Root Development and PEriodontium Flashcards
(253 cards)
1
Q
Anton van Leeuwenhoek’s addition to science
A
Simple microscope
Disoveded Animalcules
Enamel, dentin, bone (not cementum
2
Q
Marcello Malpighi addition to science
A
Malpighian corpuscles
Pyramids of kidneys
Malpighian tubules in insects
Substantia tartarea on roots of teeth
3
Q
when were compound light microscopes invented
A
early 1800s
4
Q
what did Jan Purkinje discover
A
Purkinje cells and fibers
5
Q
what did Anders Rwtzius find
A
Striae of Retzius by looking at dentin tubules
6
Q
other name for outer substance
A
Cortical substansen
7
Q
other name for bony cells
A
Osseous corpuscula
8
Q
other name for bony substnace
A
substantia ossea
9
Q
what did GReene Vardiman black do
A
Classification of caries
Amalgam preps
Foot powered drill
first detailed understanding of how cementum functions for periodontium
Recognized Sharpey’s fibers in cementum and bone unite the periodontal complex
Describe reparative cementum
10
Q
what is the tooth root
A
Root dentin
associated root canals (pulp)
11
Q
what is the support system for the tooth
A
Periodontium
12
Q
what makes up the periodontium
A
Cementum
Alveolar bone
Periodontal ligament
Gingiva: tooth associated and gingival ligaments
13
Q
what defines the edge of enamel organ during bell stage
A
The cervical loop
14
Q
what kind of structure is the cervical loop
A
A crown strucutre
15
Q
what defines the forming root
A
Hertwig’s epithelial root sheath
16
Q
when does the Cervical loop turn into hertwig’s epithelial root sheath
A
Initiation of root development
17
Q
what is Hertwig’s epithelial root sheath derived from
A
The cervical loop
18
Q
what is HErtwig’s epithelial root sheath an exention from
A
Enamel organ
19
Q
what is HErtwig’s epithelial root sheath made of
A
Bilayer strucuture of IEE and OEE
20
Q
what does Hertwig’s epithelial root sheath do
A
Architect of the root defining size and shape and number of roots (morphogenesis)
Induces root odontoblast differentiation
21
Q
How does HERS pdefine a single rooted tooth
A
Proliferates apically to define the root
22
Q
How does HERS make multiple roots
A
Epithelial interradicular processes
23
Q
what are Epithelial interradicular processes
A
Tongues of epithelium growing towards one another
24
Q
what does HERS cell migration and proliferation determine
A
Size shape and number of roots
25
what does HERS do for root odontoblasts
Causes them to differentate via epithelial-mesenchymal signaling
26
what is the dental papilla made of
Undifferentiated ectomesenchymal cells
27
what does HERS do to Dental papilla cells
Induces them to differentiate to pre-odontoblasts then odontoblasts
28
how does Root dent form
In steps with HERS proliferation
29
What does HERS signal to the Dental papilla
Smad4 transcription factor
| Sonic hedgehog secreted signal to papilla cells
30
what does HERS signalling to the dental papilla lead to
Induces Gli1 TF
Downstream Nfic TF
Odontoblast differentiation
31
what cannot be done without Nfic
Dental papilla cannot respond to HERS signaling and cells do not differentiate into odontoblasts
Rootless Teeth
32
what genetic disease causes Rootless teeth
Autsomal dominant Dentin Dysplasia type I (TF, SMOC2 and others)
33
what else might rootless teeth cuase
Short, poorly developed roots
Obliterated pulp chambers
Mobility, tooth loss
34
What are some developmental root defects
Rootless teeth
Dilaceration (deformity in shape and direction)
Taurodontism (large pulp chambers at expense of root/fucations)
35
what causes Developmental root defects
HERS growth and root dentin formation
36
DEvelopmental defects might do what to teeth
PRone to breakage, exfoliation, ankylosis, difficult extraction, ortho movement, other issues
37
What happens to the HERS over time
Disintegrates shortly after infucing root odontoblast differentiations
Some become epithelial rest of Malassez
38
how do Epithelial rests of Malassez appear
