Tooth Development- Dr. Bumann (FINAL) Flashcards

1
Q

First sign of tooth development is at:

A

6-7 weeks in utero

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2
Q

Deciduous teeth begin to calcify at:

A

13-20 weeks

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3
Q

By _____ weeks in utero all deciduous teeth have begun to calcify

A

18-20 weeks

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4
Q

Deciduous teeth typically erupt at:

A

6-30 months

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5
Q

What is the first part of the tooth to calcify?

A

Crown

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6
Q

What aspect of tooth development occurs in the dental lamina?

A

Initiation

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7
Q

What aspect of tooth development occurs in the bud stage?

A

Morphogenesus

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8
Q

What aspect of tooth development continues from bud stage to cap stage?

A

Morphogenesis

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9
Q

The process of morphogenesis occurs during what stages of tooth development?

A

Bud & cap stage

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10
Q

What aspect of tooth development occurs during the bell stage?

A

Cell differentiation

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11
Q

What aspect of tooth development occurs during the eruption stage?

A

matrix secretion

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12
Q

What is the most important part of tooth formation?

A

Cross-talk between epithelium & mesenchyme

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13
Q

Signals of tooth development originate from the:

A

Oral ectoderm

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14
Q

Signals that originate from the oral ectoderm cause:

A

The dental mesenchyme to start signaling

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15
Q

List the stages of tooth development that contribute to crown formation:

A
  1. Initiation
  2. Bud stage
  3. Cap stage
  4. Bell stage
  5. Enamel & dentin formation
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16
Q

The three main processes of tooth formation include:

A
  1. crown formation
  2. root formation
  3. supporting structures
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17
Q

Initiation of tooth formation involves the:

A

Dental placode

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18
Q

What plays an important role in getting the mesenchyme that is going to form the teeth into the proper location?

A

Neural crest mesenchyme

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19
Q

Where do the majority of our teeth originate?

A

Through the first pharyngeal arch where two parts of the maxillary & the mandibular processes are

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20
Q

What epithelium is located between the maxillary & mandibular processes?

A

Odontogenic epithelium

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21
Q

List all the processes of the developing human head:

A
  1. Frontonasal process
  2. Medial nasal process
  3. Lateral nasal process
  4. Maxillary process
  5. Mandibular process
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22
Q

Where do the four maxillary incisors originate from?

A

From the medial nasal process

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23
Q

What is the shape of the primary epithelial band?

A

Horsehoe

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24
Q

The primary epithelial band corresponds to:

A

Future dental arches

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25
Q

The primary epithelial band gives rise to:

A
  1. Dental lamina
  2. Vestibular lamina
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26
Q

In the process of tooth development, it is the _____ of gene expression that helps to define regions

A

Patternign

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27
Q

In the process of tooth development, it is the _____ of gene expression that helps to define regions

A

Patterning

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28
Q

What two genes are important in presumptive incisor region?

A

BMP4 & islet1

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29
Q

What two genes target the presumptive molar region?

A

FGF8 & FGF9

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30
Q

_____ is expressed in the epithelium and _____ is expressed in the mesenchyme where the tooth bud would form

A

Shh; Pax9

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31
Q

Mice have _____ lower incisors & ____ upper incisors & _____ molars, none of which are ____-

A

two; two; three; succedaneous

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32
Q

What is really the initiation of tooth development?

A

The dental lamina formation

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33
Q

In the process of dental lamina formation, _____ formation results from epithelial thickening

A

Placode

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34
Q

In the process of dental lamina formation, what do we see happen to the epithelium?

A

Epithelial outgrowth into the mesenchyme

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35
Q

In the process of dental lamina formation, initial odontogenic potential lies in the epithelium but subsequently shifts to:

A

Mesenchyme

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36
Q

In the process of dental lamina formation, what induces the oral ectoderm to become the dental lamina?

A

Neural crest mesenchyme

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37
Q

In the process of dental lamina formation, the neural crest mesenchyme induces the _____ to become the _____

A

Oral ectoderm —> dental lamina

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38
Q

What develops after the dental lamina formation?

A

Dental & vestibular lamina formation

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39
Q

The vestibular lamina will form the:

A

Vestibule

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40
Q

The vestibular lamina is separated from the surrounding mesenchyme by a:

A

Basement membrane

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41
Q

After the initiation of tooth development comes the ____ stage

A

Bud

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42
Q

During the bud stage of tooth development, epithelial cells show:

A

No major changes

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43
Q

During the bud stage of tooth development, what are the different signaling molecules involved in placode formation?

A

Shh
Lef-1
Eda-Edar

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44
Q

What does placode formation mean & what stage does it take place in?

A

Ectoderm thickening; bud stage of tooth development

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45
Q

During the bud stage of tooth development, what happens to the mesenchyme & why does this happen?

