Unit 1 Flashcards
1
Q
Develop similarly to tooth:
A
Hair, salivary gland, sebaceous gland, sublingual gland, and mammary gland:
2
Q
the dental pulp is made of:
A
Fibrous Connective Tissue (fibroblasts and stem cells)
3
Q
Where in the tooth are stem cells located?
A
dental pulp and PDL
4
Q
Pulp is formed by these cells:
A
fibroblasts
5
Q
Dental Epithelial Cells:
A
Ameloblasts
6
Q
Ectomesenchymal cells are derived from what?
A
Neural crest cells
7
Q
Tooth cell types that are derived from neural crest cells:
A
odontoblasts, pulp fibroblasts, cementoblasts
8
Q
What tooth structure do dental epithelial cells form?
A
enamel
9
Q
Origin of neural crest cells:
A
dorsal neural tube
10
Q
Neural tube derivatives:
A
ectodermal origin (brain, CNS, etc.)
11
Q
Neural crest derivatives:
A
ectodermal original (face, teeth, head, maxilla, mandible)
12
Q
TF? The neural tube and the neural crest both produce s structures of ectodermal origin.
A
T
13
Q
Migration of NC cells:
A
down side of face to developing head and bronchial arches
14
Q
The enamel organ is found in:
A
the lower mesenchyme
15
Q
Issue arising form completely undifferentiated NC cells:
A
craniofacial malformations
16
Q
Stomodeum:
A
primitive oral cavity
17
Q
Stomodeum is lined by:
A
oral epithelium
18
Q
The stomodeum is present at this wk of development:
A
3-wk
19
Q
How many layers of oral epi are there in the 6-7 wk old embryo?
A
3-4 cell layers
20
Q
Where is cell proliferation taking place in the oral epithelium of the 6-7 wk embryo?
A
the areas where teeth develop, thickening the tissue
21
Q
The dental epi is comprised of:
A
enamel organ and enamel formation
22
Q
This lines the gut of the 3-wk old embryo:
A
Buccopharyngeal membrane
23
Q
To where do NC cells migrate in the tooth forming areas?
A
close to dental epi
24
Q
NC’s bc this in the tooth forming areas:
A
ectomesenchymal cells (undif CT cells)
25
Are the NC cells involved in tooth development?
yes
26
These cells create CT:
odontoblasts, and pulp fibroblasts
27
Origin and function of ectomesenchymal cells:
Origin: Ectodermal, Function: mesenchyme
28
What can happen if there is a failure of NC cell migration?
adontia (absence of teeth) or micrognathia (undeveloped jaw bone)
29
4 stages of tooth development:
dental lamina, bud, cap, bell
30
Formation of what tooth structure occurs first?
crown, then root
31
What dermal layer is associated with the mesenchyme?
ectoderm
32
Stages of tooth development:
dental lamina, (ectoderm), bud, cap, bell, late bell, (crown/eruption)
33
When do neural crest cells become ectomesenchymal cells?
after they migrate close to/ into the dental epithelium
34
What can cause the failure of neural crest cells to migrate?
signallling molecules not expressed or turned on at the right time
35
Initiation of tooth development begins at day:
37
36
Initiation of tooth development begins with the formation of:
primary epithelial band, horse-hoe band of epi in upper and lower
37
2 subdivisions of each primary epi band:
dental and vestibular lamina
38
When, in utero, do both lamina appear?
