Postnatal growth

POST NATAL GROWTH OF
MANDIBLE & MAXILLA
www.indiandentalacademy.com

Post Natal Growth And
Development
WIDTH OF MANDIBLE
 Growth in width is completed before adolescent growth
spurt
 Intercanine width does increase after 12 years
 Both molar and bicondylar width shows small increase until
growth in length ends

Post Natal Growth And
Development
GROWTH IN LENGTH
• Growth in length continues through puberty
• Girls—14-15 years
• boys---18-19 years

Post Natal Growth And Development
• Main sites of post natal growth in the Mandible
• Condylar cartilage
• Posterior border of the Rami
• Alveolar ridges

Condylar cartilage
Secondary cartilage
Dual function
articular
growth
Not a pri. Centre of growth but rather
2° in evolution
2° in embryonic origin
2°in adaptive responses to changing dev.www.indiandentalacademy.com

Is the Condylar cartilage the principle
force that produces the displacement of
the mandible ?
For many years considered primary growth center
Considered secondary cartilage -no intrinsic growth
potential

Johnston et al - Detached condyle from the body of
mandible in guinea pigs
Injection of papain - Inhibition of chondrogenesis
Koski et al - Periosteal tension in condylar neck-lateral
pterygoid- controls condylar growth

• Condylar cartilage and functioning muscles translate the
mandible and in the absence of one the other does best to
compensate
• Integrity of periosteum is important
• When environment is changed compensatory contributions
are enhanced

Current Concept
• Condylar cartilage does have a measure of intrinsic genetic
programming
• But extra condylar factors are needed to sustain this activity
Physiologic
inductors
Intrinsic and extrinsic
biomechanical forces
ENLOW :
Increase pressure – growth inhibition
Decrease pressure – stimulates growth
based mainly on animal
experiments

Ramus
• Moves progressively posterior
by:-
• Deposition
• Resorption ANTERIOR PART
POSTERIOR PART

Ramus
Superior part of ramus
below sigmoid notch
Buccal - Resorption
Lingual -Deposition
Lower part of ramus
below the Coronoid
process
Buccal - Deposition
Lingual - Resorption

Ramus

Coronoid process
Superior
Medially
Follows ‘v’ principle
Lingual surface Posterior

Coronoid process
‘’V’ PRINCIPLE OF ENLOW

Coronoid process
• Deposition on lingual side
• Resorption - buccal surface
Increases
vertical length
Posterior GrowthMedial

Body of mandible
 The increase in width of the mandible occurs primarily due to
resorption on the inside and deposition on the outside
 Increase in length occurs due to drift of the ramus posteriorly
 Increase in height occurs due to eruption of the teeth

Ramus corpus junction
• Inferior Border of junction
- resorption
• Forms Antegonial notch

Antegonial notch
Size depends upon ramus – corpus angle

Lingual Tuberosity
• Grows posterior and
medial by deposition
• Resorptive field below-
Lingual fossa

Alveolar Process
• Adds to the height and
thickness of the
mandibular body
• Teeth absent fails to
develop
• Teeth extracted resorbs

Alveolar Process
• Maintain occlusal relationship during differential mandibular
& midfacial growth– buffer zones
• Maintains vertical height
• Adaptive remodeling makes orthodontic tooth movement
possible

Alveolar Process
Lingual movement of anteriors

Mental Protuberance
• Formed by mental ossicles from accessory
cartilage and ventral end of Meckel’s
cartilage
• Poorly developed in infants

Mental Protuberance
• Forms by osseous
deposition during
childhood
• Prominence is
accentuated by bone
resorption above it

Chin
• Protrusive chin is unique human trait
• More prominent in male
• Less prominent in female
Under dev. Of chin - microgenia

Symphysis Menti
• Limited growth till fusion
• No widening after fusion
Fusion occur within six
month to one year of
age.

Factors Affecting Growth
A)Systemic Factors
1. Genetic
2. Hormonal imbalance
3. Nutrition
4. Systemic illness or chronic illness
5. Localized alteration/ diseases of uterus
6. Systemic illness in mother
7. Drugs

B) Local factors
1. Vascular abnormality
2. Lymphatic disturbance
3. Neurologic disease
4. Local infection
5. Ear infection or mastoiditis
6. Ankylosis
7. Trauma or fracture
8. Birth injury
9. Habits www.indiandentalacademy.com

Anomalies of mandible
 Some of the syndromes associated with mandibular
abnormality
i) Down’s syndrome
i) Marfan’s syndrome
ii) Turners syndrome
iii) Kleinfelter’s syndrome
iv) Pierre-robin syndrome
v) Treacher- collin syndrome

1. Congenital
• Agnathia
• Micrognathia
• Macrognathia
• Facial
hemihypertrophy
• Facial hemiatropy
2. Developmental
• Infantile cortical hyperostosis
• Achondroplasia
• Torus mandibularis
• Stafne’s cyst
• Odontogenic cyst
• Odontogenic tumor

Age Changes Of The Mandible

Post natal growth of
maxilla

Post natal growth of maxilla
 Surface remodeling
 displacement
 CRANIAL BASE MAXILLA
apposition resorption
MOSS
TRANSPOSITION
TRANSLATIONSUTURES

 Surface apposition
 Sutural growth
 nasal septum growth
 Spheno occipital synchondrosis
 In contrast to cranial base maxilla is dominated by
intra membranous ossification

