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GROWTH AND
DEVELOPMENT
OF
CRANIOFACIAL
STRUCTURE

INTRODUCTION


Every pedodontist should keep in mind that
the patient on whom he works are in the state
of growth and development , which is a
dynamic and continuously changing process.
He almost never find a static picture in
pediatric patient. So a thorough understanding
of complex craniofacial growth is of great
importance for pedodontist Understanding of
developing craniofacial skeleton represents,
sum of growth of its separate parts in which
growth is highly differentiated and occurs in
different rates ,dimension and time.So keeping
all these in mind we start with seminar topic






Growth and development
can be seen in three aspects

a)
b)
c)

change in dimension
change in proportion
maturation

DEFINATION OF GROWTH


STEWERT(1982) : growth is increase in
mass physical size of cell ,tissues , organ
,or organisms as a whole

PROFIT (1986): growth refers to
increase in size or number
MOYERS (1988) : growth is normal
change in the amount of living substance
PINKHAM(1994) :growth is increase
expansion or extension of any given
tissue

DEFINATION OF
DEVELOPMENT


TODD(1931) :development is increase in
complexity
 LOWREY(1951) :development indicates
increase in skill and complexity of
function
 MOYER(1988) :development is the
unidirectional change in the life of an
individual from its existence as a single
cell to terminating in depth .
 PINKHAM(1994) :development addreses
the progressive evolution of a tissue












DIFFERENTIATION :The change from a
generalized cell to one that is more specialized .it
is change in quality and kind .
As we see that many of times
growth and development are used synonymously,
but they are not. In simple words,
* Growth is increase in size or number of
things .It is numerical .can be easily measured
with a specified scale. Ex. Height , weight of
persons.
*development is increase in skill and
complexity of fuction.
But, practically growth and development are
inseparable entities and are simultaneous on
going process which go hand in hand

THEORIES

OF GROWTH


GENETIC GROWTH
(Brodie)
 It

says, growth is cantrolled by
genetic influence in all aspect. But it
cannot be accepted in all cases. As it
has been shown that the external
factor have significant modifying
effect on growth



SUTURAL THEORY
(sicher)


It says that the proliferation of sutural
mesanchyme causes apposition of bone . It is
seen in membranous bone.
 Limitation :- lack of growth of suture if it is
transplanted .
 gowth occurs in cleft lip and cleft palate
pts.even if suture not present
 Suture also respond to external influence


CARTILAGENOUS THEORY
(James Scott) :


It says that cartilage acts as primary
growth center and has a innate growth
potential
 Ex ;
condylar cartilage for mandible

Nasal cartilage for maxilla
(nasomaxillary complex)
 If it is transplanted it grows
independently

FUNCTIONAL MATRIX THEORY
(Melvin Moss –1968)











It says that body has two element
a) skeletal element
b) functional matrix
functional matrix comprised of
1)periosteal camponent
2)capsural camponent
(neuro cranial),(orofacial)
functional matrix has primary control on
growth of skeletal unit and bone respond in
passive manner
but it can not explain all aspects of
growth

MULTY FACTORIAL THEORY

(Van Limborgh)


It says bone growth is controlled by

a) intrinsic genetic factor
 b) local epigenetic factor (nerves, brain )
– C)general epigenetic factor (harmones,
secondary messengers )
– d) local environmental factor (habit,
muscular force )
– e) general environmental factor ( oxygen,
nitrogen)

It is most satisfactory theory that explains
all aspect

It says growth is polygenic and
multifactoral

NEUROTROPISM
(recent theory )


It includes epithelial , visceral , muscular
component for these component nerve
impulses which are transmitted has
growth potential for bone .It also has
indirect effect by influencing soft tissue
growth

but by experiments it has proved that
neurotropism has negligible effec

PETROVICS HYPOTHESIS
It says that the interaction of serves
of casual changes and feedback
mechanism which determines
craniofacial growth
 ie brain---- cranium.



