1
Q
what are the stages of tooth development?
A
Initiation
Bud
Cap
Bell
2
Q
What week does odontogenesis occur?
A
6th Prental week
3
Q
What are the two tissue types of initiation of odontogenesis
A
- Oral epithelium (Dental Lamina) 2. Ectomesenchyme
4
Q
Steps of Initiation of Odontogenesis 2 steps
A
- Formation of all hard tissues and soft tissue surrounding the tooth
- Induction is the main process involved
5
Q
Hard tissue of teeth
A
Enamel
Dentin
Cementum
6
Q
Soft tissue of teeth
A
PDL
pulp
7
Q
What is the primary epithelial Band formation ?
week 6-7
A
- Thickened epithelium (ectoderm) in location of future jaw
- Rapid Cell Division
8
Q
Primary Epithelial Band Formation gives rise to …
A
Dental Lamina and Vestibular Lamina
9
Q
Bud Stage occurs at which week?
A
8th week prenatally
10
Q
What happens in Bud Stage?
A
Dental Lamina grows into a bud and penetrates/influences the growing ectomesenchyme
11
Q
What does the stellate reticulum make?
A
Glycosaminoglycans (attracts water)
12
Q
The Bud becomes the
A
Enamel organ shaped like a cap (Cap stage)
13
Q
In the Cap Stage Mesenchyme becomes
A
Dental Papilla
14
Q
In the cap stage Inner Enamel epithelial cells become
A
Ameloblasts
15
Q
What makes the Ameloblasts ?
A
Inner enamel epithelial cells
16
Q
What are Ameloblasts?
A
Cells during tooth development that deposit tooth enamel
17
Q
What are Stellate Reticulum ?
A
Star shaped cells connected to each other Makes Glycosaminoglycans
18
Q
In the cap stage the dental follicle surrounding ?
A
Dental Papilla and Enamel Organ
19
Q
Developmental Abnormalities occurring in the Cap Stage
A
- Dens in dente (Dens Invaginalis)
- Fusion
- Gemination
20
Q
Dens in dente ( dens invaginalis)
A
- Tooth within a tooth
- Enamel organ expands more than it should and it invaginates into the dental papilla
(Cap Stage)
21
Q
Fusion
A
- Fewer number of teeth
- Extra wide crown with one pulp cavity
- Union of two teeth by dentin and enamel
(Cap Stage)
22
Q
Gemmination
A
- Correct Number of Teeth
- Wide Bifid Crown
- One tooth germ attempting to divide into two
23
Q
What makes the tooth germ ?
A
- Enamel Organ
- Dental Papilla
- Dental Follicle
24
Q
Histodifferentiation
A
Bell Stage
- In the enamel organ
- Stellate reticulum →inner & outer enamel epithelia
25
Ameloblasts start forming ........
What stage?
**_Bell Stage_**
enamel at cusp tips and move outward
26
Odontoblasts start forming....
(What stage?)
**_Bell Stage_**
* start formin dentin and move inward
27
What forms the crown ?
(What stage)
**_Bell Stage_**
* inner enamel epithelium
28
When does the dental lamina disintegrates?
Bell Stage
29
Histodifferentiated enamel organ
| (What stage)
**_Early Bell Stage_**
## Footnote
Cervical loop region is supported up the basal lamina
30
Bell stage abnormalities
1. Macrodontia
2. Microdontia (peg lateral)
3. Amelogenesis Imperfect (enamel deffect -yellow)
4. Dentinogenesis Imperfecta (deffective dentin- opaque)
31
Tooth germ→Dental Follicle→ (3)
Dental Follicle→Cementoblasts→Cementum
Dental Follicle→Fibroblasts →Periodontal Ligament
Dental Follicle→Osteoblasts →Alveolar Bone
32
Tooth Germ→Dental Papilla → (2)
Dental Papilla →Odontoblasts→Dentin
Dental Papilla →Undifferentiated Mesenchymal →Pulp
cells Fibroblasts
33
Tooth germ→Enamel organ →Cervical loop
Ceverical Loop→Hertwig's root sheath→Root Form
34
Tooth Germ→Enamel Organ→?
to get to Primary Juctional Epithelium
stellate reticulum→ inner+ outer enamel epithelium→ reduced enamel epithelium→ Primary Juctional Epithelium
35
What do the inner enamel epithelial cells become?
