01/24 Flashcards

1
Q

Why is tooth development important? (3)

A

a. Clinically, need to know if primary tooth should be treated, pulled, or left
b. Parents want to know developmental stage of child
c. Also very useful for forensic odontology (identifying people as well as aging via data)

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2
Q

Types of Tooth movement (4)

A

Pre-eruptive
Eruptive
Post-eruptive
Exfoliation

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3
Q

3rd molar with root in root formation stage-over 18?

A

50/50

*just an interesting fact, nothing too important

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4
Q

When do primary teeth start to erupt

A

6months-2 years

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5
Q

When do we see eruption of 1st molars (permanent)

A

6yrs +/-9 months

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6
Q

Which erupts first? Permanent 1st molars or incisors?

A

1st molars

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7
Q

When does tooth formation begin

A

in utero

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8
Q

Second permanent teeth to come in?

A

Central incisors

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9
Q

Which tooth may come in last?

A

The maxillary canine

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10
Q

As teeth grow, what else grows with it?

A

The alveolar process and thus the face

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11
Q

In order, how does the tooth form

A

Crown, root, and then the apex -biting surface down to root

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12
Q

Is how the tooth forms (direction) variable?

A

No-crown to apex

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13
Q

First part of the tooth to form

A

cusp tips

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14
Q

How to tell the age of someone based on odontology?

A

Use statistics available to you

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15
Q

Which surface forms first, mesial or distal?

A

mesial

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16
Q

Is crown formation done before root formation

A

Almost

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17
Q

During which stage is enamel and dentin formed?

A

Bell

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18
Q

After which stage does the root form

A

After the bell stage

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19
Q

Successional lamina

A

The bud for the permanent tooth

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20
Q

What is the exception of successional lamina

A

The 1st molars?? They form seperately

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21
Q

Oldest enamel and dentin will be where?

A

Cusp tips

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22
Q

Newest enamel/dentin will be where

A

@CEJ

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23
Q

What recruits odontoblast and initiate them to secrete dentin?

A

Ameloblast

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24
Q

Initiation & formation of teeth requires the interaction of 2 types of cells:

A
Oral Ectoderm (Oral Epithelial Cells)
Oral Mesenchyme (underlying Mesenchymal Cells)
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25
Oral Ectoderm --> dental lamina --> enamel organ --> | 5
``` Enamel  Intermediate cementum  Oral epithelium  Gingival attachment  Epithelial rests of Malassez ```
26
Migrate into jaws, contribute to tooth development by integrating with enamel organ & dental papilla
Neural Crest cells
27
``` function in development of salivary glands, bone, cartilage, nerves, muscles of the face. ```
Neural crest cells`
28
``` Surround cores of mesoderm to form 6 pairs of pharyngeal/branchial arches ```
Neural Crest Cells
29
Dental Sac is also known as what
Dental follicle
30
Role of Mesenchyme | 3
Increasing number and concentration of cells around the “bud.”  Cells which form the dental papilla and dental sac appear to remain undifferentiated  But, cells of the dental papilla itself exert a powerful influence on the developing tooth.
31
Developmental structures from Ectoderm (6)
``` Dental lamina  Vestibular lamina  Successional lamina  Enamel organ (dental organ)  Hertwig’s epithelial root sheath  Epithelial diaphragm  root formation ```
32
Primary Epithelial Band Covers what? Forms what? (3) *Know this
```  Covers each arch  Divides into:  Vestibular lamina  Dental lamina  Successional lamina (extends from dental lamina) ```
33
Dental Lamina first appearence
6wks IU
34
Dental Lamina forms what?
20 primary teeth |  12 permanent molars
35
Successional Lamina forms what
Extensions of dental lamina |  Form 20 permanent non-molar teeth
36
The appearance of all the developing teeth____ on the dental lamina at the same time.
does not occur
37
2 main phases of development – divided into stages
 Crown formation: enamel, coronal dentin, coronal pulp |  Root formation & eruption
38
Associating _______ with stages in development is of great assistance in diagnosing and dealing with “problem” teeth you will see in practice.
Cellular events
39
In order to understand stages of formation, it is helpful to be familiar with _________________ involved with tooth formation, and the changes these structures undergo in the process.
ectodermal & oral mesenchymal structures
40
Papilla | Some cells sit inside the cap =
Dental papilla
41
What produces odontoblast, pulp, dentin
dental papilla
42
4 layers  Reduced enamel epithelium
 Inner enamel epithelium – become ameloblasts  Stellate reticulum  Stratum intermedium Outer enamel epithelium
43
Cervical loop | (3 things)
 Root formation activity begins here as crown formation is completed  Outer & inner epithelial cells meet  Establishes the dentinoenamel junction
44
Cell signaling results in the alignment of precursor cells for formation of:
Enamel (inner enamel epithelium cells) |  Dentin (dental papilla cells)
45
Avery: ameloblast appears____odontoblast (name change)
before
46
Ameloblasts move _____ from DEJ Odontoblasts move from the DEJ
away outward from the DEJ away inward
47
Unless predentin is produced, ____
NO ENAMEL WILL FORM
48
Fusion vs gemination
Gemination is trying to split, has one root---fusion has two roots
49
Green teeth resulting from
neonatal hyperbilirubinemia:
50
Green teeth resulting from
neonatal hyperbilirubinemia:
51
Can we grow tooth buds?
Yes-in vitro
52
If a dental papilla from a future molar is placed under the enamel organ of a future incisor, a _____ develops.
molar
53
If the dental papilla of a future incisor is placed under the enamel organ of a future molar, an _____ develops.
incisor
54
If the dental papilla is placed beneath oral ectoderm of the buccal mucosa, a _____ develops.
tooth
55
If the dental papilla from a mouse is implanted in the developing tissue of a chicken beak,
a tooth develops.
56
If the dental papilla from a mouse is implanted in the developing tissue of a chicken beak,
a tooth develops.
57
How do permanent molars develop compared to decidous teeth
They develop exactly the same fashion as the 20 deciduous teeth  They cannot appear until jaw growth accommodates their presence and the dental lamina reaches the “molar area” of the jaw
58
How permanent non molar teeth form (think origin)
A small cluster of cells forms from the dental lamina associated with each primary tooth. This is the successional lamina. It is the equivalent of the “bud” stage of the other teeth. This “bud” stage progresses in exactly the same way and produces the permanent teeth.
59
Cervical loop is inactive until
Relatively inactive until crown formation complete
60
The cervical loop goes from a what to what
4 layer to 2 layer
61
Which 2 layers of the cervical loop remain and what do they form
 Only the outer & inner enamel epithelial layers remain |  2-Layer structure is known as Hertwig’s epithelial root sheath
62
odontoblasts | Stimulate dental papilla cells to become precursor
 Inner enamel epithelial cells
63
ecrete the predentin of Tome’s granular layer
Odontoblast
64
The presence of _______ stimulates the outer enamel epithelial cells to secrete intermediate cementum
Tome’s granular layer
65
The presence of Tome’s granular layer stimulates the outer | enamel epithelial cells to secrete _______
inermediate cementum
66
Remenant Hertwigs root is called
Epithelial rests of Malassez
67
Epithelial Diaphragm
As the root sheath grows from the cervical loop, the edge of the sheath inclines inward, forming a continually narrowing opening between the dental sac & the pulp
68
Epithelial diaphragm vs. epithelial root sheath?
