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

GROWTH OF MAXILLA AND
CRANIAL BASE AND THEIR
CLINICAL IMPLICATIONS

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INDIAN DENTAL ACADEMY
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CONTENTS
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INTRODUCTION
PRENATAL GROWTH OF MAXILLA
POSTNATAL GROWTH OF MAXILLA
PRENATAL GROWTH OF CRANIAL BASE
POSTNATAL GROWTH OF CRANIAL BASE
CLINICAL CONSIDERATIONS
CONCLUSIONS
REFERENCES

INTRODUCTION
• Orthodontists are heavily involved in the
development of not just the dentition but
the entire dentofacial complex, a
conscientious practitioner may be able to
manipulate facial growth for the benefit of
the patient.
• This is not possible to accomplish without
thorough understanding of the pattern of
normal growth and the mechanisms that
underlie it , hence it is essential to study
growth.

WHAT IS GROWTH?
• Growth is physiochemical process of living matter
by which organism becomes larger

• Quantitative aspect of biologic development per
unit time :moyers

• Increase in size, change in proportion &
progressive complexity: krogman


MAXILLA


MAXILLA
• The maxilla is the second largest bone of the
facial skeleton, the first being the mandible. It is a
pneumatic bone that is paired and forms the
upper jaw.
• Either of a pair of irregularly shaped bones of the
skull, fusing in the midline, supporting the upper
teeth, and forming part of the eye sockets, hard
palate, and nasal cavity; upper jaw.

Parts of maxilla
The body of the maxilla has
four surfaces:
• Anterior or facial surface
• Posterior or infratemporal
surface
• Superior or orbital surface
• Medial or nasal surface.
• Maxillary sinus is present
within the body
It has four processes:
• Frontal
• Zygomatic
• Alveolar
• Palatine.

Articulations
• Two of the cranium: the frontal and ethmoid
• Seven of the face: the nasal, zygomatic,
lacrimal, inferior nasal concha, palatine, vomer,
and the adjacent fused maxillary bone.
• Sometimes it articulates with the orbital surface,
and sometimes with the lateral pterygoid plate of
the sphenoid.


PRENATAL
GROWTH
OF
MAXILLA


Around 4th week of
intra uterine life
five branchial
arches form in the
region of future
head and neck.
The first branchial
arch called the
mandibular arch
plays an important
role in
nasomaxillary
complex
development

Maxilla develops from:
• Frontonasal process :mesoderm covering
the forebrain which proliferates and forms
a downward projection overlapping upper
part of stomodeum.
• Maxillary processes: mandibular arches
give bud from its dorsal end called
maxillary processes

The two maxillary processes grow ventro
medially and fuse with frontonasal process
to give rise to maxilla.
The anterior part of the maxilla and part of the
nose develop from the frontonasal process.
At the end of 3rd week of intra-uterine life, this
process grows downwards to meet the
maxillary processes of the first branchial
arch, which grow forward.
These processes unite at the end of the 4th
week I.U. to form the maxillary jaw.

Ossification of maxilla
• The maxilla is ossified in
membrane(intramemranous). It is
ossified from two centers only, one for
the maxilla proper and one for the
premaxilla.


• At 6 ½ weeks I.U., the future body of the maxilla
constitutes the main mass and its frontal,
zygomatic, alveolar and palatal processes.
• In the 7 ½ week I.U., the lamella begins to grow
forward, backward and downward to form the
frontal process and alveolar wall.
• After the 3rd month I.U., there is generalized
enlargement of the face in all directions.

» The maxillary sinus appears as a
shallow groove on the nasal
surface of the bone about the
fourth month of fetal life, but does
not reach its full size until after
the second dentition.


Development of palate
Palate develops from :
• Maxillary process
• Palatal shelves of maxillary process
• Frontonasal process


Development of the bony
palate.
• Frontonasal process gives rise to premaxilla
while palatal shelves form the rest of the palate.
• Initially the palatal shelves grow vertically
downwards towards the floor of the mouth
sometime during 7th week of intra uterine life they
change to horizontal position.
• By 8 ½ weeks of intra uterine life the palatal
shelves begin to fuse.

• At 9 weeks, the shelves are in near
contact and the premaxillary – maxillary
ossification centers appear.
• At 10 weeks, the soft tissue of the palate
has fused and ossification centers of the
premaxilla – maxilla grow medially.


Palate ossifies from single centre. The anterior
part of the palate undergoes intra membranous
type of ossification . Posterior palate doesnot
ossify – forms soft palate.
At 14 weeks, the premaxillary bone supports the
incisors and the maxillary bone supports the
cuspids and first molars.The palatine bone
supports the second molars.

Mid palatal suture
Ossifies by 12 to 14 years
Mid palatal suture
• 10 1/2 weeks-fibrous layer in the
midline.
• infancy Y shape in coronal
section
•childhood
- T shape
•adolescence - Interdigitated

POST NATAL
GROWTH OF
MAXILLA


Growth of maxilla involves mainly of these
processes which occur simultaneously and in
an interdependent way.
•

Remodelling which occurs in posterior
direction.

•

Apposition of bone at sutures

•

Displacement which moves the maxilla forward
and downward.

• Hypothesis OF GROWTH OF
MAXILLA
• Additions of new bone on the posterior surface
of the elongating maxillary tuberosity "push" the
maxilla against the adjacent muscle supported
pterygoid plates. This presumably would cause a
resultant shove of the entire maxilla anteriorly
because of its own posterior bone growth
activity.
• Reason for aborting this theory was that bones
osteogenic membrane is pressure sensitive
hence tissue necrosis will occur in case of
pressure

Sutural theory
• Growth at sutures pushes apart bones
with resultant thrust of whole maxilla
anteriorly
• Sutural connective tissue is not adapted to
a pressure related growth process,sutures
are tension adapted tissues hence this
idea was also aborted.


Nasal septum theory: scott
• Basis of the “septal theory” is that pressure
accomodating expansion of the cartilage in the
nasal septum provides a source for the physical
force that displaces the whole maxilla anteriorly
and inferiorly,setting up fields of tension in
maxillary sutures which enlarge in response to
the tension created by displacement process.
• There is no actual genetic determinants within
the septal cartilage (blueprint for growth of

maxilla)


Black : bone
Stippled:cartilage


• "Multiple assurance" (Latham and Scott, 1970).
• The processes and mechanisms that " function
to carry out growth are virtually always
multifactorial. Any one determinant of the growth
process become inoperative (as by pathology or
by experimental deletion of an anatomic part),
other morphologic components in some
instances have the capacity to "compensate."
• That is, they provide an alternative means to
achieve more or less the same developmental
and functional end result, although perhaps with
some degree of anatomic distortion.

