As Orthodontists, we are interested in understanding how face changes from embryologic form through childhood, adolescence, and adulthood? The practitioner may be able to manipulate facial growth for the benefit of the patient.

1. Concept of growth and
development
Growth and development are closely related, but are not synonyms

2. Why We Are Interested.
• As Orthodontist we are
interested in understanding
how face changes from
embryologic form through
childhood, adolescence and
adulthood?
• Practitioner may be able to
manipulate facial growth for
the benefit of the patient.

3. Growth Development
• Quantitative Aspect
• Increase in size and number and
change in proportions.
• However, occasionally, the
Increase will be neither in size
and nor number, but in the
COMPLEXITY.
• Anatomical phenomenon and
its measureable.
• Progress towards maturity.
• Development connotes an
increasing degree of
Organization.
• Always increase in COMPLEXITY.
• Overtone of increasing
specialization.
• Physiological and behavioral
phenomenon.

4. Methods of Studying
Physical Growth
Measurement approach
Experimental Approach

5. Measurement approach
• Craniometrics
• Anthropometry
• Cephalometric Radiography

6. Experimental Approach
• Vital Staining.(Alizarin Dye)
• Autoradiography.
• Radioisotopes.
• Implant radiography.

7. Other Methods
• Natural markers.
• Comparative Anatomy.
• Genetic studies.
• 3 D imaging

8. Methods of Collecting Growth Data
• Longitudinal Studies.
• Cross-sectional Studies.
Type of growth data
Opinion
Observation
Rating and Ranking
Quantitative measurement.
(Direct, indirect and derived data)

9. Basic Tenets of Growth
Pattern
• Proportionality at a point of time
and change of Prop over a period
of time.
• Cephalocaudal gradient of growth.
• There is an axis of increased
growth from the head towards the
feet.
• Not all the tissue systems of body
grow at the same time

10. Scammon Curve of Growth
The overall pattern of growth is
reflection of the growth of the
various tissues making up the
whole body

11. Variability
• Degree of difference between
two growing individuals in all 4
planes of space.
• To do this we can compare the
growth of a child relative to a
standard growth chart at
present and a follow up.

12. Timing
• Most Important concept in
growth.
• Biological clock is set differently
for all individuals.
• Variation in timing of menarche.
• Difference in arrival of Sexual
Maturity.
• Rapid growers.
• Poor growers.

14. Clinical Significance of Growth Spurts
• Growth normal/abnormal.
• Treatment of C-2 malocclusion.
• Treatment of C-3 malocclusion.
• Arch Expansion
• Face mask therapy.

15. Terminologies Related to Growth
Growth Fields.
Inside and outside of every bone
is covered by growth fields which
control the bone growth. They
are both Resorptive and
Depository type.

16. Growth Sites
• Location at which only growth
occurs.
• Secondary and compensatory
activity
• May posses some intrinsic
potential to grow.
• Growth sites are dependent on
the growth centers for growth.
• Lack of direct genetic influence.
• Influenced by environment.
• Mandibular condyle and maxillary
tuberosity

17. Growth Centers
• Location at which independent
growth occurs.
• Genetically controlled growth.
• Innate growth potential.
• Can’t be influenced by
environmental factor.
• Site of endochondral ossification
with tissue separating force.
• Contributing to increase of
skeletal mass.
• Nasal septum, synchonrosis,
epiphysis

19. All Growth Centers can be
Growth Sites But not all
Growth Sites can be
Growth Centers

20. Growth Movements: 2 Types
Cortical Drift
• Interplay of bone deposition
and bone resorption.
• Movement towards the
deposition side.
• Either thickness of bone may
remains constant.
• Or thickness of bone may
increase.

21. Displacement
• Movement of whole bone as a
unit.
• 2 types
• Primary Displacement.
Displacement due to own growth.
• Secondary Displacement.
Displacement due to adjacent
bone growth.

22. Characteristics of Bone
Growth
Bone formation occur by two methods of differentiation of
mesenchymal tissue or ecto-mesenchymal (neural crest) origin.
Both methods tends to become insignificant in the post-natal life.

23. Intramembranous Ossification
• Transformation of
Mesenchymal connective,
usually in membranous sheet
like layers, into osseous tissues.
• Direct Appositional Periosteal
bone formation.
• Flat bone, Bones of skull (except
mandible), facial bones, bone
remodeling throughout life

24. Endochondral Ossification
• Conversion of Hyaline Cartilage
prototype model into Bone.
• Cartilage template is replaced
by endochondral bone
• Indirect bone growth.
• 3 D in its growth.
• Deeply Ossifying Slowly
expanding centers.

25. Modes of Bone Growth

26. • Hyperplasia
Refers to increase in size of cells.
• Hypertrophy
Refers to increase in cell number.
• Extracellular material.
Cells secrete extracellular
material.