A

Mesenchyme beneath starts to condense; factors secreted by epithelium

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46
Q

During the bud stage of tooth development, we have cross-talk between:

A

Epithelium & mesenchyme

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47
Q

During the bud stage of tooth development, ______ potential is in the epithelium

A

Odontogenic

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48
Q

Tooth number is determined during:

A

Initiation

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49
Q

Tooth size & shape are determined during:

A

Morphogenesis

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50
Q

Tooth tissues & mineralization occurs during:

A

Differentiation

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51
Q

Bud stage is extremely important in determine tooth:

A

Size & shape

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52
Q

The primary enamel knot is formed during:

A

Cap stage

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53
Q

The stage of tooth development in which the epithelium penetrates the mesenchyme & continues to condense:

A

Cap stage

54
Q

What happens to epithelium during the cap stage?

A

Proliferates

55
Q

In the cap stage, when the epithelium continues to proliferate, the mesenchyme continues to:

A

Condense

56
Q

During the cap stage, the tooth germ is compose of:

A

Enamel organ & dental papilla

57
Q

The enamel organ is the:

A

Enamel of the tooth

58
Q

Enamel is formed by the _____ which is coming from the ____, NOT the ____

A

Ameloblasts; epithelium NOT neural crest derived

59
Q

During the cap stage, the dental papilla on the outer side forms the _____ while the dental papilla on the inner side forms the ____

A

dentin; pulp

60
Q

During the cap stage, what aggregates to form the dental papilla?

A

Ectomesenchymal cells

61
Q

Bud to cap stage transition is regulated by:

A

Signaling molecules & transcription factors

62
Q

During the cap stage, following the early cap stage, we know have the:

A

Enamel knot formation

63
Q

During the cap stage, what is responsible for forming some of the supporting structures such as cementum, periodontium & alveolar bone proper?

A

Dental follicle/Dental sac

64
Q

During the cap stage, the dental follicle/dental sac forms some of the supporting structures such as:

A
  1. Cementum
  2. Periodontium
  3. Alveolar bone proper
65
Q

During the cap stage, this is the key signaling center that consists of cluster of non-dividing cells and determines cusp formation:

A

Enamel knot

66
Q

What stage of tooth development is the enamel knot formed?

A

Cap stage

67
Q

The enamel knot is a _____ that consists of ____ cells that determine _____

A

key signaling center; cluster of non-dividning cells; cusp formation

68
Q

Their are both ____ & ____ enamel knots

A

primary & secondary

69
Q

What the third part of the cap stage of tooth development (following enamel knot formation):

A

Cap stage histodifferentiation

70
Q

When cells of the enamel organ synthesize glycosaminoglycans into the ECM:

A

Cap stage histodifferentiation

71
Q

During cap stage histodifferentiation, cells in the enamel organ synthesize:

A

Glycosaminoglycans

72
Q

During the cap stage histodifferentiation, cells in the enamel organ synthesize glycosaminoglycans into the ECM & this makes these cells:

A

Hydrophilic & pull water into the enamel organ

73
Q

During the cap stage histodifferentiation, the increase in fluid volume force the cells apart leading to the formation of:

A

Star-shaped stellate reticulum cells

74
Q

During the cap stage histodifferentiation, what is the purpose of the star-shaped stellate reticulum cells?

A

Helps to form the shape of your tooth

75
Q

During the cap stage histodifferentiation, the enamel organ epithelial cells start to separate out into:

A
  1. Inner enamel epithelium (IEE)
  2. Outer enamel epithelium (OEE)
76
Q

An important regulator of tooth number (during cap stage):

A

SPRY-2

77
Q

In a study in which the SPRY-2 regulator was knocked out in mice, what occurred & why did this occur?

A

Additional tooth in diastema region; because SPRY-2 normally blocks the signaling of SHH so when you knock it out this regulation is no longer there

78
Q

Name three characteristic commonents of tooth development:

A
  1. Secondary enamel knot
  2. Ameloblasts
  3. Odontoblasts
79
Q

In the early bell stage of tooth development:

  1. Undersurface of the epithelium ____ & resembles a ____
  2. ____ formation
  3. ____ attains full size & shape
A
  1. deepens; bell
  2. stratum intermedium
  3. crown
80
Q

Where are the succedaneous teeth formed from?

A

Permanent tooth bud/successional lamina

81
Q

Permanent dentition forms ____ to the deciduous dentition

A

lingual

82
Q

Looking at gene expression, we have a higher level of gene expression of ____ & ____ as you move towards the:

A

BMP4 & MSX1 ; Buccal/cheek

83
Q

On the ____ side of the mice we have inhibition of signaling of BMP4 & MSX1 by _____

A

Lingual side; OSR2

84
Q

What would happen if we made an OSR2 knockout mouse?

A

Because we are taking away the inhibition on the lingual side we will have mice with succedaneous teeth

85
Q

OSR2 is an important regulator of:

A

Succedanous tooth formation

86
Q

What are two processes that occur during the early bell stage of tooth development?

A
  1. Morphodifferentiation
  2. Cervical loop formation
87
Q

In the early bell stage of tooth formation, low cuboidal shaped cells are forming in the:

A

OEE

88
Q

In the early bell stage of tooth formation, short columnar shape cells are forming in the _____ & will differentiate into _____

A

IEE; ameloblasts

89
Q

In the early bell stage of tooth formation, the junction of the IEE & OEE is called the _____ & is the future site of ____

A

Cervical loop (CL); CEJ

90
Q

In the late bell stage of tooth development, what happens to the dental lamina?