7 wks
39
Vestibular lamina forms:
oral vestibule
40
Ectomesenchymal cells are located around this in the dental lamina stage:
dental lamina
41
Bud stage:
dental Lamina: proliferates and eLongates, eCtomesenCymal cells: proliferate and Condense (future dental papilla)
42
Function of tooth buds:
form enamel organ, control fate of ectomesencymal cells (future dental papilla)
43
Function of ectomesencymal cell in the bud stage:
form dental papilla
44
Cap stage:
Tooth bud cells proliferate, enamel organ forms (outer, inner, stellate reticulum), ectomesencymal cells proliferate and condense to form dental papilla
45
Morphogenesis stage:
cap stage
46
In what stage does the developing tooth resemble the tooth crown?
cap stage
47
Enamel formation begins in this stage:
cap stage
48
Cells of this layer are involved in enamel formation:
enamel organ
49
What cell type forms the dental papilla?
ectomesencymal cells
50
Bell stage:
Crown shape outlined, differentiation
51
These form odontoblasts:
detnal papilla cells in contact with IEE
52
These form pulp fibroblasts:
all dental papilla cells that are not in contact with the IEE
53
Function of dental papilla:
nutrients to tooth
54
Structures found in dental papilla:
bv's and nn.
55
Shape of OEE cells:
cuboidal
56
layer of enamel organ with capillaries for oxygen and nutrient delivery:
OEE
57
Parts of the enamel organ:
OEE, IEE, Stratum intermedium, Stellate reticulum
58
Cell type of stratum intermedium:
epi cells
59
The stratum intermedium is adjacent to:
IEE cells
60
Function of stratum intermedium:
enamel mineralization
61
Function of stellate reticulum:
protection and hydration
62
Major component of stellate reticulum:
glycosoaminoglycans
63
Function of glycosoaminoglycans:
hydration
64
DP cells in contact with the IEE form:
odonoblasts
65
dental follicle is aka:
dental sac
66
Cells of the dental sac:
cementoblasts, fibroblasts, and osteoblasts
67
the PDL is made from this cell type:
fibroblasts
68
Enamel knots:
aggregated epi cells near the IEE
69
When do enamel knots appear?
cap and bell stage, transiently
70
Function of enamel knots:
synthesize and secrete FGF-4
71
Function of FGF-4:
stimulates epi cell proliferation
72
This is the regulation center for crown formation:
enamel knot
73
Type of interaction between E-M:
inductive interaction
74
E-M interaction takes places during these stages:
Bud and cap
75
Tooth bud governs:
location of ectomesenchymal cells around bud
76
ectomesenchymal cells will develop into:
dental papilla
77
How do ectomesenchymal cells influence the tooth bud?
no influence
78
The tooth bud secretes:
FGF-8 and 9 and bone morphogenetic protein-4
79
Function of FGF 8 and 9:
induce Pax-9
80
Function of BMP-4:
induces msx1/2
81
Function of Pax-9:
proliferation of dental papilla cells
82
Function of msx 1 and 2:
formation of dental papilla and CT
83
Pax-9, Msx 1 or Msx 2 knockout mice:
stops at bud stage
84
What shape do enamel organs resemble?
crown shape they will become
85
Tx of incisor or molar bud with trysin/ collagenase:
separation of enamel organ from dental papilla
86
What determines the shape of enamel organ and crown?
dental papilla
87
TF? The enamel organ determines the shape of enamel organ and crown.
F. dental papilla does
88
In what stage does the bud determine the fate of the ectomesenchymal cells to form the dental papilla?
bud stage
89
In what stage does the dental papilla determine the shape of the enamel organ and crown?
cap stage
90
Bioengineering teeth in mice:
separate epi cells from mesenchymal cells of tooth germ in CAP stage E14.5, reconstitute, culture to proliferate, transplant
91
Cell origin of oral epi:
dental epi (reverse right)
92
Cell origin of ameloblasts:
IEE
93
Cell origin of ectomesenchymal cells:
neural crest cells
94
TF? The dental papilla is formed from the neural crest.
