Growth & development

GROWTH &GROWTH &
DEVELOPMENTDEVELOPMENT
DEFINITIONS ANDDEFINITIONS AND
TERMINOLOGIESTERMINOLOGIES
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Definition of GrowthDefinition of Growth
• “Growth refers to increase in size” - Todd
• “Growth may be defined as the normal
change in the amount of living substance”-
Moyers
• “Growth usually refers to an increase in
size and number” – Proffitwww.indiandentalacademy.comwww.indiandentalacademy.com

• “Change in any morphological parameter
which is measurable”- Moss.
• “Size development , progressive
development (i.e, evolution, emergence,
increase or expansion)”- Webster’s
dictionary.
• “Self multiplication of living substance”-
J.S.Huxley.

DIFFDIFFERENT KINDS OF GROWTHERENT KINDS OF GROWTH
• Size change
• Positional change
• Proportional
change
• Functional change
• Maturational
change
• Compositional
change
• Timing and
sequential change
• a Prenatal growth
• b Postnatal
growth
• c Maturity
• d Old age

Definition of DevelopmentDefinition of Development
“Development is a progress towards maturity” –
Todd
“Development refers to all naturally occurring
progressive, unidirectional, sequential changes
in the life of an individual from it’s existence as
a single cell to it’s elaboration as a
multifunctional unit terminating in death” –
Moyers
“Development connotes a maturational processwww.indiandentalacademy.comwww.indiandentalacademy.com

Major themes of developmentMajor themes of development
• Changing complexity
• Shifts from competent to fixation
• Shifts from dependent to independent
• Ubiquity of genetic control modulated by
environment

Changing complexity
• Takes place at all level of organisation
from the sub-cellular to the whole
organism
• Normally complexity increases with
development .
• Most complex period of developing
dentition is transition of dentitions.

Shifts from competent to fixation
• Undifferentiated cells once differentiated
become fixed.
Shifts from dependent to
independent
• Development brings greater independence at
most levels of organisation.

Ubiquity of genetic control
modulated by environment
• Genetic control of development is
constantly being modified by
environmental interactions

Correlation betweenCorrelation between
Growth & DevelopmentGrowth & Development
• Growth is basically anatomic
phenomenon and quantitative in nature
Development is basically physiologic
phenomenon and qualitative in nature
• Growth may not always be associated
with increase in size, it may at times
result in decrease in size, e.g. thymus
gland after puberty
Development on the other hand is awww.indiandentalacademy.comwww.indiandentalacademy.com

Importance of growth andImportance of growth and
development to orthodontistdevelopment to orthodontist
• Serves as a backbone to understand the
etiology of malocclusion
• Helps to assess the health and nutrition of
children
• Allows comparison of growth of an
individual child with the growth of other
children
• Helps to identify abnormal occlusal
development at an earlier stage

• Makes available use of growth spurts
• Surgery is done when facial growth is
completed
• Growth affects stability of occlusion
hence retention regime should be
planned accordingly.

DefinitionsDefinitions
• Morphogenesis – “A biologic process
having an underlying control at the cellular
and tissue levels”
• Differentiation – “It is a change from
generalized cells or tissues to a more
specialized kinds during development”

• Translocation – “It is a change in
position”
• Maturation – “The term maturation is
sometimes used to express qualitative
changes which occur with ripening or
ageing”

Normal features ofNormal features of
Growth & DevelopmentGrowth & Development
• Differential Growth
• Pattern
• Normality
• Variability
• Timing, rate & direction

DIFFERENTIAL GROWTHDIFFERENTIAL GROWTH
Different organs grow at different
rates to a different amount and at
different times.
• Scammon’s curve of growth
• Cephalocaudal gradient of growth

