Growth and development of the nasomaxillary complex /certified fixed orthodontic courses by Indian dental academy

Growth and development of
the Nasomaxillary Complex

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INDIAN DENTAL ACADEMY
Leader in continuing dental education


Contents
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Introduction
Embryology & Prenatal growth
Natal growth
Post natal growth
Concepts of growth
Developmental sequence
Normal variation and malocclusion
Nasopharyngeal airway
Evolutionary changes
Anomalies
Conclusion



In the closest union there is still some
separate existence of component
parts; in the most complete
separation there still is a
reminiscence of union.
Samuel Butler


Pharyngeal arches


Early orofacial development


The development of head depends on
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Prosencephalic centre
Rhombencephalic centre

Prosencephalic centre -migrates from the primitive
streak


Induces
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Visual and inner ear apparatus
Upper 1/3 of face

Caudal Rhombencephalic centre


Induces middle and lower 1/3 of face and middle and ext ears.

Formation of the Human Face


1st characterized by an invagination in the ectoderm
below the forebrain. As it deepens,it forms an outline
of the oral cavity.



Prechordal Plate



demarcates the site of the stomodeum( 14th day)
endodermal thickening contributes tooropharyngeal membrane.
Ectoderm – forms mucosa of mouth.
 Endoderm – forms mucosa of pharynx.
 Mesoderm – does not intervene.





Face develops from 5 prominences
surrounding the stomodeum
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Frontonasal
Two maxillary processes
Two mandibular processes

1st Arch Derivatives

All prominences and arches arise from neural
crest cells-caudal stream

Frontonasal prominence
4th week iu


Develops from Cranial stream of neural crest
cells proliferate downwards to form FN process.



It surrounds the developing forebrain



Nasal placodes arises inferolaterally

5th week IU
 Face crowded between forebrain and heart
which begins to pulsate & affects development
of face because of importance of blood supply.
 The face grows downwards and forwards.
 Face is about 11/2 mm wide.


Fusion

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Fusion of MNP;LNP and MP –

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Fusion – MNP and MP provides –
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Continuity of upper jaw and lip.
Separation of nasal pits from stomodeum.

Fusion – MNP and MNP – at midline
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

Median tuberculum
Philtrum
Tip of nose
Primary palate – gives rise to premaxilla.

7th week IU
 Shift of blood supply face from ICA to ECA
because of normal atrophy of stapedial artery.
 Potential for defects upper lip and palate.


Development of Nose


derives contribution from
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FN Prominence -Bridge.
MNP’s – Median Ridge and tip
LNP’s – Alae

Cartilage Nasal Capsule – Septum and
nasal conchae.
Superficial alar field – external alar
cartilage.



5th week iu




2 raised areas appear above future mouth.
centers of these raised areas become
depressions as tissues around them start
growing

Nasal pits become nostrils-fusion of MN, MP
and LNP .


Distance between pits does not increase but pits
increase in height and length.



It is separated from stomodeum by oronasal
membrane which disintegrate to form primary
chonae (primitive posterior nares



Definite choane of adult –form by fusion of
secondary palatal shelves.




Within FNP –mesenchymal condensation
forms the precartilaginous nasal capsule
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Mesoethmoid-prologue to nasal septum
Ectethmoid-ethmoid and nasal alar cartilage

The primary nasal septum is broad – between
primary choane but builds up in a rostrocaudal
direction as the palatal shelves fuse.

NASOLACRIMAL DUCT
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Between LNP and MP-rods of epithelial cells
sink into adjacent mesenchyme.Rods extend
from conjunctival sac of developing eyelid to
external nares.They later canalize to form
nasolacrimal sacs and ducts and become
completely patent after birth


Upper Lip
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Forms in 3 steps
1-Contact between MP and MNP together
forming lamina nasal fin.

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2- fusion into a single sheet.

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3-Degeneration of this sheet resulting in
connective tissue penetration through it.

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Cranial Base
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The neurocranium can be divided into
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Calvaria-from desmocranium
Cranial base-from chondrocranium


Chondrocranium


4th week iu



Occipital sclerotomal mesenchyme
concentrates around notochord and extends
cephalically forming floor for the brain.