T
95
These stages are involved in morphogneis:
bud and cap
96
This stage is involved in cell differentiation:
bell
97
Initiation is during:
dental lamina stage
98
Stage when elongating DL cells move down into lower mesenchyme to make space for the tooth:
bud stage
99
Dental lamina cells migrate here to make space for the tooth:
lower mesenchyme
100
What happens to DL cells in the bud stage?
proliferate, elongate, and migrate to lower mesenchyme
101
Parts of enamel organ:
IEE, OEE, stellate reticulum
102
The crown is outlined in this stage:
bell stage
103
This controls which cell type they will become:
signalling molecules (regulate gene expression)
104
These cells house osteoblasts:
dental follicle/ sac cells
105
Responsible for tooth morphogenesis, makes and secretes GF’s:
Enamel knots (morphogenesis is bud and cap stage, but enamel knots are only transiently present in cap and bell stages)
106
How can tooth morphogenesis be completely blocked?
Remove GF
107
TF? 1 tooth, 1 enamel knot.
F. some have multiple
108
Mesenchyme sits below:
the oral epi
109
Mesenchymal cells:
stromal cells, fat cells
110
Organ won’t develop if you block:
cross-talk
111
Signalling molecule in tooth morphogenesis:
FGF
112
Pax-9 is found in:
mesenchymal cell
113
Cross talk is especially important in this part of tooth morphogenesis:
the early stages
114
The pulp is a core of:
soft tissue
115
Morphological differentiation is related to:
polarity
116
Functional differentiation is related to:
formation of organic matrix and mineralization
117
what dermal layer makes up the dental lamina?
ectoderm
118
The dental __ is in the bud stage and the dental __ is in the cap stage:
lamina, papilla
119
Cell type associated with the dental lamina:
ectomesenchymal cells
120
Cell type associated with the dental papilla:
odontoblasts
121
cell types involved in condensation:
Nc + em cells
122
These cells synthesize glycosaminoglycans:
stellate reticulum
123
IEE interacts with the underlying:
ectomesenchyme
124
What leads to odontoblasts formation?
Epithelial-mesenchymal interaction
125
Are pulpal cells specialized or un?
unspecialized
126
Pulp is made of:
pulp fibroblasts, nn, and bv's
127
dentinogenesis begins during this stage:
late bell stage
128
TF? There is sequential functional differentiation of odontoblasts.
T
129
What separates the OEE from the IEE in the bell stage?
stellate reticulum
130
These cells get polarized in the bell stage:
preodontoblasts
131
Changes in preodontoblasts to become secretory odontoblasts:
polarization, development of secretory machinery and dentinal tubules, elongation
132
Undifferentiated dental papilla cells are found here:
cervical loop
133
Shape of dental papilla cells:
polygonal
134
Are preodontoblasts polarized?
yes
135
What is predentin?
non-mineralized organic matrix
136
Differentiation of odontoblasts and. ameloblasts starts in this stage:
bell stage
137
the IEE contacts this on the inside and this on the outside:
DP cells, ameloblasts
138
In which direction to odontoblasts migrate as they secrete?
inward, toward pulp
139
What happens as dentin moves in?
odontoblastic processes extend
140
This allows talking and promotes e-m interaction
Break in bm
141
What initiates polarization of ameloblasts, then enamel?
preodontoblasts secreting enzyme to break membrane
142
Cell type responsible for breaking of bm:
preodontoblasts, secrete enzyme
143
mineralized core structure:
dentinal tubule
144
Epithelial-mesenchymal inductive interaction:
IEE-> Preameloblasts --> Dp cells -> preodontoblasts -> odotoblasts -> predentin -> preameloblasts -> ameloblasts -> enamel
145
What induce preameloblasts?
both IEE and predentin
146
Secretion of complexes is due to either:
ex or intrinsic signals
147
Cells with polarity:
preodontoblasts and preameloblasts (check)
148
Basal space is aka:
abluminal space
149
Degradation of the bm happens in this stage:
bell stage
150
What cells secrete the enzymes that degrade the bm?
preodontoblasts
151
Location of the preodontolbasts that secrete the enzymes that degrade the bm:
DEJ
152
3 events in bell stage:
degradation of bm, odontoblastic processes form in dentinal tubules, mantle dentin forms at DEJ
153
Odontoblastic process form here:
within dentinal tubules
154
When does mantle dentin formation start?
