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18. PRIMARY PALATE
Intermaxillary segment forms the primary palate
which becomes the future premaxilla,
bearing the four incisor teeth
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19. SECONDARY PALATE
Starts at the 6 th week
Palatine shelves emerges laterally
from maxillary process
First descends vertically
downwards due to presence of tongue
Tongue drops, shelves ascends to a
horizontal position
Moves towards each other
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Fuses with each other
20. Secondary palate . . .
FRONTAL SECTION
NASAL SEPTUM
MAXILLARY
PROCESS
PRIMITIVE MOUTH
TH
MOU
Stark compares . . .
O
UE
NG
T
Shelves fuse with each other,
With base of the shelves assume a
Tongue drops & nasal septum
Vertically downward orientation
& With primary palate anteriorly
Horizontal position. www.indiandentalacademy.com
of shelves.
BASSET HOUND
25. Shelf elevation . . . ?
Hydration & Polymerization
Hyaluronic acid
Seratonin & Acetylcholine release
Swelling of extra cellular matrix
Biosynthetic activity
Pushed by the tongue
Epithelial plug of external nares
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26. Tongue depression . . . ?
Growth of Meckel’s cartilage
Myoneural activity of tongue
Maxilla – Cranium
Growth of head
Muscle traction
Swallowing & Hiccups
Withdrawal of head from heart
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27. Shelves meet . . . ?
Rapid cell proliferation
Muscle segment homeobox
Bone morphogenic protein
Sonic hedge hog
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28. Shelf fusion . . . ?
3 mechanisms
...
Necrosis of MES due to
lysosomal autolysis
Transformation of basal MEE
to mesenchyme
Migration of epithelial cells
nasally or orally
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29. ADHESION OF SHELVES
SURFACE EPITHELIUM
BASAL EPITHELIUM
GLYCOPROTEIN RICH SEAM
MEDIAN EPITHELIAL COAT
BEFORE
24-36 HOURS - DNA SYNTHESIS STOPS
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42. OSSIFICATION OF PALATE
At end of 7th week . . .
At the junction of vertical plate & horizontal plate
Tiny cresent places antero-posteriorly
with concavity towards medial
Extends upward to form vertical plate
& medialward to form horizontal plate
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43. OSSIFICATION OF PALATE
During the 8th week . . .
spreads backward to form
pyramidal process
downwards to form
tuberosity
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44. OSSIFICATION OF PALATE
At the 9th week . . .
the two branches of the pyramidal process
are widely seperated for internal pterygoid plate
vertical plate is at 45°
later stages at right angles to the
horizontal plate
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45. OSSIFICATION OF PALATE
In the 10th week . . .
the sphenoidal & orbital
process develops
at the junction bone extends
forwards & overlaps
maxillary bone
vertical plate – fan
horizontal plate – www.indiandentalacademy.com
pyramidal
46. Dimensions . . .
Horizontal more than vertical- fetal
Equal in length – at birth
Vertical more than horizontal – after birth
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47. Mesenchymal condensation . . .
Reorientation of the Golgi bodies
Fibronectin for cluster formation
Polysaccharide prevents aggregation
Hyaluronidase breaks down
inhibitors
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49. Sutures . . .
Site of cellular proliferation &
fibre formation
Appositional osteogenesis
Growth occurs as compensation
to separating forces
Alternating oscillatory movement
Responds towww.indiandentalacademy.com and tension
pressure
50. Mid palatal suture . . .
Plane or butt-end type
First evident at 10 ½ weeks i.u
Growth ceases between
1 and 2 years
Obliteration starts in
adolescence
Complete fusion rare until
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56. More disputes . . .
Callender
–
no centre of
Schwink
Piersol
Rambaud & Renault
1
its own
centre
3 centres
Frasetto 5 centres
Jarmer
–
–
Fawcett
–
Prevomerine
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centre
57. Essential facts . . .
Premaxilla – 8 weeks
Palatine bone – 9 weeks
The centers fuse into a single mass
before the 25 mm stage (CRL)
Premaxilla contributes to anterior
nasal process after fusion
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61. REMODELING
Resorption & deposition
Genic tissues
Inferior direction
Resorption on oral side
& deposition on nasal side
Relocation of the palate
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66. DISPLACEMENT
Physical movement as a whole
Expansive force of soft tissues
Simultaneously remodels
Primary / Secondary
Forwards & Downwards
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69. Drift . . .