Functional matrix theory :Melvin
moss
This theory states that :origin form
position growth and maintenance of all
skeletal tissue and organs are always
secondary compensatory and necessary
response to chronological and
morphological prior events or processes
that occur in specifically related
nonskeletal tissue organs or funtioning
spaces

• Melvin Moss (AJODO1969) has described two basic
types of matrices are there: periosteal and capsular.
• Periosteal matrices act upon skeletal units in a direct
fashion by the process of osseous deposition and
resorption ,their net effect is to alter the form of their
respective skeletal units.
• Capsular matrices act upon functional cranial
components as a whole in a secondary and indirect
manner by altering the volumes of the capsular
matrices within which they are embedded .
• The effect of such growth is to cause a passive
translation of these cranial components in space.

Calvarial

bones are
embedded in neuro
cranial capsule and are
translated thereby ,so
are the nasomaxillary
bones embedded in the
orofacial capsule . The
primary expansion of
the functioning
oronasopharyngeal
spaces on a
morphogenetic stimulus
brings about secondary
compensatory
expansion of the
orofacial capsule.

Servosystem theory :petrovic
• STH-somatomedin, testosterone and
estrogen play primary roles in extrinsic
control of post natal growth of the upper
jaw.
• They have direct and indirect effects.


Direct effects
• Represents almost the entire influence of the
hormones on growth of spheno-occipital
synchondrosis and nasal septal cartilage.
• Small part of the effect of hormones on growth
of cranial sutures is direct. Effects the
responsiveness of preosteoblasts to regional
and local factors, stimulating the skeletal cell
multiplication.


Indirect effect
• Forward growth of nasal septal cartilage.
1.Thrust effect
2.Septomaxillary ligament traction effect.
3.Labionarinary muscle traction effect.


Thrust effect
 growth of septal cartilage-thrust on
premaxilla-stimulates growth of
premaxillomaxillary suture and
maxillopalatal suture.


Septopremaxillary ligament traction effect
• Forward growth of nasal septal cartilage has a
traction effect on the premaxillary bone through
the septo premaxillary ligament.

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

Growth of maxilla :
amount and direction


Maxillary height
• The classical studies by Bjork and skieller
confirm that maxillary height increases
because of sutural growth toward the
frontal and zygomatic bones and
appositional growth in the alveolar
process.
• Apposition also occurs on the floor of the
orbits with resorptive modeling of the
lower surfaces,simultaneously the nasal
floor is resorped while apposition occurs
on the hard palate.

Maxillary width
• Growth in the median suture is most
important for increase in maxillary width.
• Growth increase in median suture follows
general growth curve for body height.
• Mutual transverse rotation of the two
maxillae results in separation of the halves
more posteriorly than anteriorly


Maxillary length
• Length increases in the maxilla after about
the second year by apposition on the
maxillary tuberosity and by sutural growth
toward the palatine bone.Surface
resorption occurs anteriorly
• The maxilla rotates forward in the relation
to anterior cranial base.


Extensive remodeling occurs throughout the nasomaxillary complex
(B and C) as the entire region un-dergoes inferior (and anterior)
displacement (D).

Enlow & Bang (AJO 1965) studied the

complete right halves of the maxillary bones
from twelve well-preserved human skulls, all with
either deciduous or mixed dentition.

Due to the complex shape and contours of the
maxilla, the entire bone was divided into several
sections and the growth of each part was
studied individually.


The Maxillary Tuberosity
• Maxilla grows
horizontally by
remodelling of maxillary
tuberosity.Deposition
occurs on the posterior
facing periosteal surface
of the
tuberosity,endosteal
surface is resorptive.
Cortex moves
posteriorly and little
laterally.

Maxillary tuberosity is major GROWTH SITE of
maxilla in posterior region. Primary displacement
of maxilla occurs due to deposition at tuberosity.
The amount of forward movement is equal and
opposite to the posterior lengthening . This
functions to lengthen the dental arch and to
enlarge the anterioposterior dimensions of the
entire maxillary body.


Growth proceeds along the entire inner side of the
arch as well as along its posterior margin,resorptive
removal occurs from the outer cortex of the
premaxillary area and anterior surface of zygomatic
process.
Apparent direction of growth which results from
anterior thrust of the maxillary body

The whole maxilla undergoes a simultaneous
process of primary displacement in an
anterior and inferior direction as it grows and
lengthens posteriorly & superiorly.

The malar process of maxilla
•

Coordinated with tuberosity
growth is the movement of
entire zygomatic process in
posterior direction.The
posterior side of the malar
protuberance within the
temporal fossa is depository.
Together with a resorptive
anterior surface, the
cheekbone relocates
posteriorly as it enlarges.

•

The zygoma becomes
displaced anteriorly and
inferiorly in the same direction
and amount as that of
maxilla ,malar protuberance is
a part of maxilla and is carried
with it

• As the malar region grows and
becomes relocated posteriorly,
the contiguous nasal region is
enlarging in an opposite,
anterior direction. This draws
out and greatly expands the
contour between them,
resulting in a progressively
more protrusive appearing
nose and an anteroposteriorly
much deeper face.
• This is a major topographic
maturational change in the
childhood-to-adult face. i.e the
depth of the face increases.

Growth of zygomatic bone and malar process of maxilla :posterior
surface depository anterior resorptive.

The Nasal Region
• The nasal area of the maxilla together with its
separate nasal bones ,also faces in similar
lateral,anterior and superior directions.
• Growth proceeds in these directions by surface
bone deposition ,thereby increasing the internal
size of nasal cavity by an elongation and
expansion of its vertical and horizontal
dimensions.


• The bony cortex lining the inner surface of
the nasal cavity undergoes periosteal
surface removal of bone as its endosteal
surface receives simultaneous deposits of
new bone.
• Bone is removed from floor of nasal cavity
and a compensatory bone deposition
occurs on the palatal side.

The breadth of the nasal bridge in the region just below the frontonasal
sutures does not markedly increase from early childhood to
adulthood . More inferiorly in the interorbital area, however, the medial
wall of each orbit expands and balloons out considerably in a lateral
direction in conjunction with the considerable extent of lateral enlargement
of the nasal chambers.

The Maxillary Sinus
• The inner cortical lining of the sinus is
resorptive in nature.
• This contributes to enlargement of the
sinus during maxillary growth by
resorption from the inside and regional
deposition on the various outer surfaces.


