Introduction to growth and development 1 (2)

INTRODUCTION TO GROWTHINTRODUCTION TO GROWTH
AND DEVELOPMENTAND DEVELOPMENT
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DEFINITIONS OFDEFINITIONS OF
GROWTHGROWTH
ACCORDING TO MOYERSACCORDING TO MOYERS
IT IS A QUANTITATIVE ASPECT OF BIOLOGICIT IS A QUANTITATIVE ASPECT OF BIOLOGIC
DEVELOPMENT.DEVELOPMENT.
ACCORDING TO J.X HUXLEYACCORDING TO J.X HUXLEY ::
IT IS SELF MULTIPLICATION OF LIVINGIT IS SELF MULTIPLICATION OF LIVING
SUBSTANCE.SUBSTANCE.
ACCORDING TO DAVID S CARLSON:ACCORDING TO DAVID S CARLSON:
GROWTH IS AN INCREASE IN SIZE OR MASSGROWTH IS AN INCREASE IN SIZE OR MASS
BY MEANS OF INTERNALLY REGULATED PROCESS.BY MEANS OF INTERNALLY REGULATED PROCESS.

 ACCRD. TO KROGMAN:ACCRD. TO KROGMAN: INCREASE ININCREASE IN
SIZE CHANGE IN PROPORTION ANDSIZE CHANGE IN PROPORTION AND
PROGRESSIVE COMPLEXITY.PROGRESSIVE COMPLEXITY.
 ACCRD. TO MOSS:ACCRD. TO MOSS: CHANGE IN ANYCHANGE IN ANY
MORPHOLOGICAL PARAMETER WHICH ISMORPHOLOGICAL PARAMETER WHICH IS
MEASURABLE.MEASURABLE.
 ACCRD. TO MEREDITH:ACCRD. TO MEREDITH: ENTIRE SERIESENTIRE SERIES
OF SEQUENTIAL ANATOMIC ANDOF SEQUENTIAL ANATOMIC AND
PHYSIOLOGICAL CHANGES TAKING PLACEPHYSIOLOGICAL CHANGES TAKING PLACE
FROM BEGINNING OF PRENATAL LIFE TOFROM BEGINNING OF PRENATAL LIFE TO
SENILITY.SENILITY.

TYPES OF GROWTHTYPES OF GROWTH
1) ACCRETIONARY GROWTH1) ACCRETIONARY GROWTH : SEEN IN SKELETAL TISSUES: SEEN IN SKELETAL TISSUES
AND CONNECTIVE TISSUEAND CONNECTIVE TISSUE
2)2) MULTIPLICATIVE GROWTHMULTIPLICATIVE GROWTH
3)3) DIMENSIONAL GROWTH / AUXETIC GROWTHDIMENSIONAL GROWTH / AUXETIC GROWTH : SEEN IN: SEEN IN
HYPERTROPHY OF STRIATED MUSCLE FIBRES ANDHYPERTROPHY OF STRIATED MUSCLE FIBRES AND
SMOOTH MUSCLE CELLSSMOOTH MUSCLE CELLS
4)4) INTERSTITIAL GROWTHINTERSTITIAL GROWTH : ITS CHARECTERISTIC OF NEARLY: ITS CHARECTERISTIC OF NEARLY
OF ALL SOFT TISSUESOF ALL SOFT TISSUES
5)5) APPOSITIONAL GROWTHAPPOSITIONAL GROWTH

NEGATIVE GROWTHNEGATIVE GROWTH
 GENERALLY WE EQUATE GROWTH WITHGENERALLY WE EQUATE GROWTH WITH
ENLARGEMENT BUT THERE ARE INSTANCEENLARGEMENT BUT THERE ARE INSTANCE
IN WHICH GROWTH RESULTS IN DECREASEIN WHICH GROWTH RESULTS IN DECREASE
IN SIZE.IN SIZE.
 EXAMPLE: THYMUS GLANDS AFTEREXAMPLE: THYMUS GLANDS AFTER
PUBERTY. THEREFORE GROWTH MAYPUBERTY. THEREFORE GROWTH MAY
RESULT IN INCREASE OR DECREASE INRESULT IN INCREASE OR DECREASE IN
SIZE, CHANGE IN FORM OR PROPORTION,SIZE, CHANGE IN FORM OR PROPORTION,
COMPLEXITY , TEXTURE.COMPLEXITY , TEXTURE.

DEFINITIONS OFDEFINITIONS OF
DEVELOPMENTDEVELOPMENT
ACC TO MOYERSACC TO MOYERS
GROWTH +GROWTH +
DIFFERENTIATION+TRANSLOCATION.DIFFERENTIATION+TRANSLOCATION.
DEVELOPMENT REFERS TO ALL THE NATURALLYDEVELOPMENT REFERS TO ALL THE NATURALLY
OCCURING UNIDIRECTIONAL CHANGES FROM ITSOCCURING UNIDIRECTIONAL CHANGES FROM ITS
EXISTANCE AS A SINGLE CELL TO ITS ELABORATIONEXISTANCE AS A SINGLE CELL TO ITS ELABORATION
INTO A MULTIFUNCTIONAL UNIT TERMINATING ININTO A MULTIFUNCTIONAL UNIT TERMINATING IN
DEATHDEATH
ACCORDING TO TODDACCORDING TO TODD ::
PROGRESS TOWARDS MATURITYPROGRESS TOWARDS MATURITY
ACC TO PROFITTACC TO PROFITT
INCREASE IN COMPLEXITYINCREASE IN COMPLEXITY

 ACC TO CARLSON:ACC TO CARLSON:
DEVELOMENT IS A LIFE LONGDEVELOMENT IS A LIFE LONG
PROCESS THAT ENCOMPASSES ALLPROCESS THAT ENCOMPASSES ALL
OF THE STRUCTURAL ANDOF THE STRUCTURAL AND
FUNTIONAL CHANGES THAT TAKESFUNTIONAL CHANGES THAT TAKES
PLACE FROM CONCEPTION THROUGHPLACE FROM CONCEPTION THROUGH
MATURITY.MATURITY.