THEORIES

RELATED TO
CRANIOFACIAL
GROWTH



ENLOWS EXPANDING “V”
PRINCPLE


It says that most of craniofacial bones
especially intramembranous have v shape
eg:maxilla , mandible , palate ,nasal etc.

 And

growth movement occurs
towards wide end of V deposition of
bone is seen in inner side and
resorption is seen in outer surface.

ENLOWS COUNTERPART
PRINCIPLE


It explains that, growth of one bone has
influence on its adjuvant bone which is
called counter part, and this controls the
growth and proportional relationship
with its counterpart.



E.g.:- nasomaxillary complex—cranialfossa

Maxilla ----------mandible

Tuberosity areas of upper/lower jaw
Pharyngeal space -------- middle
cranial fossa



FACTORS AFFECTING
PHYSICAL GROWTH












Heredity
Nutrition
Illness
Race
Socioeconomic states
Family size
Psychogenic disturbance
Exercise
Pharmacological

characteristic properties
of growth


concept of normality



growth states are always
accessed in normality value ie. in range
but can not be explained as ideal with a
definite value

Normality differs from age to age




Different growth :



Different organs grow at
different rate , different amount, and
different time .

It can be best explained by
SCAMMONS GROWTH CURVE




CEPHALOCUADAL GRADIENT
OF GROWTH

Axis of growth increases
extending from head to feet
 ie. 3 months intra uterine life head size--50%, birth head size---30%, adult head
size---12% of whole body






Cranial growth 70% completed at birth
to 1st year
 limbs 3month IUL-1% by birth-50% of
body

GROWTH SPURTS


In spite growth is continuous process
there occurs a period when a sudden
acceleration of growth occurs called
growth spurts .

It is due to physiological alteration in
hormonal secretion
 They differ in boys and girls

This period is good for functional and orthodont
appliance use
Surgical correction involving jaws should
carried out after cessation of growth spurts .












Timings of growth spurts
A)just before birth
B)one year after birth
C) mixed dentition
 growth spurts ….girl—7-9yrs
boys- 8-11yrs
c) pre pubertal
– growth spurt ……girls ----11-13 yrs
boys -----14-16yrs

METHODS OF STUDING
GROWTH










a)measurement approach
 bimanual test height and weight
b) experiment al approach :vital staining- alzirine blue
alzirine red
lead acetate
Rdioisotopes-------- te 33 ,ca*45 ,
k*32 injected in bone
c)Implants
d)radiographs

Mechanism of bone
development




1)endochondral bone
2)intramemebranes



endochondral bone this type of bone is
proceded by formation of cartilaginous
model
 intramembranes bone – bone is directly
laiddown in fibrous membrane

prenatal growth
{day1 to 266 day}
 It

is divided into 3 periods

period of ovum (ferti. to 14th day)
 2)period of embryo (14th day to 56th
day)
 3)period of fetous(56th day to birth)
 1)




period of ovum(fertilization to 14th day)



In this period oocyte get fertilized with
spermatozoa to form zygote which is a diploid
cell. After this process cell division starts within
24 to36 hours. Cleavage continues to form ,
2,4,8,cells. In 8th cell stage process of compaction
occurs to get 1st embryo shape. 16th cell stage
called morual . Next stage called blastula which is
150 cells stage. It is of 1.5mm in length and 3 to 5
days old it has inner cell mass which forms fetus
& outer cell mass which forms yolk sack. On 5th
day blastocyte starts penetrating endometrium &
at 14th day it get implanted it self into uterine
wall.

or embryoblast

utenne epithelium

Uterine stroma

~,~~",".

Trophoblast cells


Timeo!
DNA
duplicatiof

Endometrium (progestational stage)


., ,.< ---I. ,I

Period of embryo

(14th day to 56th day)



It is the period where major development of
organ specifically craniofacial structure occur.
on 17th day process of gastrulation occurs to
form different germ layers. Ectoderm above
notochord thickens to form neural plate which
forms nervous system . On 21st day embryo is of
3mm now primordial of brain eye are seen in
prosenceophalon. On 3rd day otic &optic
plocodes are seen. In the same period most
inferior part of prosencephalon starts growing to
from front nasal process which overhangs
future oral cavity which is wide & shallow.

