Introduction to Orthodontics Fifth Year

1. Third Lecture
Growth and Development of The
Craniofacial Complex

2. Outlines
Craniofacial Complex.
Why you should be interested in growth and
development?
Factors influencing the development of
occlusion:
Definitions:
Growth
Development
March 5, 2012
Dr. Ahmed Basyouni
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3. Outlines
Types of bone formation:
Intramembranous bone
Endochondrial bone
Sites of skull growth:
Growth of the head:
Growth of the cranium:
Cranial vault.
Cranial base.
March 5, 2012
Dr. Ahmed Basyouni
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4. Outlines
Growth of the face:
Growth of the upper face (nasomaxillary
complex).
Growth of the mandible.
How to assess growth.
Why do we assess growth.
Human head shape.
March 5, 2012
Dr. Ahmed Basyouni
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5. The Craniofacial Complex
Consists of:
I. Cranium:
Cranial vault
Cranial base
II. Face:
Upper face (Nasomaxillary complex)
Mandible
March 5, 2012
Dr. Ahmed Basyouni
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6. Why you should be interested in
growth and development?
1. Knowledge of general and facial growth
provides a background of the etiology and
development of malocclusion.
2. As observer of the growing child all dentists
should be able to identify abnormal or unusual
skeletal growth patterns.
3. The dentist should be able to identify
abnormal occlusal development at an early
stage in order to undertake suitable
interceptive orthodontic treatment.
March 5, 2012
Dr. Ahmed Basyouni
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7. Why you should be interested in growth and development?
4. Poorly timed extraction (early or delayed loss)
performed by dentist during growth, cause
malocclusion.
5. Many malocclusion are due to skeletal discrepancies
between the jaws (maxilla and mandible) due to
improper differential growth of the jaws.
6. Orthodontic treatment may make use of high growth
rates attained during puberty “Growth modification”.
7. Orthognathic surgery is considered only after facial
growth has been completed.
8. Growth effects have long term effects on the stability
of the occlusion after treatment.
March 5, 2012
Dr. Ahmed Basyouni
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8. Factors influencing the
development of occlusion:
1. Bone growth & development.
2. Soft tissue morphology & behavior.
3. The relationship of size of dentition to
size of dental arch.
4. Forces of occlusion.
5. Skeletal pattern.
March 5, 2012
Dr. Ahmed Basyouni
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9. Definitions
Growth: It is a physiochemical process by
which an organism becomes larger.
Development: It is sequence of changes from
fertilization of the ovum to maturity, It is
related to cell division, differentiation, and
organization up to maturity.
March 5, 2012
Dr. Ahmed Basyouni
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10. The Growing Face
At birth, the largest to smallest dimensions of
the face are width, height and depth.
Postnatally, the face grows most rapidly in
depth, followed by height, with slowest rate of
growth being found in width.
March 5, 2012
Dr. Ahmed Basyouni
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11. The Growing Face
8 months, 6 y, 8 y and 20 y old
March 5, 2012
Dr. Ahmed Basyouni
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12. Changes in Overall Body Proportions
12%
25%
50%
Cephalocaudal Growth Gradient:
means increasing
growth rate from head to feet.
March 5, 2012
Dr. Ahmed Basyouni
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13. Not all tissue systems of the body grow at the
same rate or mature at the same time
Scammon’s Curve: Growth curves of four major tissue systems.
March 5, 2012
Dr. Ahmed Basyouni
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14. At Birth:
Infant’s Face / head = 1/8
due to the advanced state of brain growth.
In Adults:
Face / head = 1/3 to 1/2
due to postnatal facial growth.
March 5, 2012
Dr. Ahmed Basyouni
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15. Types of Bone formation
Bone is mesodermal in origin:
The mesenchymal C. T. would be differentiated into:
Mesenchymal C. T.
Mucous membrane
Cartilage
(Fibrous C.T.)
