definitions the development and growth of the face

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The development andThe development andgrowth of the facegrowth of the face

Agnieszka Pernak, D.D.S.

DEVELOPMENTDEVELOPMENT addresses the progressiveevolution of a tissue. The ameloblasts developfrom less specific ectodermal tissue.Odontoblasts derive from young mesenchymaltissue.

DEVELOPMENTDEVELOPMENT will be used to refer to anincrease in complexity, specialization.Development is physiologic and behavioralphenomenon. It is expressed by qualitativemeasure (harder).

DefinitionsDefinitions

Agnieszka Pernak, D.D.S.2

Sequence of development from genes to fetusSequence of development from genes to fetus


1.1. Genetic factors likeinherited genotypeexpression of genetic mechanisms

2.2. Environmental factors likenutritional and biochemical interactionsphysical phenomenapressureshydration, ect.

3.3. Functional factors likemuscle actionsgrowth expansionatrophic attenuation

The developmental ontogeny of the craniofacialThe developmental ontogeny of the craniofacialstomatognatic complex depends on:stomatognatic complex depends on:


GROWTHGROWTH refers to an increase in size ornumber. It is mostly an anatomic phenomenon.It is quantitively measured (longer, thicker).

GROWTHGROWTH signifies an increase, expansion, orextension of any given tissue. A tooth grows asmore enamel is deposited by ameloblasts. Thegrowth can be expressed by hypertrophy,hyperplasia and secretion.


DefinitionsDefinitions

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GROWTHGROWTH AT THEAT THE CELLULARCELLULARLEVELLEVEL

HypertrophyHypertrophy - an increase in the size of individualcells

HyperplasiaHyperplasia - an increase in the number of the cells

Secretion of extracellular materialSecretion of extracellular material - an increase insize not related to the number or size of the cells


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GROWTHGROWTH AT THE TISSUEAT THE TISSUE LEVELLEVEL

Interstitial growthInterstitial growth - goes on everywhere within thetissues /at all points within the tissue/ (soft tissues)

Surface appositionSurface apposition (hard tissues) - as the interstitialgrowth within mineralized masses is impossible ,the bone is formed by apposition of new bone tofree surfaces

Bone remodelingBone remodeling - changes of the bone shapethrough removal (resorption) of the bone in onearea and addition (apposition) of bone in another


Growth PatternGrowth PatternPATTERNPATTERN presents the physicalarrangement and proportion of tissues andparts of the body at any time. The overallpattern of growth is a reflection of the growthof the various tissues making up the wholeorganism.

Cephalocaudal gradient of growth is an axisof increased growth extending from the headtoward the feet.



CephalocaudalCephalocaudal GraGradidienentt

basically

the parts of the body, that are further away from thebrain, tend to grow slower and longer, than those,

which are closer

Cephalocaudal gradient of growth is an axis ofincreased growth extending from the head towards

the feet

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Schematic representation of the changes in overall body proportions duringnormal growth and development. After the third month of fetal life, theproportion of total body size contributed by the head and face steadily declines.(Redrawn from Robbins WJ et al: Growth, New Haven, 1928, Yale UniversityPress).


Changes in proportions of the head and face during growth. At birth, the faceand jaws are relatively underdeveloped compared with their extent in the adult.As a result, there is much more growth of facial than cranial structurespostnatally. (Redrawn from Lowery GH; Growth and development of children,6th ed. Chicago, 1973, Mosby.)



In the perspective of cephalocaudal gradient it isobvious, that

the face grows slower and longer than the cranium,

the mandible grows slower but longer than themaxilla.

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GROWTHGROWTH PPATERNATERN

GROWTHGROWTH VARIABILITYVARIABILITY

GROWTHGROWTH TIMINGTIMING



Scammon’s curves for growth of the four major tissue systems of the body.Scammon’s curves for growth of the four major tissue systems of the body.

In the normal growth pattern thetissue systems of the body do notgrow at the same rate.

As the graph indicates, growth ofthe neural tissues is nearlycomplete by 6 or 7 years of age.

General body tissues, includingmuscle, bone, and viscera, show anS-shaped curve, with a definiteslowing of the rate of growth duringchildhood and an acceleration atpuberty.