Conversion of the mesenchyme to cartilage
constituents the beginning of chondrocranium


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The chondrification centers are

Parachordal cartilages-around notochord

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Sclerotomal cartilages-occipital bone parts

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2 Hypophyseal cartilages-fuse to form
basisphenoid cartilage

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2 presphenoid cartilages- body of sphenoid

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Orbitosphenoid and Alisphenoid- wings of sphenoid
Mesoethmoid cartilage-fused presphenoid cartilages



Capsules around nasal and otic sense organs
ossify and fuse to the cartilages of cranial base
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nasal capsule- chondrifies in 2nd month to form
nasal septum which ossifies into ethmoid and
vomer
otic capsules chondrify; fuse with parachordal
cartilages to ossify as mastoid and petrous part of
temporal bone

All chondrification centres fuse to into a
single irregularwww.indiandentalacademy.com plate
porous basal

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Chondrocranial ossification
 110 ossification centers in human
 45 bones in neonatal skull
 22 bones in adult
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Centres of ossification commence with the
alisphenoids in 8 week IU

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Unossified chondrocranial remanants persist at
birth as
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alae and septum – nose
spheno-occipital and spheno- petrous junction
apex – petrous bone
between separate parts occipital bone

CRANIAL BASE ANGULATION
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prechordal and chordal parts meet at an angle at the
hypophyseal fossa
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Lower angle – from nasion to sella to basion
4 week - 150° (cartilage stage)
7-8 week - 130°
10 weeks – 115 - 120° (pre ossification Stage)
10-20 weeks–125–130° maintained postnatally.

Flattening – is caused by rapid growth of brain during
fetal period as chondrocranium retains its fetal flexure

CRANIAL BASE FORAMEN
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I – determines perforations of cribriform plate

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II and opthalmic artery -orbitosphenoid cartilage fuses
with basal plate-optic foramen.

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III, IV, V, VI and ophthalmic veins-orbitosphenoid and
alisphenoid – superior orbital fissure



Junction between alisphenoid and presphenoid cartilages
are interrupted by
V1 - Formen rotundum
V2-Foramen ovale
Middle meningeal artery-Formen spinosum

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cartilage between alisphenoid
and otic capsule –Foramen
Lacerum

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VII and VIII - otic capsule
ensures- internal acoustic meatus

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IX,X,XI and IJV - otic capsule
and parchordal cartilage- Jugular
foramen

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XII-occipital selerotomes –
anterior condylar canal

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Spinal cord – f. magnum

FACIAL SKELETON
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Upper 1/3 of face –grows rapidly
Middle and lower 1/3 grow slowly and over a
prolonged period




Facial bones develop intramembranously

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Interaction between neural crest
ectomesenchyme and overlying ectodermal
epithelium is essential for differentiation of
facial bones

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Frontonasal prominence- 8th week – nasal and
lacrimal bone

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Maxillary Prominence – 8th week
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medial pterygoid plate
vomer
Greater wing of sphenoid
Lateral pterygoid plate
Palatine

Pre maxilla
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Originates in 7th week on the external surface
of nasal capsule. It extends upwards and
backwards where it joins the maxilla proper at
8th week


Maxilla
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Acc to Jacobson it develops from a condensation of
embryonic mesenchyme within the maxillary process
of the mandibular arch
1° ossification centre-7th wk iu- at termination of infra
orbital nerve just above the canine tooth dental lamina.
2° ossification centers – zygomatic
orbitonasal
nasopalatine
intermaxillary

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Points of attachment

PM fissure – sphenoid and maxillary bone

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Pterygopalatine fossa – sphenoid and palatine

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ZT suture – zygomatic bone and temporal

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ZF suture -frontal and zygomatic bone

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MF suture-frontal and maxillary

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FN suture – frontal and nasal

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Growth of maxilla depends upon several functional
matrices that act on different areas and thus allowing
for its subdivision into skeletal units.
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a) Basal body

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b) Orbital unit

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c) Nasal unit

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d) Alveolar unit

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e) Pneumatic unit

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The complexity of action of forces results in
different effects on different sutures
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TZ suture - A-P horizontal growth - brain and s-o
synchondrosis.

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F-M, F-Z, F-N, E-M,F-E suture - vertical growth eyeball and nasal septum expansion

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N-M suture-A-P growth-nasal septum


Eyes
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Its growth provides an expanding force
separating neural and facial skeletons at FM
and FZ sutures therefore increasing the height.