MOORE PERSAUDMOORE PERSAUD
 HUMAN DEVELOPMENT IS A CONTINOUSHUMAN DEVELOPMENT IS A CONTINOUS
PROCESS WHEN AN OOCYTE FROMPROCESS WHEN AN OOCYTE FROM
AFEMALE IS FERTILIZED BY ASPERM FROMAFEMALE IS FERTILIZED BY ASPERM FROM
AMALE CELL DIVISION,CELLAMALE CELL DIVISION,CELL
MIGRATION,PROGRAMMEDMIGRATION,PROGRAMMED
CELLDEATH,DIFFERENTIATION,GROWTHANCELLDEATH,DIFFERENTIATION,GROWTHAN
D CELL REARRANGEMENT TRANSFORMD CELL REARRANGEMENT TRANSFORM
THE FERTILIZED OOCYTE ,AHIGHLYTHE FERTILIZED OOCYTE ,AHIGHLY
SPECIALIZED TOTIPOTENT CELL A ZYGOTESPECIALIZED TOTIPOTENT CELL A ZYGOTE
INTO A MULTICELLULAR HUMANBEINGSINTO A MULTICELLULAR HUMANBEINGS

BASIC CONCEPTS OF GROWTH
PHYSIOLOGY OF GROWTH
PITUITARY GLAND OR HYPOPHYSIS – 1CM DIAMETER,
0.5 – 1gm IN WEIGHT
LIES IN SELLA TURSICA AND IS CONNECTED TO
HYPOTHALAMUS BY PITUITARY STALK
PITIUTARY GLAND
ANTERIOR PITUITARY RELEASES 6 IMPORTANT
PEPTIDE HARMONES-GH, ACTH, FSH, LH, PROLACTIN
ANTERIOR PITUITARY OR ADENOHYPOPHYSIS
POSTERIOR PITUITARY OR NEUROHYPOPHYSIS

GROWTH HARMONE :
 PROTEIN IN NATURE WITH MOL WT 21500
FUNCTIONS
METABOLIC: INCREASES SYNTHESIS OF PROTEINS, INCREASES MOBILIZATION OF LIPIDS,
CONSERVATION OF CARBOHYDRATES
BONE : DIFFERENTIATION AND DEVELOPMENT OF BONE CELLS
INCREASES GROWTH OF SKELETON( LENGTH AND THICKNESS)
PARTICULARLY MEMBRANOUS BONES SUCH AS JAW BONES AND SKULL BONES BECOME
THICKER
GH HAS INDIRECT EFFECT ON BONES
GH
LIVER SOMATOMEDIN
IGF-1
IGF-2
SOMATOMEDIN C
ACTS BONE AND
CAUSES GROWTH
EFFECT ON
BONES

HYPOTHALAMUS
GHRH , GHIH SOMATOSTATIN
ALSO SECRETED BY DELTA CELLS OF
ISLETS OF LANGERHANS (PANCREAS)
STIMULATION OF
ANTERIOR PITUITARY
GH WHICH ACTS
ON LIVER,
TISSUES
SOMATOMEDIN
INHIBITION
FEED BACK INHIBITION

PHYSICAL GROWTH AND DEVELOPMENT
PRENATAL POSTNATAL
PRENATAL GROWTH:
MOST CRUCIAL IN DETERMINING A CHILDS GROWTH AND
FUTURE WELL BEING SINCE GROWTH IS AT ITS FASTEST DURING
THIS TIME
PRENATAL PERIOD – 18 TO 22 WEEKS OF GESTATION (BODY
LENGTH)
PEAK VELOCITY FOR HEIGHT – 34 WEEKS GESTATION
GREAT RATE OF GROWTH OF FETUS COMPARED WITH THAT OF
A CHILD IS LARGELY DUE TO CELLULAR PROLIFERATION.

POST NATAL GROWTHPOST NATAL GROWTH
DURING 1DURING 1STST
2 YEARS – RAPID GROWTH2 YEARS – RAPID GROWTH
FROM 2 – 5 YRS RAPIDFROM 2 – 5 YRS RAPID
DECCELARATIONDECCELARATION
FROM 5 – 8 YRS SLIGHT INCREASE INFROM 5 – 8 YRS SLIGHT INCREASE IN
GROWTH ( MID GROWTH SPURT)GROWTH ( MID GROWTH SPURT)
PUBERTY INCREASED GROWTHPUBERTY INCREASED GROWTH

Growth spurtsGrowth spurts
female malefemale male
 Infantile ----- 3yrs 3yrsInfantile ----- 3yrs 3yrs
 Mixed dentition/Mixed dentition/
juvenile - 6-7yrs 7-9yrsjuvenile - 6-7yrs 7-9yrs
Prepubertal/adolescent - 11-12yrs 14-16yrsPrepubertal/adolescent - 11-12yrs 14-16yrs