Prior to enamel formation
155
Post-mitotic cells:
odontoblasts
156
Elongated, tubular, and polarized cells:
odontoblasts
157
Dentin matrix proteins are synthesized by:
odontoblasts
158
Function of polarization:
transport and secrete dentin matrix proteins
159
Shape of pre-ondontoblasts and pre-ameloblasts:
short columnar
160
The bm is intact for these cells:
DP cells
161
The bm is broken in these cells:
pre-odontoblasts
162
Type 1 Collagen 1 is found in:
bone
163
Dentin regeneration/ formation:
DSPP and DMP (need either one of these, or preferentially both)
164
Path of cell:
start at cervical loop, migrate up cusp, then in
165
Major dentin matrix protein:
Type 1 collagen
166
Minor, non-collagenous proteins:
ostepontin, dentin matix proteins (DMP), dentin sialophosphoprotein (DSPP)
167
DSPP:
marker protein for dentin, mineralization
168
Defects in DSPP:
dentinogenesis imperfecta, hypomineralized dentin
169
Dentin matrix proteins are secreted into:
extracellular secretion
170
These extend past the terminal bar apparatus at the apical end of the odontoblast:
odontoblastic processes
171
Function of mantle dentin:
hold dentin/ enamel together
172
TF? Circumpulpal dentin is formed before mantle dentin.
F. after
173
Circumpulpal dentin is formed by:
differentiated odontoblasts
174
Mantle dentin is formed by:
NEWLY differentiaTING odontoblasts
175
Odontoblastic processes with the largest diameter are found:
close to cell body
176
Intratubular dentin is found here:
inner wall of dentinal tubule
177
Mineralization level of intratubular dentin:
highly
178
Mineralization level of intertubular dentin:
less mineralized
179
Which is more mineralized, inter or intra-tubular dentin?
intra
180
Which is more mineralized, globular or interglobular dentin?
globular ?
181
Hardness of Dentin:
Intra(peri)tubular (most mineralized/ hardest) > intertubular > Interglobular > Globular (least mineralized, softest) ?
182
2 steps of dentin mineralization:
secretion/deposition proteins & mineralization
183
calcium binds with high affinity to:
non-collagenous proteins (osteopomtin, DMP, DSPP)
184
Acts as scaffold for dentin
Type 1 collagen
185
How does crystalization occur?
non-random manner
186
TF? Mantle dentin is hypermineralized.
F. HYPO
187
Mantle dentin lacks:
DSPP
188
Collagen type found in dentin:
1
189
Regulators of mineralization:
DMP, DSPP, osteopomtin (non-collagenous proteins)
190
Calcium binds with high affinity to:
non-collagenous proteins (DMP, DSPP)
191
dental stem cells are aka:
odontoblast progenitor cells
192
Parts of the pulp-dentin complex:
odontoblastic layer, cell-free and rich zones
193
Found in cell free zone:
nerve plexus & capillaries
194
Found in cell rich zone:
odontoblast progenitor cells, reparative dentin formation
195
Reparative dentin is __' dentin:
3'
196
Pulp is made of:
bv's, fibroblasts, dendritic cells, and matrix (collagens, proteoglycans, glycoprotiens)
197
Components of pulp matrix:
collagens, proteoglycans, glycoprotiens
198
Dendritic cells are found in these areas of the tooth:
pulp and odontoblastic layer
199
Is the NB my or nonmy nn.?
both
200
immune effector cells in pulp:
dendritic cells
201
name of nerve plexus in cell free zone
Raschow nerve plexus
202
Nerve free endings extend as far as:
the dentinal tubule
203
Pulp is innervated with about __ nerves:
900
204
Most prominent nerve configuration in pulp:
bundles
205
Raschow nerve plexus is aka:
Subodontoblastic nerve plexus
206
Plexus below the cell rich zone:
Parietal neural plexus
207
Are odontoblastic processes associated with nerves?
yes
208
How could immunohistochemistry be used to identify nerves of the odontoblastic processes?
