DEVELOPMENT OF PALATE
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
FERTILIZATION
BLASTOCYST
MORULA
2 CELL STAGE
4 CELL STAGE
16 CELL STAGE
www.indiandentalacademy.com
PRENATAL DEVELOPMENT 3 – 7 weeks
first 2 weeks
3
STAGES
GERMINAL
EMBRYONIC
8 wks – 9 mths
www.indiandentalacademy.com FETAL
3 WEEKS
4
5 WEEKS
WEEKS
6 WEEKS
7 WEEKS
IN FOCUS . . . www.indiandentalacademy.com
The normal ‌. at a glance.
www.indiandentalacademy.com
The Hard Palate . . .
MID GLANDULAR INCISIVE PALATINE FATTY RUGAE PAPILLA ZONE ZONE RAPHE
www.indiandentalacademy.com
Two sides of the same coin . . . NASAL SIDE
ORAL SIDE
COLUMNAR CILIATED
STRATIFIED SQUAMOUS
www.indiandentalacademy.com
The Bony Palate . . .
PALATINE PALATO MAXILLARY PROCESS PLATE INTERMAXILLARY INTERPALATINE FHORIZONTAL .GREATER PREMAXILLA PALATINE INCISIVE F.LESSER FORAMEN PALATINE OF OF PALATINE SUTURE MAXILLA SUTUREBONE
www.indiandentalacademy.com
Nerve Blood Supply . . .
LESSER NASOPALATINE PALATINE GREATER PALATINE ARTERY NERVE NERVE
www.indiandentalacademy.com
Soft Palate . . . REDDISH MUCOSA TASTE BUDS NON KERATINISED
www.indiandentalacademy.com
Soft Palate muscles . . . Tensor veli palatini Levator veli palatini Palatoglossus Palatopharyngeus Musculus uvulae
www.indiandentalacademy.com
Functions . . . Separation of the two systems Swallowing Breathing Phonation Mastication Hearing Taste
www.indiandentalacademy.com
The Process of Development . . .
www.indiandentalacademy.com
PALATE DEVELOPMENT
PRIMARY
SECONDARY
www.indiandentalacademy.com
PRIMARY PALATE
4th week of intrauterine life Fusion of medial nasal process Forms intermaxillary segment www.indiandentalacademy.com
PRIMARY PALATE FRONTAL VIEW
VENTRAL VIEW
Medial nasal process
INTERMAXILLARY SEGMENT PRIMARY PALATE www.indiandentalacademy.com
PRIMARY PALATE
Intermaxillary segment forms the primary palate which becomes the future premaxilla, bearing the four incisor teeth www.indiandentalacademy.com
SECONDARY PALATE
Starts at the 6th 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 www.indiandentalacademy.com Fuses with each other
Secondary palate . . . FRONTAL SECTION NASAL SEPTUM MAXILLARY PROCESS
PRIMITIVE MOUTH TH MOU
Stark compares . . .
O
E U NG
T with each other, Shelves fuse With Tongue Vertically base drops of downward the & shelves nasalorientation septum assume a www.indiandentalacademy.com & Horizontal ofWith shelves. primary position. palate anteriorly
BASSET HOUND
SECONDARY PALATE VENTRAL VIEW
Coordinated formation of the primary palate, secondary palate & nasal septum www.indiandentalacademy.com
SEM view of various stages Downward shelf orientation
PRIMARY PALATE
7 WEEKS
Horizontal orientation 8 WEEKS
Fused shelves
9www.indiandentalacademy.com WEEKS 22 WEEKS
Behind The Scene . . .
www.indiandentalacademy.com
Shelf elevation . . . ? Tongue depression . . .? Shelves meet . . . ? Shelf fusion . . . ? Shelf position . . . ? www.indiandentalacademy.com
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 www.indiandentalacademy.com
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 www.indiandentalacademy.com
Shelves meet . . . ? Rapid cell proliferation Muscle segment homeobox Bone morphogenic protein Sonic hedge hog
www.indiandentalacademy.com
Shelf fusion . . . ? 3 mechanisms
...
Necrosis of MES due to lysosomal autolysis Transformation of basal MEE to mesenchyme Migration of epithelial cells nasally or orally www.indiandentalacademy.com
ADHESION OF SHELVES
SURFACE EPITHELIUM
BASAL EPITHELIUM
GLYCOPROTEIN RICH SEAM COAT MEDIAN EPITHELIAL BEFORE
24-36 HOURS - DNA SYNTHESIS STOPS www.indiandentalacademy.com
EPITHELIAL - MESENCHYMAL TRANSFORMATION
II
I TßR
TßR
Serine – Threonine Kinases Indispensable
TGF-ß Betaglycan
III
Direct modulator
TßR www.indiandentalacademy.com
II
TGF-ß3 I
TGF-ß3
IIIIII
III TGF-ß3
TGF-ß3
III TGF-ß3 I
III
III
II
II
I
III
III III
I
TGF-ß3 I
III
II
I
TGF-ß3
II
II
I
III III
TGF-ß3
TGF-ß3
III
I
TGF-ß3
I
II
I
III
II
III
IIII
I TGF-ß3
I
II
II
III
III
I TGF-ß3 I
II
III
II
I
II
II
III
II
II
I
SMAD PROTEINS www.indiandentalacademy.com
I
VERTICAL POSITION
HORIZONTAL POSITION WITH MEE
HORIZONTAL POSITION WITHOUT MEE www.indiandentalacademy.com
Shelf position . . . ? Growth of the mandible Swallowing of amniotic fluid
www.indiandentalacademy.com
Back to basics . . .