SCAMMON’S CURVE OFSCAMMON’S CURVE OF
GROWTHGROWTH
• LYMPHOID
• NEURAL
• GENERAL
• GENITAL

CEPHALOCAUDALCEPHALOCAUDAL
GRADIENTGRADIENT

PATTERNPATTERN
• Pattern in growth represents
proportionality .It refers not just to a set of
proportional relationships at a point in time
but to change in these proportional
relationships over time.
• Cephalocaudal gradient
• An important aspect of pattern is
predictablity

PredictabilityPredictability
• Predictability of growth pattern is a
specific kind of proportionality that exists
at a particular time and progresses
towards another, at the next time frame
with slight variations.
• In orthodontics,
- Morphogenetic
- Developmental

VariabilityVariability
• No two individuals with the exception of
monozygotic twins are like.
• Variability quantitatively is categorized
in terms of deviations from the usual
pattern, for which it is imp to understand
the concept of normality.

NormalityNormality
• Normality refers to that which is usually
expected, is ordinarily seen or typical –
Moyers
• Normality may not necessarily be ideal.
• Misuse of the concept of normality can lead
to many problems in clinical orthodontics &
treatment planning.•

• Statistical
• Evolutionary
• Functional
• Esthetics
• Clinical
CONCEPTS OF NORMALITYCONCEPTS OF NORMALITY

Growth chartsGrowth charts

Applications of growth charts.Applications of growth charts.
• Location of an individual relative to the
group can be established.
• Can be used to follow a child over time
and note for any unexpected change in
growth pattern.

Timing of GrowthTiming of Growth
• One of the factors for variablity in growth.
• Timing variations arise because biologic clock of
different individuals is different.
• It is influenced by:
genetic influence
sex related differences
physique related
environmental influences

Distance curveDistance curve
VsVs
Velocity curveVelocity curve
Distance
curve
Velocity
curve
Age
Height
Distance Curve (cumulative curve): In this curve growth
can be plotted in height or weight recorded at various
ages.
Velocity Curve(incremental curve): In this by amount
of change in any given interval that is growth incrementwww.indiandentalacademy.comwww.indiandentalacademy.com

Growth spurtsGrowth spurts
• Defined as periods of growth acceleration
• Sex-linked
– Normal spurts are
• Infantile spurt – at 3 years age
• Juvenile spurt – 7-8 years (females); 8-10
years (males)
• Pubertal spurt – 10-11 years(females); 18-15
years (males)

GROWTH STUDIES AND METHODS OF
STUDYING GROWTH.

• Types of growth data
• Methods of gathering growth data
• Longitudinal growth studies
• Methods of studying bone growth

Types of growth data.
Opinion
Observations.
Ratings and rankings.
Quantitative measurements.
direct data.
indirect data.
derived data.

Types of growth data.
• Opinion
It is a clever guess based on experience.
they are the crudest form of scientific
knowledge.
• Observations:
They are useful for studying all or none
phenomenon.they are used in a limited way
when more quantitative data is available.

• Ratings and rankings:
certain data is difficult to quantify and thus
may be compared to conventional rating
scale .ratings make use of comparisons with
such scales.rankings array data in ordered
sequence according to value.

Quantitative measurements:
Includes expressing an idea or fact as a
meaningful quantity or numbers.
• Direct data: derived from measurements taken
on living persons or cadaver with a measuring
device.
• Indirect data: derived from measurements
taken from images or reproductions of the
actual person.
• Derived data: obtained by comparing at least
two other measurements.

Methods of gathering growth
data.
• Longitudinal studies .
• Cross sectional studies.
• Overlapping or semi longitudinal studies.

Longitudinal studies.
• These are measurements made of the same person
or group at regular intervals through time.
• Advantages: temporary temporal problems are
smoothed with time,
Variability in development within a group is put in
proper perspective,serial comparison makes study
of specific developmental pattern of individual
possible.
Disadvantages: time consuming, expensive, sample
loss or attrition,averaging.