Root sheath forms the root itself Diaphragm -Determines size & number of root canals which open into the pulp chamber, Just the folding in part really Separates the coronal pulp from the root canal(s)  Terms used interchangeably in some oral histology texts
69
Spicule formation on radiograph of developing tooth
Furcation developing
70
Epithelial root sheath provides the stimulus for: | (2)
 Root dentin formation |  Intermediate cementum
71
What provides root dentin
Dental papilla-stimulus is from epithelial root sheath
72
Why is the root sheath always the same size even though the root becomes increasingly long?
Once the root dentin is stimulated and the intermediate cementum is produced, the root sheath is no longer needed and it disintegrates
73
When is the root sheath only visible?
When it is in the process of stimulating root dentin formation  Therefore, the only portion that is visible is the portion near the future apical end of the root
74
Why is the root sheath always the same size even though the root becomes increasingly long?
The direction of overall tooth movement is in the occlusal direction
75
When does this root formation become complete? primary and perm
 Deciduous teeth: 1-1.5 years |  Permanent teeth: 2-3 years
76
Cysts in root formation may form where
Rests of malassez
77
Problems Associated with Root Formation | 4
``` Rests of Malassez -Cysts Enamel Pearls Cementicles -Embedded -Attached -Free Accessory Foramina ```
78
3 steps of tooth eruption (not the phases, just in general)
-Emerges through oral mucosa - Comes into occlusion -Functions in mastication
79
3 Stages of tooth development
 Pre-eruptive  Movements involved with the growth and development of the teeth, alveolar bone.  Pre-functional  Movements from the time of root formation through eruption in the oral cavity until contact with an opposing tooth.  Functional  Movements associated with function of the teeth.  Continuous process  Adjusts for jaw growth, occlusal wear
80
Pre eruptive phase
Movements involved with the growth and | development of the teeth, alveolar bone.
81
Pre functional
Movements from the time of root formation through eruption in the oral cavity until contact with an opposing tooth.
82
Functional phase
 Movements associated with function of the teeth.  Continuous process  Adjusts for jaw growth, occlusal wear
83
Kid advanced skeletally, advanced dentally tooth?
Maybe not
84
When does the dental lamina differentiate
6 weeks IU
85
Except for what teeth, permanent teeth are secondary buds off of the primary teeth.
permanent molars
86
as the alveolar process grows, what happens to developing teeth
``` As the alveolar processes develop, the unerupted tooth buds/developing teeth will re-orient themselves within this bone. ```
87
Where do permanent teeth position themselves at in comparison to erupting primary teeth
 Permanent teeth position themselves at apical 1/3 of erupting primary roots.
88
Where will ant perm teeth remain as pimary move to occlusal plane
``` Anterior permanent teeth remain at the base of the alveolar process as the primary teeth move toward the occlusal plane. ```
89
Premolars are initially located _____ to the primary molars, but…
lingual
90
``` As alveolar processes develop and primary teeth move toward the occlusal plane… Premolars relocate where ```
 Premolars relocate between | the roots of the primary teeth.
91
Max molars form in what? and tip which way
tuberosities and tip distally
92
Mandibular molars form in what? Tip which way?
Rami and tip mesially
93
As the maxilla and mandible develop and grow, the molars do what
molars will assume a more upright position.
94
Pre-Functional Eruptive movements start with what
initiation of root formation
95
4 main events of pre functional eruptive movements
```  Root formation  Movement occlusally  Penetration of the epithelium  Intra-oral occlusal movement ```
96
Pre-Functional Eruptive Movements -- Occlusal Movement  Occlusal movement of the tooth occurs:  Within the ____
bony crypt  As a result of a need for space for the developing root
97
The enamel is covered by only a thin layer of proteins called the
primary cuticle
98
The primary cuticle arises from the degrading
ameloblast
99
The primary cuticle is essential in initiating the attachment of the _____ to the ename
Junctional epithelium
100
Where does pre functional eruptive movement start
at the intial emergence through the epithelium and conttinues through stable occlusal contact
101
During pre functional eruption what are recruited to aid in destruction of tissue
macrophages Monocytes from the blood begin to fuse together, forming osteoclasts. Osteoclastic activity results in the destruction of any overlying bone. Resorption of the primary teeth are a result of osteoclastic (dentinoclastic) activity.
102
What causes resorption of emerging teeth
Not necessarily the pressure from emerging tooth, but a cellular process
103
During pre functional eruption if timing is right if not?
``` permanent tooth under primary tooth follows void left by the dissolving primary tooth roots  and the tooth erupts right underneath the exfoliation site of the primary tooth. ```  Ectopic eruption  Resorption of adjacent tooth root
104
During pre functional eruption if timing is right if not?
``` permanent tooth under primary tooth follows void left by the dissolving primary tooth roots  and the tooth erupts right underneath the exfoliation site of the primary tooth. ```  Ectopic eruption  Resorption of adjacent tooth root
105
How do teeth know where to go?
Eruption pathway – believed to guide the tooth out of | the bone and into the oral cavity