Growth /fixed orthodontic courses /certified fixed orthodontic courses by Indian dental academy

GROWTH

INDIAN DENTAL ACADEMY

Leader in continuing dental education
www.indiandentalacademy.com

Changes in Overall Body
Proportions


Not all tissue systems of the
body grow at the same rate

Scammon’s Curve

Variability
Not everyone is alike in the way that
they grow
Percentile growth/ standard deviation to
the norm
Racial and ethnic differences
Boys vs Girls

Growth Curves
Boys: 2 to 18 years

Girls: 2 to 18 years

Boys reach most of their height at age of 17
whereas girls reach theirs at around 15.

Deviations from the norm in
growth
Sickness - nutrition
late/early maturers
problems with growth (hormones or
genetics)


Why do we assess growth?
To determine optimum time for
treatment (growth modification and
surgery)
to determine the amount of growth left
to determine type of growth


How to assess growth
Hand wrist x-ray

sexual maturity: onset of menarche in
girls, voice changes and facial hair in
boys
lateral cephalogram tracings:
superimpositions

Other indicators of growth
Ask parents how much
the child grew last year
(height and shoe size)
look at parent’s
phenotype: tall or short


Principles of Tissue Growth
Hypertrophy
hyperplasia
increased production of
extracellular matrix (cell
independent)


Bone, muscle and soft tissue
growth
All are dependent on each other to
some degree


Growth of the soft and cartilaginous
tissues = interstitial growth
Growth of mineralized tissues = can be
done in the surface only (periosteum)=
surface apposition of bone


Growth of Cartilage/
Endochondral Ossification
Long bones
Epiphyseal plate
contains dividing
cartilaginous cells
Rate of growth and
maturation of cells
need to be equal for
growth to occur

Epiphyseal plate


Proliferating cartilage

Intramembranous Bone
Formation
Cranial Vault and jaws
Meckel’s cartilage will be transformed
into middle ear ossicles and
sphenomandibular ligament and is not
involved with the bone formation of the
jaws


The growing face

8 months, 6 y, 8 y and 20 y old

The Human Head Shape
Brachycephalic

Dolichocephalic

• short and wide

• tall and narrow


Reasons for Describing Head
and Face Shape
The growth direction of the face and
jaws is different in each type of head
and/or face.


Reasons for Describing Head
and Face Shape
“Brachy” tends to grow horizontally;
“dolicho” tends to grow vertically.
Knowing the general pattern of growth
and the expected direction can be
helpful in orthodontic diagnosis and
treatment planning.

Soft Tissue Profile

Convex
retrognathic

straight
orthognathic


concave
prognathic

Soft Tissue Changes with
Growth
Soft tissue profile
tends to flatten
with growth
Nose and chin
growth at teenage
years may change
facial appearance

Boy growing normally
Black - 10 yo
red - 14 yo


Theories of Craniofacial
Growth
Classical: bone growth is primary, soft
tissues adjust to the growth of the
bones.
Functional matrix: soft tissue functional
demands are primary, bones grow in
response to functional demands.

Principles of Growth
Resorption
apposition

surface remodeling of a bone in the opposite
direction to that in which it is being translated
by growth of adjacent structures

Growth of the Craniofacial
Complex
Cranial Vault
Cranial Base
Maxilla
Mandible


Cranial Vault Growth

Apposition of bone in the cranial sutures
accounts for growth after birth.
Pressure from the growing brain promotes
resorption of bone in the inner surfaces of the
cranial vault = www.indiandentalacademy.com
remodeling allows for changes

Growth of the Cranial Base
The cranial base is composed mostly by
bones formed by endochondral ossification.
Bands of cartilage are formed between
centers of ossification called synchondrosis:
Spheno-occiptal synchondrosis
intersphenoid synchondrosis
spheno-ethmoidal synchondrosis

Growth of the Cranial Base

Cranial base grows by endochondral
ossification that occurs at both margins of the
synchondrosis.

Growth of the Maxilla
Remodeling of the
palatal vault moves it
in the same direction
as it is being
translated
bone is removed
from the floor of the
nose and added to
the roof of the mouth

On the anterior
surface, bone is
removed, partially
cancelling the
forward translation.
As the vault moves
downward, the
same process of
bone remodeling
also widens it.


Growth of the
surrounding soft
tissues translates
the maxilla
downward and
forward, opening
spaces in the
sutures where
bone is added.


Midpalatal suture is opened until teenage years.
Apposition of bone in the molar area accounts for
space for the third molars.

Summary:
growth of the maxilla
occurs in 2 ways:
by apposition of bone
in the sutures that
connect the maxilla to
the cranial base
by surface
remodeling.

Growth of the Mandible

Remodeling is done by resorption in the anterior
part of the ramus and deposition in the posterior
part of the ramuswww.indiandentalacademy.com

Overall growth
direction results in a
downward and
forward
displacement with
most of growth
occurring in the
ramus.

Mandibular symphysis is closed by age of 1
year.
Late mandibular growth:
can occur in the late teenage years or
adulthood
most often seen in asians and males
can cause incisor crowding when there is a
tight occlusion (overbite/overjet)

When things go wrong
Congenital craniofacial malformations:
cleft lip/palate, syndromes (Apert,
Crouzon, etc..), craniosynostosis
Non-syndromic craniosynostosis
Trauma
Ankylosis
Juvenile rheumatoid arthritis

When things go wrong
Trauma

Blow to one side of the
mandible may fracture
the condylar process on
the opposite side
pull of the lateral
pterygoid muscle
distracts the condylar
fragment including all
the cartilage =
resorption occurs

Thank you
Leader in continuing dental education


Growth /fixed orthodontic courses /certified fixed orthodontic courses by Indian dental academy

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