Growth & development /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


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INTRODUCION
BASICS
– Definitions
– What is growth & development ?
– Types of growth
THEORIES OF CRANIOFACIAL GROWTH


Krogman
“Growth was conceived by an anatomist, born to
biologist,delivered by a physician left on a chemist`s
door step and adopted by a physiologist. At an early
stage, she eloped with a statistician. Divorced him for a
pschychologist, and is now being wooed alternately and
concurrently by an endocrinologist, a biochemist, a
physicist, a mathematician, an orthodontist, an
eugenicist and the children`s bureau”

GROWTH
•

Todd 1931
Growth refers to increase in size

•

Profitt 1986
Growth usually refers to an increase in size and the
number

•

Moyers 1988
Growth may be defined as the normal changes in
the amount of living substance.



Growth is basically anatomic
phenomenon and quantitative
in nature.



Development is basically
physiologic phenomenon and qualitative in nature.

Correlation between growth & development


Development = growth + differentiation
+ translocation

•

Cellular hyperplasia: increase in the number of cell.

•

Cellular hypertrophy: increase in the size of
individual cells.
Interstitial: growth of softtissue occurs by
combination of hyperplasia and hyperthrophy ,
these process go on every where in the tissue.[ it
occurs all points with in the tissue].
Appositional :Direct addition of new bone to the
surface of existing bone and does occur through the
activity of cells in the periosteum.

•

•


•

Pattern :
–
arrangement of parts,values,events, or relations among
measurements.
• Growth trends
• Cephalocaudal gradient

•

Variability :
– Is the law of nature
• Normality
• Differential growth

•

Timing :
– Is variable & concerned with rate and division of growth
• Growth spurts

Tweed employed four angles namely:
IMPA,FMA,FMIA,ANB.
TYPE A:
Maxilla and mandibule grow downward & forward in union.
No change in the size of ANB angle;25% of pts have this
growth tendency.
TYPE B:
Although entire face grows downward & forward, maxilla
grows more rapidly than mandible resulting in the increase of
ANB angle; 15% pts fall under this category.
TYPE C:
Mandible grows rather downward & forward at a faster rate
than middle third of face. This shows lessening of ANB angle
in comparison of two standardized lateral ceph . These
constitute 60%.




CEPHALOCAUDAL GRADIENT

Thus “Cephalocaudal
gradient of
growth” , this
simply means that
there is an axis of
increased growth
extending from the
head towards the
feet.





In fetal life, at about the third month of intrauterine
development , the head takes up almost 50% of total
body length. At this stage, the cranium is large
relative to the face and represents more than half the
total head . In contrast, the limbs are still
rudimentary and the trunk is underdeveloped.
By the time of birth, the trunk and limbs have
grown faster than the head and face, so that the
proportion of the entire body devoted to the head
has decreased to about 30%.





The overall pattern of growth thereafter follows this
course, with a progressive reduction of the relative
size of the head to about 12% the adult.
All of these changes,which are a part of the normal
growth pattern, reflect the “cephalocaudal gradient
of growth”. This simply means that there is an axis
of increased growth extending from the head
towards the feet.


Normal refers to that which is usually expected , is
ordinarily seen , or is typical.
 Normal – Range & Ideal – Fixed value
 On comparison with normal, a variable can be
measured.
CLINICAL IMPLICATION :
 Diagnosis of gross variations from central tendency
of pathological condition or gross abnormal pattern
of growth





Not all tissue systems of the body grow at the same
rate. Different tissues and in term different organs
grow at different rates. This process is called
differential growth.


•

•

•

As the graph indicates, growth of the neural tissues
is nearly complete by 6 or 7 years of age.
General body tissue, including muscle, bone and
viscera, show and S-shaped curve, with a definite
slowing of the rate of growth during childhood and
an acceleration at puberty.
Lymphoid tissues proliferate far beyond the adult
amount in late childhood, and then undergo
involution at the same time that growth of the
genital tissues accelerates rapidly around the onset
of puberty.

scammons growth
curve


•

Just before birth

•

One year after birth

•

Mixed dentition period
boys : 8 – 11 yrs
girls : 7 – 9 yrs
Pre pubertal period
boys : 14 – 16 yrs
girls : 11 – 13 yrs
Pubertal period
boys : till 25 yrs
girls : 18 – 20 yrs

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•
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•


Growth spurts serve as excellent indicators for
timing of orthodontic treatment
Correlation of
a. Skeletal age,
b. Dental age
c. Chronological age.
With on set of puberty.

