Growth of midface /certified fixed orthodontic courses by Indian dental academy

Prenatal and Postnatal
Growth of Midface

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INDIAN DENTAL ACADEMY
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CONTENTS


Anatomy of Midface and associated structures.



Prenatal embryology



Origin of malformations



Post natal Development



Theories of growth

ANATOMY OF MAXILLA AND
ASSOCIATED STRUCTURES.


Consists of 5 parts
1. Body
2. Zygomatic
3. Frontal
4. Alveolar
5. Palatine process


BODY OF THE MAXILLA


Four parts
1. Anterior
2. Infra temporal
3. Orbital
4. Nasal


ZYGOMATIC PROCESS





Anterior
Posterior
Superior
Inferior


FRONTAL PROCESS






Lateral
Medial
Superior border
Anterior border
Posterior border


ALVEOLAR PROCESS


PALTINE PROCESS





Superior
Inferior
Lateral
Medial


MAXILLARY SINUS




Largest sinus
Pyramidal in shape
4 walls
Apex
Base
Roof
Floor

PALATINE BONE




2 plates
Horizontal
Perpendicular
3 process
Pyramidal
Orbital
Sphenoidal

NASAL BONE




2 surfaces
External
Internal
4 borders
Superior
Inferior
Lateral
Medial

R


L

LACRIMAL BONE




2 surfaces
Lateral
Medial
4 borders
Anterior
Posterior
Superior
Inferior

ETHMOID BONE


3 parts
Cribriform plates
Perpendicular plate
Ethmoidal labyrinths


VOMER BONE
•Midline structure
•2 surface- lateral
•4 borders
Anterior
Posterior
Superior
Inferior

ZYGOMATIC BONE




Quadrangular
in shape
Parts
3 surfaces
5 borders
2 process


Nasal cavity

Lateral wall
Medial wall


Nasal Cartilages


Prenatal Embryology


Outline







Formation of Branchial Arches
Development of Lip
Development of palatal shelves
Development of maxillary complex
Sagittal and transverse Growth of
Nasomaxillary complex
Midface before birth – Changes in the facial
propotions

Formation of Branchial Arches


1- 4 weeks –
Ovum



Zygote

Blastocyst

Gastrula

Neurulation

4- 5 weeks –
Formation of 6 arches
Face develops from 1 and 2
branchial arches


Origins of mid face at 5 weeks






Appearance of nasal pits by thickening of
the ectoderm ( ecto – ectodermal
interactions)
Forward and downward growth of the face
Formation of medial and lateral nasal
process
Migration of neural crest cells


Face at 6 – 8 weeks





Change In the optical axes
Fusion of the medial nasal processes and
maxillary process giving rise to –
Lip
Philtrum
Primary palate
Fusion of the facial primordias

Development of Lip




Occurs during the 5th week during the fusion
of maxillary and medial nasal process.
Occurs in 3 stages
1. Contact of the epithelia
2. Fusion of the epithelial process
3. Invasion of the connective tissues


Development of the palate



5 weeks – palatine process of the maxilla
Separated by the tongue






6 weeks – growth of the palatine shelves
caudally
7 weeks – descend of the tongue caudally.


Elevation of the palate






Region specific synthesis and accumulation
of the hyaluronan
It binds with water by more than 1000 times
of its own weight causing swelling and
expansion of the shelves
Alignment of the collagen fibrils and the
cells of the mesenchyme (contraction)








The process occurs when there is
maximum growth of the height of the head
Length of the meckels cartilage
Maxillary cranial base angle – 84 deg
Fusion occurs late in females - 7 days




Woo 1949–
Separate center of ossification for each premaxilla and
maxillary centers of ossification near the canine fosse
Two centers on either side have fused to form the
corpus
There is no longer any morphologically separate
premaxilla at the end of 8th week



Bertram Kraus (J. D. Res. 1960) – 7 morphological levels

The 7 Stages


1st stage


Fusion of Premaxilla and maxilla



Radiation of the trabecule from the future
canine alveolus



K-shaped configuration


1st stage


2nd stage – 9 weeks


Begins with ossification of the alveolar
crypts of the central and lateral incisors.



Thin trabecularized network of bone of the
palate



Vomer bones have appeared

3rd stage – 10 weeks






Appearance of the infravomerine processes
Separate centers and fuse quickly
Appearance of various bony trabeculae for
the formation of the palate and the palatine
bone
Formation of the first primary molar


4th stage – 11 weeks





Increase in depth of alveolar sockets
A pointed bony process midway on the
lingual alveolar border of the central and
lateral incisors
Anterior bony margin of the incisive suture


5th stage - 13 weeks




Left and right palatal processes of the maxilla
and palatine bones have reached almost to the
mid-line and have achieved their maximum
overlap.
Divided into three zones
Anterior - deeply stained trabeculae of
the maxilla
Middle - superior layer of palatine bone
and an inferior layer of maxillary bone
Posterior - horizontal trabeculae of the
palatine bone





Buccal alveolar borders of the incisors,
canine, and primary first molar have now
assumed their characteristically curved
shape
Posterior portion of the medial edge of
palate is rounded – absence of PNS


6th stage - 14 weeks




Two halves of the palatal processes are in
apposition. at the mid-line, although no
fusion has taken place and the two
processes are generally not in contact.
Formation of Posterior nasal spine


7th stage – 15 week


Development of the maxillary
complex


Sagittal and transverse Growth of
Nasomaxillary complex from 12 – 24
weeks


Alphonse Burdi ; J. Dent. Res. 1965



Landmarks –
Nasion (N)
Sella (S)
Basion (Ba)
Crista galli (CG)
Septal point (SP)
Anterior nasal spine (ANS)
Posterior nasal spine
Uvular point (UP).


Transverse growth


Palatal Breadth To Palatal Length:



The mean value is around 82 per cent for adults.
In fetuses this relationship begins with 167 per
cent and decreases to 125 per cent.
This decrease is achieved by a constantly
increasing rate of acceleration of palatal length
relative to that of palatal breadth.




Midface before birth – Changes in the
facial propotions
CHANGES FROM 12TH – 36 WEEKS
 Length – 18mm > 120mm
 Width – 12mm > 74 mm
 Height – 20 mm > 100mm






Prior to the 5th month the increase in height
is the greatest
Cranial vault : face > 40 : 1- embryo
> 5 : 1 – 4 months
> 8: 1 – birth
> 2 : 1 - adult


“And

the end of all our
exploring
Will be to arrive where we
started
And know the place for the
first time”

Thank you

Growth of midface /certified fixed orthodontic courses by Indian dental academy

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