Palatine process of maxilla
• Grows in a generally downward direction by a
combination of surface deposition on the entire
oral side of the palatal cortex with resorptive
removal from the opposite nasal side,as well as
from periosteal labial surfaces of the anterior
maxillary arch.
• It follows the V principle of growth and
hence grows inferiorly by remodelling and
expands laterally

The growth of palate by the V principle

Premaxilla
• The premaxillary part of the maxilla grows in a
downward direction. The surface orientation of
this area is such that downward movement is
brought about by resorptive removal from the
periosteal surface of the labial cortex which
faces away from the direction of growth. The
endosteal side of its cortex and the periosteal
surface of the lingual cortex receive new bone
deposits. This growth pattern also produces a
slight recession of the incisor area in a posterior
direction.


Orbital surface of maxilla
• Orbit also follows the growth by v
principle
• Sutural bone growth occurs at
the many sutures within and
outside the orbit, the orbital floor
is displaced and enlarges in a
progressive downward and
forward direction along with the
rest of the nasomaxillary
complex.


• The floor of the orbit offsets this by remodeling upward
as the whole maxilla displaces inferiorly. Deposition
takes place on the intraorbital (superior) side of the orbital
floor and resorption on the maxillary (inferior) sinus side .
• This sustains the orbital floor in proper position with
respect to the eyeball above it.
• The nasal floor, in contrast, approximately doubles the
amount of displacement movement by additional
downward cortical remodeling.
• Thus, the orbital and nasal floors are necessarily displaced
in the same direction because they are; parts of the same
bone, but they undergo remodeling relocation movements
in opposing directions.

The floor of the nasal cavity in the adult is positioned
much lower than the floor of the orbital cavity

The orbits relocates anteriorly
by the V principle ,which itself
serves to enlarge the orbital size
Also, the multiple parts of the
whole orbit become displaced out
and away from each other at the
same time in association with bone
deposition at the various orbital
sutures

Alveolar part of maxilla
• Deposition occurs on the alveolar part of
maxilla as teeth begin to erupt
• Following eruption, teeth undergo a
process of vertical drift in which the whole
socket remodells in downward direction
along with the tooth :intra memranous
remodelling


Vertical remodelling of socket


• The horizontal and, especially, the vertical
distances moved by the socket, its tooth,
and the periodontal membrane can be
substantial. By harnessing the vertical drift
movement, the orthodontist can more
readily guide teeth into calculated
positions, thereby taking advantage of the
growth process ("working with growth").

vertical drift of each tooth
in its own alveolar socket
passive carrying of the
maxillary dental arch


The Key Ridge
• Major changes occur
in surface contour
along the vertical crest
just below the malar
protruberance :key
ridge.A reversal occurs
here
Area (b) anterior to the reversal line the external
surface of maxilla is resorptive
Area (a) grows downward by periosteal deposition

Surface a is
resorptive b is
depository.arrow
indicates the
area of reversal
used as point A
in
cephalometrics

Lacrimal suture :key factor for
maxillary growth
• The lacrimal bone is a diminutive flake of a bony island
with its entire perimeter bounded by sutural connective
tissue contacts separating it from the many other
surrounding bones.
• As all these other separate bones enlarge or become
displaced in many directions and at different rates and
different times, the sutural system of the lacrimal bone
provides for the "slippage" of the multiple bones along
sutural interfaces with the pivotal lacrimal as they all
enlarge differentially. This is made possible by
collagenous linkage adjustments


• The lacrimal sutures make it possible, for the maxilla to
"slide" downward along its orbital contacts. This allows
the whole maxilla to become displaced inferiorly, a key
midfacial growth event, even though all the other bones
of the orbit and nasal region develop quite differently and
at different times, amounts, and directions.
• Without this adjustive developmental "perilacrimal sutural
system," a developmental "gridlock” would occur
among the multiple developing parts. The lacrimal bone
and its suture is a developmental hub providing key
traffic controls.


• The growing child's facial topographic profile
undergoes a characteristic clockwise rotation.
Several developmental relationships underlie the
maturational change
• The two-way combination of (1) forward remodeling of the nasal region and superior
orbital rim together with
(2) backward remodeling growth of the inferior orbital
rim and the malar area, and
(3) the essentially straight downward remodeling of the
premaxillary region, all combine to produce a
developmental rotation in the alignment of the whole
of these middle and upper facial regions

Facial topographic profile undergoes a
characteristic clockwise rotation.

Sutural growth of maxilla
• New bone is added at the frontomaxillary,
zygotemporal, zygosphenoidal, zygomaxillary,
ethmo maxillary, ethmofrontal, nasomaxillary,
naso-frontal, frontolacrimal, palatine, and
vomerine sutures.
• The displacement of the bone is caused by the
expanding soft tissues ,sutural growth occurs as
a response to it ….multiple sutural deposits are
not the pacemaker of growth.

• The suture are all
oblique and more or
less parallel to each
other . This allows
downward and
forward repositioning
of maxilla as growth
occurs.

As the whole maxillary complex is
displaced downward and forward, or as it
remodels by deposition and resorption, it
undergoes a frontal slide at sutural
junctions with the lacrimal, zygomatic,
nasal, and ethmoidal bones.



Summary diagram of maxillary
remodeling. Growth directions
involving surface resorption are
represented by arrows entering the
bone surface. Directions of growth
in-volving surface deposition are
shown by arrows emerging from the
bone surface.


3 dimensional growth of the maxilla as
revealed by the implant method
Arne Bjork and V. Skieller (BJO 1977),

described the growth of the maxilla studied by the
implant method with the help of lateral and PA
cephalograms, in nine 4 year old boys with normal
primary occlusion who were followed annually up to the
age of 21 years.

The tantalum pins inserted in the zygomatic process of the
maxilla at 4 years of age were referred to as the lateral
implants.
The implants placed in the anterior aspect of the maxilla
after full eruption of permanent incisors (10-11yrs) were
referred to as anterior implants.

Maxillary width
• Bjork showed that growth in the suture continues until
puberty.
• By measuring the distance of separation between the lateral
implants on the frontal cephalogram over time, it was shown
that sutural growth was the most important factor in the
development of the width of the maxilla.
• The mean transverse growth in the median suture,
measured between the lateral implants, from childhood to
adulthood was 6.9mm.
• The curves for cumulative growth in the width of the median
suture from year to year followed the same pattern as the
curves for the growth in body height.

