become?

Answer 54

odontoblasts

Question 55

globules of mineralised dentine formed ahead of mineralisation are known as?

Answer 55

calcospherites

Question 56

which are arranged more columnar, odontoblast or ameloblasts?

Answer 56

ameloblasts