Tooth Germ→Enamel Organ→Inner Enamel Epithelium→Ameloblasts→Enamel
36
What are the two types of Dentin?
Primary Dentin
Secondary Dentin
37
Primary Dentin
While tooth is forming and erupting
38
Secondary Dentin
After the tooth has erupted and root almost done
39
Tertiary Dentin
Response to trauma
(Attrition, Caries, Dental Restorations)
40
Types of Primary Dentin
1. Mantle Dentin
2. Interglobular ( or Globular Dentin)
3. Circumpulpal Dentin
41
Mantle Dentin
Next to DEJ
Large collagen fibers
Primary Dentin
42
Interglobular (or Globular) Dentin
know this
Globules are Calcified
Intergloubular spaces are hypomineraized
Primary Dentin
43
Circumpulpal Dentin
* Bulk of the Dentin
* Thinner in the root
* has small collagen fibers
Primary Dentin
44
Peritubular Dentin
* Hypermineralized
* Found in dentin except near pulp and interglobular dentin
45
Intertubular Dentin
* Primary product of odontoblasts
* Lies between tubules
46
Dead Tracts
1. Death of odontoblasts due to old age and trauma
2. Tubules are open
47
Sclerotic Dentinal Tubules
* Permeabile to pulp eliminated (pulp protection)
* increase with age
(Dentinal fluid in tubule crystalizes )
48
Another name for sclerotic Dentinal tubules
Transparent dentin
49
Lines of Von Ebner
* Dentin growth lines
* Every 5 days 20 microns are formed
50
Neonatal Line
* Only primary teeth
* Dentin before birth is superfical (perfect)
* Neonatal Line
* Dentin after birth is deep ( more imprefections)
51
Granular Layer of Tomes in Root Dentin
Interface of collagen and noncollagenous matrix proteins between cementum and dentin
52
Dentinogenesis
formation of dentin via
1. Odontoblasts
2. Predentin
3. Enamel
53
Predentin
Unmineralized Dentin
54
Odontoblasts remain functional for\_\_\_\_\_\_\_\_
Ameloblasts remain functional for\_\_\_\_\_\_\_\_\_
Odontoblasts- functional for life
Ameloblasts stop
55
What does the mineralization of predentin do to the odontoblast ?
Lengthens them
| (no other diifrentiation can occur)
56
Dentin is formed in two phases
1. Predentin-organic matrix deposited
2. inorganic mineral substance is added
57
Mineralization of Predentin
1. Crystals of Calcium Hydroxyapetite appear in the matrix vesicles
2. Crystals grow and rupture the membrane and clump with other crystals
58
In what stage of tooth development does dentinogenesis start?
Early Bell Stage
59
How does the odontoblast process change as it lays down dentin? What direction does it move?
It elongates outward
60
Lines of Retzius
(Enamel Striae)
may represent appositional (incremental) growth of enamel
61
Transverse section of Lines of retzius look like
Concentric rings (like growth rings in a tree)
62
Neonatal Line is an accentuated
straie of Retzius
63
Neonatal Line represents physiological changes on\_\_\_\_\_\_at birth
ameloblasts
64
Hunter-Schreger bands
* alternating dark and light lines due to changes in direction of enamel rods
* found in inner 2/3 of enamel
65
Enamel Tufts
* Groups of of hyomineralized enamel rods
* short dark projections near DEJ
(no known clinical significance)
66
Neonatal line is also found in?
Enamel
67
Enamel Spindle
* Odontoblastic remnats that become stuck durring differentiation of ameloblasts
* Extensions of dential tubules (tip)
68
Amelogenesis starts in the
early bell stage
69
Ameloblasts start to lay down...
enamel starting at the crown working down to the CEJ
70
Inner Enamel Epithelium differentiate to beome
(When does this happen)
Ameloblasts
(after some dentin has been laid down by odontoblasts)
71
Tomes' Process of the ameloblast
(Secretory Stage of Amelogenesis)
lays down enamel →moves pulpally
72
Tomes' Fiber of the odontoblast
As dentin is formed the odontoblast moves pulpally
73
As amelogenesis is completed and amelogenin is deposited
the matrix begins to mineralize
74
Ameloblast Analogy: Tome’s Process is like a frosting tip. .....