Transverse mutual rotation of the
two maxillae:
• Comparison of increase in width between the
anterior and the lateral implants showed that
increase in width between the lateral implants was
on average, 3.5 times greater than that between
the anterior implants.(3 mm and 0.9 mm
respectively).
• This indicates that the two maxillae rotate in
relation to one another in the transverse plane,
which results in decreased length of the maxilla in
the mid sagittal plane.

• Mutual transverse rotation of maxillae also
results in greater separation of lateral
segments of dental arch posteriorly, than
anteriorly.
• There is thus, greater increase in intermolar
width than intercanine width, and also a
corresponding decrease in arch length.
• Thus, shortening of arch length is related to
transverse growth of the maxilla.

A drawing of the upper dental arch in occlusal view from
photographs in natural size illustrates the marked sagittal shift since
the age of 10 years of the lateral segments of the dental arch on the
jaw base amounting to 5 mm in relation to the anterior implant, while
the forward drift of the incisor segments was 2.5 mm.

Vertical rotation of the maxillary
complex.
• Downward and forward displacement of
the maxilla during growth is associated
with varying degrees of forward rotation.
• The inclination of the nasal floor to the
anterior cranial base is however
maintained as a result of compensatory
differentiated resorption.

• Forward rotation of the maxilla is
associated with greater resorption of the
nasal floor anteriorly than posteriorly.
• Forward rotation of the face occurs
because of greater facial growth
posteriorly than anteriorly, associated with
development in height of the cranial base.

• E.L. Korn S. Baumrind (JDR 1990) did similar
study using longitudinal data on transverse
widening of maxilla from sample of normal
subjects (11 males 20 females) with metallic
implants. Measurements were done annually
between 8.5 to 15.5 yrs on frontal and lateral
cephalograms .
• Results showed transverse widening was
greater in posterior then anterior part of maxilla
• Widening continued through out the studied
duration with no tapering or cessation of growth
in the area as conventionally accepted.

Stanley Braun et al (A O 1999) C-axis: A growth
vector for the maxilla
• Nanda and Merill
proposed M-point, a
constructed point
representing the
center of the largest
circle that is tangent
to the superior,
anterior, and palatal
surfaces of the
maxilla as seen in the
sagittal plane.

• The C-axis, defined
by sella-M-point,
permits the
quantification of a
complex maxillary
growth process in
cephalometric terms
relative to various
craniofacial structures
in the sagittal plane.


• In the study 172 serial lateral cephalograms of
20 females and 174 serial lateral
cephalograms of 19 males were taken.
• The results were as follows: the rate of c axis
increase in males was from a mea n of 41.69
degrees at 7.6 yrs to 45.5 degrees at 18.6 yrs
for females it increased from 42.21 degrees at
7.4 yrs to 44.47 degrees at 18.75 yrs.
• The study showed that growth along the c axis
tends to decrease in females by age of 16.

• Jiuhui Jiang et al ( angle ortho 2007) did a
proportional analysis of longitudinal craniofacial
growth using modified mesh diagrams
• Cephalograms selected from among 900
candidates were taken at 13 yrs then at 18 yrs of
age.
• Elaborate mesh diagrams were developed using
90 anatomic landmarks and additional 172
interpolated points

Modified mesh diagram

• Results of the study showed that mesh diagrams
can provide a quantitative method of assessing
craniofacial growth.
• From 13 to 18 yrs ,two sexes with normal
occlusion displayed different growth patterns ,in
females most craniofacial regions exhibited
growth proportional to mesh core rectangle . In
males there was an upward enhanced shift of
the anterior cranial base and a downward
enhanced shift of mandible .

Mesh diagram for girls superimposition

Mesh diagram for males superimposition

CRANIAL
BASE


The cranial base or basicranium, the ventral part of the
cranium, is the most complex structure of the skeleton.
Its main function is to protect and support the brain and
to provide a platform for facial growth.
The cranial base is important in integrated craniofacial
development and growth – especially the anterior cranial
base, which has direct connections with upper-middle
face and integrates with the facial elements into a growth
complex (ethmomaxillary complex)

» The cranial base
is mainly a
midline structure
composed of
basioccipital,
sphenoid,
ethmoid and
frontal bones in
the midline and
temporal bones
laterally.


Significance of cranial base
• The housing for the brain impacts directly on
many aspects of the developing facial complex.
• The basicranium is involved in this fundamental
and important relationship because the
ectocranial side of the cranial floor is the
interface with the face suspended beneath it.
• The perimeter, alignment, and configuration of
the basicranium prescribes a "template" that
establishes the growth fields within which both
the mandible and nasomaxillary complex
develop.

PRE NATAL
GROWTH OF
CRANIAL BASE


• The earliest evidence of cranial base
formation is seen in the post or late somitic
period : 4th_ 8th week of intra uterine life.
• During this period mesenchymal tissue
derived from primitive streak,neural crest
and occipital sclerotomes condenses
around developing brain: Ectomeningeal
capsule
• From around 40th day ectomeningeal
capsule slowly starts converting to cartilage
:chondrocranium

•
•
•
•
•

This chondrification occurs in 4 regions
Parachordal
Hypophyseal
Nasal
Otic


• The chondrification centers
are– Parachordal cartilagesaround notochord
– Sclerotomal cartilagesoccipital bone parts
– 2 Hypophyseal
cartilages-fuse to form
basisphenoid cartilage
– 2 presphenoid cartilagesbody of sphenoid
– Orbitosphenoid and
Alisphenoid- wings of
sphenoid
– Mesoethmoid cartilagewww.indiandentalacademy.com
fused presphenoid

• Around 3rd month chondrocranium
consists of mass of cartilages shaped like
a capsule.
• Bones which form from cartilage are
lower occipital ,spheniod, petrous and
mastoid,portions of temporal bone,styloid
process of temporal bone,inferior turbinate
bone and ethmoid.

• Chondrocranium reaches highest
development at 3rd month of intrauterine
life.
• It includes axila region of the skull and
olfactory capsule orbital wings and bases
of temporal wings of sphenoid occipital
condyles and tectum pecterius which lies
dorsolaterally to occipital and temporal
regions.
• Except for nasal and basilar fibro cartilage
it gets replaced by bone.

