Introduction to Orthodontics Fifth Year

1. Fourth Lecture
Growth and Development of The
Craniofacial Complex

2. Growth of the Face
Growth of the upper face (Nasomaxillary
complex):
The Nasomaxillary complex is connected to the cranial base
by means of six pairs of sutures. These are:
1. Frontomaxillary
2. Frontonasal
3. Zygomatico-frontal
4. Zygomatico-temporal
5. Pterygo-palatine
6. Zygomatico-maxillary
May 22, 2012
Dr. Ahmed Basyouni
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3. Growth of the upper face
Intramembranous Ossification:
By apposition of bone at the sutures that
connect the Mx to the cranium and cranial
base.
By surface remodeling.
May 22, 2012
Dr. Ahmed Basyouni
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4. 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
May 22, 2012
Dr. Ahmed Basyouni
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5. Growth of the Maxilla
Growth of the surrounding soft tissues (eyeballs)
translates the maxilla downward and forward,
opening spaces in the sutures where bone is added.
May 22, 2012
Dr. Ahmed Basyouni
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6. Growth of the Maxilla
Midpalatal suture is opened until teenage years.
Apposition of bone in the molar area accounts for
space for the third molars.
May 22, 2012
Dr. Ahmed Basyouni
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7. Growth of the Maxilla
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.
May 22, 2012
Dr. Ahmed Basyouni
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8. Growth of the Face
Growth of the Mandible:
The mandible is mixed endochondrial and
intramembranous bone. It consists of three
major parts: the body, the alveolar process and
the two rami.
Ramus
Ramus
Alveolar
process
Body
May 22, 2012
Dr. Ahmed Basyouni
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9. Growth of the Face
Growth of the Mandible:
At birth the mandible resembles a
curved bar containing the tooth buds.
The condyle, coronoid, angular
(gonial), and alveolar processes are
poorly developed.
The mandible is formed of two halves
joined at the mental symphysis.
Postnatal closure of the symphysis
occurs during the first year of life.
May 22, 2012
Dr. Ahmed Basyouni
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10. Growth of the Mandible
Remodeling is done by resorption in the
anterior part of the ramus and deposition in the
posterior part of the ramus
May 22, 2012
Dr. Ahmed Basyouni
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11. Growth of the Mandible
The main sites of mandibular growth:
1. The mandibular condyle:
The cartilaginous growth of the condyle
is by surface apposition and interstitial
growth. Growth direction of the condyle
is upwards, backwards, and outwards so
the mandible is translated forwards and
downwards.
May 22, 2012
Dr. Ahmed Basyouni
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12. The main sites of mandibular growth:
2. Surface apposition and
remodeling resorption:
Surface apposition at the posterior
border of the mandible is the main
factor in the lengthening of the
mandible and decrease in the size
of the gonial angle from 170 at
birth to 120 degrees in adults.
May 22, 2012
Dr. Ahmed Basyouni
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13. The main sites of mandibular growth:
2. Surface apposition and remodeling resorption:
Resorption of bone at the anterior border of the
ramus takes place and contributes to the
lengthening of the alveolar bone posteriorly to
accommodate the erupting posterior teeth.
May 22, 2012
Dr. Ahmed Basyouni
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14. The main sites of mandibular growth:
2. Surface apposition and remodeling resorption:
Generalized surface apposition on the outer
surface of the mandible is responsible for
increase in its thickness.
May 22, 2012
Dr. Ahmed Basyouni
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15. The main sites of mandibular growth:
2. Surface apposition and remodeling resorption:
The mental foramen is situated during the
early years of life under the mesial cusp of the
first deciduous molar, whereas in adults it is
situated below and between the roots of the
first and second premolars, due to surface
apposition of bone.
May 22, 2012
Dr. Ahmed Basyouni
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16. Growth of the Mandible
Overall growth direction results in a downward
and forward displacement with most of growth
occurring in the ramus.
May 22, 2012
Dr. Ahmed Basyouni
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17. How to assess growth?
Hand wrist x-ray:
To assess skeletal age by comparing degree of
ossification of carpal bones of wrist, metacarpals
of hand and phalanges of the fingers to standard
atlas of hand-wrist development.
Sexual maturity: onset of menarche in girls,
voice changes and facial hair in boys.
May 22, 2012
Dr. Ahmed Basyouni
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18. How to assess growth?
Lateral cephalogram tracings:
superimpositions
Boy growing normally
Black - 10 years
Red - 14 years
May 22, 2012
Dr. Ahmed Basyouni
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19. 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 )horizontal or
vertical).
May 22, 2012
Dr. Ahmed Basyouni
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20. The Human Head Shape
Brachycephalic
• short and wide
“Brachy” tends to grow
horizontally;
Dolichocephalic
• tall and narrow
“Dolicho” tends to grow
vertically.
Knowing the general pattern of growth and the expected direction
can be helpful in orthodontic diagnosis and treatment planning.
May 22, 2012
Dr. Ahmed Basyouni
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21. Facial Profile
Convex
Retrognathic
May 22, 2012
Straight
Orthognathic
Dr. Ahmed Basyouni
Concave
Prognathic
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22. Summary of all
Definitions:
Growth
Development
Types of bone formation:
Intramembranous bone
Endochondrial bone
Sites of skull growth:
May 22, 2012
Dr. Ahmed Basyouni
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23. Summary of all
Growth of the head:
- Growth of the cranium:
Cranial vault.
Cranial base.
- Growth of the face:
Growth of the upper face (nasomaxillary complex).
Growth of the mandible.
May 22, 2012
Dr. Ahmed Basyouni
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24. Summary of all
How to assess growth.
Why do we assess growth.
Human head shape.
May 22, 2012
Dr. Ahmed Basyouni
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25. 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.
May 22, 2012
Dr. Ahmed Basyouni
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