Tooth Development

Question 1

the mature tooth rests in a boney
socket and is held in place by
_________

Answer 1

connective tissue

Question 2

during initiaton of tooth development, ectoderm lining stomodeum gives rise to _______ and then to _______; adjacent to deeper ectomesenchyme, which is derived from the ________ where both tissue types are separated by a _______

Answer 2

oral epithelium, dental lamina, neural crest
cells, basement membrane

Question 3

the bud stage begins around the ______ week

Answer 3

eighth

Question 4

the main process of the bud stage is ________

Answer 4

proliferation

Question 5

the bud stage begins the growth of dental lamina into bud shape that penetrates growing ________

Answer 5

ectomesenchyme

Question 6

the cap stage begins around the ________ week

Answer 6

ninth to tenth

Question 7

the main processes of the cap stage are _______, _______, and ________

Answer 7

proliferation, differentiation, morphogenesis

Question 8

the cap stage begins with the formation of tooth germ as _______ forms into cap shape that surrounds inside mass of _______ , with an outside mass of dental sac (DS), both from the
ectomesenchyme

Answer 8

enamel organ (EO), dental papilla(DP)

Question 9

the bell stage begins around the _________ week

Answer 9

eleventh to twelth

Question 10

the main processes of the bell stage inlcude ________, _______, and _______

Answer 10

Proliferation, differentiation, morphogenesis

Question 11

during the bell stage the differentiation of enamel organ into bell shape with ______ cell types and dental papilla into ______ cell types

Answer 11

four, two

Question 12

the apposition stage begins at various times and the main processes include ______ and ______

Answer 12

induction, proliferation

Question 13

during the apposition stage the dental tissue types are secreted in successive layers as _______.

Answer 13

matrix

Question 14

the maturation stage begins at various times and the main process is _________

Answer 14

maturation

Question 15

during the maturation stage, the dental tissue types fully ________ to mature form

Answer 15

mineralize

Question 16

_______ is a process wherein one tissue directs the development of another adjacent tissue and mediated by ________ or factors released by the ________

Answer 16

induction, cell-contact, inducing
tissue

Question 17

induction signals usually regulate ________ thereby leading the target cells toward differentiating into a specific cell type

Answer 17

gene transcription,

Question 18

Induction can be ______ and _______ so that tissue A induces
tissue B and in turn later on tissue B then induces tissue A

Answer 18

serial, reciprocal

Question 19

Primary Epithelial band gives rise to ______ and ________

Answer 19

Dental lamina, Vestibular Lamina

Question 20

the epithelial band is a result of _______ and change of orientation of mitotic cells

Answer 20

mitosis

Question 21

meckel’s cartilage is part of the ectomesenchyme that gives rise to part of the _______ and mental portion of the _______

Answer 21

inner ear, mandible

Question 22

The ________ is requisite for tooth development

Answer 22

mandibular epithelium

Question 23

the ectomesenchyme cells will become the _______

Answer 23

dental papilla

Question 24

two important ligands involved in tooth development include __________ and __________

Answer 24

fibroblast growth factors (FGF), bone morphogenetic proteins

Question 25

Transcription factors are proteins in the nucleus that regulate the pattern of _______

Answer 25

gene expression

Question 26

Ectoderm derived FGF-8 regulates gene expression in ________

Answer 26

ectomesenchyme

Question 27

FGF-8 induces _______ and ______ in ectomesenchyme very early in development

Answer 27

Lhx-6, Lhx-7

Question 28

FGF-8 is highly expressed in the ______ arch ectoderm but if the ______ arch ectoderm is used in culturing experiments the expression of FGF-8 is low and tooth placodes do not form

Answer 28

first, second

Question 29

Expression of the PAX9 transcription factor in ectomesenchymal cells is required to differentiate into __________

Answer 29

DENTAL ectomesenchymal cells

Question 30

dental placode formation requires _________ for mitosis, ________ for apoptosis and cell division and _________

Answer 30

transcription factor p63, tumor necrosis factor, ectodysplasin

Question 31

Ectodysplasin (Eda) transmembrane protein that can be cleaved by ______ to produce a secreted form, involved in morphogenesis were loss of function causes ______ and over expression caused _______

Answer 31

furin, fewer teeth, extra teeth

Question 32

sonic hedgehog (shh) has roles in ______ development, _______ differentiation, ______ morphogenesis, ______ development, and forming the ______ of the body

Answer 32

limb, neural, facial, hair and feather, midline

Question 33

sonic hedgehog is important for _______ and ________

Answer 33

invagination, tooth development

Question 34

Once ectomesenchyme has been under the control of the epithelium in early tooth development it now is competent to drive tooth formation from ________ and later on the _______ takes over

