postnatal growth of face

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Postnatal Growth of

facial Structure

Guide:

Prof. Dr. Situ Lal Shrestha

Department of Orthodontics and Dentofacial Orthopedics

Peoples Dental College and Hospital, Kathmandu, Nepal

Presented by:

Dr. Gaurav Acharya

PG Resident

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Contents

1. Nasomaxillary Complex

2. Mandible

3. Facial Soft Tissue

4. Clinical Implications

5. Summary

6. References

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Nasomaxillary Complex Contd…

Composed of-

Paired maxillae

Nasal bones

Zygomatic bones

Lacrimal bones

Palatine bones

Ethmoid

Sphenoid

Vomer

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MAXILLA

Second largest bone of face

Two in number

Form:

→Whole upper jaw

→Roof of oral cavity

→Greater part of floor and lateral wall of nasal cavity

→Part of bridge of nose.

→Greater part of floor of each orbit.

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Body

Large and pyramidal in shape

Base formed by nasal surface

Apex directed towards zygomatic process

Four processes

Frontal

Alveolar

Zygomatic

Palatine

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Zygomatic process

Alveolar process

Frontal process

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Palatine process

Maxillary sinus

Frontal process

Alveolar process

Horizontal plate of palatine

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Development is via intramembranous ossification except nasal septum

Growth occurs by:

1. Cranial Base Contribution

2. Growth at sutures

3. Surface remodeling

4. Nasal septum growth

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Cranial base growth pushes the maxilla forward which occurs up to 7 years

After that growth is at the sutures

Spheno occipital Synchondrosis

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Connected to the neurocranium by a circummaxillary suture system

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Intermaxillary suture system composed of-

→Midpalatal

→Transpalatal

→Intermaxillary and

→Internasal sutures

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Growth of maxilla can be viewed in 3 aspects:

1.Growth in the Height

2.Growth in the transverse direction

3.Growth in the anterio-posteriordirection

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HEIGHT

Sutural growth toward frontal and zygomatic bones

Appositional growth in-

• alveolar bone

• floor of orbit

• hard palate

Resorption on nasal floor

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http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Skeletal/skull/palatine_belowPA281053.JPG

http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Skeletal/skull/palatine_belowPA281053.JPG

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Deposition on oral side.

Resorption on nasal side

Increases the height of the nasal cavity

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Surface remodeling of bone in the alveolar process

Increases the height of palatal vault

Eruption of teeth

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Height of maxilla increased by displacement process i.e. primary and secondary.

Primary displacement

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Primary displacement

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Secondary displacement

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TRANSVERSE DIRECTION

Finished earlier in postnatal life.

Occurs by two processes:

Alveolar remodeling in the

lateral surface of alveolar

process

Growth of the mid-

palatine suture

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ANTEROPOSTERIOR DIRECTION

Begins in the 2nd year of life

Ceases after increase in width has taken place.

Maxillary tuberosity Palatomaxillary suture

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Primary displacement Secondary displacement

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Resorption in the anterior region of the maxilla

Amount of forward movement of anterior surface is less than

amount of displacement

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Quantitation of maxillary remodeling. Sheldon Baumrind, Edward Korn AJO JAN 1987

PNS, ANS & pt A

Uniform displacement of all 3 pts in vertical direction [downward displacement –0.3mm/year]

Horizontally, displacement of PNS was greater than ANS and pt A

Increase in length is primarily because of growth in posterior border

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ORBITAL GROWTH

Follows Enlows V principle

Endocranial side Resorptive

Orbital side Depository

Orbit is relocated anteriorly

Bone deposition at various orbital sutures

Orbit are displaced out and away from each other at same time

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Most of lining roof & floor depository

Lateral wall deposition

Medial wall resorpition

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NASAL FOSSA

Wall & floor of nasal chamber Resorptiveexcept nasal side of olfactory fossa

Lateral and anterior expansion of nasal fossa

Downward relocation of palate

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Growth of SINUS

Air filled cavity

Pneumatizationof skeleton

Humidification of the inspired air

Most sinus achieve adult size by 12 yrs

Frontal sinus continue to enlarge till 20 yrs

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Maxillary Sinus

Resorption except mesial wall

Rapid continuous downward growth

Close proximity to buccal maxillary teeth

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SINUS

Postnatal Appearance of Sinus 1

1- OM Prakash Kharbanda. Orthodontics: Diagnosis and management of Malocclusion and dentofacial deforminties

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Zygomatic Bone

Anterior surfacePosterior surface

ResorptionDeposition

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Bone deposition

Inferior edge of

the zygoma

Fronto-zygomatic

suture

Growth height of the

anterior part of zygomatic

arch

Increase in vertical

length of lateral

orbital rim

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Zygomatic Arch

Resorption on the inner aspect

Deposition on the lateral surface

Enlarge temporal fossa

Enlarge facial width

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Anterior Nasal Spine

Prominence increase due to

bone deposition

Resorption of labial cortex

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Nasal Septal Cartilage

Downward and forward growth of the midface

At birth, nasal cavity is between orbits

Nasal septal cartilage –grows until age of 6

Lower the nasal cavity below orbits.