They migrate medially due to expansion of
frontal and temporal lobes of brain

Eye balls


Grow rapidly following neural pattern of
growth and contributing to rapid widening of
the face.

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half of postnatal growth- 2 years
adult dimensions- 7 years.

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Nasal Cavity and Septum


A septomaxillary ligament arises from nasal
septum and inserts into Anterior nasal spine. It
transmits septal growth ‘pull’ on the maxilla.



Facial growth is directed downwards and
forwards by the septal cartilage

Palate
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Derived from
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two lateral max palatal shelves
primary palate of F-N prominence

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initially vertically oriented

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8th week iu transformation from vertical to horizontal

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considerable sex difference in timing. Earlier in male
than female embryos.

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Factors influencing change of orientation
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Biochemical transformations in physical consistency of
connective tissue matrices.

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Variation in vasculature and blood flow

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Sudden increase in tissue turgor.

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Rapid mitotic activity

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Intrinsic shelf force

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Muscular movements

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Withdrawl of face from heart prominence

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Fusion occurs initially - anteriorly in hard
palate, combination of degenerating epithelial
cells, and a surface coat accumulation of
glycoproteins and desmosomes facilitates
epithelial adherence


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The fusion initially produces a flat, unarched
roof.

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Junction of components -incisive papilla.
Line of fusion- mid Palatine suture.

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This fusion seam is minimized in soft palate
by invasion of extra territorial mesenchyme.

Cross-sectional
view of palate at
various ages


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Ossification - 8th week iu

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Anteriorly-primary ossification centre of
maxilla
Posteriorly- primary ossification centre of
palatine bones.

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Mid palatal suture
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10 1/2 weeks-fibrous layer in the midline.
infancy Y shape in coronal section
childhood - T shape
adolescence - Interdigitated

Paranasal sinuses
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The 4 sinuses Maxillary ,Ethmoidal ,Sphenoidal
,Frontal- 3rd month iu as outpouchings of mucous
membrane of nasal meatus and spheno-ethmoidal
recess.

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primary pneumatisation-growth of mucous membrane
sacs into the bone
secondary pneumatisation-sinuses enlarge into bones

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AT BIRTH
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Maxilla at birth -contains deciduous teeth in
various stages of completion and buds of
permanent teeth.

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Alveolar process is not developed and lies in
same plane with palate.

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Is in direct contact with bones of face and
forms floor of orbit, roof of mouth and floor
and lateral wall of nasal cavity

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Maxillary antrum - at birth has a slight
depression on the lateral wall of nasal cavity
opposite 2nd deciduous molar germ.

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it’s growth displaces the erupting deciduous
and permanent teeth


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Transverse palatine suture-according to
Woo the palatine process of maxilla and
horizontal parts of palatine bones overlap in
an anterior direction.

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Palate at birth - outer aspect has 2 parallel
grooves.
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external groove-dental groove
inner -gingival groove.

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Zygoma – anteriorly- joins maxilla through
the 1st deciduous molar.
Posteriorly through calcifying 1st permanent molar.

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Zygomatic arch grows by lateral addition and
medial resorption.


POSTNATAL GROWTH
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General Methods of Growth :
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Remodelling.
Displacement

Relocation

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Remodeling is a process of reshaping and
resizing a growing bone as it is relocated to
new levels.

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Reason- while parts of bone are moved; it
maintains the form of the whole bone and
causes its enlargement.


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carried out by the osteogenic membranes and
other surrounding soft tissues

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bone itself contributes by feedback
information


Bionator-tries to alter this equilibrium

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Fields of remodeling- resorptive and
depository on the outside and inside of bone

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Clinical significance-distalisation of molar

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Displacement – the whole bone is carried by a
mechanical force
Site -Articular contacts
1° displacement –the physical carry takes place in
conjunction with the bones own enlargement
vectors oriented–posteriorly
and superiorly
bone displaced –
anteriorly and inferiorly

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2° displacement - movement of bone and soft
tissues not directly related to its enlargement.
Temporal lobe of cerebrum

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Middle cranial fossa

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Displace nasomaxillary complex downwards
and forwards


primary movement-displacement or
remodelling?


displacement is presently believed by many
researchers to be the primary change with rate
and direction of bone growth representing a
secondary (transformative) response



It is also believed that both may be responding
to common signals that separately but
simultaneously activate both to operate in
unison



Domino effect –
Growth changes are passed on from region to
region to produce a secondary spin off in areas
quite distant. Such effects are cumulative.