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Agnieszka Pernak, D.D.S.15 16


Although age is usually measuredchronologically as the amount oftime since birth or conception, it isalso possible to measure agebiologically, in terms of progresstoward various developmentalmarkers or stages.

This graph substitutes stage ofsexual development for chronologictime to produce a biologic time scaleand shows that the pattern isexpressed at different timeschronologically, but not at differenttimes physiologically.

Growth velocity curves for earlyGrowth velocity curves for early--, average, average--, and late, and late--maturing girls.maturing girls.

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Human Growth and DevelopmentHuman Growth and Developmentin timein time

•• PRENATALPRENATAL0 – 2 weeks - the blastocyst2 – 8 weeks - the embryo8 – 40 weeks - the fetus

•• POSTNATALPOSTNATAL1 – 4 weeks - the neonate4 weeks – 1 year - the infant1 – 3 years - the toddler3 – 12 years - the child12 – 19 years - the adolescent


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DEVELOPMENT OF THE FACEDEVELOPMENT OF THE FACEAND THE OCCLUSIONAND THE OCCLUSION

• intrauterine growth of the face and jaws• postnatal growth of the face and jaws• dental exchange and development of the occlusion

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Fetal growth and development duringFetal growth and development duringpregnancypregnancy



Fertilization

21Agnieszka Pernak, D.D.S.

Fertilized Ovum

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Zygote

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Two-cell embryo


Four-cell embryo

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Eight-cell embryo


Morula

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Blastocyst


1 Umbilical cord with hernia2 Nose3 Eye4 Eyelid5 Ear (a: tragus, b: antitragus )6 Mouth7 Elbow8 Finger9 Toes10 Atrophied embryonic tail bud

TelencephalonDiencephalonMesencephalonMetencephalonMyelencephalonSpinal cord


Fetus at 8 weeks

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TTHEHE FACEFACE FORMATIONFORMATION

Frontal aspect of the face of a 5Frontal aspect of the face of a 5--week embryo.week embryo.

stomodeumstomodeum

The face derives from fiveprominences that surrounds acentral depression, the

, which is thefuture mouth.


All of five prominences and arches arise from neuralcrest ectomesenchyme, that migrates from its initialdorsal location into the facial and neck regions.

The two mandibular prominences derivatives fromthe first pair of sixth pharyngeal arches.

Union of the facial prominences occurs by either oftwo developmental events at different locations(between 4th and 8th week after conception)

• merging of the frontonasal, maxillary andmandibular prominences

• fusion of the central maxilla-nasalcomponents.

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Midline merging of the medialnasal prominences forms themedian tuberculum andphiltrum of the upper lip, thetip of the nose and theprimary palate.


The inter-maxillary segment of the upper jaw(the pre-maxilla) in which the four upper incisorswill develop, arises from the median primary palate,that is initially a widely separated pair of swellingsof the merged medial nasal prominences.

The lower jaw and the lip are simply formed by thepaired mandibular prominences merging towardsthe midline.

The merging of the lateral maxillary and mandibularprominences creates the comissurescomissures (corners) ofthe mouth.

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The face formationThe face formation

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Stages of Embryonic CraniofacialStages of Embryonic CraniofacialDevelopmentDevelopment

Time Related Syndromes(humans - post- fertilization)

Day 17

Days 19 – 28

Days 28 – 38

Days 42 – 55

Day 50 – birth

• Fetal alcohol syndrome (FAS)

• Hemifacial microsomia

• Mandibulofacial dysostosis (TreacherCollins syndrome)

• Limb Abnormalities

• Cleft lip and/or palate, other facial clefts

• Cleft palate

• Achondroplasia

• Synostosis syndromes (Crouzon’s,Apert’s, etc.)


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During the 7th week post conception,a shift in the blood supply of the face

(the formation of internal to external carotid artery)occurs as a result of normal atrophy of the

stapedial artery.This shift occurs at a critical time of midface and

palate development, providing the potential deficientblood supply and consequent defects of the upper lip

and the palate.


Unilateral lip cleftUnilateral lip cleft : more common on the left side,common congenital defect - 1 in 800 births.