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Nasal Septal Cartilage

Thrust and pull created by nasal septal growth separate the frontomaxillary, frontonasal, frontozygomatic, & zygomaticomaxillarysutures

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Removal of nasal septum

Mid face deficiency

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Effect of removal of cartilaginous nasal septum in the rabbit.

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Functional matrix

hypothesis

Skeletal UnitFunctional Matrix

Basal body Infraorbital nerve

Orbital unit Eyeball

Nasal unit Septal cartilage

Alveolar unit Teeth

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Mandible

Largest amount of growth post-natally

Largest variability in morphology.

Developmentally and functionally divisible into several skeletal sub-units

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Mandible Contd…

Moss describes the mandible as a group of microskeletal units:

1. Coronoid process

2. Condylar process

3. Alveolar process

4. Angular / gonial process

5. Ramus

6. Body

7. Chin

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Mandible Contd…

The mandible grows downward and forward by

Cartilaginous growth at the condyle

Bone remodelling

→Area relocation.

→Activity at surfaces determined by regional directions of growth.

→Principle of the V

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Mandible Contd…

At birth

Two rami of mandible are quite short

Condylar development is minimal

Thin line of fibrocartilage and connective tissue exists at midline

Wide gonial angle

Between 4 months and 1 yr

Symphyseal cartilage is replaced by bone

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Mandible Contd…

Birth – 6 months

Symmetric broadening downward and mainly forward

During the 1st yr of life

Appositional growth is active at-

Alveolar border

Distal and superior surfaces of ramus, condyle

Lower border of mandible

Lateral surface of the mandible

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Mandible Contd…

6 months – 4 years

Symmetric broadening posteriorly, downward and forward

4 – 8 years

Broadening at condyles, downward and forward

8 years onwards

Downward and forward

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Mandible Contd…

CONDYLE

Important growth site

Covered by a thin layer of cartilage called the Condylar cartilage

Adaptation to withstand the compression that occurs at the joint

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Mandible Contd…

Earlier believed that-

Main growth center of mandibular growth is the hyaline cartilage in its condyle

Condyle causes a downward and forward shift of entire mandible

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Mandible Contd…

In tissue culture and transplantation experiments, condylar cartilage was found to be incapable of independent growth

But epiphyseal cartilage produces a well organized epiphyseal-metaphyseal unit

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Mandible Contd…

Result of experimental condylectomy suggest that the condyle may not make an important contribution to the spatial displacement of the mandible

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Mandible Contd…

Current thinking is-

Condyles are not master center of growth processes for other parts of the mandible

Growth of the other portions of the mandible independent of condylar growth

Whole mandible can become displaced anteriorly and inferiorly into its functional position without a "push" against the basicranium

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Mandible Contd…

Growth of soft tissues, muscles, connective tissue carries the mandible forwards away from cranial base

Bone growth follows secondarily at the condyle to maintain constant contact with the cranial base.

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Mandible Contd…

Lingual and buccalsides of the neck have resorptive surfaces

Neck relocated into areas previously held by the much wider condyles

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Mandible Contd…

RAMUS

Remodelling of ramus -

1) Positions lower arch in occlusion with the upper

2) Facilitate lengthening of the mandibular body

3) Accommodates erupting molars

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Mandible Contd…

Resorption Anterior Part

Deposition Posterior region

Drift of ramus in a posterior direction.

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Mandible Contd…

Greater amounts of bone additions on the inferior part

Uprighting of Ramus

Greater amount of resorption inferiorly than superiorly

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Mandible Contd…

CORPUS/ BODY OF MANDIBLE

Ramus remodelling

Displacement of the ramus

Ramal bone relocates into posterior part of body of the

mandible.