Ossification of cranial base
• Described by Scott to appear from behind
forward as follows:
 A centre for basioccipital portion at about
middle of 3rd month
 2-4 centre for post sphenoid 4 th month
 2 centres for presphenoid 4 to 5 th month
 Single centre for mesethmoid 1st year after
birth

• Growth of anterior cranial base completes
between 8 to 10th year
• Post cranial base grows to adulthood


Flexure of the cranial base
• During the embryonic and early fetal period, the
cranial base becomes flexed in the region
between the pituitary fossa and the sphenooccipital junction.
• The face is hence tucked under the cranium.
This flexure of the cranial base is accompanied
by a corresponding flexure of the developing
brain stem.
• Thus the spinal chord and the foramen magnum
which during the early stages of development
were directed backwards now become directed
downwards.

Flexure of the cranial base -arrow indicating
the direction of the foramen magnum


• This downward directed foramen magnum is an
adaptation seen in man who, unlike animals,
stands erect.
• This flexure of the cranial base aids in increasing
the neurocranial capacity.
• Another consequence of the flexure is the
predominant downward rather than forward
displacement of the face during its growth from
the cranial base.
• At around the 1Oth week of intra-uterine life, the
flexion of the base is about 65°. This flattens out
a bit at the timewww.indiandentalacademy.com
of birth.

Post natal
growth
of cranial base


Post Natal Growth Of Cranial
base
•

The cranial base grows post natally by
complex interaction between –

1. Extensive cortical drift & remodelling.
2. Elongation at Synchondrosis.
3. Sutural growth.

This combination provides:
1. Differential growth enlargement between
the cranial floor and calvaria.
2. Expansion of confined contours in the
various endocranial fossae.
3. Maintenance of passages and housing
for vessels and nerves.

Basicranium
• The cranial floor is the template from which the
face develops hence what happens in the floor
of the cranium affects the structure, dimensions,
angles, and placement of the various facial parts
• The endocranial surface of the basicranium, is
characteristically resorptive in most areas. since
the alignments of the sutures do not have the
capacity to provide for the multiple directions of
enlargement and the complex magnitude of
remodeling required.

Circumcranial
reversal line

(Darkly shaded)- The lining (Lightly shaded)- The endocranial
bony surface of the whole surface of the calvaria, is
predominantly depository; note the
cranial floor is
predominantly resorptive indicated by the arrow

Schematically
represents an
enlarged human
basicranial fossa
with sutures
located at 1 and 2.
These produce
unidirectional
sutural growth as
indicated by the
arrows. However,
the two sutures
present cannot
produce the growth
for the other
directions also
needed to
accommodate brain
expansion

•

Fossa enlargement
is accomplished by
direct remodeling,
involving
deposition on the
outside with
resorption from the
inside. This is the
key remodeling
process that
provides for the
direct expansion of
the various
endocranial fossae
in conjunction with
sutural and also
synchondrosis
growth.

- = Resoptive
+ = Depository

• The various endocranial compartments are
separated from one another by elevated bony
partitions . The middle and posterior fossae are
separated by the petrous elevation ,the olfactory
fossae by crista galli, the right and left middle
fossae by midline sphenoidal elevation and the
left and right anterior and posterior fossae are
divided by midline bony ridge. All these elevated
parts are depository in nature.

Resorptive & Depository Areas At The base Of Skull

Crista galli

Petrous Elevation

Midline bony ridge

Darkly shaded areas are resorptive areas

• The midventral segment of the cranial
floor grows more slowly than the laterally
located fossae. This accomodates the
slower development of the medulla
,pons,hypothalamus ,optic chiasma etc. ,in
contrast to the massive rapid expansion of
the hemispheres.


• A markedly

decreasing and
tapering gradient of
sutural growth
occurs to provide
for the varying
extents of
expansion required
among the different
midline parts
themselves and
between the midline
parts and much
faster growing
lateral regions.

• The differential
remodelling process
maintains the
propotionate placement
of the spinal cord ,even
though the floor of the
posterior cranial fossa
,which rims the cord
,expands to greater
extent than the
circumference of the
foramen magnum.

Synchondreal growth
• The midline part of the basicranium is characterized
by the presence of synchondroses They are a
retention left from the primary cartilages of the
chondrocranium after the endochondral ossification
centers appear during fetal development. A number
of synchondroses are operative during the fetal and
early postnatal periods.
•

Mid-sphenoidal synchondrosis

•
.
•

Spheno-ethmoidal synchondrosis- Juvenile period

•

Intra Occipital synchondrosis

- Perinatal fusion.

Spheno-occipital synchondrosis – Active-12-15 years
Fuses -20 years
-

Fuses -3-5 years


Spheno occipital synchondrosis


Structure
• The basicranial synchondrosis can be
characterized structurally as bipolar growth
cartilages ,it is involved in endochondral
ossification in two opposing directions.
• The structure is similar to the basic plan for all
“primary cartilages”
• The synchondrosis is composed of wellorganised cell bands.


•

From middle to distal ends, 3 zones are
present:
1. A resting zone composed of
chondrocyte precursors which direct
formation and organization of the
synchondrosis.
2. Proliferation zones
3. Hypertrophic zones.

• R – resting zone
• Pr – proliferating
zone
• H – hypertrophic
zone


Synchondrosis is like two epiphyseal plates put back to back
And separated by common zone of reserve cells.

• The sphenooccipital synchondrosis is the
principal growth cartilage of the basicranium.
• As with all growth cartilages associated directly
with bone development, the sphenooccipital
synchondrosis provides a pressure adapted
bone growth mechanism.
• This is in contrast to the tension adapted sutural
growth process of the calvaria, lateral
neurocranial walls, and the endocranial fossae.

• Endochondral bone growth by the sphenooccipital synchondrosis relates to primary
displacement of the bones involved. The
sphenoid and the occipital bones become
sieved apart by the primary displacement
process and at the same time, new
endochondral bone, is laid down by the
endosteum within each bone.

The posterior boundary of
the maxillary complex is
developmentally positioned
to exactly coincide with, the
boundary between, the
anterior and middle cranial
fossae, a like amount of
forward displacement of
both the anterior cranial
fossa and the nasomaxillary
complex suspended
beneath it occurs.

The direction of sphenooccipital
Synchondrosis is upwards it
therefore carries the midface
forward and downward.


• The enlarging middle
cranial fossa does not in
itself push the mandible,
anterior cranial fossa, and
maxillary complex forward.
The temporal and frontal
have fibrous attachments
to the middle and anterior
cranial fossae,
respectively. As both
expands, these two fossae
are thus pulled away from
each other, but both also
being moved together in a
protrusive direction.