Rotation –2 types
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

Remodelling rotation
Displacement rotation.



Nasomaxillary complex- displacement rotation
in either a clock or counter clock wise
direction depending on growth activities of
basicranium and sutural system.



Palate- remodeling rotation occurs in a counter
direction.

NASOMAXILLARY COMPLEX
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

Remodeling - Posterosuperiorly
Displacement – Anteroinferiorly
Remodeling –

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Lacrimal suture
Max tuberosity
Vertical drift of teeth
Nasal airway
Palatal remodelling.

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Lacrimal suture- is a bone surrounded by
Osteogenic sutural connective tissue capable
of responding to growth signals



allowing a slide of bones along their sutural
surfaces;eg: it allows the maxilla to slide down
its orbital contacts and thus displace inferiorly.




Maxillary Tuberosity :major
growth site

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Post surface -deposition –
lengthens arch
Buccal surface – deposition –
widens arch posteriorly
Alveolar ridge and lateral side
-deposition - downward
growth
Endosteal side -resorptive –
sinus enlargement

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Resorptive areas of nasomaxillary complex


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Vertical drift -As the maxilla and mandible
enlarge and develop the teeth drift horizontally
and vertically to keep pace in their anatomic
positions.



the tooth and its alveolar socket drift together
as a unit


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Palatal Remodelling -In a child the maxillary arch
and nasal floor lie very close to the orbital rim.
Remodelling results in downward relocation of the
palate so that the arch lies considerably below the
inferior orbital rim.



nasal region of the adult occupies an area where the
bony max arch used to be located during childhood.



The palate widens according to Enlows V principle.

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Also growth at the mid palatal suture widens the
palate and the alveolar arch
In RPE - maxilla is1st displaced laterally;
remodelling of the displaced segments follows

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Nasal airway remodelingethmoidal concha
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deposition-lateral and inferior surface
resorption-superior and medial surface

This moves them downwards and laterally


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Displacement- Maxilla
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primary displacement-antero -inferior direction
grows and lengthens- posteriorly


Maxillary sutures:
Primary displacement-multidirectional and thus
a slide of bones along interface occurs.
 Nasomaxillary complex undergoes a frontal
slide at junction with lacrimal, zygomatic,
nasal and ethmoidal bones.



Cheek bone and Zygomatic Arch


malar protuberance- relocates posteriorly
Posterior side depository
anterior side resorptive

Zygoma -inferior edge-depository.
Zygomatic arch -laterally and inferiorly
Deposition- laterally downwards
 resorption -opposite cortical sides



Orbital Growth


Orbital roof -floor of anterior cranial fossa
remodels antero-inferiorly



Lateral wall - resorption medially
deposition laterally



Floor of the orbit-remodels upwards
deposition-superiorly
resorption-inferiorly

Growth of maxilla


Earliest concept – maxillary growth pushes it
against pterygoid plates causing a resultant
force on it anteriorly



discarded coz - bone’s osteogenic membrane is
pressure sensitive and compression of
capillary plexus causes necrosis.



Acc to Moss 3 types of bone growth
changes are to be observed in the maxilla.



Due to 1)primary expansion of the orofacial
capsule.
 2) alterations in maxillary functional
matrices eg: orbital mass.
 3) maintenance of the form of the bone



Enlow and Bang- principle of “area
relocation”


As growth continues, “specific local areas come to
occupy new actual positions in succession, as the
entire bone enlarges. These growth shifts and
changes involve corresponding and sequential
remodeling adjustments in order to maintain the
same shape, relative position and constant
proportion of each individual area in maxilla as a
whole”




STH-somatomedin

Direct effect-stimulates preosteoblasts
prechondroblasts



Indirect effect-growth of septal cartilage
1.