drift is the movement of bone in space by virtue of
apposition on one side of a cortex or surface & resorption
on the other
palatal drift - classic example
nasal floor – resorptive &
roof of mouth - depository
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70. VERTICAL DRIFT or ERUPTION
Takes place in addition to eruption
Occurs by resorption & deposition
periodontal connective tissue membrane
Provide adjustments for palatal
displacement rotations to level
the occlusal plane
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71. COUNTERPART PRINCIPLE
growth of any given facial or cranial part
relates specifically to other structural &
geometric counterparts
if each regional part & its counterpart enlarge
to the same extent , balanced growth results
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74. Sicher’s Sutural dominance theory . . .
Reasons for failure . . .
Growth site
Vs
Growth centre
After transplantation
tissue did not grow
Suture are areas that react
to stimulus
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75. Compare man . . .
. . . & his best friend !
...A
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76. Axis .
Maxillo mandibular apparatus . . .
Cranium . . .
Less
Big prominent
Vertical
More
Smallprominent
Horizontal
Human skull
Dog skull
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Striking differences . . .
77. Reasonable hypothesis . . .
Feature
s
Pronograde – four footed
Olfactory sense – the first sense !
Tactile sensation of the snout
Eating style
Other functions – tactile, holding, breaking, fighting etc.
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78. Reasonable hypothesis . . .
Plantigrade – two footed
Well developed brain – frontal lobe
Liberty of limb movements
Eating style & defence
Cooked food – weaker muscles
Speech – broader arches ,forward chin
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Feature
s
79. Evolution of Palate . . .
d
ape
- sh
UA. Afarensis
3
7
4
DEEP . . .
Homo Erectus
H.Neanderthalensis
12
P.Robustus
P.Boisie
A. Africanus
14
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SHALLOW . . . for speech.
8
Homo sapiens
15
c
boli
a
Par
80. Foramen . . .
Constant remodeling throughout life
Decreases in size – physiological or pathological
contents are not affected in physiologic change
compressed in pathologic conditions
eg.cervical stenosis (intervertebral foramen)
appears to change in position due to changes in
neighboring structures
eg. Mental foramen
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83. Premaxilla . . . A Problemaxilla?
Separate . .
Suture line
- Fetal
Fused . .
No suture line
- Adult
Suture on palate
Ossification defect
Ossification time Later fuse
All mammals
Humans exception
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85. The difference of opinions . .
Separate ossification centres
Maxillary bone grows & spreads
over the facial surface of
premaxilla
No separate centre for premaxill
c – shaped maxillary centre
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86. Convincing Proof . . .
Histological evidence . . .
Distinction between calcified bone
of maxilla and osteoid of the
premaxilla
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96. CVS TEST
( CARDIOVASCULAR SYSTEM ? )
(CHORIONIC VILLI SAMPLING)
Detects chromosomal abnormalities
Done at 10 – 12 weeks of
pregnancy
The sample is removed
by suction
Risk of miscarriage
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103. Concluding . . .
“If the rate of growth of the first month
of embryonic life were to be maintained
until adulthood, the resultant individual
would be 1,28,350 to the 1,100 power of
light years in length.”
-Robert Bean
( Anatomist)
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104. 4 years . . .
6 years . . .
Adult . . .
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105. Thank you . . .
For the patience!
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Notas do Editor
……………………..fision of the 3 palatal components initially prodices a flat , unarched roof of the mouth.the fusing lateral palatal shelves overlap the anterior palatal shelves as indicated later by the sloping pathways of the junctional incisive neurovascular canals that carry the previously formed incisive nerves and blood vesels.the site of junction the 3 palatal components is marked by the incisive papilla overlying the incisive canal.the line of fusion of the palatal shelves in adults is traced by the midpalatal suture .and on the surface by the raphae. This fusion seam is reducd in soft palate by the invasion of extraterritorial mesenchyme.
Palatopharyngeal incompetance due to muscle hypoplasis of uvula.paralysis following diphtheria due to action of toxin on nerve cells of medulla oblongata. Voice becoms nasal and fluid regurgiatesinto nose.palate is motionless and anaesthetic.other pathology of glossopharyngeal vagus accessory nerve or their nuclei in medulla odlongata causes palatal paralysis.