P
rimitive pit and
neurenteric canal

A mnion

Wallo!
yolk sac

Cloacal plate
(membrane)

A

N ot oc hordal plat e

c

E
ndoderm

I nt raem bry onic m es oderm

Ex t raem bry onic
m es oderm

E

Notochord
- ,u :1 I "e+r ~ t;n a for ,


I ~.

,f/,'~
M.
W,'.
:~:i:
:> "-'.~
,


on 3-4week oral groove starts deepening.
Same time bud for max and man process
show their presence lat to oral groove.
Deepened oral cavity is now called
stomodium and is separated by hind gut
with a membranes formed by endoderm
and ectoderm called buccopharyngeal
membranes . on 4th week the embryo is
5mm . Now frontal elevation shows some
ectodermal proliferation which form future
nasal placode and olfactory epithelium
optic placodes which are formed are
placed very widely apart

Otic placode

Lens
placode

Limb
ridge

B


28 days



Front nasal process show more growth
mesially than laterally which forms medial
nasal process. As medial nasal process
grows faster, in future it unites with
maxillary process to form part of upper lip
specifically along line of philtrum . lateral
nasal process mainly contribute formation
of columella .on 5th week caudal to
frontonasal and maxillary process brachial
arches show their development they are
totally six with 5th one turning to be
rudimentary. 2nd brachial arch develop faster
than other and covers other brachial arches

;
Pharyngeal pouch
Endoderma! epithelium

Nerve

1 st pharyngeal
arch

Cartilage

cleft

Ectodermal
epithelium.

2nd arch with ner ve,

artery, and
c<1rtllage

Mesenchymal tissue in
4th arch

A


Auditory tube

Primitive
tympanic
cavity

Ventral side of
phary nx

External
auditory
meatus

- Foramen cecum
f

f

,

I
f
!
I
f

Palatine tonsil

,
I

,
'¥

Superior parathy roid gland
(f rom 4th pouch)

Thy roid gland
Inf erior parathy roid gland
(f rom 3rd pouch)

Ultimobranchial body

Foregut



same time between and around primordial
of brian and eye Mesenchymal
condensation appears which gives a shape
of skull. Mesenchyma of brachial arch also
appears by 5th week. 1st brachial grows
faster to become distant .In 6th week
mandibular arch show accentuated growth
to divide in maxillary and mandibular
process both process grows medially .
medial nasal process from above also
grows downwards and towards midline as
a result by the 7th week fusion between
maxillary and frontonasal process occurs
and this time embryo is 14.5mm in length



Now eye starts migrating towards midline
Mesenchymal of cranial and brachial arch
differentiates into cartilage (CHONDRIFICATION)

cartilage in the base of skull thins to join
with nasal and optic capsules. same time centers
for endochondral ossification appears in the
cartilage of base of skull, also Mesenchymal
condensation in intramembranous bone is seen.
At 8th week nasal septum further narrows to
become a prominent structure ,also external ear
starts its development. nasal pit breaks down to
form nostrils. Demarcation seen between lateral
nasal and maxillary to form nasolacrimal groove
which in future closes to form nasolacrimal duct .



primary palat starts its development at
8th week .so till this time their occurs a
direct communication between oral and
nasal cavity . lidless eyes increase their
movement towards midline .both lateral
halves of mandibular process fuse by 8th
week. at this time embryo is 18mm in
length .
 Rough head and face shape is almost
completed by 8th week . By end of 8th
week embryo increases in length almost
by 4 times to that of 7th week

















main structures formed in the embryonic period are
neural plate -2
buccopharyngeal membrane -2
mandibular arch –3
hypoglossal muscle—5
median and lateral nasal process-5
lens of eye-5, retina—5
external carotid artery-6
middle ear-6
larynx -6
maxillary process -6
external ear -7
nasal septum-8
palatal shelves-8 www.indiandentalacademy.com
*IN WEEKS OF IUL