As clumps, strands, or networks of cells in the PDL
39
what surrounds the Epithelial rests of Malassez
Basement membrane
40
Where are Epithelial rests of Malassez found
Close to root
| sometime several cell layers away
41
Function of Epithelial rests of Malassez
Can cause cysts
periodontal homeostasis or regeneration
but not sure
42
is root dentin continuous with crown dentin
they are continuous
43
how is dentinogenesis different in Root and crown
nearly the same, but interacts with IEE of HERS instead of enamel organ
44
Cell differentiation within the Root Dentin
Ectomesenchym, Dental Papilla, Pre-odontoblasts, Odontoblasts
45
types of dentin in the root
Mantle
Circumpulpal
predentin
Primary, secondary, tertiary
46
what deffines the types of Cementum
Presence/absence of cells within its matrix
| Origin of collagen fibers of the matrix
47
what is another name for Primary cementum
Acelular cementum
| Aceullar extrinsic fiber cementum
48
what is another name for secondary cementum
Cellular cementum
| Cellular intrinsic fiber cementum
49
how much of the root is covered with Primary or secondary cementum
Primary: upper 2/3 of the root
Secondary: appilcal 1/3 of the root
50
What are the types of cemenetum
Major: primary acellular and secondary cellular cementum
| additional types: Acellular afibrillar Cementum (AAC), cellular mixed stratified cementum
51
what is Cellular mixed stratified cementum
Mix of alternating acellular and cellular layers
52
are all types of Cementum separated completely
No, they overlap
53
what does Acellular cementum cover
the cervical 2/3 of root
54
what is the primary cementum
the first formed cementum ( Acellular)
55
cells of Acellular cementum
No cells
56
what does Cellular cementum cover
apical 1/3 of root
57
what is the secondary cementum
the second formed cementum (cellular cementum)
58
cells of Cellular CEmentum
Cementocytes
59
special function of cementum
Attachment
Protection
Adjusting
Sealing
60
attachment roll of cementum
important for strong periodontal structure cementing the tooth in the socket
61
what type of cementum does attachment
Acellular cementum primarily
62
how doe cementum protect
Protects roots from resorption and repairing resorption pits
63
what is the adjusting roll of cementum
adjusts tooth position
64
what type of cementum does the adjusting
Cellular
65
Sealing roll of cemntum
seals the dentin tubles (hydrodynamic theory of dental sensitivity and inhibits bacterial invasion)
66
composition og cementum
like bone and dentin
50% inorganic HA
35% organic
15% water
67
Organic components of cementum
Collagen type I(90%)
other collagen type III and VII
non collagenous proteins
glycosaminoglycans (10%)
68
How is cementum different from bone
Avascular
No innervation
No turnover (growth by apposition)
69
Origin of cementoblasts
Derived from dental follicle (ectomesenchym)
70
Function of Cementoblasts
Make acellular and cellular cementum
71
Product of cementoblasts
Collagens
ECM proteins
Enzymes for cementum mineralization
72
Fate of Cementoblasts
Remain in PDL close to cementum surface
Regulate slow cementum growth through life
direct cementum repair
73
origin of Cementocytes
Subset of cementoblasts
| embedded in cellular cementum matrix (dental follicle, ectomesenchyme)
74
function of cementocytes
unknown
75
produces of cementocytes
less than cementoblasts
76
Features of cementocytes
Reside in lacuna
| extend dendrites through canaliculi to communicate and receive nutrients
77
Fate of Cementocytes
Remain in lacunae for life
| may die their
78
origin of Dental follicle
Ectomesenchymal
79
What is the dental follicle a precurosor for
CEmentoblasts
PDL fibroblasts
Osteoblasts
80
what happens right before Cementum forms
Root dentin exists
| HERS disintegrates to expose the root dentin surface
81
what do Cementoblasts differentiate from
the dental follicle
82
what do the Cementoblasts secrete to initiate cementogenesis