Cross sectional studiesCross sectional studies
ADVANTAGES
• Quicker
• Less costly
• Statistical treatment made easier
• Allows repeating
DISADVANTAGES
• Variation in development amongst individuals
within the sample cannot be studied

Semi longitudinal studies.
• Longitudinal and cross sectional studies can
be combined to to seek the advantages of
both.in this way one might compress 15
years of study into 3 years of gathering
growth data.

LONGITUDINAL GROWTH
STUDIES.

Longitudinal growth studiesLongitudinal growth studies
• Bolton brush growth study
• Burlington growth study
• Michigan growth study
• Denver child growth study
• Iowa child welfare study
• Forsyth twin study
• Meharry growth study

• Montreal growth study
• Krogman philadelphia growth study
• Fels growth study
• Implant studies
• the mathews implant collection
• the hixon oregon implant study
• Cleft palate study

Bolton Brush growth study.
• Initiated by Prof T Wingate Todd in 1926
• Aim- studying skeletal development .
• Initiated concurrently by Dr Holly Broadbent Sr in
1929.
• Aim- studying normal development of facial
skeleton.
• Sample size:5000 normal healthy children.
• Records:series of x-rays,casts,dental and medical
examination and psychological tests.

• The two collections merged officially in 1970.
• In 1975 the Bolton standards of dentofacial development
growth were published by Dr Holly Broadbent jr.
• These standards are a series of averages that represent
optimum facial and developmental growth and form a
baseline for understanding and assessing craniofacial
growth.

Burlington growth study
• AIM
• Malcclusion
• Evaluate preventive and interceptive orthodontic
treatment.
• Obtain a set of growth records as a database for
future studies.
• Sample size:1632 subjects followed
longitudinally.

• Records :series of x-rays,
casts,photographs,height and weight
records and medical examination.
• The original concept for the study was
presented by Robert Moyers& the
records were gathered under Frank
Popovich.

Burlington growth study
• More than 247 investigations & 322 studies are
based on this growth study
• Longitudinal studies by Thompson & Popovich to
derive cephalometric norms of a representative
sample was based on 210 children followed for 15
years at the Burlington growth center.
• age sex and growth type specific craniofacial
templates were derived and static and dynamic
analysis were proposed on the basis of this study.

The Iowa child welfare study.
• Sample size:it is a diminishing longitudinal
study which began with 20 males and 15
female 4 year old subjects. Followed till 17
years of age. Non -orthodontically treated
patients of entirely European origin were
used.
• Records:lateral and PA views and dental
casts.
• The study as done under Samir Bishara.

• Based on this study the changes in facial
dimensions & relationships as well as in
standing height were evaluated.
• The dentofacial relationships of 3 normal facial
types (long, average, short) from 5-25 yrs of
age was described & compared.

CLEFT PALATE STUDIES.
• LANCASTER PA:includes 850 record sets obtained
annually from birth to 15 years.
• HOSPITAL FOR SICK CHILDREN(Toronto):over
4000 subjects ranging in age from 5-20 years
• .CENTER FOR CRANIOFACIAL
ANOMALIES(Chicago);annual records of 1000
subjects.
• Records include series of x-ray films, casts, medical
and orthodontic treatment records.
• All subjects had surgical repair and minor to extensive
orthodontic treatment.

Methods of studying bone
growth
c e p h a lo m e tr y .
a n th r o p o m e tr y .
c r a n io m e tr y .
m e a s u r e m e n t a p p r o a c h e s .
a u to r a d io g r a p h y .
n u c le a r v o lu m e m o r p h o m e tr y .
r a d io is o to p e s .
p o la r is e d lig h t.
flu o r e s c e n t la b e ls .
m ic r o r a d io g r a p h y .
m in e r a lis e d s e c tio n s .
a t m ic r o s c o p ic le v e l.
fin ite e le m e n t m o d e lin g .
im p la n t m a r k e r s
a t m a c r o s c o p ic le v e l.
n a tu r a l m a r k e r s .
c o m p a r a tiv e a n a to m y .
v ita l s ta in in g .
a t b o th le v e ls .
e x p e r im e n ta l a p p r o a c h e s .