www.indiandentalacademy.com
Origin of mesenchyme . . . Neurulution From mid & hindbrain into branchial arches Pluripotent Cells Facial mesenchyme Homeobox genes www.indiandentalacademy.com
Differentiates . . . Bone formation
OSTEOBLASTS MYOBLASTS
Muscle development
HAEMOCYTOBLASTS LYMPHOBLASTS
Blood vessels Lymphoid tissue
www.indiandentalacademy.com
Muscle development of soft palate‌
www.indiandentalacademy.com
Tensor Veli Palatini 40 days Palatopharyngeous 45 Days Levator Veli Palatini 8th week Palatoglossus Uvular
9th week 11 week th
www.indiandentalacademy.com
Origin‌.
Levator Veli Palatini & Palatopharyngeus
Palatoglossus Uvular Tensor Veli Palatini www.indiandentalacademy.com
Ossification of Palate ‌
www.indiandentalacademy.com
INTRAMEMBRANOUS OSSIFICATION LOOSE MESENCHYME
COLLAGEN FIBRES
MESENCHYMAL CONDENSATION
COLLAGEN FIBRE OSTEOID BUNDLES GELATINOUS MATRIX
OSTEOBLASTS www.indiandentalacademy.com
OSTEOCYTES
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 www.indiandentalacademy.com
OSSIFICATION OF PALATE During the 8th week . . . spreads backward to form pyramidal process downwards to form tuberosity
www.indiandentalacademy.com
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 45째 later stages at right angles to the horizontal plate www.indiandentalacademy.com
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
Dimensions . . . Horizontal more than vertical- fetal Equal in length – at birth Vertical more than horizontal – after birth
www.indiandentalacademy.com
Mesenchymal condensation . . . Reorientation of the Golgi bodies Fibronectin for cluster formation Polysaccharide prevents aggregation Hyaluronidase breaks down inhibitors www.indiandentalacademy.com
Sutures . . .
www.indiandentalacademy.com
Sutures . . . Site of cellular proliferation & fibre formation Appositional osteogenesis Growth occurs as compensation to separating forces Alternating oscillatory movement Responds to pressure and tension www.indiandentalacademy.com
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 30yrs www.indiandentalacademy.com
INFANCY
www.indiandentalacademy.com
Y
CHILDHOOD
www.indiandentalacademy.com
T
ADOLESENCE
HIGHLYwww.indiandentalacademy.com INTERDIGITATED
Ossifying centres . . .
www.indiandentalacademy.com
DISPUTES IN OSSIFYING CENTRES
Kรถlliker
Albrecht
One centre
Two centre
www.indiandentalacademy.com
More disputes . . . Callender – no
centre of its own
Schwink Piersol Rambaud & Renault
1 centre
Jarmer – 3 centres Frasetto – 5 centres www.indiandentalacademy.com Fawcett – Prevomerine centre
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 www.indiandentalacademy.com
GROWTH
www.indiandentalacademy.com
CRANIAL Vs FACIAL GROWTH
POSTNATAL – MORE FACIAL THAN CRANIAL www.indiandentalacademy.com
REMODELING Vs
DISPLACEMENT
www.indiandentalacademy.com
REMODELING Resorption & deposition Genic tissues Inferior direction Resorption on oral side & deposition on nasal side Relocation of the palate www.indiandentalacademy.com
REMODELING Changes bone size Relocates bone Shapes the bone Fine tune fitting of bone Adapts the bone www.indiandentalacademy.com
FETAL SKULL
ADULT SKULL
Relocation Increase in vertical dimension www.indiandentalacademy.com
REMODELING
Resorption
Nasal side Oral side
Deposition
Downwards www.indiandentalacademy.com
REMODELING Resorption outer side Deposition inner side
s d r a w o t d n g e n i r v o ide M W
Change in position Change in size
V
n i r P
e l p ci
Palate becomes wider www.indiandentalacademy.com
DISPLACEMENT Physical movement as a whole Expansive force of soft tissues Simultaneously remodels Primary / Secondary Forwards & Downwards www.indiandentalacademy.com
DISPLACEMENT
1
2 3
REMODELLING DISPLACEMENT
www.indiandentalacademy.com
GROWTH ROTATION Compensatory remodeling rotation Fields reversed
Displacement rotation www.indiandentalacademy.com
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
www.indiandentalacademy.com
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 www.indiandentalacademy.com
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
www.indiandentalacademy.com
COUNTERPART PRINCIPLE
Anterior palate cranial fossa
Palate www.indiandentalacademy.com
Maxillary base
THEORIES OF GROWTH SICHER’S THEORY
SCOTT’S THEORY
MOSS THEORY www.indiandentalacademy.com
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
www.indiandentalacademy.com
Compare man . . . . . . & his best friend !
