Early Stage of Development

Prepared By : Haval Jalal

Prenatal Influences on Facial Development

Embryologic DevelopmentAll tissue of face & neck ( muscles and skeletal elements )originate from

ectoderm. Stages Of Embryonic craniofacial Development

Stage Time Related syndromes

Germ layer formation & initial organization of structure Day 17 Facial alcohol syndrome

Neural tube formation Day 18-23 Anencephaly

Origin , Migration, and interaction of cell population Day 19-28

Hemi facial microsomia Teacher Collins syndrome

Limb abnormality

Formation of Organ SystemPrimary Palate

Secondary Palate

Days 28-38Days 42-55

Cleft lip and /or PalateOther Facial Cleft

Cleft Palate

Final Differentiation of Tissue Day 50 - birth Achondroplasia Synostosis syndromes

NEURAL CREST CELL PROBLEMS Many problems arise from in 3rd stage of development, since most of face structure derived from

migrating neural crest cells, its not surprising that interference with this migration produce facial deformatities .

At completion of migration of the neural crest cells in 4 th week , they form particularly all of the loose mesenchymal tissue in the facial region that lies between the surface ectoderm & underlying Forebrain, Eyes, And Mandibular Arch.

Most of N.C.Cs. In the facial area latter differentiate into skeletal and C.Ts. Including bones of the jaw & the teeth.

Altered N.C.Cs. Development due to excessive cell death in the trigeminal ganglion will cause cretin syndromes.

HEMIFACIAL MICROSOMIA its asymmetrical problem characterize by lack of tissue in the affected side ( external ear, Ramus of mandible , And soft tissue ) it arise primarily from early loss of N.C.Cs.

N.C.Cs. With longest path of migration, are those take circuitous route to the lateral & lower areas of the face, are most affected, whereas those going to the center of the face tend to complete their migratory movement..this explain why midline facial defect (including cleft) rarely are part of syndrome.

N.C.Cs. Migration to the lower region are important in the formation great vessels (aorta, pulmonary artery ) they may cause defect in these vessels as in ( Tetralogy of Fallot ) which is common in children with hemi facial microsomia.

Hemi facial microsomiaTeacher Collins

Syndrome

Facial Cleft Problem Most common congenital defect involving the face is cleft lip

and palate, it arise during 4th stage of development , it location determined by the site at which various facial process failed to fuse.

CLEFT LIP occur because of failure of fusion between

median and lateral nasal processes and maxillary prominence, which occur normally at 6th week , its usually affect area in alveolar ridge containing central and lateral incisors. Usually about 60% of individual with cleft lip also have cleft palate.

ISOLATED CLEFT OF SECONDARY PALATE is the result of problem arose after complete of lip closure, du to incomplete fusion of secondary palate, which produce a notch in posterior extent .

OBLIQUELY DIRECTED CLEFT OF FACE is occur due to failure of fusion between maxillary and lateral processes which is rare condition.

SYNOSTOSIS PROBLEMS This syndrome occur in the final stage of facial development, which result

from early closure of the sutures between the cranial and facial bones. Crouzons’s Syndrome is the most frequently occurring member of this

group. characterize by:

This syndrome occur due to early fusion of the superior and posterior sutures of the maxilla

along with the wall of the orbit. Such early fusion may prevent maxilla from translate

forward and downward resulting sever underdeveloped of midrace.Surgical release of the suture in early age is necessary.

Underdevelopment of the mid face

Eyes that seem to bulge from their socket

Late Fetal Development & Birth At 6th month of I.U. life the fetus Wight is about 1000 gm, during

last 3 months there will be a rapid growth till it reach about 3000 gm.

The proportion of total body mass represented by the decrease of head size from 4 month onward, At the birth the head still half of the body mass but its longer and narrower to facilitate delivery, this is possible due to the presence of relatively large un calcified fontanelles, The lack of growth of the lower jaw also make birth easier.

Birth is traumatic process, the child iterance in to the new world need a set of physiological adaptation, For a short period growth ceased & often there is small decrease in weight ( during first 7-10 days ), Such interruption in growth produce a physical effect in skeletal tissue because of orderly sequence of classification, its noticeable on bone & teeth ( on enamel as Neonatal line) across surface of primary teeth, which have varied position from tooth to other, it can only seen by magnification.