It secretes the vesicles which carry the enamel products that will make up enamel rods and interrods.
75
Secretor stage
mineral deposit % of enamel
25% - intial mineral deposit Ameloblast
70%- mineral deposit from growth of crystals
4-5%- organic and water
76
Time between enamel matrix depostion and mineralization is
short
77
secretory/maturative stage
enamel matrix formation and mineralization start at the cusp tips then goes cervically to the CEJ
78
Pulp Zones
1. Odontoblasts
2. Cell free Zone of Weil
3. Cell rich zone
4. Pulp ( pulp proper, central zone)
79
Pulpal Innervation
Can onlt transmit only pain signals
no proprioceptors
80
Proprioceptors
are sensory receptors that respond to position and movement
81
What is the plexus in the pulpal innervation?
Plexus of Raschkow (parietal layer)
82
Plexus of Raschkow consists of
consists of myelinated and unmyelinated nerves
83
Types of nerves in the pulp
A Delta fibers
C Fibers
84
A delta fibers
* Myelinated sensory nerve fibers
* Fast, sharp, pricking pain
* 90% of nerve fibers are A delta
85
Where are A delta fibers located ?
coronal (odontoblastic) area of pulp
86
C Fibers
* Unmyelinated
* Slow, dull, burning, aching pain
87
Types of Cementum
Acellular (primary) Cementum
Cellular (Secondary) Cementum
88
Acellular (primary) Cementum
* Thin layer surrounding the root next to the dentin
* Has no cells
89
Cellular (secondary) cementum
* Less mineralized
* thicker
* along the apical root and interradicular areas of multi rooted teeth
90
Cementocytes
1. cemntoblasts enclosed in a self-generated matrix (lacunae)
2. Matrix mineralized
3. Cemntoblasts stop secreting become **Cementocyte**
91
Periodontal Ligament Forms from
ectomesenchyme present in the dental follicle
92
Periodontal Ligament differntiate to fibroblasts and create
collagen fibers
sharpey's fibers (type 1 collagen)
93
Cells of the periodontal Ligament
1. Fibroblasts
2. Macrophages, mast cells , eosinophils (aid in defense)
3. Osteoclast
4. Undifferentiated mesenchymal cells
5. Cementoblasts, Cementoclasts
94
Fibroblasts in the periodontal ligament
most abundant cells
PDL has high collagen content
Rapid Replacement of fibers
makes collagen
95
Principle Fibers
1. Gingival Group
2. Dentoalveolar Group
3. Fibers are collagen bundles that attach teeth to gingiiva or bone
96
Which fibers attach teeth to teeth?
Transseptal fibers
97
Apical Fibers
1. Group
2. Function
3. Attach
1. Dentoalveolar Group
2. Resist Vertical Forces
3. Attach tooth to gingiva
98
Oblique Fibers
1. Group
2. Function
3. Attach
1. Dentoalveolar Group
2. Resist Vertical and Intrusive Forces
3. Attach teeth to bone
99
Horizontal Fibers
1. Group
2. Function
3. Attach
1. Dentoalveolar
2. Resist horisontal and tipping forces
3. Attach teeth to gingiva
100
Alveolar Crest
1. Group
2. Function
3. Attach
1. Dentoalveolar
2. Resist Vertical and intrusive forces
3. teeth to gingiva
101
Interradicularr
1. Group
2. Function
3. Attach
1. Dentoalveolar group
2. Resist vertical and lateral movement
3. attach teeth to gingiva
102
Transseptal Fibers
1. Group
2. Function
3. Attach
1. gingival group
2. resist tooth movement mesial distal
3. teeth to teeth
103
Name all the dentoalveolar fibers
Apical
Obliqe
Horizontal
Alveolar Crest
Interradicular
A, O, H, AC, I
104
Circular Fibers
1. Group
2. Function
3. Attach
1. Gingival Fiber Group
2. Form a bandaround tooth, interlacing with eachother
3. attach tooth to gingiva
105
Dentogingival
1. Group
2. Function
3. Attach
1. Gingival Fiber
2. 3 Most numerous, ectend from cervial cementum to lamina propria of attached and free gingiva
106
Alveologingivial fiber
## Footnote
1. Group
2. Function
3. Attach
1. extend from the bone of the alveolar crest into the lamina propria of the attached and free gingiva
107
Dentoperiosteal
## Footnote
1. Group
2. Function
3. Attach
1. Gingival fibers
2. run apically over periosteum and into the vestibule or floor of the mouth
108
Oxytalin Fibers
* type of elastic fiber
* go obliquely from cementum to blood vessels
109
Sharpey's Fibers
* Collagnours Fibers
* Embedded in Cementum and alveolar bone proper
110
Osteoclasts
bone resorption in periodontal disease
111
Alveolar Bone is made of
1. Alveolus
2. Alveolar Bone Proper
3. Supporting Bone
112
name of tooth socket
Alveolus
113
Bone linninig the tooth socket
Alveolar Bone proper
114
Lamina dura
is alveolar bone proper in radiographic terms
115
cancellous bone that inderlies the alveolar bone proper
supporting bone
116
another name for alveolar bone proper ?