...A www.indiandentalacademy.com
Axis . . apparatus Maxillo mandibular Cranium .. ... Vertical Big Less prominent Small More Horizontal prominent
Human skull
Dog skull
www.indiandentalacademy.com Striking differences . . .
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.
www.indiandentalacademy.com
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 www.indiandentalacademy.com
Feature s
Evolution of Palate . . . ed p a - sh
UA. Afarensis
3
7
4
DEEP . . . Homo Erectus
H.Neanderthalensis 12
P.Robustus
P.Boisie
A. Africanus
14
www.indiandentalacademy.com SHALLOW . . . for speech.
8
Homo sapiens 15
l ic o b a Par
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 www.indiandentalacademy.com
The debated Premaxilla . . .
www.indiandentalacademy.com
PARTICIPANTS . . .
Separate . . .
VERSALIUS 1543 COLUMBUS 1559 FALLOPIUS 1561 CAMPER 1778 KOLLIKER 1882 FAWCETT 1911 ALBINUS 1746
Fused . . .
WOODJONES 1929 LAWRENCE 1838 ROUSSEAU 1858 - 59
GOETHE 1786 KOSENMUELLER 1804
www.indiandentalacademy.com
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
www.indiandentalacademy.com
BAT
AUSTRALOPITHECUS AFARENSIS
PE A
-
CHIMPANZEE
AUSTRALOPITHECUS AFRICANUS
GORILLA
HOMO SAPIENS
E K LI
3RD BRANCH
4TH BRANCH
www.indiandentalacademy.com
15TH BRANCH
The difference of opinions . . . Separate ossification centres Maxillary bone grows & spreads over the facial surface of premaxilla
No separate centre for premaxilla c – shaped maxillary centre www.indiandentalacademy.com
Convincing Proof . . . Histological evidence . . .
Distinction between calcified bone of maxilla and osteoid of the premaxilla
www.indiandentalacademy.com
Premaxilla . . . Problemaxilla?
The argument continues . . . . . www.indiandentalacademy.com
Dimensional changes . . .
www.indiandentalacademy.com
CHANGES IN UTERUS 7 - 18 WEEKS
4 MONTHS
Length increases Width increases www.indiandentalacademy.com
CHANGES OUT OF UTERUS AT BIRTH
Equal
POST NATAL
Length increases
www.indiandentalacademy.com
The factors influencing. . .
www.indiandentalacademy.com
Genetics . . . IGF-II R / TGF-ß2 / cdK4 - Break In circuit TGF –ALPHA A2 MUTATION OF OSR-2 & TBX22 GENE FOR GAD67 www.indiandentalacademy.com
Environmental . . . DRUGS Corticosteroids Anticonvulsants Benzodiazepines Methotrexate Thalidomide Phenobarbitones www.indiandentalacademy.com
HABITS Smoking –
Maternal smoking leads to cleft
Thumb sucking Mouth breathing - leads to narrowing of palate www.indiandentalacademy.com
DIETARY AGENTS Vitamin A Folate
INVESTIGATIONS Radiation CVS testing www.indiandentalacademy.com
A W LF U G
R
CVS TEST ( CARDIOVASCULAR ?) (CHORIONIC VILLISYSTEM SAMPLING)
Detects chromosomal abnormalities Done at 10 – 12 weeks of pregnancy The sample is removed by suction Risk of miscarriage www.indiandentalacademy.com
The abnormalities . . .
www.indiandentalacademy.com
CLEFT PALATE
CROUZAN’S PIERRE SPRENGEL’S MARFAN’S TREACHER APERTS ROBIN COLLINS
TREACHER PIERRE KLIPPEL CROUZON’S MARFAN’S DOWN’S APERT’S ROBIN FEIL COLLINS’ SYNDROME SYNDROME SYNDROME SYNDROME SYNDROME SYNDROME SYNDROME www.indiandentalacademy.com
Epstein’s pearls Bohn’s nodules Dental lamina cysts Nasopalatine duct cyst Torus platinus www.indiandentalacademy.com
. . .of soft Palate muscle hypoplasia of musculus uvulae Paralysis
www.indiandentalacademy.com
Orthodontic perspectives‌. www.indiandentalacademy.com
Occlusion Landmark in cephalometrics Spongy bone Nasorespiratory function Mid Palatal suture Onplants Support www.indiandentalacademy.com baseplate
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) www.indiandentalacademy.com
4 years . . .
6 years . . .
Adult . . .
www.indiandentalacademy.com
Thank you . . .
For the patience! www.indiandentalacademy.com