Thrust effectgrowth of septal cartilage-thrust on
premaxilla-stimulates growth of suture



Histologically-collagen fibers connecting
cartilage and bone

2

Septopremaxillary ligament traction effect



Forward growth of septal cartilage-traction effect
on premaxilla-through this ligament



Studies(Petrovic;Stutzmann)-showed greater
osteoblastic at this ligament junction with
premaxilla



Histologically-ligament not able to provide traction



After resection-it has a local,induction like
stimulating effect on subperiosteal growth

3

Labionarinary muscle traction effect-



Septal cartilage growth produces traction on
premaxilla through this muscle causing
forward growth of upper jaw.



Cleft lip-absence of muscle attachment on
nasal septum-bone malformations



Unilateral resection-unilateral decreased
growth of operated side



What is the primary growth center or
pacemaker for the maxilla?



Moss and Greenberg-basic maxillary skeletal unit infraorbital neurovascular triad.basal boneprotection mechanism for the trigeminal nerve.This
neurotrophic influence maintains the spatial
constancy for the infraorbital canal with respect to
the anterior cranial base and produces a similar
constancy of the basal maxillary skeletal unit
relative to the cranial base.

NEUROCRANIUM


The original pattern of skeleton-maintained.
Stationary biologic center-body of the
sphenoid



The Basicranium - “template” that establishes
the growth fields within which nasomaxillary
complex grows






endocranial surface-resorptiveReason-sutures cant provide for multiple directions of
enlargement and remodeling

Fossa enlargement- direct remodeling



deposition-outside
resorption -inside




endocranial compartments-separated by bony
partitions





depository in nature.
reason-fossae expand outward by resorption, the
partitions between them must enlarge inward, in
proportion, by deposition.

Remodeling of basicranium -stability for nerve
and vessels . The foramen undergo drift to
maintain proper position










Synchondroses- retention from primary
cartilages of chondrocranium after the
endochondral ossification centers appear
during fetal development
Pressure adapted bone growth
Sphenoethmoidal-5 to 25 years (max contribution- 6yrs)
intersphenoidal- disappears at birth
spheno-occipital
intraoccipital - 3rd to 5th year



Recent research shows SE synchondrosis has
important ramifications in cleft palate
rehabilitation.



synchondroses are primary centers of growth
is supported by research of Sarnat, Burdi,
Baume, Petrovic, and others.



Koski says these exist primarily to adjust the
cranial base to needs of the brain and
respiratory area.



sphenoid and occipital bones move apart by
primary displacement , and endochondral bone
is laid down by the endosteum within each
bone.



cortical (intramembranous) bone formed
around the endochondral bone




Synchondrosis zones- reserve, cell
division, hypertrophic, and calcified
zones.



Chondroblasts -aligned in distinctive
columns along line of growth,with
bipolar direction of linear growth




Is displacement caused by growth
expansion, or the endochondral growth a
response to displacement caused by other
forces?



Does the cartilage have an intrinsic genetic
program that actually regulates growth?




Cranial cartilages-autonomous growth units
that develop in conjunction with the brain, but
somehow independent of it.



Experimental studies show the independent
proliferative capacity of synchondrosis is not
greater than epiphyseal plates (more than
condylar cartilage) suggesting extrinsic control
factors are also required



synchondrosis relates to the midventral axis
and not the entire cranial floor.



Enlargement



Midline-less
middle cranial fossae-more because it houses the
various lobes which enlarge much more(laterally)


Effect on maxillary complex


middle cranial fossa-causes
secondary displacement of
nasomaxillary complex



maxillary complex posterior
boundary positioned to
coincide with the boundary
between the anterior and
middle cranial fossa



Temporal and frontal
lobes expand (5-6 yrs).






two fossae- pulled away
tension fields in the frontal,
temporal, sphenoidal, and
ethmoidal sutures.
Both fossae-enlarge
nasomaxillary complex is
carried along anteriorly



Acc to Weinmann and Sicher the sutures are
all oblique and parallel to each other. Thus
causing the maxilla to move downward and
forward (or the cranium upward and
backward).