FETAL PERIOD
(56days--9 months )
 Eye

lid formation occurs .eyes get
close . nostrils are formed.
 This period shows accelerated rate
of craniofacial growth resulting in
an increase size and proportion In
8th to 12 weeks fetus increases in
length by 22—60mm .
 mandible increases in size and
anteroposterior relationship of both
jaws develop as it is seen at birth



Development of tongue

Appears in embryo at 4th week of IUL . in the
form of two lateral swellings and one median
swelling that is tubercular impar .all are from
1st pharyngeal arch
 Another median swelling copula (hypobranchial
eminance) from 2,3 and 4th arch .posterior part
of 4th arch gives rise to epiglottis
 Two lateral swellings grows medially and
anteriorly and overgrows on TI . both half meet
each other to form anterior two third of tongue
 Muscles of tongue develop from occipital
myotomes





Thyroid gland :




Thyroid appears as epithelial
proliferation of in the floor of tongue
between TI and HE
 Then it descends in front of pharyngeal
gut and forms bilobed diverticulum's
which forms two lobes




GROWTH OF CRANIAL BASE
As we have seen that by 4th to 8th week of IUL
evidence of cranial base formation is seen .the
Mesenchymal form is derived from primitive
streak of neural crest and occipital
schlerotomes.
 condensed mesanchyma forms capsule around
brain called ectomenix basal portion of this
capsule gives rise future cranial base. The
process by which ectomeningeal capsule get
convert into cartilage is called chondrification .
 it mainly occurs in 4 regions









Para chordal—around cranial end of
notochord
Hypophyseal—it occurs in 4 centers
post sphenoid—body of
sphenoid
pre sphenoid –body of sphenoid
mesethmoid---plate of ethmoid
cristagalli




orbito sphenoid---lesser wing
ali sphenoid – greater wing



Nasal-nostril
 Otic-mastoid

OCCIPITAL BONE







It ossifies both endochondrally and
intramembranously. It has 2 intra membranous
centers and 5 endochondral centers

supra nuchal sq. part – one pair ---8th
week

infra nuchal sq.part --1 pair -------10th
week

basilar part –single median center -11thweek

foramen magnum occipital condyle ---1
pair –12th week








TEMPORAL BONE
It has 11 centers of ossification
Sq, part –1 center (IM)—8TH week
Tympanic ring 4 centers (IM)------12th
week
Petrous temporal bone ---4 centers
(EC)-----5th month
Styloid 2 centers (EC) 5th month









ETHMOID BONE
Its an endochondral bone with 3 centers
Median floor of anterior cranial
fossa –1 centers
Nasal capsule 2 lateral centers



SPHENOID BONE



It has 15 centers of ossification
Lesser wing –2 orbito sphenoidal cartilage
Greater wing ,lateral pterygoid plate2(IM)1alisphenoid
Median pterygoid plate -2 secondary
cartilage of hamular process
Anterior part of body of sphenoid- 5 (EC)
Posterior part body of sphenoid - 4 (EC)
Cranial base chndrocraniam is relatively
stable during growth compared to cranial vault
and face so cranial base is taken as bases
against which cranial vault and facial skeleton
can be compared in cephalometric studies

















FLEXURE OF CRANIAL BASE
In early fetal period cranial base becomes flexed
in the region between pituitary fossa and
sphenooccipital junction this is accompanied by
developing brain stem so that spinal chord and
foramen magnum directed downwards from their
initial position of backwards this adaptation only
seen in human beings
It increases neurocranial capacity
It facilitates predominant downward growth of
face
At 10th week of intrauterine life flexure angle is 65
degrees with then flattens. anterior and posterior
part of cranial base grows at different rates that is
between 10th to 40th week anterior cranial base
increase in width bywww.indiandentalacademy.com
7 times but posterior increase
by 5 times



Development of palate
 Main part of palate arise from maxillary
process & small premaxilla is formed by
deeper part of medial nasal process.
initially medial nasal process gives rise to
small triangular projection which forms
futer premaxilla .then from maxillary
process lateral segments arise which are
placed vertically. In this period mandible
is small & already formed tongue is
pushed upwards in nasal cavity so lateral
segments of maxillary process grow
vertically .