Significance of growthSignificance of growth
spurtsspurts
 TO DIFFERENTIATE WHETHER GROWTHTO DIFFERENTIATE WHETHER GROWTH
CHANGES ARE NORMAL/PATHOLOGICCHANGES ARE NORMAL/PATHOLOGIC
 IN TREATMENT OF SKELETALIN TREATMENT OF SKELETAL
DISCREPANCIES{mixed dentition growthDISCREPANCIES{mixed dentition growth
spurt}growth modification can be carried outspurt}growth modification can be carried out
during growth spurts but surgical correction isduring growth spurts but surgical correction is
carried out only after cessation of growth spurtscarried out only after cessation of growth spurts

CATCH UP GROWTH
Growth in man is very carefully regulated
process
Children are meant to achieve a certain height
determined in large part by genetic factors
If growth is interrupted by acute
malnutrition/illness and this is then corrected
then child catches up his/her original growth
This increased velocity of growth following
correction of adverse circumstances is termed
catch up growth

FACTORS AFFECTING
GROWTH
GENETIC FACTORS
 PHENOTYPE
 CHARECTERISTICS OF PARENTS
 RACE
 BIORYTHM AND MATURATION
 SEX
 GENE ABNORMALITIES

ENVIRONMENTAL
FACTORS
 NUTRITION SUPPORT
 OBSTETRIC PROBLEMS
 TERATOGENIC AGENTS
 INFECTIONS
 HARMONES
PRENATAL FACTORS

POSTNATAL FACTORS
 INFECTIONS
 NUTRITION
 CHEMICAL AGENTS
 TRAUMA
 SOCIAL FACTORS
 CLIMATE
 EMOTIONAL FACTORS
 CULTURAL FACTORS

METHODS OF STUDYINGMETHODS OF STUDYING
GROWTHGROWTH
 TYPES OF GROWTH DATATYPES OF GROWTH DATA
1 OPINION1 OPINION
2 OBSERVATION2 OBSERVATION
3 RATING AND RANKING3 RATING AND RANKING
4 QUANTITATIVE MEASUREMENTS4 QUANTITATIVE MEASUREMENTS
a --- DIRECT DATAa --- DIRECT DATA
b ---- INDIRECT DATAb ---- INDIRECT DATA
c --- DERIVED DATAc --- DERIVED DATA

METHODS OF GATHERINGMETHODS OF GATHERING
GROWTH DATAGROWTH DATA
 LONGITUDINALLONGITUDINAL
 CROSS SECTIONALCROSS SECTIONAL
 SEMI LONGITUDINALSEMI LONGITUDINAL

METHODS OF STUDYINGMETHODS OF STUDYING
GROWTH DATAGROWTH DATA
 1 MEASUREMENT APPROACH1 MEASUREMENT APPROACH
a. craniometrista. craniometrist
b. anthropometricsb. anthropometrics
c. cephalometric radiologyc. cephalometric radiology

CRANIOMETRYCRANIOMETRY
 IT IS MEASUREMENT OF SKULLSIT IS MEASUREMENT OF SKULLS
FOUND AMONG HUMAN SKELETALFOUND AMONG HUMAN SKELETAL
REMAINSREMAINS
 ADVANTAGESADVANTAGES
PRECISE MEASUREMENTS CAN BEPRECISE MEASUREMENTS CAN BE
MADE ON DRY SKULLSMADE ON DRY SKULLS
DISADVANTAGEDISADVANTAGE
BYNECESSITY ALL GROWH DATA MUSTBYNECESSITY ALL GROWH DATA MUST
BE CROSSSECTIONALBE CROSSSECTIONAL

ANTROPOMETRYANTROPOMETRY
 IN THIS STUDY VARIOUS LANDMARKSIN THIS STUDY VARIOUS LANDMARKS
ESTABLISHED IN STUDIES OF DRYESTABLISHED IN STUDIES OF DRY
SKULL ARE MEASURED IN LIVINGSKULL ARE MEASURED IN LIVING
INDIVIDUALS SIMPLY BY USINGINDIVIDUALS SIMPLY BY USING
SOFTTISSUE POINTS OVERLYINGSOFTTISSUE POINTS OVERLYING
THESE BONY LANDMARKSTHESE BONY LANDMARKS

CEPHALOMETRICCEPHALOMETRIC
RADIOLOGYRADIOLOGY
 IT HAS THE BOTH ADVANTAGE OFIT HAS THE BOTH ADVANTAGE OF
BOTH CRANIOMETRY ANDBOTH CRANIOMETRY AND
ANTHROPOMETRYANTHROPOMETRY
 IT IS ASLO IMP IN CLINICALIT IS ASLO IMP IN CLINICAL
EVELUATION OF ORTHODONTICEVELUATION OF ORTHODONTIC
PATIENTSPATIENTS

Experimental approachExperimental approach
 1. Vital staining1. Vital staining
 2. Auto radiography2. Auto radiography
 3. Radioisotopes3. Radioisotopes
 4. Implant radiography4. Implant radiography
 5.biometric tests5.biometric tests
 6.implants6.implants