Surface apposition

Sutural growth

Spheno occipital synchondroses

 Growth in height vertical
 Growth in width transverse
 Growth in length A - P

HEIGHT
 DEPOSITION ON
THE ORAL SIDE
 RESORPTION ON
THE NASAL SIDE
ENLOW AND BANG ‘V’
PRINCIPLE

Sagittal view Coronal view
HEIGHT - ‘V’ PRINCIPLE

HEIGHT
APPOSITION IN THE
ALVEOLAR PROCESS
ERUPTION OF TEETH

Primary displacement
HEIGHT

PRIMARY DISPLACEMENT
 SUTURAL THEORY
 CARTILAGENOUS THEORY
 FUNCTIONAL MATRIX HYPOTHESIS

SUTURAL THEORY
 SUTURES HAVE
INNATE
GROWTH
POTENTIAL
 OBLIQUE
NATURE
 SLIDING EFFECT
SICHER

CARTILAGENOUS THEORY
 NASAL SEPTUM –INNATE GROWTH
POTENTIAL
 THRUST EFFECT– SEPTOPREMAXILLARY
LIGAMENT
 MORE ROLE IN A-P THAN VERTICAL
 SURGICAL REMOVAL OF NASAL
SEPTUM-def. of mid face
SCOTT

Removal of nasal septum –mid face
deficiency

FUNCTIONAL MATRIX HYPOTHESIS

 BASAL BODY INFRAORBITAL
NERVE
 ORBITAL UNIT EYEBALL
 NASAL UNIT SEPTAL CARTILAGE
 ALVEOLAR UNIT TEETH
BY MOSS
SKELETAL UNITS FUNCTIONAL MATRIX

FUNCTIONAL MATRIX HYPOTHESIS

HEIGHT
ENLARGING
ORO
FACIAL
CAPSULE
REMODELING
CHANGES IN
THE ORBIT

WIDTH
 Finished earlier in postnatal life
 WIDTH GROWTH IN MID PALATINE
SUTURE
REMODELING IN THE LATERAL
SURFACE OF ALVEOLAR
PROCESS
Mutual transverse rotations of
maxillary halves give palate ‘u’
shape

LENGTH
 Begins rapidly in the 2 nd year of life
Maxillary
tuberosity
Palato -
maxillary
suture
primary secondary
displacementwww.indiandentalacademy.com

QUANTITATION OF MAXILLARY REMODELING
 Uniform displacement of all 3 pts in vertical
direction [downward displacement –0.3mm/year]
 Horizontal direction posterior displacement of all 3
pts [however the displacement of PNS was greater
than ANS and pt A ]
 THE INCREASE IN LENGTH IS PRIMARILY
BECAUSE OF GROWTH IN POSTERIOR BORDER
Sheldon Baumrind,Edward
Korn AJO JAN 1987

Maxillary tuberosity
 Established by the posterior boundary of anterior
cranial fossa
 Helps in posterior and horizontal lengthening of
arch
Anterior displacement
= posterior lengthening

Key ridge
Reversal occurs at
the key ridge
Posterior - apposition
Anterior - resorption

Maxillary sinus
 PRE NATAL
 lateral evagination of mucous membrane in middle
meatus –3rd month IUL
 AT BIRTH
 2mm -long, 1mm in width + height

Maxillary sinus
AGE CHANGES
Expands - 2mm
vertically
3mm A-P - every
year
> in size -
resorption in walls +
alveolus

Maxillary sinus
 POST NATAL
 All internal
surfaces undergo
resorption
[expect medial]
 Rapid continues
downward growth
close proximity to
buccal maxillary
teeth

Zygomatic region
Posterior relocation
Anterior
[resorption]
Posterior
[deposition]
Lateral growth-
Medial resorption &
lateral deposition
displacement
Zygomaticotemporal [anterior]
Frontozygomatic [inferior]

Nasal airway
Lining surface of bony
wall and floor resorptive
Downward relocation of
palate
Lateral and anterior
expansion

Nasal airway
 Ethmoidal
conchae
lateral + inferior
deposition
medial + superior
resorption
 Inter nasal
septum
Lengthens
vertically at
sutural
junctions

Post natal growth

Post natal growth
AT BIRTH
Hard palate : length = width
maxillary sinus : not visible
radiographically
1 – 2 years
Extensive remodeling descent
of palate /enlargement of nasal cavity

Post natal growth
mid palatine suture
starts closing at 9-
10 years
RME BEST DONE
BETWEEN 9-14 yrs
THE MIXED DENTITION YEARS
Growth in width of the
dental arch anterior to
the first molar
Ceases by 5-6 yrs
Inter canine width
completed
12 yrs - females
18 yrs - males

Post natal growth
 THE DEPOSITORY GROWTH POTENTIAL OF
TUBEROSITY ALLOWS FOR ARCH EXPANSION
BY MOVING THE TEETH POSTERIORLY INTO
THE AREA OF BONE DEPOSITION

 EXTENSIVE SCOPE FOR GROWTH
MODIFICATION BEFORE ADOLESCENT
GROWTH SPURT
THE MIXED DENTITION YEARS

Post Natal Growth
THE EARLY PERMANENT
DENTITION YEARS
•Growth modification still possible
in boys
•RME can still be tried till 12 -15 yrs
•>15 years complete
closure[synostosis]
Orthognatic surgery

Age changes
 All para nasal sinuses increase in size
 Vertical height decreases
 Vertical changes > AP > width
 Soft tissue changes > skeletal
 Nose growth continues till 25 years
 Inclination of palatal plane increases[post
downwards]
Alveolar
process resorb
Tooth
loss

THANKS

Postnatal growth

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