Tooth Development- Dr. Bumann (FINAL) Flashcards
1
Q
First sign of tooth development is at:
A
6-7 weeks in utero
2
Q
Deciduous teeth begin to calcify at:
A
13-20 weeks
3
Q
By _____ weeks in utero all deciduous teeth have begun to calcify
A
18-20 weeks
4
Q
Deciduous teeth typically erupt at:
A
6-30 months
5
Q
What is the first part of the tooth to calcify?
A
Crown
6
Q
What aspect of tooth development occurs in the dental lamina?
A
Initiation
7
Q
What aspect of tooth development occurs in the bud stage?
A
Morphogenesus
8
Q
What aspect of tooth development continues from bud stage to cap stage?
A
Morphogenesis
9
Q
The process of morphogenesis occurs during what stages of tooth development?
A
Bud & cap stage
10
Q
What aspect of tooth development occurs during the bell stage?
A
Cell differentiation
11
Q
What aspect of tooth development occurs during the eruption stage?
A
matrix secretion
12
Q
What is the most important part of tooth formation?
A
Cross-talk between epithelium & mesenchyme
13
Q
Signals of tooth development originate from the:
A
Oral ectoderm
14
Q
Signals that originate from the oral ectoderm cause:
A
The dental mesenchyme to start signaling
15
Q
List the stages of tooth development that contribute to crown formation:
A
- Initiation
- Bud stage
- Cap stage
- Bell stage
- Enamel & dentin formation
16
Q
The three main processes of tooth formation include:
A
- crown formation
- root formation
- supporting structures
17
Q
Initiation of tooth formation involves the:
A
Dental placode
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
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
20
Q
What epithelium is located between the maxillary & mandibular processes?
A
Odontogenic epithelium
21
Q
List all the processes of the developing human head:
A
- Frontonasal process
- Medial nasal process
- Lateral nasal process
- Maxillary process
- Mandibular process
22
Q
Where do the four maxillary incisors originate from?
A
From the medial nasal process
23
Q
What is the shape of the primary epithelial band?
A
Horsehoe
24
Q
The primary epithelial band corresponds to:
A
Future dental arches
25
The primary epithelial band gives rise to:
1. Dental lamina
2. Vestibular lamina
26
In the process of tooth development, it is the _____ of gene expression that helps to define regions
Patternign
27
In the process of tooth development, it is the _____ of gene expression that helps to define regions
Patterning
28
What two genes are important in presumptive incisor region?
BMP4 & islet1
29
What two genes target the presumptive molar region?
FGF8 & FGF9
30
_____ is expressed in the epithelium and _____ is expressed in the mesenchyme where the tooth bud would form
Shh; Pax9
31
Mice have _____ lower incisors & ____ upper incisors & _____ molars, none of which are ____-
two; two; three; succedaneous
32
What is really the initiation of tooth development?
The dental lamina formation
33
In the process of dental lamina formation, _____ formation results from epithelial thickening
Placode
34
In the process of dental lamina formation, what do we see happen to the epithelium?
Epithelial outgrowth into the mesenchyme
35
In the process of dental lamina formation, initial odontogenic potential lies in the epithelium but subsequently shifts to:
Mesenchyme
36
In the process of dental lamina formation, what induces the oral ectoderm to become the dental lamina?
Neural crest mesenchyme
37
In the process of dental lamina formation, the neural crest mesenchyme induces the _____ to become the _____
Oral ectoderm ---> dental lamina
38
What develops after the dental lamina formation?
Dental & vestibular lamina formation
39
The vestibular lamina will form the:
Vestibule
40
The vestibular lamina is separated from the surrounding mesenchyme by a:
Basement membrane
41
After the initiation of tooth development comes the ____ stage
Bud
42
During the bud stage of tooth development, epithelial cells show:
No major changes
43
During the bud stage of tooth development, what are the different signaling molecules involved in placode formation?
Shh
Lef-1
Eda-Edar
44
What does placode formation mean & what stage does it take place in?
Ectoderm thickening; bud stage of tooth development
45
During the bud stage of tooth development, what happens to the mesenchyme & why does this happen?