 BIOMETRIC TESTSBIOMETRIC TESTS : THEY ARE: THEY ARE
TESTS IN WHICH PHYSICALTESTS IN WHICH PHYSICAL
CHARECTERISTICS SUCH ASCHARECTERISTICS SUCH AS
WEIGHT ,HEIGHT,SKELETALWEIGHT ,HEIGHT,SKELETAL
MATURATION AND OSSIFICATION AREMATURATION AND OSSIFICATION ARE
MEASURED AND COMPARED WITHMEASURED AND COMPARED WITH
STANDARDSSTANDARDS

 VITAL STAININGVITAL STAINING : DYES USED ARE: DYES USED ARE
ALIZARIN RED 5,ACID ALIZARINALIZARIN RED 5,ACID ALIZARIN
BLUE,TRYPON BLUEBLUE,TRYPON BLUE
,TETRACYCLINE,LEADACETATE,TETRACYCLINE,LEADACETATE
 RADIOISOTOPESRADIOISOTOPES: TECHNETIUM: TECHNETIUM
33,CALCIUM45,POTASSIUM 3233,CALCIUM45,POTASSIUM 32

 IMPLANTS: MAXILLAIMPLANTS: MAXILLA
1. hard palate behind deciduous1. hard palate behind deciduous
caninescanines
2. below anterior nasal spine2. below anterior nasal spine
3.two implants on either side of3.two implants on either side of
zygomatic process of maxillazygomatic process of maxilla
4.border between hard palate and4.border between hard palate and
alveolar process medial to first molaralveolar process medial to first molar

 MANDIBLE:MANDIBLE:
1.anterior aspect of symphysis in midline1.anterior aspect of symphysis in midline
below roottipsbelow roottips
2.two pins on right side of mandible one under2.two pins on right side of mandible one under
the first premolar and second under secondthe first premolar and second under second
premolarpremolar
3.one pin on external aspect of right ramus in3.one pin on external aspect of right ramus in
leevl with the occclusal surface of molarsleevl with the occclusal surface of molars

Growth curvesGrowth curves
 Cumulative / distance curveCumulative / distance curve

INCREMENTAL GROWTH /INCREMENTAL GROWTH /
VELOCITY GROWTH CURVEVELOCITY GROWTH CURVE

CRITICAL PERIODS OF GROWTHCRITICAL PERIODS OF GROWTH
 ACCORDING TO SMITH CRITICALACCORDING TO SMITH CRITICAL
PERIODS ARE THE PERIODS OF RAPIDPERIODS ARE THE PERIODS OF RAPID
CHANGE AND DIFFERENTIATION INCHANGE AND DIFFERENTIATION IN
WHICH DEVELOPING TISSUES ANDWHICH DEVELOPING TISSUES AND
ORGANS ARE MOST SUSCEPTIBLE TOORGANS ARE MOST SUSCEPTIBLE TO
HUMORAL AND ENVIRONMENTALHUMORAL AND ENVIRONMENTAL
INSULTS LEADING TO GROWTHINSULTS LEADING TO GROWTH
DEFICIENCY AND RESULTANTDEFICIENCY AND RESULTANT
MALFORMATIONSMALFORMATIONS

PATTERN OF GROWTHPATTERN OF GROWTH

 CEPHALO CAUDAL GRADIENT OFCEPHALO CAUDAL GRADIENT OF
GROWTHGROWTH
THERE IS AN INCREASED ACCESS OFTHERE IS AN INCREASED ACCESS OF
GROWTH EXTENDING FROM HEADGROWTH EXTENDING FROM HEAD
TOWARDS FEETTOWARDS FEET

PATTERN OF FACIAL GROWTHPATTERN OF FACIAL GROWTH
 INFANTS HAVE MUCH LARGERINFANTS HAVE MUCH LARGER
CRANIUM AND A MUCH SMALLERCRANIUM AND A MUCH SMALLER
FACE THIS CHANGE IN PROPORTIONFACE THIS CHANGE IN PROPORTION
WITH AN EMPHASIS ON GROWTH OFWITH AN EMPHASIS ON GROWTH OF
FACE RELATIVE TO CRANIUM ISFACE RELATIVE TO CRANIUM IS
IMPORTANT ASPECT OF PATTERN OFIMPORTANT ASPECT OF PATTERN OF
FACIAL GROWTHFACIAL GROWTH

SCAMMONS GROWTHSCAMMONS GROWTH
CURVECURVE

VARIABILITYVARIABILITY
 ITS AN IMPORTANT CONCEPT IN STUDY OF GROWTH ANDITS AN IMPORTANT CONCEPT IN STUDY OF GROWTH AND
DEVELOPMENTDEVELOPMENT
 VARIABILITY OF AN INDIVIDUAL CAN BE EVALUATED BYVARIABILITY OF AN INDIVIDUAL CAN BE EVALUATED BY
USING GROWTH CHARTS.USING GROWTH CHARTS.
 GROWTH CHARTS CAN BE USED TO FOLLOW A CHILD OVERGROWTH CHARTS CAN BE USED TO FOLLOW A CHILD OVER
TIME TO EVALUATE WHETHER THERE IS AN UNEXPECTEDTIME TO EVALUATE WHETHER THERE IS AN UNEXPECTED
CHANGE IN GROWTH PATTERN.CHANGE IN GROWTH PATTERN.
 THE CHILDS GROWTH SHOULD PLOT ALONG SAMETHE CHILDS GROWTH SHOULD PLOT ALONG SAME
PERCENTILE LINE AT ALL AGES.PERCENTILE LINE AT ALL AGES.
 IF THE PERCENTILE POSITION OF AN INDIVIDUALRELATIVEIF THE PERCENTILE POSITION OF AN INDIVIDUALRELATIVE
TO HIS OR HER PEER GROUP CHANGES ESPECIALLY IFTO HIS OR HER PEER GROUP CHANGES ESPECIALLY IF
THERE IS A MARK CHANGE THE CLINICIAN SHOULD SUSPECTTHERE IS A MARK CHANGE THE CLINICIAN SHOULD SUSPECT
SOME GROWTH ABNORMALITY.SOME GROWTH ABNORMALITY.
 GROWTH CHARTS ALSO HELP IN LOCATION OF ANGROWTH CHARTS ALSO HELP IN LOCATION OF AN
INDIVIDUAL REALTED TO A GROUP.INDIVIDUAL REALTED TO A GROUP.www.indiandentalacademy.comwww.indiandentalacademy.com