• This sets up tension fields in the various
frontal, temporal, sphenoidal, and
ethmoidal sutures, and this presumably
triggers sutural bone responses (in
addition to direct basicranial remodeling ).
• Both fossae are thus enlarged, and the
nasomaxillary complex is carried along
anteriorly with the floor of the anterior
cranial fossa from which it is suspended.

• The anterior fossae and the maxillary
complex are carried anteriorly by the
frontal lobes ,which is moved forward
because of temporal lobe enlargement
behind it.


(I)Deposition on the orbital face
of the sphenoid and in the.
sphenofrontal suture
(2)Forward displacement of the
anterior cranial, fossae as the
frontal lobes are displaced
anteriorly
(3)The petrous elevation
(4)Deposition on the endocranial
surface, and lengthening of
the clivus occurs by growth at
the sphenooccipital
synchondrosis
(5)The foramen magnum is
progressively lowered also
contributes to the lengthening
of the clivus
(6) The perimeter of the foramen
enlarges
(7) Addition to growth at the
basicranial sutures.


•

•

•

•

1) A decreasing gradient of
sutural growth occurs
approaching the midventral
part of the basicranium is
schematized (lightly shaded
areas)
(2)The endocranial fossae
enlarge by a corresponding
gradient of direct cortical
remodeling, as shown by the
darkly shaded areas
(3)The clivus lengthens by
endochondral bone growth
at the sphenooccipital
synchondrosis
Also by direct downward
remodeling of the
basicranial floor.


• Each anterior cranial fossa enlarges in
conjunction with the expansion of the frontal
lobes. Whereever suture are present ,they
contribute to the increase in the circumference
of the bones involved.
Sphenofrontal,frontotemporal,sphenoethmoidal,f
rontoethmoidal, and frontozygomativ sutures all
participate in a closely coordinated ,traction
adapted growth response to brain and other soft
tissue enlargements.

• The bones all get displaced away from
each other:primary displacement
• Together with this ,the bones also enlarge
outward by ectocranial deposition and
endocranial resorption.


•As long as the frontal lobes of
cerebrum enlarge ,the inner
table of the forehead
correspondingly remodels
anteriorly.
• When frontal lobe
enlargement slows and
largely ceases sometime
before about the 6th year,
the growth of the inner
table stops with it.. The
outer table, however,
continues to remodel
anteriorly

• Arndt Klocke (Ajodo 2002) did a study in which
two groups of untreated subjects were formed
on the basis of a small and large cranial base
angle N-S-Ar at the age of 5 years: the large
cranial base angle group consisted of subjects
with an N-S-Ar angle larger than 125° and the
small cranial base angle group included subjects
with an N-S-Ar angle of less than 120°
Cephalometric data of the 2 groups were
analyzed at subject ages 5 and 12 years.

• The presence of a large or small cranial base
angle N-S-Ar had a rather limited effect on the
development of sagittal jaw discrepancies during
the longitudinal follow-up. In subjects with a
large cranial base angle, the individualized ANB
angle indicated a skeletal Class II tendency at
the initial observation and at the longitudinal
follow-up.
• On the basis of variables SNB, S-Ar, S-N, and
Ar-N, at the age of 12 years, it was possible to
classify 88.1% of the initial large and small
cranial base angle subjects, indicating a
constancy of the skeletal pattern during the
longitudinal follow-up. The relationship between
cranial base flexure and skeletal pattern of the
jaws seems to be established before the age of
5 years.

Melvin moss (Angle ortho 1955) conducted a study on
151 randomly seleted human crania to study the
post natal growth of cranial base. Additionally 28
cases of class 2 and 21 cases of class 3 were
abtained.
On the tracings 3 angles were
marked and measured.
1) Orbital angle formed by roof
of the orbit
2) Cribriform angle formed by
cerebral surface of
cribriform plate of
ethmoid
3) The palatal angle


The results of the study were as follows
The uniformity of the cribriform angle
indicate that the median areas of the skull
base are essentially stable while the lateral
areas undergo prolonged change indicated
by the orbital angle which shows
progressive alterations
Class 3 group shows significant alterations
from the normal in the spatial relations of
the medial pre sella portion of the skull base
which has a greater downward inclination
relative to the www.indiandentalacademy.com
clivus.

• Frans P.G.M. Vander Linden (Angle ortho,1972)
studied the growth of anterior cranial base on 80
human skulls ,the endocranial surface was
studied in detail. A short brass wire was glued in
transverse direction to the sphenoid bone to
mark its most anterior median point. The
distance between marker and midpoint between
the wings of the anterior base level was
evaluated. The latter has been indicated as SE
by Enlow and by Knott as pt W.
s

w

Results of study showed:
Point W forms an adequate representation of
the anterior outline of the middle cranial
fossae and can be used for a demarcation of
the head in the anterio posterior direction .
Distance between sella and pt W is constant
from 6 to 15 yrs of age.


Cranial base and maxilla:
mutual interdependence


• Growth of cranial base has direct effect on
placement of midface,as anterior cranial
base and cranial fossa elongate
underlying space occupied by enlarging
nasomaxillary complex pharynx and
ramus increases corresponding . The
spheno occipital complex elongate
displacing entire midface anteriorly.

• Forward and
downward inclined
middle cranial
fossamaxillary protrusive

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


• Upwards and
backward inclined
middle cranial fossa
• Maxilla- placed backward
• Mandible-rotates in a
protrusive position.
• Class III molar
relationship


Hunter enlow growth equivalent
concept
• a : anterior
cranial base
• b :spehno
occipital
complex
• c : nasomaxillary
complex
• d : mandible


CLINICAL CONSIDERATIONS


Orthodontist an applied biologist
• It is essential that the orthodontist be an applied
biologist. The traditional overconcern with the
alignment of teeth must be subordinated to a
broader appreciation of bone system and neuro
muscular system involved
• Surveys have shown that two thirds of the cases
seen for orthodontic therapy involve types of
malocclusion in which growth and development
play a significant role in the success or failure of
mechanotherapy.

Growth spurts :important clinical
consideration
• Differential growth (different organs grow at
different rates) and growth spurts are of vital
importance to the orthodontist who must
schedule his therapy so that it coincides with the
most favorable growth period. Differential growth
is time linked
• Cranial base grows quite rapidly and attains
adult size considerably before the face . Growth
in cranial depth is most rapid ,with growth of
width and height following in same order.

• In the face ,height shows the greatest change
,followed by depth and width. In the differential
growth of various parts ,the height of the
cranium and width of the face are closest to the
adult size at birth.
• Growth is essentially completed first in the head,
then in width of the face and last in depth of the
face.