BilateralBilateral liplip cleftcleft: is due to medial nasal prominences'failure to fuse with the maxillary prominence on either sideof the midline.

MedianMedian liplip cleftcleft: is due to incomplete merging of the twomedial nasal prominences (therefore leading in mostcases to bifid nose).

MacrostomiaMacrostomia: merging of the maxillary and mandibularprominences short of the site for normal mouth size.

MicrostomiaMicrostomia: merging of the maxillary and mandibularprominences beyond the site for normal mouth size.

AstomiaAstomia: fusion of maxillary and mandibular prominences.38


FORMATION OF THE SECONDARYFORMATION OF THE SECONDARYPALATEPALATE

The stomodeal chamber divides into separate oral and nasalcavities when the frontonasal and maxillary prominencesdevelop horizontal extensions into the chamber (from 8th to12th week in uteri)

The coincidental development of the tongue from the floor ofthe mouth fills the oronasal chamber, intervening between thelateral palatal shelves. These shelves are initially orientedvertically (downward), but become horizontaly oriented whenthe stomodeum expands and the intervening tonguedescends. The embryo's face removes from against the heartprominence by the uprighting of the head, what enables jawopening and the tongue descends from between palatalshelves. 39


Moreover, the mandible at that moment becomesmore prognatic (giving even more space for tongue todescend), but maxillary width remains stable allowingshelves contact to occur. The shelves elevate. Theelevation of the shelves enables their mutual contactin the midline and their contact with the primarypalate anteriorly and the nasal septum superiorly.Fusion of the shelves, which starts a third of the wayfrom the front, proceeds both anteriorly andposteriorly. The shelves also fuse with the nasalseptum, except posteriorly, where the soft palate anduvula remain unattached.

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MethodsMethods for studying physical growthfor studying physical growth

• Craniometry• Anthropometry• Cephalometric radiology

• Three-dimensional imaging


The Difference Between PhysicalThe Difference Between PhysicalGrowth and PsychologicalGrowth and Psychological

DevelopmentDevelopment

•• PhysicalPhysical growthgrowth can be considered with theoutcome of an interaction between geneticallycontrolled cell proliferation and environmentalinfluences that modify the genetic program.

•• PsychologicalPsychological developmentdevelopment can be observedthrough cognitive (intellectual) and emotional(individual) development.


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The Difference Between PhysicalThe Difference Between PhysicalGrowth and PsychologicalGrowth and Psychological

DevelopmentDevelopment (continues)(continues)

• Social and Behavioral development can beconsidered as the result of an interactionbetween inherited or instinctual behaviorpatterns and behaviors learned after birth.


In animals:In animals:

the majority of behaviors

are instinctive.

In humans:In humans:

the majority of behaviors

are learned.Agnieszka Pernak, D.D.S.

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Erikson’s stages of emotional developmentErikson’s stages of emotional development

Erikson’s ’’eight ages of man”

Erikson claims that some adults never reach the final steps on the developmental staicase


Cognitive developmentCognitive developmentCognitive development is the development of intellectual capabilitieswhich can be divided into four major stages

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Facial GrowthFacial Growth



Facial GrowthFacial Growth

A background in craniofacial growth anddevelopment is essential in learning orthodontics.

Today there are many methods, which ables tomanipulate the facial growth for the benefit of thepatient.

It's not possible to do so without understanding ofthe pattern of normal growth and it's mechanisms.

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Changes from infancy to adulthoodChanges from infancy to adulthood

“baby face”“baby face”

-Large eyes

-Dainty jaws

-Small pug nose

-Puffy cheeks

-High intellectual forehead

-Light eyebrows

-Small mouth

-Wide short proportions

= cute face= cute face


TheThe neurocraniumneurocraniumis the fastest growing areaof the craniofacial skeleton

at birth.


