NBDE ANATOMICAL SCIENCE: Tooth Development Flashcards Preview

NBDE PART 1 BIOCHEM/PHYSIOLOGY > NBDE ANATOMICAL SCIENCE: Tooth Development > Flashcards

Flashcards in NBDE ANATOMICAL SCIENCE: Tooth Development Deck (86):
1

The dental lamina, a thickening of oral epithelium that produces the swellings of the enamel organs is first seen histologically around _ week in utero

6th week = dental lamina

2

by the __ week after conception the primitive mouth (stomodeum) has formed

3rd week

3

after the primitive mouth (stomodeum forms) in the 3rd week. Over the next few weeks the _ develop

tongue, jaws, and palate

4

during the 6-8th week the formation of _ commences

teeth

5

by the __th week in utero, all of the primary (deciduous) incisors, canines, and molars are descernible

6th

6

tooth development appears to be initiated by the __inductive influence on the overlying ectoderm

mesenchymal

7

early in the 6th week the oral epithelium thickens into a U-shaped band called the

dental lamina

8

at certain points on the dental lamina, the ectodermal cells proliferate and produce swellings that become the _

enamel organ

9

at certain points on the dental lamina, the ectodermal cells proliferate and produce swellings that become the

enamel organ

10

inside the depression of the enamel organ an area of condensed mesenchyme becomes the

dental papilla

11

surrounding both the enamel organ and dental papilla is a capsule-like structure of mysenchyme called the

dental sac (follicle)

12

when does the enamel organ separate from the dental lamina?

after the first layer of dentin is deposited

13

each tooth is the product of 2 tissues that interact during tooth development: the _ and the_

oral epithelium and the underlying ectomesenchyme

14

the oral epithelium grows down into the __ and forms small areas of condensed __ which become tooth germs

ectomesenchyme
mesenchyme

15

name the components of a tooth germ

enamel organ
dental papilla
dental sac

16

the primordium of the permanent succedaneous tooth lingual to the primary tooth germ is in which stage

bud stage

17

when enamel maturation is completed, the ameloblast layer and the adjacent papillary layer regress together constitute the __ that covers the tooth thru eruption

reduced enamel epithelium

18

the reduced enamel epithelium remains until the tooth

erupts

19

as the tooth passes through the oral epithelium the part of the reduced enamel epithelium situated incisally is ___ while the cervical interacts with the oral epithelium to form

destroyed

junctional epithelium

20

the junctional epithelium (epithelium attachment) attaches to gingival tissues via

hemidesmosomes

21

the reduced enamel epithelium is formed after the

completion of enamel apposition when enamel organ undergoes compression of its many layers on the enamel surface

22

epithelial cells of the inner and outer epithelium proliferate from the cervical loop of the enamel organ to form a double layer of cells known as

Hertwig's epithelial root sheath
(HERS)

23

the structure responsible for root development is the

cervical loop

24

the cervical loop is the most cervical portion of the

enamel organ

25

the cervical root is a bilayer rim that consists of only _ of the enamel organ

inner and outer enamel epithelium

26

Hertwig's sheath is an epithelial diaphragm that is derived from the

inner and outer enamel epithelium of the enamel organ

27

after crown formation the Hertwig's sheath grows down and shapes the root of the tooth and induces formation of

root dentin

28

1. uniform growth of Hertwig's sheath will result in the formation of a _ rooted tooth
2. medial outgrowths or evaginations of the Hertwig's sheath will produce _ rooted teeth

1. single
2. multi

29

1. after the first root dentin is deposited, the cervical portion of Hertwig's sheath breaks down and this new dentin comes into contact with the ___
2. this interaction of dentin and the dental sac stimulates cells to differentiate into

dental sac
2. cementoblasts to produce cementum = cementogenesis

30

communication bw pulp tissue and the PDL other than thru the root apex =

accessory canals

31

accessory canals are the result of a localized failure in the formation of

Hertwig's sheath during embryonic stages of tooth formation = leads to failure of odontoblastic differentiation and dentin formation

32

an __ is a non-neoplastic excrescence of enamel where enamel is not supposed to be, ex on root surface

enamel pearl

33

enamel pearls r usually found

bw roots (furcation) of molars

34

most common location of an enamel pearl is the furcation areas of

max and MD 3rd molar roots

35

Enamel pearls are formed from

Hertwig's epithelial root sheath

36

the cervical lop is composed of the most cervical portion of the __ and is responsible for _

enamel organ
root development

37

Hertwig's epithelial root sheath is formed from the _ of the cervical loop and is responsible for the _ of roots and induction of _

elongation
shape
root dentin

38

inner enamel epithelium differentiate into

ameloblasts

39

Korff's fibers are found in the

pulp

40

what forms the middle part of the enamel organ

stellate reticulum

41

name the 4 layers of the enamel organ

outer enamel epithelium (OEE), Inner enamel epithelium (IEE), Stratum Intermedium (SI), Stellate reticulum(SR)