Any disturbance in growth during infancy and early childhood lasting 1-2 weeks or more such as febrile illness ( fever ) will leave visible record on enamel.

Infancy & Early childhoodThe growth after birth continued by increasing height and Weight in steady rate, 3

circumstances need special attention :

Premature birth ( low birth weight ): infants with weight less than 2500 gm are

in great risk of

problem in the post natal period. Until recent years children bellow 1500 gm did not

survive. if the

premature infant survive the neonatal period, the growth will follow normal pattern

later on.

Chronic Illness: skeletal growth is a process need energy, 90% of available energy

must used for

survival & activity other 10% used for growth .

Any chronic illness alter this balance, and leave less energy for growth, chronic

illness reduce the

growth rate while acute illness lead to period of growth cessation.

Nutritional status: for growth to occur, there must be a nutritional supply,

Chronically in adequate

nutrition has effect similar to chronic illness, On other hand once a level of

nutritional adequacy has

been achieved, additional nutritional intake is not stimulus to more rapid growth .

Maturation of Oral FunctionPrinciple physiological function of oral cavity are:Respiration , Swallowing , Mastication , Speech

Respiration: Respiration needs are primary determination of posture of the mandible and tongue.

At birth the newborn need to establish an airway within minutes to survive, to open airway the

mandible must positioned downward and the tongue moved downward and forward , this allow

air to move through the nose and across pharynx.

Swallowing : swallowing occur in last months of fetal life , as fetus swallow amniotic fluid for

activation of immune system,.The new born infants need to feed on his mother milk, this is done by process of suckling

rather than sucking which is done by stimulation of the smooth muscles of mother nipple by nibbling movement of lip which lead to squirt of milk, now the infant just need to groove his tongue

and allow milk to flow posteriorly to pharynx as tongue placed anteriorly in contact with lower lip.This whole process called infantile swallowing which disappear after 1st year of life

As infant matures, there is an increase in activity of elevator muscles of the mandible, the tongue will be

used in more complex way as diet change to contain solid food, the tongue gather up the bolus,

position it along the middle of the tongue, and transport it posteriorly.

After eruption of primary molar during 2nd year cup replaces drinking from bottle, the lip activity sized

(relaxed lip)the tongue tip placed against alveolar process behind upper incisors, and posterior teeth

brought in to occlusion during swallowing.

These are all characteristic of adult swallowing.

Mastication: the chewing pattern of adult is quite different from that of children, an adult typically open

straight down, then moves the jaw laterally and bring the teeth into contact , whereas child moves jaw

laterally on opining .

The transition from the juvenile to adult chewing appear to develop in conjugation with

permanent canine eruption about 12 years .

Adult who do not achieve normal function of the canine teeth because of sever anterior open bite

retain the juvenile chewing pattern

SpeechThe 1st speech sounds are the bilabial sounds /m/ , /p/, & /b/.

Some what later , the tongue tip consonants like /t/ & /d/ appear .

The sibilant /s/ & /z/ sounds, which require that the tongue tip be placed close to

but not against the palate .

The last speech sound /r/ which requires precise positioning of the posterior tongue

often not acquired until age 4-5.

Eruption of the Primary teethAt birth, neither the maxillary nor the Mandibular alveolar process is well developed.

The timing and sequence of eruption of deciduous teeth will be as follow :

Spacing is a normal characteristic of primary dentition

But its most noticeable in 2 locations called Primate spaces

In the maxillary arch located between lateral incisor and

canines, where as in Mandibular arch the space is between

The canine and 1st molar.

Developmental spacing between incisors is often present.

These spacing are required for proper alignment of

permanent incisors.

tooth eruption

maxillary Mandibular

Central 10 months 8 months

Lateral 11 months 13 months

Canine 19 months 20 months

1st molar 16 months 16 months

2nd molar 29 months 27 months

Physical Development in the Late Childhood Late childhood is the period from 5-6 years to the onset of puberty and its

characterized by;

1. Physical development pattern of previous period continue but in different rate for different tissue system.

2. The brain & brain case are as large as they will ever be.

3. Lymphoid tissue thorough the body has proliferate beyond the usual adult level, as large tonsils & adenoids are common.

4. The growth of sex organs has hardly begun.

5. The rate of general body growth decline from rapid (in infancy) to stabilized at lower level.