Answer 34

skin epithelium, neural crest

Question 35

during tooth bud proliferation the _______ invaginates and moves into the ectomesenchyme that is made up of _________

Answer 35

oral ectoderm, neural crest cells

Question 36

the tooth bud stage is the stage where the ______ has a significant effect directing the development of the tooth

Answer 36

ectoderm

Question 37

The ectoderm of the dental lamina plus the underlying ectomesenchyme develop into the _______

Answer 37

tooth germ

Question 38

during the cap stage as the ectoderm develops and invaginates into the ectomesenchyme it begins to surround the cells that will become the _______

Answer 38

dental papilla

Question 39

the six molecules involved in the bud and cap stages includes _____, ______, _____, ______, _____ and _____

Answer 39

msx-1, bmp-4, bmp-2, SHH, activin-BA, Pax-9

Question 40

SHH is needed for the _____ stage

Answer 40

cap

Question 41

activin-BA and Pax-9 permit development past the ____ stage

Answer 41

bud

Question 42

The cap stage sees the formation of the dental organ (tooth germ) which includes the ________, _______ and ________

Answer 42

Enamel organ, Dental papilla, Dental follicle

Question 43

The enamel organ is attached to the ectoderm by the _________, has an _____ enamel epithelium, an ______ enamel epithelium all surrounding a _______

Answer 43

dental lamina, outer, inner, stellate reticulum

Question 44

Within the enamel organ, cells of the developing stellate reticulum secrete ________ accumulate which are ______ and draw in _____

Answer 44

glycosaminoglycans (GAGs), hydrophilic, water

Question 45

Water accumulation forms stellate reticulum by separating cells that remain attached in part through _______

Answer 45

desmosomes

Question 46

the stellate reticulum is transient and lost after ______ formation

Answer 46

enamel

Question 47

the enamel organ will eventually form the _______ of the tooth

Answer 47

enamel

Question 48

the dental papilla will eventually form the _______ and ______ of the tooth

Answer 48

dentin, pulp

Question 49

the dental sac/follicle will eventually form the _____, ______, and ______

Answer 49

Cementum, periodontal ligament, alveolar process

Question 50

Enamel "knot" are clusters of non- dividing epithelial cells and are part of the ______ enamel epithelium

Answer 50

inner

Question 51

in the enamel knot there is expression of FGF4, _____ first, then ______, and then ______, _____, _____, and _____

Answer 51

p21, SHH, Bmp2,4,7, Fgf-4.9, Wnt-10b, Slit-1

Question 52

the outer enamel epithelium serves as protective barrier for the ______

Answer 52

enamel organ

Question 53

stellate reticulum supports the production of _________

Answer 53

enamel matrix

Question 54

the stratum intermedium between the _____ enamel epithelium and _________ supports the production of _________

Answer 54

inner, stellate reticulum, enamel matrix

Question 55

the inner enamel epithelium will differentiate into _______ that form enamel matrix

Answer 55

ameloblasts

Question 56

outer cells of dental papilla will differentiate into ______ that form dentin matrix

Answer 56

odontoblasts

Question 57

Central cells of dental papilla will differentiate into ________

Answer 57

pulp tissue

Question 58

inner enamel epithelium cells are cuboidal with centrally placed nuclei and will differentiate into _______ epithelium

Answer 58

preameloblasts

Question 59

preameloblasts epithelium cells are columnar with nuclei closer to the __________

Answer 59

stratum intermedium

Question 60

during the bell stage the tooth assumes its ______

Answer 60

final shape

Question 61

Early in the Bell Stage the tooth germ maintains contact with the ectoderm via the dental lamina and proceeding through the Bell Stage ______ and _______ begin to form

Answer 61

enamel, dentin

Question 62

________ is found in the inner enamel epithelium

Answer 62

Glycogen

Question 63

_________ is found in the stratum intermedium

Answer 63

Alkaline phosphatase

Question 64

The junction of the inner and outer enamel epithelium is the _______

Answer 64

cervical loop

Question 65

in the later bell stage the dental lamina break up so tooth no longer connected to _______

Answer 65

oral epithelium

Question 66

the apposition stage is also called the secretory stage were _____ , ____ and ______ are secreted

Answer 66

dentin, cementum, enamel

Question 67

_______ is where ectodermal tissue of the enamel organ and ectomesenchymal tissue of the dental papilla and dental sac interact to signal the other layer to differentiate and begin secretion