Membranes of nerve cell body, fibers and terminals have Nerve Growth Factor receptors
209
Antibody against the nerve:
parafin (red)
210
Marker for odontoblasts:
nestin (green)
211
Do nn. exted to the DEJ.
no
212
3 dental pain theories:
neural, hydrodynamic, odontoblastic transduction
213
What is the receptor in the Odontoblastic Transduction Theory?
the odontoblast (acting as a nerve ending/ pain receptor), synaptic junction w nerve
214
What is the receptor in the Neural Theory?
free nerve endings in dentinal tubules, directly stimulated, receptors at the DEJ cause excitation
215
What is the receptor in the Hydrodynamic Theory?
Fluid transmits signal to nerve free endings around odontoblast, mechano-sensitive nocioceptors
216
Hydrodynamic theory, fluid moves within these:
dentinal microtubules
217
Science pointing toward Odontoblastic Thransuction Theory:
they transduce signals, have Na pumps that induce AP from resting potential, synapses bw them and nerve fibers
218
NT's invovled in odontoblast-nerve synaptic communication:
anykyrin (and Beta2)
219
What initiates transduction in the odontoblast transduction theory?
Fluid movement disturbs OP
220
Stimuli for hydrodynamic theory:
mechanical/ chemical
221
Cause of mechanical stimulation in hydrodynamic theory:
drilling exposes dentinal tubule, fluid leaks out
222
How are chemicals involved in stimulation in the hydrodynamic theory
penetrate dentinal tubules, change osmotic pressure leading to fluid movement
223
Odontoblastic processes are encased in:
dentinal tubule
224
Most accepted theory of dentinal pain transmission:
hydrodynamic
225
What causes the dull lasting pain created by hot drink/food?
more displacement of the odontoblastic process
226
In which direction does fluid flow in response to hot food/drink?
down, from infront of the furthest extent of the odontoblastic process
227
In which direction does fluid flow in response to cold food/drink?
up, from behind the odontoblastic process
228
Age changes of pulp:
Less cells, blood vessels and nerves, more collagen, dentin, and pulp stones (at IEE, right?), smaller pulp chamber
229
What is deposited in granulation tissue in response to a bacteria?
osteodentin (reparative dentin)
230
TF? Bacteria is too large to enter dentinal tubules.
F.
231
Proliferation of precursor cells in pulp happens here:
cell-rich zone
232
Reparative dentin is aka:
osteodentin
233
How does osetodentin resemble bone?
no dentinal tubules, trapped cells
234
Which zone responds to inflammation of the dentin?
Cell rich zone
235
Steps in reparative dentin formation:
cell-rich zone cells proliferate and differentiate into odontoblasts-LIKE cells, lay down matrix, tertiary/ reparative/ osteodentin
236
Why are there no tubules in reparative dentin?
bc there are no odontoblastic processses
237
The stratum intermedium lays bw:
stellate reticulum and the IEE
238
Enamel mineralization pattern seen in seen in tumors:
fish scale
239
Abnormal dentin mineralization pattern:
tubular
240
This disorder is common to supernumerary pts:
Ameloblastic Fibro-Odontoma
241
Pulp capping:
initiate reparative dentin formation to create a layer of nerve free tissue
242
REVIEW IMAGES!!!!!
ok
243
Fxns of ameloblasts:
synthesis, secretion, mineralization and resorption of enamel matrix proteins
244
4 stages of differentiaiton of IEE cells into ameloblasts:
presecretory, secretory, maturation, protection
245
At what tooth structure is the protection stage taking place?
cusp tip
246
At what tooth structure is the secretory stage taking place?
midway bw cervical loop and cusp tip
247
At what tooth structure is the presecretory stage taking place?
cervical loop
248
In what stage do IEE cells differentiat into preameloblastst?
pre-secretory stage
249
Pre-ameloblasts have increased numbers of these organelles:
RER, mitochondria, Golgi
250
Alignment of pre-ameloblasts:
in parallel
251
How are adjacent pre-ameloblasts connected?
desmosomes, tight and adhesion junctions (TAD)
252
TF? Ameloblasts are differentiating during the presecretory stage.