Importance of Growth Spurts:
 Pubertal increments offers best time for,
determining the predictability, growth
direction, patient management and total
treatment time.


Understanding the growth, predictability of
future growth of maxilla, mandible and
alveolar process helps in diagnosing and
achieving excellent results of the malocclusion.

Large number of cases for the
orthodontic and orthopedic
correction of Maxilla and
Mandible.
Growth spurts serve as
excellent indicators for timing
of orthodontic treatment.
For eg: orthognathic surgeries
after growth spurt completion.
Growth spurt is the best
period for Interceptive
orthodontics.

For ex:
 classII malocclusion with mandibular retrognathism can
be managed by activator thearpy.


classII malocclusion with maxillary prognathism can be
managed by the use of headgear.



classIII malocclusion with mandibular prognathism can
be controlled by chincap and headgrear.



classIII malocclusion with maxillary retrognathism can
be managed by nakamuras applince which promotes
the growth of maxilla.

Malocclusion of dental arches can
be treated taking Advantage of
growth spurts during the active
growth periods.

Arch expansion & rapid
skeletal expansion can be
undertaken during periods of
maximum growth.

Theories of Growth and Development


•

Genetic theory – brodie 1941

•

Sutural theory – sicher 1955

•

Cartilaginous theory – scott’s 1956
Funtionalmatrix theory – melvin moss 1962
Enlow’s expanding “v” principle – enlow 1963
Enlow’s counterpart principle
Van Limborgh’s theory - 1970
Servosystem – petrovic hypothesis - 1974

•
•
•
•
•




Mainly based on observations

-

No evident scientific data

-

Lacked scientific understanding and soon replaced
by other theories.




Sutural theory Proposed by Sicher in 1955:
According to Sicher

-

“The primary event in sutural growth is the
proliferation of the connective tissue between the
two bones. If sutural tissue proliferates, it creates
the space for appositional growth at the border of
the bones”.




We now know that functions of suture are :

1.

Unite the bone

2.

Absorb the forces,

3.

Act as a joint

4.

Act as a growth site and not growth centre



Evidences Against Sicher’s Theory:

1.

Auto transplants of sutures fail to grow in cultural
medium though provided with same environment
and conditions.

2.

Extripation of sutures has no appreciable effect on
growth of skeletal.

3.

The shape and growth within sutures is dependent on
external stimuli.

4.

It is possible to bring the sutural growth to halt by
mechanical stress applied across the sutures.



Cartilagenous Theory (James Scott-1956)

•

The fact that, for many bones of the hand and legs,
cartilage does the growing while bone merely
replaces it makes this theory attractive for the bones
of the jaws.



According the Scott:-

•

Spheno-occipital synchondrosis cartilage
-responsible for the growth of cranial base.

•

Nasal septal cartilage – Responsible for the growth
of maxilla

•

Condylar cartilage – Responsible for the growth of
mandible

1. Spheno ethmoidal
2. Inter-sphenoidal
3. Spheno-occipital


-

Important growth center of craniofacial skeleton,
especially cranial base.



Cartilage of Nasal Septum:



Spheno-occipital Synchodrosis:

-

Growth of maxilla is difficult to explain on the
cartilage theory. Proponents of the cartilage theory
hypothesize that the cartilaginous nasal septum
serves as a pacemaker for other aspects of maxillary
growth.


• Removal of a segment of the Nasal Septal
Cartilage in humans and rabbits showed mid-facial
deformities.


-

Two kinds of experiments have been carried out to test
the idea that cartilage can serve as a true growth center.



1. Transplanting nasal cartilage to cultural medium or
any other place did not give equivocal results, that is
sometime it grew, sometimes it did not. Indicating
doubtful growth potential of the nasal septal cartilage
whereas, if a piece of the epiphyseal plate of a long
bone is transplanted, it will continue to grow in a new
location or in culture, indicating that these cartilages
do have innate potential.

•

Since longtime, its being hypothesized that condylar
cartilage is the growth center for the growth of
mandible.

•

Experiments of transplanting condylar cartilage
showed little or No growth potential.

•

It is no clear that condylar cartilage is secondary
cartilage, which grows by appositions and not by
intestitial deposition. Whereas, epiphyseal cartilage
is primary cartilage.mandibular condylar thus do not
have innate growth potential and not a growth
center.