Sutures- increase the circumference bones involved



Hunter and Enlow-growth equivalents theory


analyzed the effect cranial base growth on facial
growth



emphasize both the timing of endochondral and
intramembranous growth and the correlation of
vectors and increments


CONCEPTS OF GROWTH

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


SUTURAL THEORY
CARTILAGINOUS THEORY
FUNCTIONAL MATRIX CONCEPT
MULTIPLE ASSURANCE
VAN LIMBORGH’S THEORY
CYBERNETIC THEORY




Sicher sutural growth theory-



growth at maxillary sutures-pushes bone apart
causing anteroinferior thrust on maxilla



discarded as - suture growth is tension
adapted and is not adapted to pressure.



now believed-displacement of a bone produces
tension which acts as a stimulus for sutural
bone growth



Scotts cartilaginous growth theory


It is specifically adapted to pressure related
growth



Supported by research by Ohyama on rats
In cleft palate cases,nasal septum grows normally





inhibition of sutural growth considered as of lack
of cartilage growth –no cartilage growth, no
sutural growth, no proliferation of connective
tissue.



Scott attributed an epiphyseal plate like effect
to the nasal septum.



Recent research shows- nasal septum seems
more important in anteroposterior than vertical
growth.



Questioning Scott’s hypothesis –



periosteal growth is controlled by intrinsic factors
why the periosteal membrane should be different
in its action than sutural growth

Functional matrix concept


any given bone grows in response to
functional relationships established by the sum
of all soft tissues operating in association with
that bone.



functional matrix is apparent in craniostenosis;
discontinuation of sutural growth of calvaria,
with the brain still growing, pressure is exerted
on other areas, causing the eye to bulge, and
producing other effects



Brain rests on the chondrocranium and
theoretically exerts the same amount of force
downward as it would on desmocranium.



This apparent high degree of independence of
bone growth is further substantiated by the fact
that it is very difficult to distort the
chondrocranium in contrast to desmocranium.



Thus, there is apparent support for part of the
Scott hypothesis while much research supports
the Moss functional matrix explanation

Multiple Assurance – by Latham and Scott
1970
The process and mechanisms that function to
carry growth are multifactorial. If 1 becomes
inoperative other components have a capacity
to ‘compensate’ ie: provide alternate means to
achieve same developmental and functional
and result.


Van limborgh’s theory


synchondroses and endochondral
ossification- controlled by intrinsic genetic
factors.



intrinsic factors controlling intramembranous
bone growth are small in number and of a
general nature.



cartilaginous skull parts- growth centers.



sutural growth-controlled by cartilaginous
growth and growth of other structures.



periosteal bone growth depends on the
growth of adjacent structures.



intramembranous bone formation can also be
influenced by local environmental factors.


Cybernetic theory


THE DEVELOPMENTAL SEQUENCE
Balanced growth-form and proportion remain
constant


The face –balanced+ imbalanced craniofacial
parts



Enlow’s counterpart principle-growth of any
given part relates specifically to other
structural and geometric parts


Part and counterpart
grow equal-balanced growth
 Unequal-imbalanced growth




Stage 1-



remodeling of maxillary
tuberosity



PTM moves posteriorly



Maxillary arch length
increases same amount as
PTM moves posteriorly




Stage2-



displacement anteriorly



Amount of fwd
displacement equals
amount of posterior
lengthening



Stage3-



temporal lobes and middle
cranial fossa –remodel



The expansion projects it
beyond reference line




Stage4-



All parts anterior to reference
line-displaced forwards



Reference line moves-same
extent as MCF



Maxillary tuberosity-constant



Stage5-



floor ACF and forehead







Deposition-ectocranium side
Resorption-endocranial side

Nasal bone displaced anteriorly
ACF-in balance with maxillary arch
Nasal region-equivalent growth
increments horizontally



Stage6-



vertical lengthening of
nasomaxillary region



Primary displacement
Remodelingresorption-superior part of palate
 Deposition-inferior side




Thus relocating it inferiorly
;thereby providing for vertical
enlargement of above nasal
region



Stage7-



bone deposition –maxillary sutures



equal to –maxillary displacement
inferiorly



Palate and maxilla


1-2- remodeling
2-3 primary displacement and sutural
growth





Teeth


1-2 –vertical drift
2-3-displacement of www.indiandentalacademy.com
maxilla



Stage 8



zygoma and malar arearemodel posteriorly




Stage 9-



malar area-primary
displacement-anteriorly
and inferiorly


Changes in growing face
Postnatally face increases primarily in length,
less in A-P depth and least in lateral width.