• Milton I Houpt (AJODO 1975)investigated
changes in craniofacial complex in human
fetuses between 12 to 19 weeks.(31 male and
38 female fetus were studied)
• The growth rates of components of craniofacial
complex is constant between 12 to 19 weeks, no
significant gender differences were seen
• With exception of mandible the components of
craniofacial complex grow faster in length than
height or width, the rate of growth of cranium is
two to four times greater than the face.

• Sex linked
nature of
growth with
female pubertal
spurt occurring
ahead of that of
male has been
shown (Bjork
and helm 1967)


• Woodside (1969) ,in his study of Burlington
group
• Points out that growth spurts are really possible
and sex linked.
• The greatest increment of growth are actually at
the 3 year age level. The second peak is from 6
to 7 years in girls and 7 to 9 years in boys. The
third peak is 11 to 12 yrs in girls and 14 to 15 yrs
in boys. The tendency is for boys to show two or
three peaks and girls largely show only two
peaks.

• The clinical implications are obvious for the
orthopedic correction of maxillomandibular
malrelationships. Pubertal increments offer the
best time for large number of cases.
• Very few girls show mixed dentition growth spurt
and jaw change objectives are more likely to be
successful during this period among boys.


•
•
•
•
•

Monique Henneberke Birte Prahl-Andersen (AJODO
1994.)
Growth changes of the cranial base (S-N, N-Ba, and
S-Ba) were evaluated.
The cranial base displayed sexual dimorphism in the
timing and amount of growth.
All dimensions measured in girls were significantly
smaller than in boys (p < 0.05).
No adolescent growth spurts were found in girls; boys
showed adolescent growth spurts for S-N and N-Ba.
Adolescent growth velocities were significantly greater
for boys than for girls.

• Similarly if an orthodontist is looking for
growth in width of denture area ,he is likely
to be disappointed after the fifth or sixth
year of life since little change occurs then
in the width of the dental arch anterior to
the first permanent molars. In the
mandibular arch the inter canine width is
complete by nine to ten years of age in
both sexes.

• In the maxilla the intercanine width is complete by 12 yrs
in females and continues till 18 yrs in males. The clinical
implications are quite obvious here .The final horizontal
growth increments in the mandible ,particularly in the
males cause a forward movement of the mandibular
base. This basal change eliminates any persisting flush
terminal plane tendencies,however the bodily mandibular
thrust forward is unmatched by the comparable maxillary
horizontal growth changes.
Hence, the maxillary intercanine dimensions serves as a
“safety valve “ for this basal discrepancy.


• Another variable to be considered is
direction of growth .
• Since both maxilla and mandible grow
downward and forward at a more rapid
rate then the cranium after 4 and 5 th yr ,an
orthodontist can modulate growth
,stimulate deficient maxillary growth or
retard and redirect its growth.

• Orthodontist is literally an “orthopedic
surgeon” and channeling of growth offers
the greatest hope to the orthodontist at
present.
• Head gear and face mask have been
successfully used to redirect growth of
maxilla and modify the skeletal
malocclusions.

• Jeremy J et al (AO ;2003)have conducted study to prove
that various orthopedic therapies including head gear
,facemask and functional appliances may induce sutural
strain ,leading to modification of otherwise natural suture
growth.
• Mechanical stresses induced by the appliances are
capable of modulating the sutural growth, because
mechanical stresses transmit through bone their effects
are experienced in a hierarchial manner sequentially as
tissue level bone strain, interstitial fluid flow that in turn
induces cell level strain on bone cells and subsequently
anabolic or catabolic effects.

Head gear :
• Forces applied on to the
maxilla can be used to
restrict its downward and
forward growth. The distal
force in this case is
applied through the
centre of resistance of the
maxilla .Forces in range
of 350 -450 gms on each
side for a minimum of 12
to 14 hrs /day are
required.
• This effect can be best
tapped during the www.indiandentalacademy.com
pre
adolescent period.

• Kazuo Tanne(angle ortho 1996) in his article on
association between the direction of orthopedic
headgear force and sutural responses in the
nasomaxillary complex has shown the stress
distribution in the sutures produced by
orthopedic appliances.
• Finite elements analysis was employed using a
3 d model of the craniofacial complex that
consisted of 2918 nodes and 1776 solid
elements. The model also included 18 sutural
systems in the complex

• When 30° inferior, parallel, and 30° superior forces
were applied, considerable variation in normal
stresses at the sutural interfaces was observed in
association with substantial shear
stresses.
• In loading with forces in 52.4° and 60° superior
directions, compressive stresses were similarly
generated in most anatomic areas and both the
normal and shear stresses reduced and
exhibited a convergence to a certain level.
• As the force direction approached that of the CRe,
mean principal stresses approached a uniform level
of compressive stress

Face mask or reverse head
gear
• Given when anterior protractory force is
required on the maxilla.
• Amount of force required to bring skeletal
change is about 450 gms per side /day for 12 to
14 hrs with a 15 to 20 degree downward pull to
the occlusal plane to produce a pure forward
translatory motion of the maxilla ,if the line of
force is parallel to the occlusal plane ,a forward
translation as well as upward rotation takes
place.

Patients wearing face mask


• Gregory A. Vaughn et al (AJO 2005) has
shown through randomised trial study that
early face mask therapy is effective to
correct the skeletal class 3 malocclusions.
• If face mask therapy is preceded by rapid
maxillary expansion the effect is greater
compared to face mask therapy without
rapid maxillary expansion

• Gautam P., Valiathan A. (AJODO 2007) evaluated stress
distribution along craniofacial sutures and displacement
of various craniofacial structures with rapid maxillary
expansion (RME) therapy.
• They concluded that :
• RME facilitates expansion of the maxilla in both the
molar and the canine regions. It also causes downward
and forward displacement of the maxilla and thus can
contribute to the correction of mild Class III
malocclusion. The downward displacement and
backward rotation of the maxilla could be a concern in
patients with excessive lower anterior facial height. High
stresses along the deep structures and the various
sutures of the craniofacial skeleton signify the role of the
circummaxillary sutural system in downward and forward
displacement of the maxilla after RME.

Maxillary expansion
• The inter maxillary and interpalatine sutures
make up the mid palatal suture. Rapid maxillary
expansion should be initiated prior to ossification
of this suture to bring about skeletal type of
expansion in maxilla.
• The opening of the midpalatal suture is fan
shaped with the maximum opening occuring at
the incisor region and gradually diminishing
towards the posterior part of the palate.