Initial collagen fibers
83
what do the initial collagen fibers in cementum do
Intermingle with unmineralized dentin at the CDJ
84
what do the initial collagen fibers connect to
Intrinsic and not yet connected with the PDL (Doesn't even exist yet)
85
what happens to the dentin once the cementum initial collagen fiber bundles intermingle with dentin collagen fibers
Dentin completes mineralization
86
hardness of the DCJ
less hard to serve as a cushion between cementum and dentin
87
how were the origin of cementoblasts and cementum found
60s-90s
Electron microscopy
Ultrastructural evidence
88
what makes up the Hertqigs epithelial root sheath
Inner enamel epithelium
| Outer enamel epithelium
89
does the PDL exist during cementogenesis
No, the dental follicle consists of loose collagen fibers around the developning tooth
90
what do the Pre cementoblasts do the outer enamel epithelium
break through it do go the the Dnetin to eventually prenetrate into the dentin matrix
91
what do the cell processes of the PRe-cementoblasts contain
Microfilaments and ribosomes
92
how do Cementoblasts look
Hang out on the root surface
| Well developed Golgi, rER
93
what happens to the IEE once cementoblasts form
remnants of IEE away from the root sruface
94
what do PDL fibroblasts produce
primary collagen fiber bundles of PDL space
95
what do the primary collagen fiber bundles of the PDL space do
stitched to first cementum intrinsic fibers
96
what are the extrinsic fibers
a continuation of the initial intrinsic fibers
97
what do the extrinsic fibers become
mineralized sharpey's fibers within cementum
98
what is the major fiber group for acellular cementum
Extrinsic fibers
99
what is the density of extrinsic fibers in acellular cementum
high density
100
importance of extrinsic fibers to accellular cementum
critical to the function
101
where do sharpey's fibers insert
insert into both acellular cemntum and alveolar bone
102
what are sharpey's fibers
Mineralized collagen fiber bundles for a strong anchorage of tooth-PDL-bone
103
Roll of Cementoblasts in cementogenesis
PRomote HA deposition betweena nd within collagen fibers
104
what are Sharpeys fibers made of
Mineralized collagen fibers cont with PDL in cementum and alveolar bond
105
how does Mineralization of cementum occur(Directyion)
from the root sruface out towards the bone
106
what is the scaffold for Cementum mineralization
Fiber fringe at the cementum-PDL interface made of Collagen substrated (Type I and Others)
107
what do Cellular secretions of ECM (non collagen) proteins participate in
Mineral precipitation
108
where do cells direct mineralization
in and between collagen fibers by ECM proteins and enzymes
109
how are extrinsic collagen fibers mineralized
Progressive mineralization
110
what is the fiber before cementum initiation
Fiber fringe
111
what happens when the Fiber fringe becomes engulfed and mineralized
Sharpey's fibers
112
how does Mineralization of the Acellular cementum do
Mineralizes slowly over time (abuot 3 micrometers a year)
113
Aceullar cementum thickness over tie
Becomes thicker over time
114
what do secondary cementoblasts produce
Cementum matrix rapidly (cementoid)
| produce intrinsic collagen fiber deposited into the cellular cementum ECM
115
what teeth have little cellular cementum
Incisors and canines (little role in tooth attachment)
116
how is Cellular cementum adaptive
Maintains tooth in proper occlusal position by compensating for enamel attrition throughout life
117
where can cellular cementum repair cementum resporption
anywhere on the root
118
how does Cellular cementum look before mineralization
a clear unmineralized cementoid quivalent to predetin or osteoid
119
steps of Cellular cementum mineralization
Cementoblast secreete collagen and other proteins
Time lag
Matrix mineralized
120
what can lead to delayed Mineralization
Excess cementoid
121
what conditions affect cementoid similarly to the osteoid