TIMING OF GROWTHTIMING OF GROWTH
 MAJOR CONCEPT IN PHYSICAL GROWTH AND DEVELOPMENTMAJOR CONCEPT IN PHYSICAL GROWTH AND DEVELOPMENT
IS THAT OF TIMING.IS THAT OF TIMING.
 VARIATION IN GROWTH AND DEVELOPMENT DUE TO TIMINGVARIATION IN GROWTH AND DEVELOPMENT DUE TO TIMING
IS MAINLY EVIDENT IN HUMAN ADOLESCENTIS MAINLY EVIDENT IN HUMAN ADOLESCENT
 SOME CHILDREN GROW RAPIDLY AND MATURE EARLY WHILESOME CHILDREN GROW RAPIDLY AND MATURE EARLY WHILE
OTHERS GROW AND DEVELOP SLOWLY.OTHERS GROW AND DEVELOP SLOWLY.
 VARIATION IN TIMING CAN BE SEEN PARTICULARLYVARIATION IN TIMING CAN BE SEEN PARTICULARLY
 CLEARLY IN GIRLS IN WHOM THE ONSET OF MENSTRUTIONCLEARLY IN GIRLS IN WHOM THE ONSET OF MENSTRUTION
OFTEN REFFERED TO AS MENARCHE GIVES AN EXCELLENTOFTEN REFFERED TO AS MENARCHE GIVES AN EXCELLENT
INDICATOR OF ARRIVAL OF SEXUAL MATURITYINDICATOR OF ARRIVAL OF SEXUAL MATURITY
 BECAUSE OF TIME AND VARIABILITY CHRONOLOGICAL AGEBECAUSE OF TIME AND VARIABILITY CHRONOLOGICAL AGE
IS OFTEN NOT A GOOD INDICATOR OF INDIVIDUAL GROWTHIS OFTEN NOT A GOOD INDICATOR OF INDIVIDUAL GROWTH
STATUSSTATUS

THEORIES OF GROWTHTHEORIES OF GROWTH
 GENETIC THEORYGENETIC THEORY
 SUTURAL DOMINANCE THEORY –SUTURAL DOMINANCE THEORY –
SICHERSICHER
 CARTILAGENOUS THEORY – SCOTTCARTILAGENOUS THEORY – SCOTT
 FUNTIONAL MATRIX THEORY – MOSSFUNTIONAL MATRIX THEORY – MOSS
 VONLIMBORGS THEORYVONLIMBORGS THEORY
 ENLOWS EXPANDING V PRINCIPLEENLOWS EXPANDING V PRINCIPLE

SUTURAL THEORYSUTURAL THEORY
 POINTS AGAINST THIS THEORY AREPOINTS AGAINST THIS THEORY ARE ::
1, WHEN AN AREA OF SUTURE IS1, WHEN AN AREA OF SUTURE IS
TRANS PLANTED TO ANOTHER LOCATIONTRANS PLANTED TO ANOTHER LOCATION
THE TISSUE DOES NOT CONTINUE TOTHE TISSUE DOES NOT CONTINUE TO
GROW THIS INDICATES THE LACK OFGROW THIS INDICATES THE LACK OF
INNATE GROWTH POTENTIAL IN SUTURESINNATE GROWTH POTENTIAL IN SUTURES
2,MICROCEPHALY AND HYDROCEPHALY2,MICROCEPHALY AND HYDROCEPHALY
RAISED DOUBTS ABOUT INTRINSICRAISED DOUBTS ABOUT INTRINSIC
GENETIC STIMULUS OF SUTURESGENETIC STIMULUS OF SUTURES

FUNTIONAL MATRIXFUNTIONAL MATRIX
THEORYTHEORY
 FUNTIONAL CRANIAL COMPONENTFUNTIONAL CRANIAL COMPONENT
 SKELETAL UNITSKELETAL UNIT
 FUNTIONAL MATRIXFUNTIONAL MATRIX
 NEUROTROPISMNEUROTROPISM
PERIOSTEAL CAPSULAR

VANLIMBORGHS THEORYVANLIMBORGHS THEORY
 According tohim five factors tht controlAccording tohim five factors tht control
control growthcontrol growth
 Intrinsic genetic factorsIntrinsic genetic factors
 Local genetic factorsLocal genetic factors
 General epigenetic factorsGeneral epigenetic factors
 Local environmental factorsLocal environmental factors
 General environmental processGeneral environmental process