27. Growth Control
• The human growth has a
complex growth pattern.
• Growth of brain case or
calvarium is related to growth
of brain itself.
• While growth of facial and
masticatory bones is
independent of brain growth.
• Coordination?
Controlling and Modifying Factors
1. Intrinsic genetic factors
2. Epigenetic factors
3. Local and general
Environmental factors

28. Theories of Skull growth Control
1. Genetic theory:
• Control of the skull growth
largely to intrinsic genetic
factors.
• Sutural Dominance Theory
• Proliferation of connective
tissue and its replacement by
bone in the suture being a
primary consideration.
2. Cartilaginous Theory
• Cartilaginous growth centers.
• Intrinsic and growth controlling
factors are present only in the
cartilage and in the periosteum.
• Growth in sutures is secondary.
• Synchondroses of cranial vault.

29. Theories of Skull growth Control
3. Functional matrix Hypothesis
• Neither cartilage nor bone are
determinant for growth of
craniofacial skeleton.
• Control lies in adjacent soft tissue.
• Epigenetic control of soft tissue
growth.
• Brain. Microcephaly,
hydrocephaly.
• Eye and the Orbit.
• Volume of neural mass is
important whether or not it
contain normal amount of brain
tissue.
• Expansion of this closed capsular
matrix volume is primary event in
the expansion of the capsule.

30. Theories of Skull growth Control
Servo-system theory
• Processes that control postnatal
craniofacial growth.
• STH-somatomedin complex on
growth of primary cartilage has
cybernetic form of control and no
local feedback loops.
• Quite the contrary, the growth of
secondary cartilage comprises not
only direct but also indirect
(regional and local) factors
Primary cartilages
• Epiphyseal car of long bones
• Car of Nasal septum.
• Spheno-occipital Synchondrosis.
• Car of Ethmoid, sphenoid bone.
Secondary cartilages
• Condyler, coronoid, angular car of
mandible, mid-palatal suture,
callus bone repair.

31. Architectural analysis of the Skull
Frames and Trusses of skull
• Triangular frame and
tetrahedral truss resist
distortion from external force.
• Rectangular frame and cubic
truss collapses by external
force.

32. Architectural analysis of the Skull
Mandible
• Moveable part of complicated
lever system.
• Designed as strong central bar.
• Runs condyle to condyle.
• Resembles shaft of long bone.
• Bar is reinforced in the midline
by bulging chin.
• Resist action of muscles

33. Prenatal growth of Cranium,
Facial and Oral Structure

34. Prenatal growth Phases
Following are three phases
Period of ovum
• From fertilization to 14 day
Period of Embryo
• From 14 day to 56 days.
Period of fetus.
• From 56 day to birth.

35. Prenatal Growth proper
• Growth of cranial, facial and
oral structure begins about 21st
day.
• Embryo size 3mm and head
takes shape.
• Head and Tail folds are near
each
• Developing brain and
pericardium form two bulging
on ventral aspect.

36. Stomodaeum
• In between bulgings, depression
called stomodaeum.
• Floor is formed by bucco-
pharyngeal membrane.
• This membrane separate
stomodaeum from foregut.
• Mesoderm covering the
developing brain overlap the
upper stomodaeum, called
frontonasal process.

37. Pharyngeal or the brachial arch
• 4 in numbers and the 5th one disappears
soon.
• Appear in the elongated region between
stomodaeum and pericardium.
• 1st is called mandibular Arch.
• 2nd is called hyoid arch
• Separated by groove and innervated striated
muscle, ectoderm and endoderm.
• Dorsal end called maxillary prominence.
• Ventral part called mandibular prominence.
• Nasal pits, medial nasal process and lateral
nasal process are formed.

38. Development of the skull
Development of skull is a blend of three main skull entities

39. The Neuro-cranium
.
• Brain case, Brain pan.
• The calvaria or vault of skull
covers the brain.
• It is derived from intra-
membranous bone.
• Also called Desmocranium.
• Cranial base is derived from
cranial floor.

40. The face
• Cranial base is associated with
capsular investment of nasal
and auditory sense organs.
• These are derived from
endochondral bone.
• Its cartilaginous precursor is
called chondro-cranium.
• Orognathofacial complex is
derived from branchial arch
structures.

41. The Masticatory Apparatus
• Branchial arch structures are
formed from intramembranous
bone, called
splanchnocranium forms
oromasticatory apparatus.
• The dentition is derived from
ectodermal placoid scales,
develop from oral ectodermal
dental lamina.