Conditions that delay/inhibit mineralization
122
What is embedded in cellular cementum atrix
Cementocytes
123
what are cementocytes connected to
connected to one another and the surface (PDL)
124
what are Cementocytes equivalent to
Osteocytes in bone
125
what types of cementum grow slowly throughout life
Both acelular and cellular cementum
126
how does CEmentum grow
no remodeling/turnover
| grows via appositional growth
127
appositional growth
addition to the existing layer
128
what indicates successive layers of cementum
Longitudinal lines/striations/appositional growth lines
129
does resporption of cementum occur
sometimes
130
Classical hypothesis for cementum original
Ectomesenchym
dental follicle
cementoblasts
131
Alternative hypothesis for cementum origin
Dental epithelium
HERS
epithelial-mesenchymal transformation to cementoblasts
132
what allows follicle cells (pre-cementoblasts) to access root surface
Fenestration of HERS
133
too little cementum
cementum aplasia
| Hypoplasia
134
too much cementum
Hypercementosis, may lead to ankylosis
135
loss of cementum
External root resorption
| Deriodontal diseases
136
what is Hypophosphatasia
A rare skeletal disease leading to High ppi
| Acellular cementum aplasia or hypoplasia
137
what is mutated in Hypophosphatasia
mutations in ALPL gene for tissue nonspecific alkaline phosphatase (TNAP an TNSALP)
138
roll of TNAP
breaks down pyrophosphate an inhibitor of mineralization
139
what does Hypophosphatasia affect
`bone (skeletal and craniofacial
Dentin
enamel
Acellular cementum most dramatic in terms of severity and prevalencedefec
140
defective/absent cementum due to hypophophatasia leads to
loose teeth
| premature loss of primary and secondary teeth as fully rooted HPP teeth
141
Excessive cementum growth
Hypercementosis
142
Cause of Hypercementosis
TRauma
Genetics
Idiopathic
143
symptoms of Hypercementosis
Generally asymptomatic
ankylosis
difficult in extraction
144
genetic hypercemetnosis is the opposite of what
HPP
145
protein for Acellular cemetnum
Bone sialoprotein (BSP)
146
where was Bone sialoprotein found
First discovered in bone but also in dentin and cementum
147
roll of bone sialoprotein
Promotes ha formation
| acellular cementum formation in mice
148
knockout of Bone Sialoprotein leads to
Cementum hypoplasia
PDL detachment
Periodontal breakdown
149
human equivalent to Bone Sialoprotein knockout in mice
consistent with aspects of aggressive periodontitis
150
what does external root resporption
Odontoclasts (osteoclast like cells)
151
how common is root resportion
common to be mild in 1 or more teeth
152
Root resportion is caused by
Excessive orthodontic force (usually apical effect)
related to trauma, severe periodontitis, genetics
also idiopathic
153
Multiple idiopathic cervical root resporption
agressive as 19 teeth affected over 30 yeras
| 11 extracted/exfoliated
154
treating Multiple idiopathic cervical root resportion
effective treatment
155
what causes root surface caries
Bacteria/plaque
156
what is the Root (surface) caries
Exposed root surface
| Soft, progressive lesion distinct from clastic resporption
157
when does Reparative cementum form
Following root cementum resorption by osteoclasts and odontoclasts
158
what does Reparative cementum form
Fills resporption pit (Howship's lacuna)
159
what kind of CEmentum is reparative cementum
Cellular regardless of location
160
Concerns with Reparative cementum
How well is it bound to dnetin
| is new cementum well attached to PDL
161
what does the alveolar process/bone form
the socket that holds the tooth
162
types of bone in the alveolar bone
```
cortical plates buccal and lingual
Trabecular bone (spongiosa)
```
163
what part of the alveolar bone is invovled with periodontal function
alveolar plate
164
the alveolar bone lining the socket, inner aspect facing tooth root
Bundle bone or alveolar bone proper
165
what is included int he alveolar bone