Views of vanlimborgh can beViews of vanlimborgh can be
summarised assummarised as
 1,chondrocranial growth is controlled by intrinsic genetic1,chondrocranial growth is controlled by intrinsic genetic
factorsfactors
 2, desmocranial growth by few genetic factors2, desmocranial growth by few genetic factors
 3,cartilaginous parts of skull must be regarded as growth3,cartilaginous parts of skull must be regarded as growth
centerscenters
 4,sutural growth is controlled mainly by influences4,sutural growth is controlled mainly by influences
originating from the skull cartilages and from otheroriginating from the skull cartilages and from other
adjacent skull structuresadjacent skull structures
 5,sutural growth and periosteal growth are additionally5,sutural growth and periosteal growth are additionally
goverened bylocal non genetic environmental influencegoverened bylocal non genetic environmental influence

Enlows expanding v principleEnlows expanding v principle
 1,according to him many facial bones or parts of1,according to him many facial bones or parts of
bones have a “v” shaped pattern of growthbones have a “v” shaped pattern of growth
 2,bone deposition occurs on inner side of wide2,bone deposition occurs on inner side of wide
end of v and bone resorption occurs onend of v and bone resorption occurs on
outersurfaceoutersurface
 3,deposition aslo occurs at ends of two arms of v3,deposition aslo occurs at ends of two arms of v
resulting in growth movement towards endsresulting in growth movement towards ends
 4, examples are base of mandible ,ends of long4, examples are base of mandible ,ends of long
bones ,mandibular body ,palatebones ,mandibular body ,palate

Enlows counterpart principleEnlows counterpart principle
 According to this growth of any given facial orAccording to this growth of any given facial or
cranial part relates specifically to othercranial part relates specifically to other
structural and geometric counterparts in facestructural and geometric counterparts in face
and craniumand cranium
 There are regional relational ships through outThere are regional relational ships through out
the whole face and craniumif each regional partthe whole face and craniumif each regional part
and its counter part enlarge to same extent thenand its counter part enlarge to same extent then
balanced growth occursbalanced growth occurs

BONE HISTOGENESISBONE HISTOGENESIS
 ENDOCHONDRALENDOCHONDRAL
 INTRAMEMBRANOUSINTRAMEMBRANOUS

ENDOCHONDRALENDOCHONDRAL
OSSIFICATIONOSSIFICATION
 PROLIFERATION AND MATURATION OFPROLIFERATION AND MATURATION OF
CHONDROCYTESCHONDROCYTES
 REPLACEMENT OF CHONDROCYTES BYREPLACEMENT OF CHONDROCYTES BY
OSTEOCYTESOSTEOCYTES
A) PRIMARY HYALINE CARTILAGEA) PRIMARY HYALINE CARTILAGE
FORMATIONFORMATION
B) PERIOSTEAL BONE COLLARB) PERIOSTEAL BONE COLLAR
C) PRIMARY CENTER OF OSSIFICATIONC) PRIMARY CENTER OF OSSIFICATION
D) SECONDARY CENTER OFD) SECONDARY CENTER OF
E) EPIPHYSEAL GROWTH PLATEE) EPIPHYSEAL GROWTH PLATE

INTRAMEMBRANOUSINTRAMEMBRANOUS
 DURING IM. OSSIFICATION OSTEOCYTES RDURING IM. OSSIFICATION OSTEOCYTES R
FORMED AS A RESULT OF 1 OF 2 RELATEDFORMED AS A RESULT OF 1 OF 2 RELATED
PROCESSESPROCESSES
A) OSTEOBLASTS DIRECTLY ARISE FROMA) OSTEOBLASTS DIRECTLY ARISE FROM
MESENCHYMAL CELLS THAT R COALESCED INTOMESENCHYMAL CELLS THAT R COALESCED INTO
DENSE FIBROUS CONNECTIVE TISSUE MEMBRANEDENSE FIBROUS CONNECTIVE TISSUE MEMBRANE
B) DIFFERENTIATION OF OSTEOCYTES DIRECTLYB) DIFFERENTIATION OF OSTEOCYTES DIRECTLY
FROM THE OSTEOGENIC LAYER OF PERIOSTEUMFROM THE OSTEOGENIC LAYER OF PERIOSTEUM
C) THESE OSTEOBLASTS SECRETE AN OSTEOIDC) THESE OSTEOBLASTS SECRETE AN OSTEOID
MATRIX WHICH THEN CALCIFIES TO FORM BONEMATRIX WHICH THEN CALCIFIES TO FORM BONE
AS OSTEOBLASTS CONTINUE TO FORM OSTEOIDAS OSTEOBLASTS CONTINUE TO FORM OSTEOID
THEY BECOME ENTRAPPED IN THEIR OWN MATRIXTHEY BECOME ENTRAPPED IN THEIR OWN MATRIX
AND TRANSFORM INTO OSTEOCYTESAND TRANSFORM INTO OSTEOCYTES

SITES AND TYPES OF GROWTHSITES AND TYPES OF GROWTH
IN CRANIOFACIALIN CRANIOFACIAL COMPLEXCOMPLEX
 CRANIAL VAULTCRANIAL VAULT