Lamina dura
cribiform plate
117
Another name for Trabecular Bone ?
Supporting
Cancellous
spongy
118
Bundle Bone
inner linning of the alveolar bone
where the periodontal ligament fibers (sharpey's fibers) connnect to bone
119
Cortical Bone vs. cancellous (trabecular) bone
Cortical (outside)
cancellous (inside)
both have haversian (osteon) systems
120
Another name for Haversian system is
Osteon ( cylindrical in shape)
121
Types of Gingiva
Free or marginal gingiva
Attached Gingiva
122
Free or marginal gingiva
| (attached gingiva)
1. keratinized
2. From gingival margin to the free gingival groove
123
oral mucosa, attached
* keratinized
* Bound to the alveolar bone and the tooth
* goes from free gingival groove to muccogingival junction
124
Junctional Epithelium
* Not attached to enamel , but parts of the cementum
* where gingiva attaches to the tooth creating a seal
125
Junctional Epithelium attachment apparatus
hemidesmosomes attach to the basal lamina
cej
126
Interdental Papilla
* Stippling of the attached gingiva similar to surface of an orange peel
* occupy the embrasure (cervical space where teeth contact)
127
128
Interdental Col
Valley between buccal and lingual peaks
(Near contact point of two adjacent teeth)
129
Oral Mucosa
stratified squamous epithelium and lamina propia(CT)
130
Lamina Propria
made of type I and III collagen, elastic fibers, and ground substance
(fibroblasts, endothelial, immune cells, blood vessels)
1. Papillary Layer
2. Reticular Layer
131
papillary layer
\*\*\*\*know this
(part of lamina propria)
* Btwn epithelial ridges
* collagen fibers are thin and loose
132
Reticular Layer
(part of Lamina Propria)
1. collagen fibers are thick , wavey and parallel
133
Succedaneous teeth
teeth that take over a position formerly occupied by a primary tooth
(Incisors, canines, and bicuspids/premolars)
134
Nonsuccedaneous
Teeth are Molars. Do not move into position formerly occupied by a primary tooth
135
Pre-eruptive Functional Phase
Reduced enamel epithelium fuses with the epithelial layer
this will become junctional epithelium
136
Gubernacular Cord
Pre-eruptive Functional Phase
* Follicular cells develop a gubernacular cord directed toward the surface mucosa
* guides tooth eruption
137
How is the reduced enamel epithelium associated with the junctional epithelium?
Reduced Enamel Epithelium become Junctional Epithelium
138
Primary teeth has __ teeth
20
139
Eruption Sequence - Primary Dentition
A B D C E
140
Eruption Sequence Permanent entition Upper arch
6 1 2 4 5 3 7
141
Eruption Sequence Permanent dentition
lower arch
6 1 2 3 4 5 7
142
Leeway space
**_Mixed dentition_**
Mesiodistal widths of the primary molars **\>**
mesiodistal width of the permanent molars
Permanent molar can move mesially to close the space
143
Leeway space and crowding
need to hold teeth back to create room for the primary teet
144
Rule of four
(Primary teeth erupion sequence )
***Eruption of _four teeth_ every _four months_ starting with fourth teeth at _7 months_ of age***