Lengthening of body of mandible

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Mandible Contd…

Angle of the mandible

Lingual side

→resorption on posterio-inferior aspect

→deposition on antero-superior aspect

Buccal side

→resorption on antero-superior part

→deposition on postero-inferior part

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Mandible Contd…

Gonial Angle

Obtuse (140° or more) in infants

About 110° in adults

Closes with growth to prevent change in the occlusal relationship between the upper and lower arches

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Mandible Contd…

Anti- gonial notch

Single field of surface resorption present on inferior edge of mandible

At the ramus corpus junction

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Mandible Contd…

Anti- gonial notch

Growth of the mandibular condyle fails to lower mandible

Masseter and medial pterygoidgrowth cause the bone in the

region of angle to grow downward

Produce Antegonial notching.

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Mandible Contd…

Antegonial notch determined by:

Gonial angle

Extent of bone deposition on just posterior or anterior to the notch.

Less prominent gonial angle closed

More prominent gonial angle opened

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Mandible Contd…

Singer and Hunter (AJO 1987)

Evaluatation of depth of antegonial notch as an indicator of mandibular growth potential

Deep notch

Diminished mandibular growth potential

Vertically directed mandibular growth pattern

Required a longer duration of orthodontic treatment than shallow notch patients.

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Mandible Contd…

Chin

Specific human characteristic

Found in its fully developed form in recent man only.

Most stable area within the outline of the mandible

Deposition on the anterioinferiorsurface

Resorption in anteriosuperiorly

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Mandible Contd…

Chin

Underdeveloped in infant

As age advances growth of the chin becomes significant.

Influenced by sexual and specific genetic factors

Males have prominent chins as compared to females.

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Mandible Contd…

Alveolar Process

Controlled by dental eruption

Resorbs when teeth are exfoliated or extracted.

Serves as a “buffer zone” maintain occlusal relationships during differential mandibular and midface growth

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Mandible Contd…

Growth persists even after corpus growth is over

Compensate for the occlusal surfaces wear of teeth

Maintain occlusal height in adulthood

Adaptive remodeling makes orthodontic movements possible.

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Mandible Contd…

CORONOID PROCESS

Enlarging V principle, with the V oriented vertically

Lingual side faces three general directions all at once: posteriorly, superiorly, and medially

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Mandible Contd…

Rotation of mandible during growth

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Mandible Contd…

Rotation of mandible during growth

Internal Rotation – occurs in the core of each jaw.

External Rotation – produced by the surface changes and alterations in the rate of tooth eruption that mask the internal rotation.

Change orientation of mandible, as determined by mandibular

plane

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Mandible Contd…

Forward rotation

When anterior vertical growth > posterior growth

Compensatory remodelling

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Mandible Contd…

Backward rotation

When posterior vertical growth > anterior growth

Compensatory remodelling

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Facial Soft tissue

Lips

Growth of soft tissue is not parallel to underlying hard tissue

Growth of lip lag behind growth of facial skeleton until puberty

11 14 18

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Facial Soft tissue Contd…

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Nose

Nasal bone growth completes at age 10

After 10, growth of cartilaginous & soft tissue.

10 12

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14 17

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Clinical Implications

Trauma

Effects on skeletal growth are not so much caused by the trauma itself as by the resulting scarring within the soft tissues that restricts further growth

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Clinical Implications Contd…

Pronounced forward rotation of mandible

Risk of deep bite

Prevented by

Stabilizing appliance, such as bite plane, introduced before puberty

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In case of backward rotation

Opening of the bite

Difficult to prevent

Postpone treatment until pubertal growth spurt is nearly over.

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At birth

Hard palate : length = width

Maxillary sinus : not visible radiographically

1 – 2 years

Extensive remodeling descent of

palate /enlargement of nasal cavity

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Aging Changes in Soft tissue

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Summary

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References

William R Proffit, Henry Fields, David M Server; Contemporary Orthodontics, 5th

edition

Graber, Vanarsdall, Vig; Orthodontics -Current principles and Techniques

Enlow & Hans- Essential of facial growth, 1st

edition

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References

G.H.Sperber, Craniofacial Development

OM Prakash Kharbanda. Orthodontics: Diagnosis and management of Malocclusion and dentofacial deforminties

Sameer E Bisara, Textbook of orthodontics, W.B.Saunders Company

Singer and Hunter. Evaluatation of depth of antegonial notch as an indicator of mandibular growth potential. AJO 1987

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References

Steve Galella, Daniel Chow, Jones; Guiding Atypical Facial Growth Back to Normal; IJO, vol 22, 2011

Sheldon Baumrind, Edward L et al. Quanttitation of maxillary remodeling. AJODO June 1987

Thomos Rakosi. Color atlas of Dental Medicine

Netters Atlas of Human Anatomy.

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Thank You…

postnatal growth of face

Health & Medicine

growth of midpalatine

nasal floor

displacement process

nasal surfaceapex

shape base

internasal sutures

circummaxillary suture

largest sinus