CRANIOMETRY.
Involves measurements of skull
used to study the Neanderthal
and Cro-magnon skull.
give information of extinct
population and pattern of growth
Advantages: Precise measurements.
Disadvantages:All growth data must be cross sectional.

ANTHROPOMETRY:
• measurements using soft tissue points overlying
bony landmarks in living individuals.
• can also be done on dried skulls but variation in
soft tissue thickness would produce different
results.
• Possible to follow the growth of an individual
directly.

• CEPHALOMETRIC RADIOGRAPHY:
• allows direct measurement of bony skeletal
dimensions and follow up of the same individual
over time .
• Disadvantages
•:Depends upon precise orientation of head and precise
control of magnification.
• 2D representation of 3D structurewww.indiandentalacademy.comwww.indiandentalacademy.com

Mineralized sections.
• Fully mineralized sections are superior to
demineralized specimens as there is less processing
distortions and both organic and inorganic matrix can
be studied simultaneously.
• Cellular details and resolutions can be enhanced by
reducing the thickness of the sections.
• Specific stains can be used to enhance both cellular and
extra cellular details.
• Thin sections can however quench more rapidly

Microradiography.
• High resolution of images of bone sections
• Differential density between primary and
secondary bone.
• Strength of the bone-proportional to degree of
mineralisation.
• secondary bone has more strength than primary
bone.
• Secondary mineralisation process takes about 8
months to form and hence the minimum retention
period after active orthodontic correction should
be 6-8 months.

Fluorescent labels.
• Administered in vivo calcium binding labels
• anabolic time markers of bone formation.
• Mechanism of bone growth determined by
analysis of label incidence and interlabel distance.
• Sequential use of different colored labels assess
bone growth,healing and functional adaptation.
• Tetracycline,calcein green,xylenol orange,alizarin
complexone,demeclocycline and oxytetracycline
commonly used labels.

Radioisotopes.
• Radioisotopes of certain elements or compounds
are often used as in vivo markers for studying
bone growth.
• Such labeled material is injected and after some
time located within the growing bone by means
of autoradiographic techniques.
• Commonly used markers are :
1. Technetium 99
2. Calcium 45
3. Potassium 32

Autoradiography.
• Histological sections are coated with a nuclear track
emulsion to detect radiographic precursor for
structural and metabolic material.
• Specific radioactive labels for protein carbohydrates
or nucleic acids are injected.

• Quantitative and qualitative assessment of the label uptake
is a physiologic index of cell activity.
• Commonly used autoradiographic labels are:
• A. 3
H thymidine.
• B. 3
H proline.
• C. Bromodeoxyuridine.

Polarized light.
• indicates the orientation of collagen fibers within
the bone matrix.
• Most lamellar bone consists of collagen fibers
oriented at right angles.
• However 2 other configurations can also be
noted:longitudinally aligned(L osteons).

• And mixed fiber pattern.(both L and A osteons).
• Loading condition at the time of bone formation
dictate the orientation of collagen fibers . Thus
bone formation can adapt to different loading
conditions by changing the internal lamellar
organization of bone tissue.

Nuclear volume morphometry.
• cytomorphometric procedure to measures the
nuclear size for assessing the stages of
differentiation of osteoblastic precursor cells.
• Pre osteoblasts have significantly larger nuclei
than their precursors.
• used in determining the relative differentiation of
PDL and other bone living cells.

Teleradiology.Teleradiology.
• Introduced in 1982 at international
conference of PACS.
• Universal method of storing and
transporting digital images .
• Currently American college of radiology
have developed DICOM to allow the
transmisssion of images over the internet.

Vital staining
• reported by Belchier in 1796
• John Hunter- alizarin dye
• Alizarin reacts with calcium at sites of bone
calcification i.e. sites of active skeletal growth
thus marking these locations
• Other dyes : tetracyline
trypon blue
lead acetate
procion

• Vital staining aids in studying:
Manner in which bone is laid down
site of bone growth
the direction and amount of growth
and the timing and relative duration
of growth at different sites.