The face and jaws are relativelyThe face and jaws are relativelyunderdeveloped. Therefore there is muchunderdeveloped. Therefore there is much

more facial growth than cranial growthmore facial growth than cranial growthpostnatalpostnatal


Growth is a “differential” processGrowth is a “differential” processi.e. different parts of the cranio-skeletonundergo the process of growth at differenttimes, in different directions and involvedifferent but interdependent functions

Yet somehow an individual face maintainsit’s integrity



BONEBONE FORMATIONFORMATIONENDOCHONDRAL OSSIFICATIONENDOCHONDRAL OSSIFICATION - the bone has

the embryonic cartilaginous model, in which thecenters of ossification appear and where thecartilage is transformed into bone

INTRAMEMBRANOUS BONE FORMATIONINTRAMEMBRANOUS BONE FORMATION - bysecretion of bone matrix directly within connectivetissues, without intermediate formation of cartilage(cranial vault and both jaws)

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Sutural & Synchondrosal RemodellingSutural & Synchondrosal RemodellingSutural, synchondrosal and cartilaginous remodellingare secondary to displacement


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In the intrauterine development at first cartilaginous/chondrocraniumforms. It is supplied by diffusion through the outer layers. As the brainbecomes bigger in fourth months in utero development there is an ingrowth of blood vascular elements into chondrocranium because thediffusion is not sufficient anymore.

These areas of in growth become centers of ossification, at whichcartilage is transformed into bone. Than the old chondrocranium formsonly small areas of cartilage interposed between the large sections ofthe bone. The type of growth at these cartilaginous connections issimilar to the growth in the limbs. In the long bones the areas ofossification appear in the middle of the bones and at the ends: diaphysisand epiphysis. Between them a remaining area of uncalcified cartilage iscalled the epiphyseal plate, where the actively dividing cells mature andsecrete an extracellular matrix, which degenerates as the matrixmineralizes to the bone. The growth occurs as long as the rate ofproliferating cells is equal to the rate of maturating cells. In the end ofgrowth the rate of maturation is bigger than the rate of proliferation andthe epiphyseal plate disappears.


INTRAMEMBRANOUS BONEINTRAMEMBRANOUS BONEFORMATIONFORMATION

The mandible forms in the same area as the cartilage of firstpharyngeal arch (the Meckel’s cartilage) but a little bit lateralto it, and undergoes an intramembranous bone formation.(Meckel’s cartilage disappears and remnants of it formossicles of the middle ear.) The condylar cartilage developsinitially as an independent secondary cartilage, and than itfuses with the developing mandibular ramous.

The maxilla forms from a center of mesenchymal condensationin the maxillary process.

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For a better understanding of growth it isuseful to divide the head into four areaswith a different types of growth :

•• cranial vault,cranial vault,•• cranial base,cranial base,•• nasonaso--maxillarmaxillar complex,complex,•• mandible.mandible.


CRANIAL VAULTCRANIAL VAULT

is formed by intramembranous bone formation, withoutcartilaginous precursors. The growth is the result ofperiosteal activity at the surfaces of the bones in the cranialsutures (growth) and on the inner and outer surfaces of thebone (remodelling). At birth the wide sutures andfontanelles allow a deformation of the skull, when it passesthrough the birth canal. After birth, apposition of the boneeliminates fontanelles quickly, but sutures are fusing afterthe growth competition in adult life.

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CRANIAL BASECRANIAL BASE

is formed by endochondral ossification in cartilage.Early in embryonic life centers of ossification appearin chondrocranium, and as the ossification proceedsonly bands of cartilage (synchondroses) remainbetween them

Spheno-occipital synchondrosisIntersphenoid synchondrosisSpheno-ethmoidal synchondrosis

They look like two-sided epiphyseal plate.

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Forward growth of the anterior cranial baseForward growth of the anterior cranial base


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Changes in cranial base deflectionChanges in cranial base deflection

Forward displacement ofmandible

Downward displacementof mandible



NNASOASO--MAXILLARMAXILLAR COMPLEXCOMPLEXis formed by intramembranous ossification and is growing:• by bone apposition at the sutures, connecting the maxilla to the craniumand cranial base. The growth occurs on both sides of a suture, so the bonesto which the maxilla is attached also become larger. As a consequence ofthis the maxilla moves downward and forward (translation).• by bone apposition at the midpalatal suture, which ceases early between 1and 2 years of age, but the suture completely fuses rather after 30 years ofage.• by surface remodeling

bone apposition at the tuberosity region (posterior border of themaxilla), what creates the additional space for primary andpermanent molar teeth,

bone removal from the anterior surface (opposing effect to bonetranslation),

bone apposition on the roof of the mouth (additional downwardmovement of palate and enlargement of nasal cavity) + bone removalfrom the floor of nasal cavity,

bone apposition on the lateral surfaces, which continues until 7 years ofage.

