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5. What is post natal growth??
Post natal growth is the first 20 years of
growth after birth.
It comprises of 3periods;
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6. How does it differ from prenatal
growth??
Prenatal growth is characterized by a
rapid increase in cell numbers and fast
growth rates
Postnatal growth is characterized by
declining growth rates and increasing
maturation of tissues.
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8. Terminologies
Deposition –
addition of new bone to the bony
surface by osteoblastic activity
Resorption – removal of bone due to
osteoclastic activity
++
+
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10.
Remodeling –
reshaping of the outline of the bone by
selective resorption of bone in some areas
and deposition in other areas
Relocation –
relative movement in space of a bony
structure, due to bone deposition on one
side and resorption on the other side
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14. Enlow’s counterpart principle
Growth of any given facial or cranial part relates
specially to other structural and geometric
counterparts in the face or cranium
Regional relationships exist ---craniofacial region
Balanced
counterparts
growth
=
Regional
and
corresponding
enlarge to same extent
Imbalance in regional relationship is due to differences
in
Amount of growth
Direction
Time
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15. Different parts and their counterparts
Part
Counterpart
Palate
Anterior cranial fossa
Middle cranial fossa
Ramus of the mandible
Maxillary arch
Mandibular arch
Maxillary tubeosity
Lingual tuberosity
Bony maxilla
Corpus of the mandible
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17. Five steps to Endochondral bone
formation
Hypertrophy of chondrocytes and matrix
calcifies
Invasion of blood vessels and the
connective tissue
Osteoblasts differentiate and produce
osteoid tissue
Osteoid tissue calcifies
Membrane covers bone and is essential
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18. Five steps to Intramembranous
bone formation
Osteoblasts produce osteoid tissue
Cells and blood vessles are encased
Osteoid tissue is produced by
membrane cells
Osteoid calcifies
Essential membrane covers the bone
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21. Cranial vault
Functions: protection of brain- primary
function
Growth
1)Mechanisms and sites
Cranium grows ---as brain grows
Accelerated during infancy, 90% of it is
complete by 5th year
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22.
As brain expands, bones of calvaria are
displaced correspondingly outwards
Primary displacement causes tension in
the sutural membranes – immediate
response– sutural edges
At same time new bone is also formed on
the flat surfaces– both, ecto- &endocranial
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26. To summarise,
Increase in cranial width
Primarily
through “fill-in” ossification of
proliferating
connective
tissue
in
the
coronal.lamboidal.interparital.paritosphenoidal
and paritotemporal sutures.
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27.
Increase in cranial length
Growth of the cranial base– active response
at the coronal suture
Increase in cranial height
Activity
of parietal sutures along with
occipital,
temporal
and
sphenoidal
contiguous ossious structures
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28. According to Davenport
Length of brain case at different ages is as
follows: Age
Growth in %
Birth
63
6 months
76
1 year
82
2 year
87
3 years
89
5 years
91
10 years
95
15 years
98
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29. Timing
Growth under the influence of the
expansion of the enclosed brain
Brain growth largely completed by early
childhood
Cranial vault --- one of the first regions
to attain full size
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30. Basicranium
Functions
Adapted to upright the body posture
Development
of
large
cerebral
hemispheres
Articulates
the
skull
with
vertebral
column, mandible and maxillary region
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31.
Buffer zone between brain, face and
pharyngeal region
Template for facial growth
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32.
The neural side of cranial floor different
from calvaria
The endocranial surface of basicranium
is resorptive in most areas
Further,
fossa
accomplished
by
enlargement
direct
is
remodeling
involving on the outside with resorption
inside.
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34.
Middle and posterior fossae divided by
the petrous elevation
Olfactory fossae separated by crista galli
The right and left middle cranial
fossae--- longitudinal midline sphenoidal
elevation
Right and left anterior and posterior
cranial fossae---- longitudinal midline
bony ridge
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35. Mechanism and Sites
Elongation at synchondroses
Cortical drift and remodeling
Sutural growth
This combination provides
Differential growth enlargement between
the cranial floor and calvaria
Expansion of confined contours in the
various endo cranial fossae
Maintenance of passages and housing for
vessels and nerves
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36.
Midventral segment of cranial floor
grows much slowly than the floor of the
laterally located fossae.
Expansion of hemispheres--- sutural
growth and cortical drift
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40.
Intra-occipital
Ossifies by 3-5 years
Spheno-occipital
Principal growth cartilage during childhood
period
Provides a pressure adapted bone growth
mechanism
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42. Bone remodeling seen in
cranial base
1- resorption on
the anterior wall of
middle
cranial
fossa
2- deposition on
the orbital face of
sphenoid
3-anterior
displacement
of
ant. cranial fossa
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43.
4-Elevation of petrous temporal bone
Lowering of the foramen magnum
Perimeter of the foramen enlarges
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45. Nasomaxillary complex
Functions
Important role in mastication
(attachments of teeth and muscles)
Provides significant portion of airway
Houses olfactory nerve endings
Encloses eyes
Adds resonance to the voice through the
sinuses contained within the region
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46. Nasomaxillary complex
Mechanisms and Sites
Growth observed at
Sutures
Nasal septum
Periosteal and endosteal surface
Alveolar process
According to Mills “maxilla increases in
size by subperiosteal activity postnatally
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47. Maxilla
The growth mechanism is produced by
Displacement
Growth at sutures
Surface remodelling
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48.
Primary displacement
Active, downward and forward
Maxillary tuberosity lengthening posteriorly
Secondary displacementPassive, downward and forward direction
Cranial base– middle cranial fossa grows
anteriorly
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49. Which is the biomechanical force underlying the
maxillary displacement??
Primary displacement- anterior and inferior
as it grows and lengthens posteriorly
Nature of this displacement--- reviewed
historically
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51.