At birth
Width - 57% of adult



Height- 40%
Depth - 33%



Face height –



cartilages of nasal septum, upper facial
skeleton and condyle determine the direction
of growth of face height.



From mid-fetal life to 5 years facial growth
increases by 1/3.



Face shows a sustained and longer duration
growth.



Face depth –


According to meredith



the face depth increases at a slower rate
as age increases.



Avg face depth is approx 3% larger in
boys than girls.




Sex differences in Face Growth –



Girls complete A-P growth at puberty while
boys continue till maturity.



Girls face grows in height more than males till
15 years.



Males - growth - Depth > Height > Width
Female - growth -Depth > Height –(upto 11 yrs)
Height > Depth – (11-18yrs)



NORMAL VARIATION AND
MALOCCLUSION


Range of facial differences exists- brainlarge and variable
Broadly divided into





Dolichocephalic
Brachycephalic



Brachycepahlic

Wider and A-P shorter
basicranium



Closed basicranial flexure



Vertically and protrusively
shorter ;wider midface



the anterior cranial fossa sets up
a wider but shorter and more
shallow palate and maxilla.



Nasomaxillary complexretrusively placed


horizontal length short



Composite result -relative retrusion




DolicocephalicLong and narrow basicranium

elongate and open and basicranial
flexure
A-P and vertical elongate facial
pattern
anterior cranial fossa sets up a
narrower and deeper maxillary



nasomaxillary complex-

protrusive position; lowered
relative to the condyle
downward and backward
rotation of mandible
Occlusal plane rotated in a
downward-incline

Male versus female
Dolichocephalic- features parallel those of the
male face
Brachycephalic- features parallel those of the
female face.

Comparison- is relative whole body and lung
size

Child versus adult


Youthful face- brachycephalic

brain precocious relative to facial development.



facial and pharyngeal airway is yet small



Anterior cranial fossa is developmentally
precocious-nasomaxillary complex- carried to a
more protrusive position than the mandible



face is vertically short because


Nasal part of the face is still diminutive



Primary and secondary dentition not fully
established



Jaw bones not yet grown to the vertical extent.




Forward and downward
inclined middle cranial
fossa






maxillary protrusive
mandibular retrusive effect

Maxilla- offset anteriorly
Mandible- down and back
Class II molar relationship



Upwards and
backward inclined
middle cranial fossa







mandibular protrusion effect

Maxilla- placed backward
Mandible-rotates in a
protrusive position.
Class III molar relationship



Nasomaxillary complexvertically long




Mandible- downward-backward
rotation

Class II molar relationship




Nasomaxillary region vertically short


mandibular -protrusive effect



Mandible rotates forward and
upward



Class III molar relationship



Maxillary retrusive and mandibular
protrusive effects-




Maxillary protrusive and mandibular
retrusive effects-




EFFECT OF NASOPHARYNGEAL
AIRWAY
Acc to Moss
functional spaces (oral, nasal, pharyngeal) are
not simply left over areas; but volumetric
growth of these spaces is 1° morphogenetic
event in facial skull growth.
The functional reality of respiratory and
digestive system is patency of these space



Theories proposing a relationship between
mouth breathing and dentofacial form-

I. COMPRESSION THEORY
II. DISUSE ATROPHY THEORY.
III.ALTERED AIR PRESSURE.
IV.SOFT TISSUE STRETCH HYPOTHESIS




Compression Theory-Tomes-1872.
Enlarged adenoids
Low tongue position
Unbalanced muscle equilibrium
Excessive force on maxillary arch buccal segments
V-shaped dental arches.



Disuse Atrophy Theory:
inactivity of nasal cavity causes an alteration
in maxillary arch



Nordlund (1918)- obstruction of nasal
respiration due to adenoids
nasal cavity undergo disuse atrophy
relative elevation of palatal vault as alveolar
process grows downward



Moss stated that in Congenital Bilateral
Choanal Atresia - absence of Nasorespiratory
function.



Marked underdeveloprment of functional
space occurs




Altered Air Pressure:


alteration of air pressure within nasal and
oral cavities during mouth breathing effects
dentofacial form.



Bloch (1903) and Michel (1908)
upward stream of oral airflow pressure on palate
leads to higher palatal vault.