Extrainsic collagen fiber bundles, mineralized sharpey's fibers (similar to acellular cementum)
166
size of primary fiber entering bundle bone vs cementum
PRimary fibers are larger and less dense in bundle bone
167
what is the lamina fura
a radiopaque layer lining the socket of alveolar bone
168
why is lamina dura more radiopaque
from thick bone without trabeculation not increased mineral content
169
radiooapquiolucenticity of PDL
PDL is radiolucent
170
is the compact bone of the alveolar process entirely solid
Not entirely solid
171
performations of the compact bone of the alveolar processis for
Blood vessels and nerves to enter the PDL space
172
what is the cribiform plate
a strucuture pierced by many small holes
173
cells of the alveolar bone
```
Hematopoietic stem cells
Monosyte/macrophage
Osteoclast
Extomesenchyme
dental follicle/mesenchymal stem cells
Pre-osteoblast
Osteoblast
lining cell
osteocyte
```
174
what cells work in function to do bone remodelling
Osteoclasts and osteoblasts
175
the fastest remodling bone in the body
Normal remodeling of the alveolar bone
176
Normal bone resorption allows for what
Tooth eruption
177
Normal tooth resporptions occures when
When decidious teeth are exfoliated
178
when does abnoraml tooth resporption occure
when clasts resorb the roots of permanent teeth
179
roll of the alveolar bone
Distribute occlusal loads
180
existance of alveolar bone depends on what
the interaction with teeth
181
the mechanostate thtoery of bone loading
Bone loading cuases growth
| bone unloading cuases loss
182
what happens to alveolar bone of edentualous mandible
gradually lost
183
Wolff's law/ frosts mechanostate model of reponse to bone loading
bone loading cuases bone growth
| Bone unloading cuases bone loss
184
what are periodontal ligaments
soft fibrous connective tissue between tooth and alveolar bone
185
ligament
fibrous connective tissue connecteing bone to bone
186
PEriodontal ligametn
Connects bone to tooth in a unique joint called a gomphosis or tooth socket
187
width of the periodontal ligament
.1-.4 mm but varius with person and healthy
188
Functions of pdl
```
Supportive
Nutritive
sensory
Defensive
maintenance/reparative
adaptive
```
189
supportive function of the pdl
primary collagen fibers attach tooth to bone
190
nutritive function of the pdl
Blood supply to cells of the region, including cementoblasts and cemetocytes
191
sensory function of the PDL
innervated for sensing posotion and pain
192
defensive function of the PDL
delivers immune cells including macrophages and neutrophils
193
Maintenacne/reparative function of the PDL
contains stem and progenitor cells that can repair or regenerate pdl, bone, cementum
194
adaptive roll of PDL
based on mech loading, adpats fiber orientation and influences neighboring alveolar bone remodeling
195
how does the PDL arrange itself
to accept and distribute tensile forces from mastication
196
what happens to PDL after ortho movement
returns to the same width
197
components of the PDL
Ground substance
Collagen fibers
Oxtalan fibers
198
GRound subance of the PDL
amorphous background material of proteins, proteoglycans, and water
199
what types of collagen are in the PDL
I, III, XII
200
what does the Collagen fibers make up in the PDL
```
fiber bundles (spliced rope)
97% of fibers
```
201
oxytalan fibers
small elastic fibers, support collagen fibers and blood vessel walls
202
commonness of Oxytalan fibers
3%
203
elastic fibers in the pdl
None, PDL is more stiff for wistanding forces
204
organization of the PDL in pre-emergence stage
PDL collagen fibers disorganized parallel to tooth/root
205
what happens to the PDL in the pre-functional and functional stage
Increase org
More fibers perpendicular/oblique to root/bone
Cementum as attachment
206
Collagen fibers bundles spand from what to what in the PDL
from mature tooth to bone (except transseptal group is tooth to tooth
207