•

The fact that after the condylar fracture in children
do not all together inhibit growth of mandible
indicates that condyle is not a growth center.

•

Studies carried out in Scndinavia in 1960’s
demonstrated that after the fracture of mandibular
condyle in child, there was an excellent chance that
the

condylar

process

would

regenerate

to

approximately its original size and small chance that
it would overgrow after the injury.


FUNCTIONAL MATRIX CONCEPT
(MELVIN MOSS)


This concept attempts to comprehend the relation
between form & function.



This concept claims that origin, form, position,
growth & maintenance of all skeletal tissues and
organs are always secondary, compensatory and
necessary

response

to

chronologically

&

morphologically prior events or processes that occur
in specifically related non-skeletal t


issues, organs or www.indiandentalacademy.com .
functioning space

Functional cranial component

Skeletal unit

Functional matrices

Macroskeletal

Microskeletal

Eg-coronoid,
angular

Eg-endocranial
surface Of calvaria

Periosteal

Eg-teeth and
muscles


Capsular

Eg-orofacial,
neurocranial

a) Skeletal unit – it protects &/or support its specific
functional matrices.
b) Functional matrix – which carries out the function.


Skeletal unit:


All skeletal tissues associated with a single function
are called skeletal unit.



The skeletal unit may be comprised of bone,
cartilage and tendinous tissue.


MACRO SKELETAL UNIT Adjoining portions of number of neighbouring
bones carrying out a single function eg- endocrainal
surface of calvaria


MICROSKELETAL UNIT
Bones consisting of number of small skeletal units
MAXILLA-orbital
-pneumatic
-palatal
-basal
MANDIBLE-coronoid
-angular
-alveolar
-basal www.indiandentalacademy.com

The Functional matrix
Divided into:
1. Periosteal matrix
2. Capsular matrix
 Periosteal matrices






Act directly & actively upon their related skeletal
units.
Alterations in their functional demands produce a
secondary compensatory transformation of the size
or shape of their skeletal units
Such transformations are brought about by the
inter related process of bone deposition and
resorption.



Best explanation – coronoid process and temporalis
muscle ,removal denervation and post infectively
decrease in the size or total disappearance , hence in
simple terms it can be stated coronoid process does
not grow itself first and thus provide a platform
upon which the temporalis muscle can alter its
function but it is the opposite which is true


Capsular matrices


Act indirectly and passively on their related skeletal
units producing a secondary compensatory
translation in space.



The skeletal units are passively & secondarily
moved in the space as their enveloping capsule is
expanded. This kind of translative growth is not
brought about bywww.indiandentalacademy.com resorption.
deposition and

FOUR CAPSULES ARE PRESENT
NEURO CRANIAL

ORO FACIAL

OTIC

ORBITAL









Each of these capsules is an envelop containing
functional cranial component
Sandwitched between two covering layers
Capsules expands due to volumetric increase of
capsular matrix
This results in the translative movement of the
embedded bones


• :







Surrounded by skin and mucous membrane ,
Surrounds and protects oro-naso-pharyngeal space
on either side.
Originates by process of enclosure.
Volumetric growth of these spaces is the primary
morphogenetic event in facial skull growth


Orofacial Capsule




Primary function is maintaining airway this is
accomplished by “AIRWAY MAINTENANCE
SYSTEM”-BOSMA



Growth of functional spaces-increase in the size of
capsule



Followed by passive movement of functional cranial
component

Functional matrix theory revisited
Melwin Moss in 1997 proposed continuation of his
classical functional matrix theory with the new
concept. He published series of articles in American
Journal of Orthodontics in 1997.
This has lead to the inclusion of two topics:
i.The Mechanisms of Cellular Mechanotransduction
ii.Biologic Network Theory



According to this concept the mechanical
stimulus is pursued by the specialized cells by
process called as mechanoperception. Then these
signals are transmitted through the tissues by way
mechanoconduction or mechanotrasmision.
Finally, these signals are transmitted to the genome
of the bone were protein synthesis is taking place.




These signals alter the protein metabolism
depending upon the severity and longativity of the
mechanical stimulus. In short the earlier concept of
FMH theory remained same as form is determine
by the function.



Moss also recognizes the important role of genetics
and human genome in determining the ultimate size
and shape of the craniofacial skeleton. He quotes
reference of human genome project which is being
carried in a mega scale allover the world.
According to the human genome project human
chromosomes contain the genetic informations
necessary for buildingup of entire human body.