Mesenchyme beneath starts to condense; factors secreted by epithelium
46
During the bud stage of tooth development, we have cross-talk between:
Epithelium & mesenchyme
47
During the bud stage of tooth development, ______ potential is in the epithelium
Odontogenic
48
Tooth number is determined during:
Initiation
49
Tooth size & shape are determined during:
Morphogenesis
50
Tooth tissues & mineralization occurs during:
Differentiation
51
Bud stage is extremely important in determine tooth:
Size & shape
52
The primary enamel knot is formed during:
Cap stage
53
The stage of tooth development in which the epithelium penetrates the mesenchyme & continues to condense:
Cap stage
54
What happens to epithelium during the cap stage?
Proliferates
55
In the cap stage, when the epithelium continues to proliferate, the mesenchyme continues to:
Condense
56
During the cap stage, the tooth germ is compose of:
Enamel organ & dental papilla
57
The enamel organ is the:
Enamel of the tooth
58
Enamel is formed by the _____ which is coming from the ____, NOT the ____
Ameloblasts; epithelium NOT neural crest derived
59
During the cap stage, the dental papilla on the outer side forms the _____ while the dental papilla on the inner side forms the ____
dentin; pulp
60
During the cap stage, what aggregates to form the dental papilla?
Ectomesenchymal cells
61
Bud to cap stage transition is regulated by:
Signaling molecules & transcription factors
62
During the cap stage, following the early cap stage, we know have the:
Enamel knot formation
63
During the cap stage, what is responsible for forming some of the supporting structures such as cementum, periodontium & alveolar bone proper?
Dental follicle/Dental sac
64
During the cap stage, the dental follicle/dental sac forms some of the supporting structures such as:
1. Cementum
2. Periodontium
3. Alveolar bone proper
65
During the cap stage, this is the key signaling center that consists of cluster of non-dividing cells and determines cusp formation:
Enamel knot
66
What stage of tooth development is the enamel knot formed?
Cap stage
67
The enamel knot is a _____ that consists of ____ cells that determine _____
key signaling center; cluster of non-dividning cells; cusp formation
68
Their are both ____ & ____ enamel knots
primary & secondary
69
What the third part of the cap stage of tooth development (following enamel knot formation):
Cap stage histodifferentiation
70
When cells of the enamel organ synthesize glycosaminoglycans into the ECM:
Cap stage histodifferentiation
71
During cap stage histodifferentiation, cells in the enamel organ synthesize:
Glycosaminoglycans
72
During the cap stage histodifferentiation, cells in the enamel organ synthesize glycosaminoglycans into the ECM & this makes these cells:
Hydrophilic & pull water into the enamel organ
73
During the cap stage histodifferentiation, the increase in fluid volume force the cells apart leading to the formation of:
Star-shaped stellate reticulum cells
74
During the cap stage histodifferentiation, what is the purpose of the star-shaped stellate reticulum cells?
Helps to form the shape of your tooth
75
During the cap stage histodifferentiation, the enamel organ epithelial cells start to separate out into:
1. Inner enamel epithelium (IEE)
2. Outer enamel epithelium (OEE)
76
An important regulator of tooth number (during cap stage):
SPRY-2
77
In a study in which the SPRY-2 regulator was knocked out in mice, what occurred & why did this occur?
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
Name three characteristic commonents of tooth development:
1. Secondary enamel knot
2. Ameloblasts
3. Odontoblasts
79
In the early bell stage of tooth development:
1. Undersurface of the epithelium ____ & resembles a ____
2. ____ formation
3. ____ attains full size & shape
1. deepens; bell
2. stratum intermedium
3. crown
80
Where are the succedaneous teeth formed from?
Permanent tooth bud/successional lamina
81
Permanent dentition forms ____ to the deciduous dentition
lingual
82
Looking at gene expression, we have a higher level of gene expression of ____ & ____ as you move towards the:
BMP4 & MSX1 ; Buccal/cheek
83
On the ____ side of the mice we have inhibition of signaling of BMP4 & MSX1 by _____
Lingual side; OSR2
84
What would happen if we made an OSR2 knockout mouse?
Because we are taking away the inhibition on the lingual side we will have mice with succedaneous teeth
85
OSR2 is an important regulator of:
Succedanous tooth formation
86
What are two processes that occur during the early bell stage of tooth development?