Bone formed from fibrous C.T. is
called
Bone formed from cartilage is
called
Intramembranous bone
Endochondrial bone
March 5, 2012
Dr. Ahmed Basyouni
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16. Intramembranous bone:
– by secretion of bone matrix
directly within C.T. without
any intermediate
formation of cartilage
– Through the activity of cells
in the periosteum
– Cranial vault, face (Mx &
body of Md)
and the clavicles.
March 5, 2012
Dr. Ahmed Basyouni
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17. Endochondrial bone:
– Cartilage is replaced by bone
– Cranial base, Md condyle
Epiphyseal plate
Proliferating cartilage
March 5, 2012
Dr. Ahmed Basyouni
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18. Sites of Skull Growth
Sutural growth
Surface apposition and remodeling
resorption
Growth of the contained organs as the
brain, eye balls, and the tongue
March 5, 2012
Dr. Ahmed Basyouni
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19. 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
March 5, 2012
Dr. Ahmed Basyouni
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20. 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.
March 5, 2012
Dr. Ahmed Basyouni
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21. Growth of the Head
Growth of the cranium:
a) Cranial vault
{completed at 8 years}
Intramembranous
b) Cranial base
{ Anterior C B at 10 years &
Posterior C B at 20 years}
Endochondrial
March 5, 2012
Dr. Ahmed Basyouni
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22. Growth of the Head
Growth of the Face:
a) Upper face (Nasomaxillary complex)
{completed at 16-18 years}
Intramembranous
b) Mandible {completed at 20-25 years}
Mixed
March 5, 2012
Dr. Ahmed Basyouni
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23. Growth of the Cranium
Cranial vault is made up of frontal bone, the two
parietals, squamous part of the temporal bone and squamous
part of the occipital bone. All intramembranous, and separated
by sutures.
March 5, 2012
Dr. Ahmed Basyouni
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24. Growth of the Cranium
Cranial vault
• Apposition of new bones at the cranial sutures,
& periosteal activity (remodeling) due to the
pressure from the growing brain.
March 5, 2012
Dr. Ahmed Basyouni
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25. Growth of the Cranium
Cranial Base is made of midline base and
three cranial fossae.
The bones forming the floor of the anterior
cranial fossa are the orbital plates of the frontal
bone, the cribriform plates of the ethmoid and
the lesser wings of the sphenoid.
March 5, 2012
Dr. Ahmed Basyouni
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26. Growth of the Cranium
Cranial Base
The bones forming the floor of the middle
cranial fossa are the body and the greater
wings of the sphenoid, the upper surface of the
petrous temporal bone and the petrous part of
the occipital bone.
March 5, 2012
Dr. Ahmed Basyouni
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27. Growth of the Cranium
Cranial Base
The bones forming the floor of the posterior
cranial fossa are the occipital in its floor and
the posterior surface of the petrous temporal
bone in front.
March 5, 2012
Dr. Ahmed Basyouni
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28. Growth of the Cranium
Bands of cartilage are formed between centers of
ossification called synchondrosis:
– a) Spheno-occipital synchondrosis
– b) Inter-sphenoid synchondrosis
– c) Spheno-ethmoid synchondrosis
March 5, 2012
Dr. Ahmed Basyouni
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29. Summary
Craniofacial Complex
Why you should be interested in growth and
development?
Factors influencing the development of
occlusion:
Definitions:
Growth
Development
March 5, 2012
Dr. Ahmed Basyouni
29

30. Summary
Types of bone formation:
Intramembranous bone
Endochondrial bone
Sites of skull growth:
Growth of the cranium:
Cranial vault.
Cranial base.
March 5, 2012
Dr. Ahmed Basyouni
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31. Who Works With Their Minds are
Scientists.
Who Works With Their Hearts are
Artists.
Who Works With Their Hands are
Workers.
Who Works With All of Them are
Orthodontists.
March 5, 2012
Dr. Ahmed Basyouni
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