T
253
The basement membrane is being boken down during this stage:
presecretory stage (bell stage(
254
Ameloblast are tallest during this stage:
secretory stage
255
Function of ameloblasts in the secretory stage:
transport and secrete enamel matrix proteins
256
In which stage are Tome's processes seen?
secretory stage
257
On which end of the ameloblast is the Tomes process located?
apical
258
Where is enamel matrix secreted through?
Tomes process
259
What type of extension is Tome's process:
pyramidal, cytoplasmic
260
What determines the architecture of the enamel rods?
Tomes' prcess
261
Where are secretory products synthesized in ameloblast?
RER
262
TF? 1 ameloblast, 1 enamel rod.
T
263
TF? Tomes' process is located at the secretory end of the ameloblast.
T, apical end
264
How to id Tomes' processes in slides:
Little triangle at apical end of ameloblasts, nuclei along basolateral end
265
This is just apical to the Tomes' process:
enamel matric
266
Secretion from ameloblasts occurs here:
Tomes' processes
267
Configuration of the developing enamel rod:
rod/ interrod configuration
268
Basic structural unit of enamel:
enamel rods (prisms)
269
This has a key hole-like structure:
enamel / enamel rod
270
Shape of Tomes' processes:
pyramidal
271
Diameter of enamel rod:
5um
272
The head of the key hole is:
rod enamel
273
Physical properties of enamel:
strong, brittle
274
The forming face is the rod/interrod enamel:
rod/ head
275
Which faces secrete enamel?
forming faces
276
Orientation of proximal formative face:
perpendicular to membrane, interrod enamel
277
Distal formative face:
apical, enamel rod
278
This is adjacent ot the ameloblast body on the basolateral end, where the nucleus is positioned:
startum intermedium
279
How many Tome's processes make up the interrod?
4, the one that laid the rod also contributes to the interrod
280
Rod sheath is made from:
edge of Tomes' process
281
How many Tomes' processes make up each rod?
1
282
Is rod made from the distal or proximal part of Tomes' process?
distal
283
Is interrod made from the distal or proximal part of Tomes' process?
proximal
284
The lateral aspect of this looks like an uprooted tree:
Secretory stage ameloblast
285
Each successive layer of secreteory stage ameloblasts fit here:
Tail region of Tomes process fits into apical end of ameloblast
286
This makes up 90% of enamel matrix protein:
amelogenin
287
Amelogenin is rich in these AA's
proline, leucine and glutamic acid
288
Amelogenins bind this with high affinity:
Ca2+
289
Structural unit of the enamel rod:
hydroxyapetite
290
Genes encoding amelogenin:
both X and Y, different manifestations in the sexes
291
Defective ameiogenin gene can lead to:
amelogenesis imperfecta (hypoplastic/ hypomineralized/ hypocalcified)
292
Amelogenesis imperfecta results in enamel that is:
hypoplastic/ hypomineralized/ hypocalcified
293
This makes up 10% of enamel matrix protein:
Non-amelogenins
294
List non-amelogenins:
Tufteline, enamelin, ameloblastin, proteases (TAPE)
295
Tufteline is involved in the formation of:
enamel tuft
296
enamelin is involved in the formation of:
rod, interrod enamel
297
ameloblastin is involved in the formation of:
sheath
298
Function of protease during secretory stage:
degrade enamel matrix proteins (MMP-20, enamelysin and KLK-4)
299
KLK-4 sf:
Kalikrein-4
300
MMP-20 sf:
Matrix metalloproteinase-20
301
When is MMP-20 secreted?
secretory phase
302
When do we degrade MMP-20's?
once we have established crystal orientation
303
When is KLK-4 secreted?