• An increase of 10 mm
can be achieved by
RME ,rate of
expansion is 0.2 to
0.5 mm per day.
Rapid palatal expander

• John f Cleall et al (angle ortho 1965 )
conducted a study on rhesus monkeys to
study the effect of expansion on mid
palatal suture. It was seen that the forces
disrupted the mid palatal suture and
resulted in increase in maxillary width ,the
resultant defect is rapidly and completely
healed following restoration of normally
growing suture.

Growth anomalies
and role of
orthodontist


CLEFT PALATE
• Cleft palate is a condition in which the two plates
of the skull that form the hard palate (roof of the
mouth) are not completely joined. Cleft palate
occurs in about one in 700 live births worldwide.
• Palate cleft can occur as complete (soft and hard
palate, possibly including a gap in the jaw) or
incomplete (a 'hole' in the roof of the mouth,
usually as a cleft soft palate. It occurs due to the
failure of fusion of the lateral palatine processes,
the nasal septum, and/or the median palatine
processes (formation of the secondary palate).


Patients with cleft palate

Orthodontic intervention
• One role of orthodontic intervention is to minimize
the severity of the growth disturbance. Interventions
vary according to the type of cleft.
• In CL/P, orthodontic appliances can be used to
realign the premaxilla into a normal position prior to
lip closure. Orthodontic interventions in patients
with cleft palate are frequently aimed at maxillary
arch expansion, correction of malocclusion, and
correction of an often developing class III skeletal
growth pattern. The most beneficial period for
orthodontic interventions in isolated cleft palate may be
during the mixed dentition period.


Other syndromes involving mid
facial anomalies
•
•
•
•
•
•
•
•

Pre-maxillary aplasia or hypoplasia
Median Cleft face syndrome
Treacher Collins' syndrome
Aperts syndrome
Achondroplasia,
Stickler syndrome
Crouzon syndrome
The main role of an orthodontist is to minimize
the gross deficiency by early orthopedic
interventions as well as later fixed appliance
therapy to correct dental malocclusions.

Conclusion
• No craniofacial component is self contained and
self regulated . Growth of a component is not an
isolated event unrelated to other parts: it is a
composite change of all components
• Meaningful insight into all this underlies the
basis for clinical diagnosis and treatment
planning . The direct target for clinical
intervention must be the control process
regulating the biology of growth and
development.

REFERENCES
•

1)Enlow DH, Bang S. Growth and remodelling of
the human maxilla. Am J Orthod. (1965, 51:
446-464).

•

2)Bjork A, Skieller V. Growth of the maxilla in
three dimensions as revealed radiographically
by the implant method. Br J Orthod. 1977, 4: 5364.

•

3)Enlow DH. Handbook of facial growth. 3rd
Ed.,1996, W. B. Saunders Company.

•

4)Melvin L.Moss Postnatal Growth Of Human

•

5)Stanley Braun, Robert T. Rudman, Hugh J.
Murdoch, Shaun Hicken, Russell Kittleson,
Donald J. Ferguson, C-axis: A growth vector
for the maxilla AO 1999:69;539-42.

•

6)Kazuo Tanne; Susumu Matsubara,
Association between the direction of
orthopedic headgear force and sutural
responses in the the nasomaxillary complex
( A O 1996;66(2):125-130.)

•

7)Moyers RE. Handbook of orthodontics. 4th
Ed., 1988, Year Book Medical Publishers.

• 8)Graber TM. Principles and practice
of orthodontics. 3rd Ed.,1966.
• 9)Proffit WR. Contemporary
orthodontics. 3rd Ed., 2000, Mosby,
Inc.
• 10)Salzmann JA. Practice of
orthodontics vol.1. 2nd Ed., 1966, J.
B. Lippincott Co.

• 11) Sadler TW. Langman’s medical embryology.
9th Ed., 2004, Lippincott, Williams & Wilkins
• 12)Jeremy J. Mao, Xin Wang, Ross A. Kopher:
Biomechanics of Craniofacial Sutures:
Orthopedic Implications(Angle Orthod
2003;73:128–135.)

• 13)J.J. Mao Mechanobiology of Craniofacial
SuturesJ Dent Res 81(12):810-816, 2002
• 14)John F Cleall et al ,expansion of the mid
palatal suture in the rehus monkey (angle ortho
1965,23 -34 ) www.indiandentalacademy.com

• 15)Melvin moss, The primary role of functional
, matrices in facial growth ;(AJODO,1969 55:566 577)
• 16)Gregory A. Vaughn , The effects of maxillary
protraction therapy with or without rapid palatal
expansion ;a prospective randomised trial ;
AJODO,2005 :299 to 309
• 17)E.L.Korn S. Baumrind, Transverse
development of the human jaws between ages
8.5 and 15.5 studied longitudinally with use of
implants ( JDR 1990, 69:1298 to 1306)

• 18)Nie X. Cranial base in craniofacial
development: Developmental features, influence
on facial growth, anomaly, and molecular basis.
Acta Odontol Scand. 2005, 63: 127-135.
• 19)S. Eugene Coben ,The spheno-occipital
synchondrosis: The missing link between the
profession’s concept of craniofacial growth and
orthodontic treatment(AJODO1998;114:709-12)
• 20)Kristine S.West, and James A. McNamara,
Changes in the craniofacial complex from
adolescence to midadulthood: A cephalometric
study (AJODO 1999;115:521-32)

• 21)Surender K. Nanda, Differential growth of the female
face in the anteroposterior dimension A O 1992: 62;23-34

• 22)Sejrsen B, Jakobsen J, Skovgaard LT, Kjaer I. Growth in
the external cranial base evaluated on human dry skulls,
using nerve canal openings as references. Acta Odontol
Scand. 1997, 55:356-364.

• 23)Toshio Deguchi , Very early face mask therapy in Class
III children(angle orthod, Vol. 69, No. 4, pp. 349–355.
• 24)Arndt Klocke,,, Ram S. Nanda,, Bärbel ,Role of cranial
base flexure in developing sagittal jaw discrepancies ,Ajodo
2002 122 (4) :386 391

• 25)Bjork ,Helm,Prediction of age of maximum
pubertal growth in body height. (angle ortho
1967 ,37:134-143)
• 26)Milton I. Houpt,growth of craniofacial complex
of the human fetuses (AJODO 1975,58:4;373378 )
• 27)Gautam P. ,Valithan A. , Adhikari R., Stress
and displacement patterns in the craniofacial
skeleton with rapid maxillary expansion: a finite
element method study. (Ajodo 2007,july 132;1:111)

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