 CRANIAL VAULTCRANIAL VAULT ::
1, THE BONES THAT COVER THE OUTER AND UPPER1, THE BONES THAT COVER THE OUTER AND UPPER
SURFACES OFSURFACES OF
THE BRAIN IS MADE UP OF NUMBER OF FLAT BONES THATTHE BRAIN IS MADE UP OF NUMBER OF FLAT BONES THAT
AREARE
FORMED DIRECTLY BY INTRAMEMBRANOUS BONE FORMATIONFORMED DIRECTLY BY INTRAMEMBRANOUS BONE FORMATION
OFOF
CARTILAGENOUS PRECURSORS.CARTILAGENOUS PRECURSORS.
2, AT BIRTH THE FLAT BONES OF THE SKULL ARE RATHER2, AT BIRTH THE FLAT BONES OF THE SKULL ARE RATHER
WIDELYWIDELY
SEPERATED BY RELATIVELY LOOSE CONNECTIVE TISSUESEPERATED BY RELATIVELY LOOSE CONNECTIVE TISSUE
AFTER BIRTH APPOSITION OF BONE ALONG EDGES OFAFTER BIRTH APPOSITION OF BONE ALONG EDGES OF
FONTANELLE ELIMINATES THESE OPNED SPACES FAIRLYFONTANELLE ELIMINATES THESE OPNED SPACES FAIRLY
QUICKLYQUICKLY
BUT THE BONE REMAIN SEPERATED BY A THIN PERIOSTEUMBUT THE BONE REMAIN SEPERATED BY A THIN PERIOSTEUM
LINEDLINED

 CRANIAL BASECRANIAL BASE ::
BONES OF BASE OF SKULL R FORMED INITIALLY INBONES OF BASE OF SKULL R FORMED INITIALLY IN
CARTILAGE AND R LATER TRANFORMED BYCARTILAGE AND R LATER TRANFORMED BY
ENDOCHONDRAL OSSIFICATION BY BONE.ENDOCHONDRAL OSSIFICATION BY BONE.
AS OSSIFICATION PROCEEDS BANDS OFAS OSSIFICATION PROCEEDS BANDS OF
CARTILAGE CALLED SYNCHONDROSIS REMAINCARTILAGE CALLED SYNCHONDROSIS REMAIN
BETWEEN CENTERS OF OSSIFICATION.BETWEEN CENTERS OF OSSIFICATION.
THESE IMPORTANT GROWTH SITES ARETHESE IMPORTANT GROWTH SITES ARE
A) SPHENO-OCCIPITAL SYNCHONDROSISA) SPHENO-OCCIPITAL SYNCHONDROSIS
B) INTER SPHENOID SYNCHONDROSISB) INTER SPHENOID SYNCHONDROSIS
C) SPHENO ETHMOIDAL SYNCHONDROSISC) SPHENO ETHMOIDAL SYNCHONDROSIS

MAXILLA (NASO MAXILLARYMAXILLA (NASO MAXILLARY
COMPLEX)COMPLEX)
 MAXILLA DEVELOPS ENTIRELY BY IM.MAXILLA DEVELOPS ENTIRELY BY IM.
OSSIFICATION.OSSIFICATION.
 GROWTH OCCURS BYGROWTH OCCURS BY
APPOSITION OF BONE AT SUTURESAPPOSITION OF BONE AT SUTURES
THAT CONNECT MAXILLA TOTHAT CONNECT MAXILLA TO
CRANIUM AND CRANIAL BASECRANIUM AND CRANIAL BASE
NEXT BY SURFACE REMODELLINGNEXT BY SURFACE REMODELLING

 SUTURES ATTACHING THE MAXILLA POSTERIORLYSUTURES ATTACHING THE MAXILLA POSTERIORLY
AND SUPERIORLY ARE IDEALLY SITUATED TOAND SUPERIORLY ARE IDEALLY SITUATED TO
ALLOW ITS DOWNWARD AND FORWARDALLOW ITS DOWNWARD AND FORWARD
REPOSITION.REPOSITION.
 AS DOWNWARD AND FORWARD MOVEMENTAS DOWNWARD AND FORWARD MOVEMENT
OCCURS THE SPACE THAT COULD OTHER WISEOCCURS THE SPACE THAT COULD OTHER WISE
OPEN UP AT THE SUTURES IS FILLED IN BY THEOPEN UP AT THE SUTURES IS FILLED IN BY THE
PROLIFERATION OF BONE AT THESE LOCATIONS.PROLIFERATION OF BONE AT THESE LOCATIONS.
 AS THE MAXILLA GROWS DOWNWARDS ANDAS THE MAXILLA GROWS DOWNWARDS AND
FORWARD ITS FRONT SURFACES AREFORWARD ITS FRONT SURFACES ARE
REMODELLED AND BONE IS REMOVED FROMREMODELLED AND BONE IS REMOVED FROM
MOST OF ITS ANTERIOR SURFACE.MOST OF ITS ANTERIOR SURFACE.