Maturation phase
304
This is secreted during secretory phase and serves to break down its own protein:
enamelysin
305
Ameloblasts are shorter in this stage:
maturation
306
Maturation stage:
not synthesizing, degradation of organelles, Tomes disapprar, R or S-ended ameloblasts appear
307
Ruffle-ended or smooth-ended ameloblasts appear in this stage:
maturation
308
Main functions of maturation stage:
protein absorption and mineralization
309
What are enamel matrix proteins replaced with?
Ca/PO4 (99% replaced)
310
Proteases degrade theses in the enamel matrix:
amelogenins
311
TF? The maturation stage is a terminal differentiation stage.
F. modulation bw S and R
312
How is mineralized enamel formed in the maturation stage?
absorption of degraded enamel matrix proteins
313
Amelogenins are involved in this process:
mineralization
314
Calcium hydroxyapetite:
Ca10(PO4)6OH2
315
Function of ruffle-ended ameloblasts:
to strengthen the matrix
316
These promote pumping Ca into mature enamel:
lysosomes, Ca binding proteins and Ca ATPases
317
1% of enamel is made of:
protein
318
Function of smooth-ended ameloblasts;
remove water and proteins
319
TF? Smooth ended ameloblasts have leaky distal junctions.
T
320
Smooth-ended proximal junctions:
tight
321
Ruffle-ended proximal junctions:
leaky
322
Ruffle-ended distal junctions:
tight
323
TF? Active resorption of intact proteins by ameloblasts is the main mechanism for loss of organic matrix during maturation.
F
324
TF? Intracellular enzymes digest matrix proteins into fragments small enough to leave leave enamel layer.
F. extracellular
325
How do fragments leave enamel?
pass bw leaky distal junctions of smooth ended cells
326
Where are fragments leaving enamel taken up?
along basolateral surface
327
Importance of distal leaky junctions of smooth ended ameloblasts:
Fragments of matrix proteins pass thru and diffuse laterally to be taken up at the basolateral surface of the ameloblast
328
Longitudinal enamel crystal growth occurs in this stage:
secretory
329
Widening of the enamel crystal occurs in this stage:
maturation
330
Enzyme for amelogeninn degradation in the secretory phase:
MMP-20
331
Enzyme for amelogeninn degradation in the maturation phase:
KLK-4 (Kalikrein-4)
332
MMP-20 is aka:
enamel lysin
333
Which is a stronger protease, MMP-20 or KLKK-4?
KLK-4
334
TF? Some MMP-20 is still active during the maturation phase.
T
335
Shape of enamel crystals in X-section:
hexagonal
336
Shape of dentin bone in X-section:
hexagonal
337
Ameloblast differentiation occurs in this stage:
protection stage (bell)
338
Ameloblasts at protection stage;
shutting things down, crystals completed, cells die off, short cells, not secreting, not modifying, not active, minimal organelles, reduction of enamel epi
339
What covers the enamel surface during the protection stage?
ameloblasts (check)
340
Is the reduction of the enamel epithelium at the beginning or end of protection stage?
End
341
Components of enamel organ in the protection stage:
OEE, stellate and stratum intermedium
342
Function of reduced dental epi:
protect enamel
343
The reduced dental epi will become:
junctional epi
344
What makes the reduced dental epi?
condensation of OEE, stellate and stratum intermedium
345
Is polarization decreasing or increasing as we proceed through maturation and protection?
decreasing
346
Function of pre-secretory ameloblast:
differentiating
347
Function of secretory ameloblast:
synthesis and secretion
348
Functions of ameloblast during maturation:
mineralization, resorption, Ca2+ transport
349
Enamel rod is first present in the stage of ameloblast differentiation:
Secretory
350
What cause Striae of Retzius?
developmental disturbances
351
These lines reflect activity of ameloblasts on a daily period:
cross striations/ cross lines
352
From where do the Straie of Retzius run?
obliquely rom DEJ to enamel surface
353
Perikymata:
furrows (depressed lines) on enamel surface, manifestation of S. Retzius on enamle surface
354
This is a manifestation of S. Retzius on enamel surface:
perikymata
355
TF? Perikymata and Straie of Retzius are both part of the enamel
T
356
TF? Enamel prism is visible in a cross section of enamel showing the Straie of Retzius.