Natural markers.
• The persistence of certain developmental features
has led to their use as natural markers by means of
serial radiography.
• Eg: trabaculae,nutrient canals and lines of arrested
growth can be used for reference to study
deposition, resorption and remodeling.
• Certain natural markers are used as cephalometric
landmarks.

Implant markers.
• Bjork devised a method of implanting tiny bits of
tantalum or biologically inert alloys into growing
bone which served as radiographic reference
markers for serial cephalometric study.
• The method allows precise orientation of serial
cephalograms and information on the amount and
sites of bone growth.

Mechanism of growthMechanism of growth
• 3 mechanisms at the cellular level
– Hyperplasia
– Hypertrophy
– Secretion of extracellular matter

Mechanism of growth inMechanism of growth in
soft tissuessoft tissues
• In soft tissues growth occurs by a combination of two
mechanisms namely:
• hyperplasia and hypertrophy
• These result in interstitial growth.

Mechanism of growth in hardMechanism of growth in hard
tissuestissues..
• The craniofascial skeleton grows by three
unique processes:
• Chondrogenesis: formation of cartilage
• Endochondral bone formation: process of
converting cartilage into bone
• Intramembranous bone formation: process of
bone formation from undifferentitaed
mesenchymal tissue.

Comparison of physiologicComparison of physiologic
properties of bone and cartilageproperties of bone and cartilage
• Characteristic cartilage
bone
• Calcification Non calcified Calcified
• Vascularity Avascular Vascular
• Surface membrane Nonessential Essential
• Pressure resistance Tolerant Sensitive
• Rigidity Flexible Inflexible
• Modes of growth Interstitial
Appositional
and appositional

Endochondral bone formationEndochondral bone formation
• Definition:It is the process of converting
cartilage into bone.
• Occurs in regions exposed to high levels of
compression
• In craniofacial region it is seen in areas like
• Synchondrosis at the cranial base
• Condylar cartilage
• Nasal septal cartilage

Steps of chondrogenesisSteps of chondrogenesis
• Chodroblasts produce matrix
• Cells become encased in matrix
• Chondrocytes enlarge,divide and produce
matrix
• Matrix remains uncalcified
• Membrane covers the surface but is not
essential

Steps of endochondral boneSteps of endochondral bone
formationformation
• hypertrophy of chondrocytes and matrix
calcifies
• Invasion of blood vessels and connective
tissue cells.
• osteoblasts differentiate and produce
osteoid tissue.
• osteoblast tissue calcifies.

Intramembranous boneIntramembranous bone
formationformation
Definition: it is the process of bone formation
from undifferentiated mesenchymal tissue
• Derived from neural crest cells
• Occurs in areas exposed to tension
• It differs from endochondral bone formation
by formation of bone directly from
mesenchymal tissue

–Seen in areas like:
– Cranial vault
• Maxilla
• Mandible except condylar
cartilage

Steps of intramembranous boneSteps of intramembranous bone
formationformation
• Osteoblasts produce osteoid tissue.
• Cells and blood vessels are encased.
• Osteoid tissue is produced by membrane
cells.
• Osteoid calcifies.
• Essential membrane covers bone.

Bone metabolismBone metabolism
• Bone is the primary calcium reservoir of the body
(99% stored in skeleton)
•Bone structure is sacrificed to maintain the critical
serum calcium levels at 10mg %

Bone metabolismBone metabolism
Calcium homeostasis is supported by 3 mechanisms :
1. Rapid instantaneous flux of calcium from bonefluid (seconds) by
selective transfer of calcium ions into and out of bone fluid.
2. Shorterm control of serum calcium levels affects rates of bone
formation $ resorption
3. Longterm regulation of metabolism- have effects on skeleton
.