42. The Calvaria
• The vault of skull or calvaria is
of recent origin and covers
expanded brain and is formed
from intramembranous bone
called desmocranium.
• Ossification of calvarial bones
depends upon presence of
brain.
• Several primary and secondary
ossification centers form
individual bone of calvarium

43. Ossification sites of the bones of the skull
• Ossification is
intramembranous, depends
upon presence of brain.
• In ancephaly no bony calvaria
develops.
• Primary and secondary
ossification centers develop in
ectomeninx and form individual
skull bones.

44. • A pair of frontal bones appear
from single primary ossification
center.
• Three pairs of secondary
centers appear in zygomatic
processes, nasal spine and
trochlear fossae.
• Parietal bones appear from
primary centers.

45. The Cranial Base
• 110 ossification centers in
embryonic skull.
• Many fuse to form 45 neonatal
bones.
• In young adults 32 bones are
identified.
• Center of ossification for the
cranial base appear at 10th
week of IU as endochondral
bone but also have
intramembranous components

46. The Cranial Base

47. The Facial skeleton
The face is divided into following
• The upper face.
Corresponding to frontonasal
process, embryologically.
• The middle face.
Corresponding to maxillary process,
embryologically.
• The lower face
Corresponding to mandibular
process, embryologically.

48. Facial proportions
• Upper 3rd, neuro-cranial
composition, grows rapidly in
association with the growth of
frontal lobe.
• Growth of middle 3rd and lower
3rd is slow and prolonged.
• Facial bones develop intra-
membranously from ossification
centers.

49. The Maxilla
• 8th week of IU
• Maxilla forms within the Max
prominence
• Mostly Endochondral Bone
formation.
• Little Intra-membranous Bone
formation.
• Ossification of maxilla begins
slightly later than mandible.
• Primary and 2nd Ossi centers exists

50. The Palate
• Special interest for
orthodontist.
• 3 elements that form the
secondary definitive palate are
Lateral maxillary processes,
Primary palate or frontonasal
process
• Initially widely separated, later
unite.
• Ossification 8th week

51. The Palate

52. Cleft lip and palate

53. The Mandible
• Mandibular nerve is first
structure to develop in the
primordium of lower jaw,
postulated as being necessary
for development of mandible.
• Mandible is develop as
intramembranous bone lateral
to the Meckel’s cartilage of
mandibular arch.
• At 36 to 38 days IU.

54. • Both Endochondral and
Periosteal activity are important
in the growth of mandible.
• Displacement created by Base
of the skull on TM joint is
negligible.
• Endochondral replacement
occur at condylar cartilage.
• All other areas of Man grow by
direct surface remodeling.

55. Pattern of growth of Mandible
When Cranium is Reference
• Chin moves forward and
downward.
Data from Vital Staining experiment
• Minimal changes in the body and chin.
• Principal site of growth are posterior surface of
ramus, condylar and coronoid processes.

56. Correct Concept
Mandible is translated downward
and forward and grow upward
and backward in response to this
translation, maintaining its
contact with the skull.

57. • The body of the mandible grows
longer as the ramus moves
away from the chin, this occurs
by removal of bone from the
anterior surface of the ramus
and deposition on the posterior
surface.
• What was the posterior surface
at one time becomes the
becomes the center and
anterior surface as remodeling
proceeds

58. Postnatal Growth of
Craniofacial Complex
The Cranial Vault
The Cranial Base
The Nasomaxillary Complex
The Mandible

59. The Cranial Vault
• Enlarging Brain.
• 90% growth achieved by 5th year.
• Intramembranuous Ossification.
• Apposition and selective resorption of bone.
• Newborn metopic suture, no Frontal Sinus.
• Later development Of F.S
• Brain case length increase due to growth of
cranial base, active response at coronal
suture.
• Height of brain case  activity of Parietal
suture along with bony structures

60. The Cranial Base
• Dependent upon brain growth
and some intrinsic guidance, bit
similar to that of facial skeleton.
• Midline Structures
Endochondral Ossification.
• Laterally more Sutural growth.
• Spheno-occipital Syn growth
20th year.

61. The Nasomaxillary Complex
• This complex emerges from
beneath the Cranium.
• Attached to cranial base, Strong
Influence.
• Upper face move upward and
forward
• Lower face downward and
forward.
• Expanding

62. • As the maxilla is translated
downward and forward, bone is
added at the suture and
tuberosity area posteriorly.
• But at the same time, surface
remodeling removes the bone
from the anterior surface.(except
anterior nasal spine).
• Hence amount of anterior
movement is less than the
displacement.

63. • In the roof of the mouth,
surface remodeling adds bone
while bone is resorbed from the
floor of the nose.
• The total downward movement
of the palatal vault is greater
than the amount of
displacement.

64. The Mandible
• Both endochondral and
periosteal activities in the
growth of mandible.
• Cartilage cover the condyle.
• Rest all other direct surface
apposition& selective
resorption.
• Continuous growth of alveolar
bone with developing dentition
increases the height of Man
body.