Answer 67

Reciprocal Induction

Question 68

Preameloblasts induce the outer dental papilla cells to become _______

Answer 68

odontoblasts

Question 69

Preameloblasts become polarized with the base of the cell located along the _______

Answer 69

stratum intermedium

Question 70

________ are polarized in the opposite direction of the ameloblasts and the nucleus is at the opposite end of the cell from the ______

Answer 70

Odontoblasts, dentin

Question 71

Polarized odontoblasts secrete _______ toward the preameloblasts

Answer 71

predentin

Question 72

after predentin formation, preameloblasts are induced to become presecretory and then secretory ameloblast which then secrete ______

Answer 72

enamel

Question 73

Preameloblasts become _________ and they begin amelogenesis

Answer 73

ameloblasts

Question 74

Tomes processes of ameloblasts appear as the enamel matrix is produced where predentin is made and forms around ________

Answer 74

dentinal tubules

Question 75

Dentinal tubules contain odontoblastic processes and some odontoblast processes get surrounded by enamel at the tips and become _______

Answer 75

enamel spindles

Question 76

the appositional stage is where _______ and _______ are formed

Answer 76

dentin, enamel

Question 77

Amelogenesis imperfecta in the permanent dentition is a hereditary type of enamel dysplasia where the teeth have either _______ or _______ that chips off, leaving the yellow crowns of dentin, which undergo extreme attrition

Answer 77

no enamel, very thin enamel

Question 78

Dentinogenesis imperfecta in the permanent dentition is a hereditary type of dentin dysplasia that results in _______ with an opalescent sheen, chipped enamel, and crowns of dentin with severe attrition

Answer 78

blue-gray teeth

Question 79

The cervical loop is responsible for ___________

Answer 79

root formation

Question 80

Inner enamel epithelium of ________ induces odontoblasts of the root

Answer 80

Hertwigs root sheath (HERS)

Question 81

After root dentin formation the _______ disintegrates

Answer 81

HERS

Question 82

Some epithelial cells of the HERS may remain as Cell rests of _______, they may become cystic and are susceptible to infection and they end up being located in the ________

Answer 82

Malassez, Periodontal Ligament

Question 83

after the HERS disintegrates, cells of dental sac contact root dentin and become _________ which lay down cementum

Answer 83

cementoblasts

Question 84

cells are surrounded by cementum and become _________

Answer 84

cementocytes

Question 85

dental lamina forms at around ____ to ___ days

Answer 85

42, 48

Question 86

the bud stage of deciduous incisors, canines and molars begins at ___ to ____ days

Answer 86

55, 56

Question 87

bell stage for deciduous teeth and bud stage for permanent teeth begins at around _____ weeks

Answer 87

14

Question 88

dentin and functional ameloblasts in deciduous teeth begins at around ____ weeks

Answer 88

18

Question 89

dentin and functional ameleoblasts in permanent first molars begins at ____ weeks

Answer 89

32

Question 90

primary dentition begins to form at around ______ weeks in utero

Answer 90

6-8

Question 91

successional/permanent teeth from the successional lamina begin forming at the _____ week of gestation to ______ postnatal month

Answer 91

20th, 10th

Question 92

the first molars begin forming at around the ______ week of gestation onward

Answer 92

20th

Question 93

third molars begin forming at around the ______ of life

Answer 93

5th year

Question 94

Successional lamina arises from the _______ and gives rise to ________

Answer 94

dental lamina, permanent teeth

Question 95

the successional lamina gives rise to the _____, _____ and _____

Answer 95

incisors, canines, premolars

Question 96

Permanent molars arise ______from dental lamina

Answer 96

de novo

Question 97

the permanent molars grow _______ as jaw enlarges

Answer 97

posteriorly

Question 98

The reduced enamel epithelium appears as the tooth moves to erupt and it consists of the fused _______ enamel epithelium, _________, __________ and ________

Answer 98

outer, stellate reticulum, stratum intermedium, ameloblasts

Question 99

during eruption, as _______ enamel epithelium reaches ______ epithelium they fuse and epithelial integrity is maintained

Answer 99

reduced, oral

Question 100

Central cells degenerate and form the _________ and the rest of cells form the _______ epithelium and the ______ epithelium

Answer 100

eruption canal, junctional, gingival

Question 101

the shape of a tooth is the result of ________ activity

Answer 101

differential mitotic

Question 102

The type of tooth that develops once past the bud stage is dependent of the _______ and not the ______

Answer 102

ectomesenchyme, ectoderm

Question 103

_______ genes are transcription factors actin in the nucleus to regulate patters on gene expression and thus cell differentiation and development

Answer 103

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