Kantorowicz (1916) and James and Hastings
(1932)
In mouth breathing
negative pressure in sealed oral cavity lost
Palate not carried downward with growth
of maxillary alveolar process




Soft Tissue Stretch Hypothesis: Solow and
Kreiborg (1977)



Posturally induced stretching of soft tissue of
facial region might influence craniofacial
morphological development



Hypothetically an extension of head, i.r.t
cervical column - passive stretching of soft
tissue enclosing face and neck.



Effect-backward and downward forces

In adenoid obstruction -increased cranio
cervical angulation.
 changes in Craniofacial morphology
corresponding to this changed head
posture.



Studies showing association between
nasopharyngeal obstruction and dentofacial
form Experimental studies done on primates-



(1973)
They blocked the Nasal passages of Rhesus
monkeys and the monkeys gradually adapted
from Nasal breathing to oral respiration
HARVOLD, CHIERICI & VARGERVIK




Critical review of literature- by 0’ Ryan et al-



suggests that simple cause and effect
relationship between nasorespiratory
function and dentofacial development does not
exist, rather it is a complex interaction
between hereditary and environmental
influences


The Role of Ear in determining facial form


It’s role as space occupying organ ambiguous and minimal. The internal ear
reaches its adult size in- 5-6 month iu.



It is the only organ that reaches full adult size
by this age and thus minimises any influence
on subsequent growth of facial skeleton.


EVOLUTION OF HUMAN FACE


Brain Enlargement,
Basicranial Flexure



cerebrum expands around
smaller and lesser-enlarging
midventral segment-causes a
bending of the whole
underside of the brain. The
flexure of the basicranium
results



orbital rotation-



Two separate axes

Vertical; horizontal



forehead- rotated into vertical plane
by brain, the superior orbital rims are
carried with it.



temporal lobes- rotate orbits towards
the midline



Orbital rotation reduces the interorbital
space and the structural base of the bony
nose.




Reduction in nasal protrusion
accompanied less equivalent reduction of
the upper jaw






Downward rotation of olfactory bulbs and
anterior cranial floor by the frontal lobes has
caused a downward rotation of the
nasomaxillary complex.
.The plane of the nasomaxillary region
-perpendicular to the olfactory bulbs.







Nasomaxillary
Configuration
Mammals-triangular.
Man-rectangular




rotation of occlusion in a
horizontal plane adapting to the
vertical rotation of the midface.

suborbital compartmentoccupied by maxillary sinus




Face also became markedly
widened of the increased
breadth of the brain.



The face now lies beneath
the frontal lobes of the brain.




downward – directed external nares aim the
inflow of air obliquely upward towards
sensory nerve endings in the olfactory bulbs


Growth Field Boundaries




forward boundary of the brain and
nasomaxillary complex is shared
A line is drawn from the forward edge of the
brain to prosthion.-MIDFACIAL PLANE




Upper boundary



the nasal part of the face relates to the olfactory
bulbs and nerve.

The nasomaxillary complex develops in a
growth field out to the edge of the brain
perpendicular to the olfactory bulbs.




Posteriorly 

Direction of growth- established visual
sense. The maxillary tuberosity is located
beneath the floor of the orbit and aligned
perpendicular to its axis.




The posterior plane of midface extends from
junction between the anterior and middle
cranial fossa,downwards in a direction
perpendicular to the neutral axis of the orbit



Posterior maxillary (PM) plane.


developmental interface between counterparts
ahead and behind it




Inferior boundary- established when
growth is complete by inferior surface of the
brain and basicranium


ANOMALIES


Unilateral, bilateral cleft lip



Oblique facial cleft and cleft
lip



Median cleft lip and nasal
defect



Median mandibular cleft



Unilateral microstomia



Ancephaly
Abs of neural crest cells –
neurocristopathy



Treacher Collins syndrome



Anhidrotic ectodermal
dysplasia



Downs syndrome






Cleft palate-



Cleft lip and palate



Fetal alcohol syndrome

CONCLUSION
Nasomaxillary complex growth is a
process requiring intimate morphogenic
interrelationships among all of it’s
component growing, changing and
functioning soft and hard tissue parts. No
part is developmentally independent and
self contained.

Thank you
Leader in continuing dental education


Growth and development of the nasomaxillary complex /certified fixed orthodontic courses by Indian dental academy

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