Nasal septum from above starts growing
downwards & backwards by 7th week of IUL .
Mandible shows accelerated growth so tongue
falls back & transformation of position of
palatal selves occurs from vertical to horizontal
this transformation takes place within hrs .
 Both palatal selves properly approximate by 8
½ to form hard palate & posterior part use to
form sot palate entire palate does not close at
once . initial contact occurs in central region of
secondary palate posteriorly to pre maxilla
from this point closure occurs both anteriorly
&posteriorly also from above end of nasal
septum fuses with palate .
 Palatal ossification (IM) 1 center 8th week
 mid palatal suter ossifies at 12 to 14 years

 development

o maxillary sinus



It is formed around at 3rd month of IUL
It develops by expansion of nasal mucous
membrane into maxillary bone
 It enlarges later by internal resorption of
wall of maxilla


 meckels cartilage
 it derived from first brachial arch on 41st to
45th day of IUL .extends from cartilaginous otic
capsule to sysmphysis .it acts as template and
guide for growth of mandible . a major portion
of this disappears and remaining part develops
in to

mental ossicle

incus, malleus

spine of sphenoid

ant. Ligament of malleus

sphenomandibular ligament
 1st structure that develops in promordia of
man. Is mandibular division of 5th nerve this is
followed by osteogenesis (neurotropic theory )



on 6th week of IUL single ossification
center for each man. Arise in the region
of bifurcation of inferior alveolar nerve
in to mental and incisive. ossifying
membrane is located lateral to meckels
cartilage .IM ossification spreads dorsally
and ventrally to form body and ramus of
man. Ossification continues till region of
future linguala. meckels cartilage
continues into middle ear and develops in
to auditory ossicle that is malleus and
incus and SML



Endochondral bone formation in man.
Seen in3 areas
 condylar process
 mental region
 coronoid process
 condylar process; at 5th week of IUL
mesanchymal condensation seen above
ventral part of man. By 10th week it
develops into cone shaped cartilage. by
14th week it starts ossifying. it then
migrates inferiorly and fuse with man.
Ramus by4th months . by 6-7 th month of
IUL much of cartilage ossifies except
upper end which ossifies at adult hood





mental region
on either of symphysis 2 small cartilage
appears in 7th month of IUL .it then
incorporates into body . symphysis
ossifies after 1yr after birth

 coronoid


process

it is formed by secondary cartilage.
appears at 10-14th week of IUL. it grows
as response to temporalis muscle. it then
join with ramus


TMJ











In IUL it develops in three phases
Blastamic stage (7—8th week) corresponds with
organization of condyle ,articular disc and
capsule
Cavitations stage (9—11th week) initial
formation of inferior joint cavity
Maturation stage (from 12thweek)
At birth articular disc is flat but it then
transforms into S shape
Articular disc at birth is 1.5mm thick. it then
thins down and replaced by endochondral
ossification
It grows in post . sup. Lat. Direction

 POST

NATAL DEVELOPMENT
AND GROWTH



Maxilla and mandible are attached to
cranial base by means of sutures and TMJ
respectively. so any growth change in CB
affect growth of jaw













cranial base
CB grows post natally by complex interaction between
1)
cortical drift and remodeling
2)
elongation at synchondrosis
3)
sutural growth
cortical drift and remodeling ; remodeling is
apposition or resorption of bone which bring about
change in size shape and relationship of bone
cranial base is divided into many components by
bony elevations called ridges .These ridges show bony
deposition and other part show resorption by this
process CB develops
in the area where blood vessels and nerves pass CB
,show cortical drift ie by bone deposiotion and
resorption and maintain constant position