T (I don't think they are visible on the outer surface where the perikymata are visible)
357
Enamel tufts:
incomplete resorption of enamel proteins
358
If an enamel protein persists that was incompletely resorbed, this can form:
tuftline
359
Are enamel tufts hypo or hyper mineralized?
hypo
360
How far do enamel tufts extend?
Up to 1/2 of enamel thickness
361
TF? Tufts reach the tooth surface.
F
362
TF? Tufts are associated with decay.
F. Can be a trap if the lesion gets to the tuft
363
TF? Tufts are regularly spaced.
T
364
Where are enamel spindles found?
DEJ
365
What forms enamel spindles?
odontoblastic processes trapped during early enamel formation, short, thin, cyclindrical
366
TF? enamel spindles are regularly spaced.
F
367
TF? Enamel lamellae play a potential pathoogic role.
T. in contact with oral cavity
368
Enamel lamellae:
group of hypomineralized rods with incomplete resorption, sheet-like structure, DEJ to enamel surface, susceptible to caries and fracture
369
Hunter-Schreger Bands:
seen only with reflected light, light and dark bands, DEJ to 2/3 of enamel, commonly in incisal or occlusal region
370
What does the direction of the Hunter-Schreger Bands reflect?
alternating direction taken by groups of enamel rods as they move away from the DEJ
371
TF? Hunter-Schreger Bands can be visualized with transmitted light.
F, polarized light
372
TF? Hunter-Schreger Bands are found in the dentin.
F. enamel only
373
Which bands are broader in Hunter-Schreger Bands?
bright bands
374
Orientation of broad, bright bands of Hunter-Schreger Bands:
longitudinally-oriented enamel rods
375
Rodless enamel is aka:
prismless enamel
376
Prismless enamel is found here:
DEJ and enamel surface
377
prismless enamel is formed by:
ameloblasts w/o Tomes' processes
378
Prismless enamel is common in:
deciduous teeth
379
Arrangement of enamel crystals in rodless enamel:
parallel to DEJ or enamel surface
380
TF? Tetracycline will stain all dentition, even unerupted, if given in excess to a child.
F. Does not stain unerupted teeth, ie 3rd molars
381
What color banding is seen in enamel due to Tetracycline staining?
greyish, yellow -> brown/ grey
382
This can occur with F concentrations that are too high:
modeling ?
383
What color discoloration is associated with fluoride:
white/brown
384
What color discoloration is associated with minocycline:
green-gray/ blue-grey (braod specrum tetracycline antibiotic)
385
What color discoloration is associated with ciprofloxacin:
greenish (antibiotic)
386
Does tetracycline stain dentin, enamel, or both?
both, dentin more heavily
387
Why does staining occur with tetracycline?
forms complexes with Ca2+ ions on surface of hydroxyapetite crystals
388
Tetracycline should not be given to pregnant women from this wk of pregnancy on:
29th wk, crosses placental barrier (or breast feeding mothers)
389
Don't give tetracycline to children until they reach this age:
12 yo, because permanent teeth are still developing
390
Most critical time to avoid tetracycline use for deciduous dentition:
4 mo in utero to 5 mo post-partum (incisors and canines)
391
Most critical time to avoid tetracycline use for permanent dentition:
4 mo post-partum to about 7yo (incisors and canines)
392
Reparative dentin is formed in this zone:
Cell-rich zone
393
When does the dental lamina form?
when cells in the dental epithelium actively proliferate and grow (bud stage)
394
Odontoblast formation occurs during this stage:
late bell stage