Function of the PDL principle fiber groups
Resist intrusive and extrusive forces, tipping, and lateral movements
208
groups of PDL principle fiber
```
transseptal
Alveolar crest
horizontal
oblique
apical
Interradicular group
```
209
the main PDL group resisting occlusal loads (intrusive)
Oblique group
210
what PDL travesl from tooth to tooth
TRansspetal fibers
211
major cell of the PDL
Firboblasts (lots)
212
roll of Fibroblasts in the PDL
secrete and remodel matrix
213
what does the PDL fibroblasts associate with
Collagen fibers to act as mechanotransducers
214
Cells of the PDL
```
Fibroblasts
Osteoblasts, osteoclasts
Epithelial rests of Malassez
Stem/progenitor cells
Immune cells
```
215
Roll of Stem/progenitor cells of the PDL
Ability to differentiate and regenerate
216
what gives blood tothe PDL
Superior and interior alveolar arteries
217
the major route of blood flow to the PDL
PErforating vessels (alveolar or intra-alveolar)
218
what are the extra routes of blood flow to the PDL
Apical routes and gingival vessel routes
219
what way does Venous drainage occure
axial direction
220
were is gingival crevicular fluid found
Found in the sulcus/gingival margin
221
importance of gingival crevicular fluid
transudate from vasculature
| Diagnostic value
222
forces of mastication
LArge forces across short distances via hard teeth
223
what controls the forces of amstication
peripheral feedback (stops toooth damage and supporting tissues)
224
proprioception
periodontal complex to provide sensory feedback on tooth psosition, bite force, presence of objects....
225
do all bites occur at the same force
NO depends on consistency
226
how sensitive is the dental sensation in periodontius
detect 1 grain of sand between teeth
227
tyeps of nerve endings in the PDL
Free ending, tree like
Ruffini ending (slow adpating, found in skin)
coiled endings
Encapsulated endings
228
most common ending in the PDL
Free endings, tree-like
229
where are free endings found in the PDL
founding along the length of the root
230
receptors of free endinds in te PDL
nociceptors and mechanorecetpors
231
where are Ruffini endings found
near apex
232
receptors of Ruffini endings
Mechanoreceptors
233
were are coiled endings found in the PDL
mid region of the PDL
234
function of coiled endins
Unknown
235
where are ENcapsulated endings found in the PDL
near the apex
236
function of encapsulated endins
Unknown
237
Nociceptors
sensory receptor for painful stimuli
238
what odd things may be found in the PDL space
ERM
Cementicle
Ankylosis
239
Cementicle
Ectopic cementum in PDL attached or unattached
240
Ankylosis
Cementum-bone fusion leading to a loss of PDL space
241
epithelium of the gingiva
Oral epithelium
sulcus epithelium
Junctional epithelail
242
where is junctional epithelium found
enamel and cementum
243
roll of junctioanl epithelium
Barrier to microbial invastion with a fast turnover
244
what is junctional epithelium made from
Leftover enamel organ/reduced enamel epithelium
245
what are gingival liagemnt goupds
not pdl, but collagen fiber bundles spaning from tooth/bone to gingiva connective tissue
246
where are gingival ligament groups found
in lamina propria (underlying connective tisssue) of the gingiva
247
function of the gingival ligament groups
Resist gingival displacement
248
tyesp of gingival ligament groups
Circular group
Dentogingival
Dentoperiosteal
Alveologingival
249
what causes periodontal disease
Infection via a perio pathogens (porphyromonas gingivalis)
250
what does PEriodontal disease lead to
Inflammation
| loss of periodontal strucutres (cementum, PDL, alveolar bone)
251
Inflammation of periodontitis is caused be
Inflammatory cytokines
matrix metalloproteinases
Osteo/odontoclasts
252
how does one do periodontal regeneration
scaling
root planing
antibitoic therapy
Guided tissue regeneration
253
protein used in periodontal regeneration
Emdogain and other growth factors that rely on stem/progenitor cells