1. Morphodifferentiation
2. Cervical loop formation
87
In the early bell stage of tooth formation, low cuboidal shaped cells are forming in the:
OEE
88
In the early bell stage of tooth formation, short columnar shape cells are forming in the _____ & will differentiate into _____
IEE; ameloblasts
89
In the early bell stage of tooth formation, the junction of the IEE & OEE is called the _____ & is the future site of ____
Cervical loop (CL); CEJ
90
In the late bell stage of tooth development, what happens to the dental lamina?
Dental lamina breaks & separates tooth from oral epithelium
91
In the late bell stage of tooth development, the IEE completes folding forming the:
Future crown pattern
92
In the late bell stage of tooth development, the folding of IEE is due to:
Differential rates of mitotic division in IEE
93
In the late bell stage of tooth development, under the influence of IEE, mesenchymal cells differentiate into ____ that makes ____
Odontoblasts; dentin
94
In the late bell stage of tooth development, after the mesenchymal cells differentiate into odontoblasts (under influence of IEE) to make dentin, the IEE:
Differentiate into amelobladst to make enamel
95
What differentiates into ameloblasts to make enamel?
IEE
96
In the late bell stage of tooth development, the site at which IEE differentiates determines:
future cusp formation
97
Following the bell stage of tooth development, what processes occur?
Enamel, dentin & pulp formation
98
Enamel formation may also be called:
Amelogenesis
99
What are the stages of amelogenesis?
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
What stage of amelogenesis is the most active laying down of enamel?
Secretory stage (with tomes process)
101
Are tomes process involved in the initial secretory stage of amelogenesis?
NO
102
We see intense synthetic & secretory activity in the ____ stage of amelogenesis
secretory stage
103
During the secretory stage of amelogenesis we have formation of:
Enamel rod & inter-rod
104
During amelogenesis the ameloblasts secrete granules on the newly formed:
Mantle dentin
105
The most outer layer of laid down dentin:
Mantle dentin
106
Secretory proteins involved in amelogenesis include:
-amelogenin
-ameloblastin
-enamelin
107
The proteases involved in amelogenesis include:
-enamelysin (mmp20)
-kallikrein
108
During enamel formation this structure is involved in the orientation of enamel:
Striae of Retzius
109
What type of cells make dentin?
Odontoblasts
110
What type of cells differentiate into odontoblasts to make dentin?
Mesenchymal cells
111
First layer of dentin formed by newly differentiated odontoblasts, hypo mineralized & only in the crown of the tooth (30-50 micrometers thick)
Mantle dentin
112
Dentin formed during tooth development (4 micrometers per day)
Primary dentin
113
Dentin formed after tooth eruption (0.4 micrometers per day)
Secondary dentin
114
Dentin produced in response to injury to protect the pulp (cariogenic or trauma)
Tertiary dentin
115
Holds the odontoblasts together & shoot out their odontogenic processes into the dentin:
Junctional apparatus/complex
116
TAKE HOME:
We have preodontoblasts that differentiate into ______ & these start to lay down ____
Odontoblasts; dentin
117
TAKE HOME:
Over the initial layer of dentin, laid down by odontoblasts we have breakdown of the:
Basement membrane
118
TAKE HOME:
The breakdown of the basement membrane (over the initial layer of dentin) is where we see _____ go to ______
Pre-ameloblasts go to pre-secretory ameloblasts
119
TAKE HOME:
The pre-secretory ameloblasts in combination with the dentin turn into ____ & the ____ can be laid down
dentin; secretory ameloblasts; enamel
120
What happens first, root development or crown calcification?
Crown calcification
121
In root formation, the IEE & OEE form the cervical loop & proliferate downward to form a double-layered structure called _____ also the site of ____
Hertwig's epithelial root sheath; CEJ
122
In root formation, _____ differentiate, and ______ forms
Odontoblasts; dentin
123
The completion of root formation occurs as it grows apically down, towards the:
Alveolar bone
124
Unlike bone, cementum lacks:
Blood & nerve supply
125
During cementum formation, we have fragmentation of _____ causing it to be mostly removed before the cementum is laid down:
Hertwig's epithelial root sheath
126
During cementum formation, we have the differentiation of:
Cementoblasts
127
During cementum formation, remnants of HERS are called:
Epithelial rests of malassez
128
Cementum may be ____ or ____
Cellular or acellular
129
The type of cementum that seems to very lightly line the outside of the root:
Acellular
130
The type of cementum found at the apex & towards the bottom of the root:
Cellular cementum
131
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 _____
Odontoblast processes; sensitivity