TYPE OF BONESTYPE OF BONES
• Lamellar bone
• Non lamellar bone
• Fine cancellous bone
• Coarse cancellous bone
• Woven bone
• Bundle bone
• Composite bone

LAMELLAR BONELAMELLAR BONE
• Comprises 99% of human skeleton
• Strong highly mineralised
• Mineralised in two stages:
• primary mineralisation
• secondary mineralisation

Clinical significance
• Full strength of lamellar bone
supporting an orthodontically moved
tooth is not attained for upto a year after
completion of active treatment.

Non Lamellar boneNon Lamellar bone
• Makes up fine cancellous bone tissue
• No distinct stratification in fibre orientation

Woven boneWoven bone
• Type of non lamellar bone
• Weak , disorganised, poorly mineralised
• Not found in adult human skeleton under
normal conditions
• First bone formed in response to
orthodontic loading.

Bundle boneBundle bone
• Present adjacent to periodontal ligament
• Presence of perpendicular striations called
sharpey’s fibres.
• Formed on depository side of socket, laid
dowm in the direction toward the moving
tooth root.

Composite boneComposite bone
• Predominant bone type during early
retention phase
• Most rapid means of producing strong
bone
• Formed by deposition of lamellar bone
within a woven bone lattice.

Fine cancellous bone tissueFine cancellous bone tissue
• Formed by periosteum and endosteum
• Marrow spaces are fine
• It is located in cortex e.g. posterior border
of a growing ramus in a child
• Fastest growing of all bone types

Coarse cancellous boneCoarse cancellous bone
• Produced by endosteum only
• Irregular marrow spaces containing red or
yellow marrow
• Irregularly arranged trabeculae
• Present in medulla

Mechanisms of bone growthMechanisms of bone growth
• Deposition and resorption
• Growth fields
• Modelling
• Remodelling
• Growth movements
drift
displacement

Deposition and resorptionDeposition and resorption

Deposition and resorptionDeposition and resorption
• -periosteal bone
• -endosteal bone

Enlow’s V principalEnlow’s V principal
• Most useful and basic
concept
• Deposition and
Resorption

Transverse histologic section of bone:
A.Periosteal surface -
endosteal surface +
B.New endosteal bone on inner surface.
C.Endosteal layer produced covered by
periosteal layer following outward
reversal.
D.Cortex made entirely of periosteal
bone….outer surface depository and
inner surface resorptive.

Example with V oriented verticallyExample with V oriented vertically
• When bone + on
coronoidprocess, the
ramus increases in
vertical dimension.

Example of V oriented horizontallyExample of V oriented horizontally
• Same + of bone
posterior direction
of growth
movement.
• backward
movement of
coronoid processes

• Same deposits carry
base of bone in
medial direction as in
fig 1.
• Hence, the wider part
undergoes relocation
into a more narrow
part as the whole v
moves towards the
wide part (fig 2)

Growth fieldsGrowth fields
• Inside and outside of
every bone is covered
by growth fields which
control the bone
growth.
• They are both
resorptive and
depository types..

Growth sitesGrowth sites
• Growth fields having
special role in the
growth of the
particular bone are
called growth sites
• e.g. mandibular
condyle, maxillary
tuberosity,
synchondrosis of the
basicranium, sutures
and the alveolar
process.

Growth sitesGrowth sites
– Such special sites
do not out the
entire carry
growth process
but the entire
bone takes part

Growth centersGrowth centers
• Special areas which are
believed to control the
overall growth of the bone
e.g.mandibular condyle.
• Force, energy or motor
for a bone resides
primarily within its growth
centre.
• Now believed that these
centers do not control the
whole growth process.

MODELINGMODELING

CONTROL FACTORS FORCONTROL FACTORS FOR
BONE MODELINGBONE MODELING
– Mechanical Peak
load in Micro strain.
1. Disuse atrophy <200.
2. Bone Maintenance 200
—2500.
3. Physiological Hypertrophy 2500
—4000.
4. Pathological Overload
>4000.