MANDIBLEMANDIBLE
 In contrast to maxilla both endochondral andIn contrast to maxilla both endochondral and
periosteal activity are important in growth of theperiosteal activity are important in growth of the
mandiblemandible
 Principle sites of growth of mandible arePrinciple sites of growth of mandible are
posterior surface of ramus,condylar andposterior surface of ramus,condylar and
coronoid processes.coronoid processes.
 Body of mandible grows longer by periostealBody of mandible grows longer by periosteal
apposition of bone on its posterior surfaceapposition of bone on its posterior surface
while ramus grows higher by endochondralwhile ramus grows higher by endochondral
replacement at condyle accompanied by surfacereplacement at condyle accompanied by surface
remodellingremodelling

Genes in growth andGenes in growth and
developmentdevelopment
 Hox genes:{homeobox genes}:they are anHox genes:{homeobox genes}:they are an
excellent example of molecularstudies asexcellent example of molecularstudies as
applied to craniofacial embryogenesis isapplied to craniofacial embryogenesis is
homeobxgeneshomeobxgenes
 These were first discovered infruitflyThese were first discovered infruitfly
[drosophila}research and subsequent[drosophila}research and subsequent
similar genes were aslo discovered insimilar genes were aslo discovered in
other organismsother organisms

 This high similarity of genes in which more thanThis high similarity of genes in which more than
400 have been indentified in human ,fly400 have been indentified in human ,fly
underlines the universality of basic biologicunderlines the universality of basic biologic
templates from which developmentaltemplates from which developmental
mechanisms evolvemechanisms evolve
 A recentlu developed hox genes 7 8 9 isA recentlu developed hox genes 7 8 9 is
expressed in range of neural crest derivedexpressed in range of neural crest derived
tissues and areas of putataive epithelialtissues and areas of putataive epithelial
mesenchymal interactions duringmesenchymal interactions during
embryogenesisembryogenesis

Growth factors in growth andGrowth factors in growth and
developmentdevelopment
 They are mitigenic polypeptides thtThey are mitigenic polypeptides tht
influence cell differntiation andinfluence cell differntiation and
morphogenesismorphogenesis
 Three imp growth fators areThree imp growth fators are
 TGF-BETATGF-BETA
 EGFEGF
 FGFFGF

TGF-BETATGF-BETA
 IT IS IMP GROWTH FACTOR INIT IS IMP GROWTH FACTOR IN
EMBRYOGENESISEMBRYOGENESIS
 IT IS MAINLY USEFUL INIT IS MAINLY USEFUL IN
 CHEMOTACTIC PROLIFERATIONCHEMOTACTIC PROLIFERATION
 APOPTOSISAPOPTOSIS
 CONTROL THE EDEVELOPMENT ANDCONTROL THE EDEVELOPMENT AND
MAINTANENCE OF MOST TISSUESMAINTANENCE OF MOST TISSUES

 TGF BETA SIGNALLING PATHWAY ACTSTGF BETA SIGNALLING PATHWAY ACTS
MAINLY BY PHOSPORELATION OG SMADMAINLY BY PHOSPORELATION OG SMAD
PROTIENSBY SERINE AND THREONINEPROTIENSBY SERINE AND THREONINE
KINASEKINASE
 THEY REGULATE SPECIFICATION OFTHEY REGULATE SPECIFICATION OF
CRANIAL NEURAL CREST CELLSCRANIAL NEURAL CREST CELLS
 THEY PLAY MAJOR ROLE IN DEVELOPMENTTHEY PLAY MAJOR ROLE IN DEVELOPMENT
AND MAINTANENCE AFFECTING BOTHAND MAINTANENCE AFFECTING BOTH
CARTILAGE AND BONE METABOLISM ITCARTILAGE AND BONE METABOLISM IT
AFFECTS BOTH OSTEOBLATS ANDAFFECTS BOTH OSTEOBLATS AND
OSTEOCLASTSOSTEOCLASTS

FGF PATHWAYFGF PATHWAY
 FGF CONSTITUTE LARGE FAMILY OFFGF CONSTITUTE LARGE FAMILY OF
POLYPEPTIDE GROWTH FACTORSPOLYPEPTIDE GROWTH FACTORS
 THERE SIGNALLING PATHWAY IS THROUGHTHERE SIGNALLING PATHWAY IS THROUGH
RECEPTOR TYROSINE KINASERECEPTOR TYROSINE KINASE
 THEY HELP INTHEY HELP IN
 APOTOSISAPOTOSIS
 CELL SURVIVALCELL SURVIVAL
 CHEMOTAXISCHEMOTAXIS
 CELL ADHESIONCELL ADHESION
 CELL MIGRATIONCELL MIGRATION
 CELL DIFFERNTIATIONCELL DIFFERNTIATION
 AND PROLIFERATIONAND PROLIFERATION

REFERENCESREFERENCES
 INTRODUCTION TO CRANIOFACIAL BIOLOGY BYINTRODUCTION TO CRANIOFACIAL BIOLOGY BY
DAVID S CARLSONDAVID S CARLSON
 ESSENTIALS OF MEDICAL PHYSIOLOGY BYESSENTIALS OF MEDICAL PHYSIOLOGY BY
DICKSON AND TORTORADICKSON AND TORTORA
 ESSENTIAL PEDIATRICS BY GHAIESSENTIAL PEDIATRICS BY GHAI
 DENTISTRY FOR CHILD AND ADOLESCENT BY MCDENTISTRY FOR CHILD AND ADOLESCENT BY MC
DONALD EIGHTH EDITIONDONALD EIGHTH EDITION
 CONTEPORARY ORTHODONTICS 3CONTEPORARY ORTHODONTICS 3RDRD
EDITION BYEDITION BY
WILLIAM R PROFITTWILLIAM R PROFITT
 MOYERS TEXT OF ORTHODONTICS 3 EDITIONMOYERS TEXT OF ORTHODONTICS 3 EDITION
 STEWARTS TEXT OF PEDIATRIC DENTISTRYSTEWARTS TEXT OF PEDIATRIC DENTISTRY

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