Genes now beyond doubt have been proved to effect

•

the physical growth of the person, behavior of person
and

•

psychology of person.



Thus Moss FMH revisited theory states the ultimate

•

growth controlling factor of the craniofacial skeleton
depends on two factors.

1.

Genetic factors

2.

Environment factors.



Morphogenesis is regulated by both genomic and
epigenetic processes and mechanisms both are
necessary causes, neither alone are sufficient causes.



Their integrated activities provide the necessary and
sufficient causes for growth and development


ENLOWS EXPANDING ‘V’ PRINCIPLE
 Growth

movements

&



enlargements of these bones
occur towards the wide ends of
the

‘V’

differential

as

a

result

deposition

of
&

selective resorption of bone
 Bone deposition occurs on the
inner side of the ‘V’ and bone
resorption
surface.

on

the

outer


 Deposition also takes place at
the end of two arms of the ‘V’


resulting in growth movement
towards the ends.

 The ‘V’ pattern occurs in a
number of regions such as
base of the mandible, ends of
long bones , mandibular body,
palate etc.


•

•

The growth of any given facial or cranial part
specifically to other structural and geometric
counterparts in the face and cranium
There are regional relationships through out the whole
face and cranium. If each regional part and its particular
counterpart enlarge to the same extent, balanced growth
occurs.








Antr – cranialbase ----- maxilla
middle – cranialbase --- pharyngealspace
middle – cranialbase ----- width of ramus
Maxilla ---------- mandible
Maxilla tuberosity ----- lingual tuberosity


VAN LIMBORGH’S THEORY


Process of growth & development in a view that combines
all the 3 existing theories.



He suggested following 5 factors[multifactorial theory]
Intrinsic genetic factors

They are the genetic control of the skeletal units
themselves.
Local epigenetic factors

Bone growth is determined by genetic control
originating from adjacent structures like brain,eyes etc…



General epigenetic factors
They are genetic factors determining growth from
distant structures.
e.g. sex hormones, growth hormone etc…



Local environmental factors
They are non genetic factors from local external
environment.
e.g. habits, muscle force etc.



General environmental factors
They are general non-genetic influences such as



The views expressed by Van Limborgh’s can be
summarized in 6 points
1. Chondrocranial growth is controlled mainly by the
intrinsic genetic factors. Eg; Base of the skull
2.Desmocranial growth is controlled by a few intrinsic
genetic factors. Eg; calvaria.
3. The cartilaginous parts of the skull must be considered
growth centers.

4 .Sutural growth is controlled mainly by influences
originating from the skull cartilages & from other
adjacent skull structures.
5.Periosteal growth largely depends upon growth of
adjacent structures.
6.Sutural & periosteal growth are additionally governed
by local non genetic environmental influence



Proposed by petrovic accordingly, the growth of
maxilla and mandible and cranial base depends
upon cybernetic control.

This cybernetic control is

mainly by Secretion of hormones. These hormones
mainly include growth hormone - somatomedin,
testosterone and estrogen.




Author describes the secretion of hormones is by the
signal established independed of the feedback system.

•

This signal secretion is described as COMMAND .

•

This signal is transmitted to the Reference input
elements. In maxilla they include septal cartilage,
septopremaxillary frenum, the labionarinary muscles
and the maxillary bones. In mandible reference input
elements include muscle attachments to the mandible
that is lateral pterygoid, medial pterygoid and
tempralis muscles.



The commanding signal is first established in the
maxilla through the above quoted reference input
elements and thus maxilla grows in sagittal and
vertical direction. The corresponding actuating
signal followed to the above process is felt in the
mandible through the reference input elements and
mandible growth occurs.




Neurotrophism is a non impulse transmitting neural
function that involves axoplasmic transport and
provides for longterm interaction between neurons
and innervated tissues that homeostatically regulates
the morphological, compositional ,functional
integrity of those tissue.


•

•

•

Neuro-epithelial trophism:Epithelial mitosis and
synthesis are neurotropiclly controlled by release of
neurotrophic substances by the nerve synapses.
Ex;taste buds sensation.
neuro-muscular trophism:Embryonic myogenesis is
independent of neural innervation and trophic
control.
Neuro-visceral trophism:The salivary glands,fat
tissue and other organs are trophically regulated.









Contemporary Orthodontics ---William
R.Proffit
Orthodontics Practice and Principles– TM
Graber
Orthodontics The Art and science-S.I. Bhalaji
Textbook of Orthodontics --Gurkeerat singh


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