•Endocrine.
1.Bone metabolic hormones-PTH,Vit
D,Calcitonin.
2.Growth Hormones-Somatotropin,IGF 1,IGF
2.
3.Sex steroids-Testosterone,Estrogen.

RemodellingRemodelling
• Required differential growth activity required for
bone shaping.
• It involves deposition and resorption occuring on
opposite ends
• Four types
– Biochemical remodelling
– Haversian remodelling
– Pathologic remodelling
– Growth remodelling

• E.g. The ramus moves
posteriorly by the
combination of
deposition and
resorption.
• so the anterior part of
the ramus gets
remodeled into a new
addition for the
mandibular corpus.

Functions of RemodelingFunctions of Remodeling

Functions of RemodelingFunctions of Remodeling
1. Progressively change the size of whole
bone
2. Sequentially relocate each component of
the whole bone
3. Progressively change the shape of the bone
to accommodate its various functions

4. Progressive fine tune fitting of all the
separate bones to each other and to their
contiguous ,growing, functioning soft tissues
5. Carry out continuous structural adjustments
to adapt to the intrinsic and extrinsic
changes in conditions .

DriftDrift
• It is remodeling
process and a
combination of
deposition and
resorption.

DisplacementDisplacement
• Displacement is a physical movement of
the whole bone as it remodels
• Two types:
primary displacement
secondary displacement

DisplacementDisplacement

Primary displacementPrimary displacement
• It is a physical
movement of a
whole bone and
occurs while the
bone grows and
remodels by
resorption
deposition
• E.g. in maxilla

Secondary displacementSecondary displacement
• It is the movement of
a whole bone caused
by the separate
enlargement of other
bones

Combination of remodeling &Combination of remodeling &
displacementdisplacement
• Both these
mechanisms carries
out two general
functions
• Positions each bone
• Designs and
constructs each bone

RotationRotation
• According to Enlow,
growth rotation is due
to diagonally placed
areas of deposition
and resorption
• Two types
– Remodelling rotations
– Displacement rotations

Principle of ‘Area relocationPrinciple of ‘Area relocation’’
Both remodeling and
displacement together
cause a shift in existing
position of a particular
structures with
reference to
another
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Counter part principleCounter part principle
• “Growth of any given
facial or cranial part
relates specifically to
other structural and
geometric
counterparts in the
face and cranium” -
Enlow

Growth equivalent principleGrowth equivalent principle
This principle proposed by Hunter & Enlow:
relates the effects of cranial base growth on
the facial bone growth.

REFERENCES:REFERENCES:
• Proffit:contemporary orthodontics.
• Moyers:handbook of orthodontics.
• An inventory of United states and
Canadian growth record sets.S.Hunter ,
Baumrind S AJO 1993.
• Craniofacial imaging in orthodontics :S
Kapila et al AO 1999:69
• Essays in honour of Robert moyers
CFGS.monograph 24.

ReferencesReferences
• Bone biodynamics in
orthodontics:CFGS.27
• Atlas of craniofacial growth in
Americans of African descent CFGS.26
• Growth changes in the nasal profile
from 7-8 yrs AJO 1988:94 Meng H ,R
Nanda
• Longitudinal changes in 3 normal facial
types .S Bishara,AJO1985:88
• S Bishara,J R Peterson, changes in the
facial dimensions & relationships
between the ages 5-25yrs.AJO 1984:85www.indiandentalacademy.comwww.indiandentalacademy.com

ReferencesReferences
• Lewis A B, Roche AF pubertal spurts in
cranial base & mandible AJO 1985:55
• Popovich.Thompson. Craniofacial
templates for orthodontic case analysis.
• Baumrind S,Korn EL,quantitation of
maxillary remodeling. AJO 1987:91
• Atlas of craniofacial growth CFGS
monograph 2.
• Moyers,Van Der Linden standards of
human occlusal development CFGS:5
• B Grayson 3D cephalogram
theory,technique and clinical
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