42

this layer outlines the shape of the future developing enamel organ

outer enamel epithelium (OEE),

43

the innermost cellular layer of the enamel organ that will become ameloblasts and produce enamel

Inner enamel epithelium (IEE)

44

lies lateral to the Inner enamel epithelium (IEE) and is thicker. this layer is essential to enamel formation since it prepares nutrients for the ameloblasts of the IEE

stratum intermedium

45

this area is the central core of the enamel organ and the bulk. contains a lot of intercellular fluid (mucus type fluid rich in albumin) and is lost just before enamel deposition

stellate reticulum

46

after enamel formation all 4 layers of enamel organ become one and form the _ which is impt in the formation of the _

reduced enamel epithelium
DEJ

47

the DEJ is an area where the _ and _ come together as the tooth erupts into the mouth

enamel and epithelium

48

the enamel and epithelium come together to form the __, which later migrates down the tooth to assume normal position

initial junctional epithelium (epithelial attachment)

49

name the 8 stages of tooth development

initiation, bud, cap, bell, apposition, calcification, eruption, attrition

50

induction is the main process in

initiation

51

in initiation (6-7th week) ectoderm lining stomodeum gives rise to oral epithelium and then to dental ___

lamina

52

congenital absence of teeth (anodontia) and supernumerary teeth result from an interruption in what stage of tooth development

initiation

53

bud stage (8th wk): growth of dental lamina into a bud that penetrates the ectomesenchyme = __ is the main process

proliferation

54

tooth germ forms in _ stage

cap stage

55

dens in dente, germination, fusion and tubercle formation occurs in which phase of tooth development

cap stage

56

proliferation, differentiation and morphogenesis are main processes in which stage

cap stage

57

11-12th week is the __ stage = final shaping of tooth. cells differentiate into specific tissue forming cells (ameloblast, odontoblast, cementoblast, fibroblast) in the enamel organ.

bell

58

Histodifferentiation and morphodifferentiation are main processes involved in _

bell stage

59

macrodontia and microdontia occur in _ stage

bell

60

deposition of specific dental tissues (enamel/dentin/cementum/pulp) in this stage

apposition

61

enamel dysplasia, concrescence and enamel pearls occur in _ stage

appostion

62

Amelogenesis imperfect and dentinogenesis imperfect occur in _ stage

bell

63

in adults the epithelial cell rests of Malassez persist next to the root surface within

the PDL

64

rest of Malassez are functionless but are the source of epithelial lining of dental __ that develop in rxn to inflammation of the PDL

cysts

65

the rests of Malassez are remnants of __

Hertwig's epithelial root sheath found in PDL

They are discrete clusters of residual cells from Hertwig's epithelial root sheath (HERS) that didn't completely disappear

66

Some rest of Malassez degenerate and others calcify and become__

cementicles in the PDL

67

2 purposes of Hertwig's epithelial root sheath

-shape root and induce dentin formation by stimulating odontoblasts

68

the continuity of Hertwig's epithelial root sheath must be broken in order for _ to be deposited

cementum

69

Hertwig's epithelial root sheath forms _ in the PDL when its functions have been accomplished

rests of Malassez

70

Hertwig's root sheath does not have all 4 layers of the enamel organ. it only has which 2?

outer and inner enamel epithelium. does not have stratum intermedium or stratum reticulum

71

the structure responsible for root development is the _

cervical loop (most cervical part of enamel organ)

72

histologically the dentin in the root is distinguished from the dentin of the crown by the presence of

granular layer of Tomes = only under the surface of dentin where the root is covered by cementum. only seen in ground sections.

73

granular layer of Tomes increases as you go

toward the apex from the DCJ

74

the granular layer of Tomes appears

spotty

75

globular dentin

areas of both primary and secondary mineralization of dentin

76

interglobular dentin

UNMINERALIZED or HYPOMINERALIZED dentin where globular zones of mineralization (calcospherites) have failed to fuse

77

interglobular dentin is seen most frequently in the _ dentin just below the mantle dentin where the pattern of mineralization is largely globular

circumpulpal

78

which product is NOT ectodermal origin:

junctional epithelium
enamel
hertwig's epithelial root sheath
pulp
ameloblasts

pulp

79

the dental organ is aka

tooth germ

80

is dental organ the same thing as enamel organ

no!

81

dental organ aka tooth germ is made of 3 things

dental sac (follicle)
dental papilla
enamel organ

82

enamel organ is formed from __ epithelium

oral epithelium which is derived from ectoderm

83

the enamel organ will give rise to __ and eventually forms _

enamel
Hertwig's epithelial root sheath (HERS)

84

Dental follicle (aka dental sac) is formed from __ which is derived from __

mesenchyme (ectomesenchyme)
neural crest cells

85

dental papilla is formed from __ which is derived from __

mesenchyme (ectomesenchyme) which is derived from neural crest cells

86

both the dental papilla (forms pulp and dentin) and the dental sac (follicle forms PDL, cementum and alveolar bone proper) are derived from

mesenchyme (ectomesenchyme) derived from neural crest cells