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1. Remodeling - deposition and resorption

The Growth ProcessThe Growth Process


Remodeling of the palatal vault moves itdown. Bone is removed from the floor ofthe nose and added to the roof of themouth.

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2. Displacement - a change in position


Remodelling and displacementRemodelling and displacementof the naso-maxillary complex


Displacement of the maxilla downwardDisplacement of the maxilla downward


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MANDIBLEMANDIBLEis formed by endochondral and periosteal activity

• cartilage on the surface of the mandibular condyle at theTMJ

• surface apposition and remodeling• syndesmosis in the midline becomes synostosis 4-12

month after birth

Growth in width is completed first, than growth in length , andfinally growth in height.

Growth in width tends to be completed before adolescentgrowth spurt.

Growth in length and height continues through the period ofpuberty (in length in girls - 2 to 3 years after firstmenstruation; in height - to early twenties in boys).

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1. Remodeling - deposition and resorption

The Growth ProcessThe Growth Process


Mandibular growth reveal minimalchanges in the body and chin area, whilethere is exceptional growth andremodeling of the ramous, moving itposteriorly.

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The correct concept of the mandibulargrowth is that the mandible is translateddownward and forward and growthsupward and backward in response to thistranslation, maintaining its contact withthe skull.

As the mandible grows in length, theramus is extensively remodeled, somuch that bone at the tip of thecondylar process at an early age can befound at the anterior surface of theramus some years later. Given theextent of surface remodeling changes, itis an obvious error to emphasizeendochondral bone formation at thecondyle as the major mechanism forgrowth of the mandible.


2. Displacement - a change in position

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Remodelling and displacementRemodelling and displacementof the mandible


Compensatory growthCompensatory growth


Compensatory growthCompensatory growth


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Rotational changes of the mandibleRotational changes of the mandible


Bjork and Skieller 1983

PositiveRotation

NegativeRotation


Rickett’s SuperimpositionRickett’s Superimposition -- BasionBasion--Nasion at CCNasion at CCIdentified a centre of growth of the face

CC point

Gnomic Growth

- the facial form remains constant

- unaltered facial growth is seen as

concentric patterns

Polar Axis

- skeletal landmarks grow away from

CC point in straight lines

- the more distant the landmark from

CC the more rapidly it grows away


Facial patternFacial pattern in relation to the height, width and depth of the skull.


EuryprosopicEuryprosopic typetype Leptoprosopic typeLeptoprosopic type

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• When the pattern of facial growth is knownorthodontic treatment can be optimised

• It may be possible to reduce intervention andlength of treatment with correct timing

• When natural growth can be predicted itbecomes possible to superimpose knowntreatment response and estimate outcome

• It also makes it possible to predict cases that areunlikely to respond favourably and planalternative treatment e.g. surgery


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A few clinical casesA few clinical cases


Aberrations from normal growthAberrations from normal growthDentoalveolar modifications


Changes in morphology with growthChanges in morphology with growth


Absence of cartilaginous growthAbsence of cartilaginous growth

Profile view of a man whose cartilaginous nasal septum was removed at age 8, afteran injury. The obvious midface deficiency developed after the septum was removed.


Skeletal modificationsSkeletal modifications -- condylar fracturecondylar fracture


External fixation for lengthening the mandible by distraction osteogenesis ina child with hemifacial microsomia.


Hemifacial microsomiaHemifacial microsomia

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Ankylosis of the mandible followingAnkylosis of the mandible followinginfectioninfection

Profile view of a girl in whom a severe infection of the mastoid air cells involvedthe temporomandibular joint and led to ankylosis of the mandible. The resultingrestriction of mandibular growth is apparent.


ConclusionConclusion

• Excellent orthodontic treatment relies on agood understanding of natural growth anddevelopment. As well as an understandingof the ability of various mechanicalinterventions to produce changes in thecraniofacial skeleton.



Thank you!Thank you!

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definitions the development and growth of the face

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