elongation of synchondrosis



cartilage at various junction of bone
called SY

they act as important growth sites as
they are primary cartilages

main synchondrosis are

sphenooccipital

sphenoethmoid

intra sphenoid

intra occipital





spheno occipital SY ; it is active up to age
12—15years .these segments fuse in
midline by 20yrs . it shows pressure
adapted bone growth. direction of bone
growth at SY is upwards so it carries ant.
Part of cranium bodily forwards closure
of this SY occurs at 13-15yrs
 spheno ethmoid : it ossifies at 5-25yrs
 intra sphenoid : it ossifies at birth
 intra occipital:ossifies at 3–5yrs



sutural


growth : --

growth seen sutures are

spheno frontal
 fronto temporal
 sphenoethmoid
 frontoethmoid
 frntozygomatic
 main timing of CB growth
 by birth 55%-60%
 4—7yrs 94%
 8—1yrs 98%www.indiandentalacademy.com


• post natal growth of
maxilla
– nasomaxillary complex grows by

displacement
 growth at suture
 surface remodeling
 displacement: as before discussed maxilla
attached attached CB by sutures so as CB
grows secondary displacement is seen in NMC
in downwards and forwards direction . it
mainly seen at 6—12yrs age. growth at
tuberosity seen in postrior direction to shift
maxilla in forwards direction



growth at

suture



main sutures at which growth seen are
 frontonasal
 frontomaxillary
 zygomaticotemporal
 zygomaticomaxillary
 pterygopalatine
 these sutures are obliquely placed and by
this maxilla grows in forwards and
downwards direction . soft tissues carry
maxilla also in same direction



surface remodeling ;



the remodeling changes seen in NMC.
resorption occurs on lat. Surface of orbital region so
that eye moves laterally .on medial rim deposition seen
floor of orbit due to remodeling grows in sup .lat. and
ant. Direction
bone deposition occurs on posterior margin of maxillary
tuberosity which causes lengthening of dental arch and
enlargement of antero posterior dimension of entire
maxilla
bone resorption seen on lateral wall of nose to increase
size of nasal cavity
bone resorption seen in floor of nasal cavity and
deposition in palatal side so net downward shift occurs
leading to increase in maxillary height











zygomatic bone moves in posterior
direction by resorption on anterior
surface and deposition on posterior
surface
 face enlarges in width by formation of
lateral surface of zygomatic arch and
resorption on medial surface
 anterior nasal spine increase in
prominence by deposition
 tooth eruption ,increase maxillary
height by alveolar bone deposition
 entire wall of sinus except mesial wall
undergoes resorption by which maxillary
sinus increase in size

 post. Natal growth of man.
 Of facial bone man. Has largest amount
of growth post natally
 Ramus : it moves posteriorly by bone
remodeling
 Resorption occurs in anterior part and
deposition occurs in posterior region so it
results in post . drift
 Body of man.: its growth depends on
remodeling growth of ramus so former
ramus converts into posterior body



Angle of mandible



On lingual side of angle resorption takes place on
posteroinferior aspect and deposition occurs in
anterosuperior aspect on buccal side exactly opposite
process occurs this results in flaring of angle of
mandible as age advances
Lingual tuberosity : it is vary similar to maxillary
tuberosity grows posteriorly and lingually
Alveolar bone grows as tooth erupts in oral cavity
Chin in infancy is under developed due to position of
head and precordial bulge its growth mainly influenced
by sexual and specific genetic factor
Males have prominent chin
In childhood mental protuberance forms and ossifies its
prominence is accelerated by bone resorption that
occurs in alveolar region which creates concavity

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Condyle : it is main growth site its growth has 2 schools

of thought
 Earlier it was believed that growth occurs at surface of
condyle by bone deposition so condyle grows towards
CB condyle pushes against CB .so entire man. Is
displaced forwards and downwards
 Now it is believed that growth of soft tissue that is
muscle and CT carry man. forwards away from CB (
carry away phenomenon) and bone grows secondarily to
maintain contact with CB . condylar growth which peak
at 12—14yrs and stops at 20yrs
 Coronoid process : it follows enlows V principle ,
deposition occurs on lingual surface and with it vertical
dimension also increase so it gets a characteristic twist
that is sup. Post. Med.

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