A

Dental lamina breaks & separates tooth from oral epithelium

91
Q

In the late bell stage of tooth development, the IEE completes folding forming the:

A

Future crown pattern

92
Q

In the late bell stage of tooth development, the folding of IEE is due to:

A

Differential rates of mitotic division in IEE

93
Q

In the late bell stage of tooth development, under the influence of IEE, mesenchymal cells differentiate into ____ that makes ____

A

Odontoblasts; dentin

94
Q

In the late bell stage of tooth development, after the mesenchymal cells differentiate into odontoblasts (under influence of IEE) to make dentin, the IEE:

A

Differentiate into amelobladst to make enamel

95
Q

What differentiates into ameloblasts to make enamel?

A

IEE

96
Q

In the late bell stage of tooth development, the site at which IEE differentiates determines:

A

future cusp formation

97
Q

Following the bell stage of tooth development, what processes occur?

A

Enamel, dentin & pulp formation

98
Q

Enamel formation may also be called:

A

Amelogenesis

99
Q

What are the stages of amelogenesis?

A
  1. Morphogenetic stage
  2. Histodifferentation stage
  3. Initial secretory stage (NO TOMES PROCESS)
  4. Secretory stage (TOMES PROCESS)
  5. Ruffle ended ameloblasts of the maturation stage
  6. Smooth ende ameloblasts of the maturation stage
  7. Protective stage
100
Q

What stage of amelogenesis is the most active laying down of enamel?

A

Secretory stage (with tomes process)

101
Q

Are tomes process involved in the initial secretory stage of amelogenesis?

A

NO

102
Q

We see intense synthetic & secretory activity in the ____ stage of amelogenesis

A

secretory stage

103
Q

During the secretory stage of amelogenesis we have formation of:

A

Enamel rod & inter-rod

104
Q

During amelogenesis the ameloblasts secrete granules on the newly formed:

A

Mantle dentin

105
Q

The most outer layer of laid down dentin:

A

Mantle dentin

106
Q

Secretory proteins involved in amelogenesis include:

A

-amelogenin
-ameloblastin
-enamelin

107
Q

The proteases involved in amelogenesis include:

A

-enamelysin (mmp20)
-kallikrein

108
Q

During enamel formation this structure is involved in the orientation of enamel:

A

Striae of Retzius

109
Q

What type of cells make dentin?

A

Odontoblasts

110
Q

What type of cells differentiate into odontoblasts to make dentin?

A

Mesenchymal cells

111
Q

First layer of dentin formed by newly differentiated odontoblasts, hypo mineralized & only in the crown of the tooth (30-50 micrometers thick)

A

Mantle dentin

112
Q

Dentin formed during tooth development (4 micrometers per day)

A

Primary dentin

113
Q

Dentin formed after tooth eruption (0.4 micrometers per day)

A

Secondary dentin

114
Q

Dentin produced in response to injury to protect the pulp (cariogenic or trauma)

A

Tertiary dentin

115
Q

Holds the odontoblasts together & shoot out their odontogenic processes into the dentin:

A

Junctional apparatus/complex

116
Q

TAKE HOME:

We have preodontoblasts that differentiate into ______ & these start to lay down ____

A

Odontoblasts; dentin

117
Q

TAKE HOME:

Over the initial layer of dentin, laid down by odontoblasts we have breakdown of the:

A

Basement membrane

118
Q

TAKE HOME:

The breakdown of the basement membrane (over the initial layer of dentin) is where we see _____ go to ______

A

Pre-ameloblasts go to pre-secretory ameloblasts

119
Q

TAKE HOME:

The pre-secretory ameloblasts in combination with the dentin turn into ____ & the ____ can be laid down

A

dentin; secretory ameloblasts; enamel

120
Q

What happens first, root development or crown calcification?

A

Crown calcification

121
Q

In root formation, the IEE & OEE form the cervical loop & proliferate downward to form a double-layered structure called _____ also the site of ____

A

Hertwig’s epithelial root sheath; CEJ

122
Q

In root formation, _____ differentiate, and ______ forms

A

Odontoblasts; dentin

123
Q

The completion of root formation occurs as it grows apically down, towards the:

A

Alveolar bone

124
Q

Unlike bone, cementum lacks:

A

Blood & nerve supply

125
Q

During cementum formation, we have fragmentation of _____ causing it to be mostly removed before the cementum is laid down:

A

Hertwig’s epithelial root sheath

126
Q

During cementum formation, we have the differentiation of:

A

Cementoblasts

127
Q

During cementum formation, remnants of HERS are called:

A

Epithelial rests of malassez

128
Q

Cementum may be ____ or ____

A

Cellular or acellular

129
Q

The type of cementum that seems to very lightly line the outside of the root:

A

Acellular

130
Q

The type of cementum found at the apex & towards the bottom of the root:

A

Cellular cementum

131
Q

In individuals who have a larger gap between their cementum & enamel (some people do not have gap at all, some even overlap), _____ are exposed and theses patients will often complain of _____

A

Odontoblast processes; sensitivity