Bone growth within the various maxillary
sutures produces pushing-apart of the
bones, with resultant thrust of whole
maxilla being displaced anteriorly and
inferiorly as well.
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52. Nasal septum theory – Scott
Pressure accomodating expansion of
nasal septal cartilage– source of physical
force
Drawbacks
Source of displacement is multifactorial
Experimental
studies– surgical deletion
affected the growth process; not that they
control growth process
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54.
Functional matrix concept
Facial bones grow in a sub-ordinate
growth control relationship with all
surrounding, pace-making soft tissues
Note
Concept five
Operation of growth fields – carried out by
osteogenic
membrane
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and
other
55. Growth at sutures
Fronto-nasal
Fronto- maxillary
Zygomatic-temporal
Zygomatico-maxillary
Pterygo-palatine
All are oblique; more or less parallel to
each other
Downward and forward growth
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58.
Resorption occurs on the lateral surface
of orbital rim leading to lateral
movement of the eye ball
Floor of orbit-deposition in superior,
lateral and anterior direction
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64.
Zygomatic bone moves in posterior
direction.
Anterior
nasal
spine prominence
increases due to bone deposition
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65. Maxillary height
Sutural growth toward the frontal and zygomatic bones
Appositional growth towards the alveolar process
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66. Maxillary width
Growth in median sutures
Vertical drift of posterior teeth with lateral
expansion---- alveolar divergence
Mutual transverse rotations of maxillae--separation of the halves more posteriorly
than anteriorlyMaxillary length
Apposition on the maxillary tuberosity
Sutural growth towards the palatine bone
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67. Mandible
Mandible undergoes the largest amount
of growth post-natally and also exhibits
the largest variability
The functional parts includeRamus
Corpus
Angle of mandible
Lingual tuberosity
The alveolar process
The chin
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69. Ramus
Function
Provides an attachment base for
masticatory muscles
Plays key role in placing the corpus and
dental arch into ever-changing fit with the
growing maxilla and the
limitless
structural variations of face
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70. Mechanisms and sites
Moves posteriorly ; combination of
resorption and deposition
Resorption –anterior ramus while
deposition posteriorly---drift posteriorly
Functions of remodel—
Accommodate the increasing mass of
masticatory
Enlarged breadth of pharyngeal space
Lengthening of corpus
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71. Corpus
As anterior border of ramus resorbs –
posterior drift
Conversion of earlier ramus into
posterior part of the body.
Thus body of the mandible lengthens
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72. Ramus to corpus remodeling conversion
Ramus relocated in a posterior direction;
Bony arch length increased
Resorption of anterior border of
ramus---- making room for the last molar
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73. Coronoid process
Follows V principle
Lingual surface faces- 3 directions—
posterior, superior and medial
Lengthens vertically- V oriented
vertically
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74.
Deposition occurs on lingual surface
Also posterior movement seen – V
oriented horizontally
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75. Angle of the mandible
Lingual side- resorption antero-inferiorly
while deposition postero-superiorly
Buccal side vice versa
This results in flaring of mandible
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77. Alveolar process
Develops in response to tooth buds
As teeth erupt the alveolar process erupt
Adds height and thickness to body of
mandible
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78. Chin
A specific human characteristic; recent
man only
As age advances the growth of chin
becomes significant
Sexual and genetic factors
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79. Mechanism
Cartilage is special
non-vascular tissue
Secondary
type of
cartilage
Endochondral
mechanism of bone
formation—due
to
variable
levels
of
compression
Proliferative process –
upward and backward
growth of condyle
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80. Height
Ramus height increases correlate with
corpus length
Anterior mandibular height is related to
dental
development
and
overall
downward and forward growth of
mandible
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81. Width
Bigonial
and bicondylar diameter
increase– divergence of mandible
Most width increases as it grows longer
(Enlow’s V principle)
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82. Length
By combination of resorption and
deposition at the ramus-corpus interface
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84. Facial form and anatomic
basis for malocclusions
Dolicocephalic facial form
Brain inhorizontally long and relatively
narrow
Basicranium more flat and horizontally
longer
Nasomaxillary complex in a protrusive
position relative to mandible
Mandible – downward and backward
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85. Brachycephalic
Brain – rounder and wider
Basicranium more upright and short
Nasomaxillary complex is short
horizontally
Retrusive maxilla and a more relatively
prognathic mandible
Prognathic profile, Class III molar
relarionship
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86. Condyle
Anatomic part of special significance
Evolutionary changes
Earlier thought to be the master center;
now a regional field of gowth– regional
adaptive growth
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87.
Interrelationship among brain form,
facial profile & occlusal type predisposes
--- facial form and malocclusion
Examples
Caucasian groups-dolichocephalic
headform, Class II malocclusions and
retrognathic profile
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88. Clinical implications of growth
in 3 dimensions
Sequence of growth cessation
Growth in width --- transverse plane
Growth in length ---- antero-posterior
plane
Growth in height----- vertical plane
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90.
Minimally affected by adolescent growth
changes
Example 1: 13 year old girl with cross bite;
transverse growth ceased.
procedures ruled out.
Interceptive
Role
of midpalatal suture in lateral
displacement of palatal shelves is minimal
○ Maxillary expansion even after suture closure
should be possible
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91. Antero-posterior plane,
Jaws to continue throughout puberty
For example,
13 yearold girl- orthognathic maxilla and
retrognathic mandible; myofunctional
appliances can be given
In case of retrognathic maxilla, protraction of
maxilla not indicated beyond 14 years
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92. Vertical plane
Growth occurs upto 18-19 years
Most common discrepancies
Open bite--- Skeletal / Dental
Deep bite--- Skeletal / Dental
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