At an undergratute level of undestanding basics on post natal development of cranial base maxilla and mandible

1. 1
Anoop J P
IVth Yr I BDS
SSDC, Varkala

2. GROWTH
 Growth, according to Todd, it’s the increase in size
 According to Krogmann, it’s the increase in size, change
in proportion, & progressive complexity
2
GROWTH & DEVELOPMENT

3.  According to Todd, Development is the progress
towards maturity.
 According to Moyers ,all naturally occurring
progressive, unidirectional sequential change occurring
in the life of an individual as its existence as single cell
to its elaboration as a multifactorial unit , terminating
towards death
3
DEVELOPMENT

4.  Bones of the base of the skull /cranial base are formed
initially in cartilage &are later transformed by
endochondral ossification to bone.
 Early in embryonic life , centers of ossification appears in
chondrocranium , indicating the eventual location of
basioccipital, sphenoid , & ethmoid bones that form cranial
base
4

5. 5

6. 6

7.  ossification proceeds bands of cartillage called
Synchondroses remain b/w the centers of
ossification.
 as
7
Remains of primary cartilaginous skeleton of cranial
base
Bands of cartillage present b/w sphenoid, ethmoid &
occipital bones
Form important growth sites at the base of the skull

8. Types of Synchondroses
 Intersphenoidal Fuses at birth
 Intraoccipital Fuses at 3-5 yrs
 Spheno-occipital Fuses at 20 yrs
 Spheno-ethmoidal exactly not known
8
Cranial base grows by cartilaginous growth in Synchondroses
which later get calcified

9. 9
Fig: Synchondroses

10.  Fig. showing growth at the synchondrosis. A band of immature
proliferating cartilage cells is located at the center of synchondrosis,
while the band of mature cartilage cells proliferate on both sides, away
from the center & endochondral ossification takes place on both
margins. Growth at synchondrosis lengthens this area of synchondrosis10

11.  Spheno occipital Synchondroses are responsible
for most of the lengthening of the cranial base
b/w foramen magnum & Sella turcica postnatal
which in turn helps in the lengthening /growth
of the Naso maxillary complex
11

12.  Morphologically, a synchondrosis is similar to the long
bone growth plate, except that growth at the
synchondrosis is not unipolar , but bipolar.
 The synchondrosis can be regarded as two growth
plates positioned back to back so that they share a
common zone of actively proliferating chondroblasts,
or the “rest zone”.
12
HISTOLOGY OF SYNCHONDROSES

13.  The different zones of the synchondrosis mirror each other
such that there is cartilage in the centre and bone at each end.
 Synchondroses is an area of cellular hyperplasia &
hypertrophy in the center with bands of maturing cartilage
cells extending in both directions which eventually being
replaced by bone.
13

14. 14
Fig. shows histologic appearance of
synchondrosis with ossification taking place
on both sides of primary cartillage

15.  Cranial base flexion is a unique cranial feature of
modern human beings and also a reflection of brain
evolution
 Fusion along the Spheno-occipital Synchondroses is
believed to be responsible for cranial base flexion,
which develops in concert with the development of the
upper airway and the ability to vocalize.
15
CRANIAL BASE ANGLE

16.  During development, the anterior and posterior cranial base
flexes at the sella turcica in the middle sagittal plane and thus
constitutes an angle in the cranial base, termed the cranial
base angle or saddle angle
16

17.  Abnormal growth of cranial base can result in
severe dentofacial deformity eg – Craniofacial
Dysostosis
 An obtuse cranial base angle increases the
depth of maxilla & causes Mandibular
retrognathism & vice versa
17
Clinical implications of growth of cranial base

18. 18
An Obtuse cranial Base
angle causing Maxillary
Prognathism
An Acute Cranial Base
angle causing Mandibular
Prognathism

19. 19
Craniofacial

20.  Enlow’s Counterpart Principle
Counterpart principle of craniofacial growth states
that the growth of any given facial/cranial part
relates specifically to other structural counterparts
in face & cranium.
 cranial base growth have effect on maxillary &
mandibular growth .
 Maxillary growth is based on growth of Anterior
Cranial Fossa
20

21.  Similarly width of pharyngeal cavity depends on
width of middle cranial fossa
 Width of Mid-cranial fossa is same as that ramus
width
 ANS- Posterior Nasal Spine length of maxilla
determine the length of Corpus of mandible
21

22.  Maxillary tuberosity determining the width of lingual
tuberosity
 Posterior cranial Fossa determine the mandibular
position
 Amount , direction & magnitude of cranial base
determine the amount , direction & magnitude of
maxilla & mandible
22

23. POSTNATAL DEVELOPMENT OF MAXILLA
1. Zygomatico-
maxillary
2. Zygomatico-
frontal
3. Intermaxillary
4. Frontomaxillary
Connective tissue growth “Bone fill at the space”
23
RemodelingGrowth at sutures Translation
Active growth at
tuberosity
Periosteal
matrix
funtion
Deposition/
resorption
Passive
Forward &
downward
Capsular
matrix
Nasal
septum

24.  2 Types -
24
Growth Movements
Drift Displace
ment

25.  Internal displacement of Nasomaxillary complex
itself due to growth .
 It’s the movement of bone surface caused by
deposition & resorption towards the depository
surface .Its otherwise called Transformation
25
DRIFT

26.  Displacement is the growth of bone as a whole unit
so that the bone is taken away from its articulation
with other bones.
 Also called as Translation
26
DISPLACEMENT

27.  Maxilla articulate with the surrounding bone with
help of sutures.
Sutures incl. Zygomaticomaxillary,
Frontomaxillary, Pterygopalatine ,
Zygomaticotemporal etc..
According to sicher
Growth in sutures Move
maxilla downwards & forwards
27
CONNECTIVE TISSUE PROLIFERATION

28.  But it’s only a secondary & not a primary mechanism
28

29. 29

30.  Translation/Displacement is process by which
specific local areas come to occupy new actual
positions in succession as entire bone enlarges.
 2 types
30
Active/Primary
Passive/Secon
dary

31.  Active displacement takes place when the growth at
the tuberosity of the maxilla pushes the maxilla
forward.
Passive displacement takes place when maxilla grows
downward & forward by the growth of the Spheno-
Occipital Synchondrosis of the cranial base /growth of
nasal septum.
31
Active/Primary Displacement
Passive/Secondary Displacement

32.  Passive displacement also takes place when the
maxillary bone is translated in space by the growth
of corresponding capsular matrices
 Three main capsules w.r.t Nasomaxillary complex
32
ORBITA
L
NASAL ORAL

33.  In Remodeling simultaneous resorption and
deposition of the maxilla while maintaining the
integrity & shape of bone.
 Maxillary growth matures first in Width followed
by Length & Height
 Width across the 2nd molar & 3rd molar increases
until the end of growth in len`gth
33
REMODELLING

34.  Midpalatal suture is active up to 15 yrs. There is
bone fill in the midpalatal area due to sutural growth
resorption in lateral aspect.
 In case of Maxillary sinus sinus
enlarges Resorption on inner aspect
& deposition on outer aspect
34
MAXILLARY WIDTH

35.  There is removal of bone from periosteum, lining
the inner aspect of the nasal cavity & deposition
takes place in the endosteal surface , allowing the
expansion of nasal cavity
35
NASAL CAVITY

36.  In the antero-posterior direction there is growth by
apposition in the posterior tuberosity area so that
there is increased space for permanent teeth.
 As the maxilla moves forward , there is resorption
of the anterior surface of the periosteum from ANS
to alveolar margin incisors, result
Concave anterior margin
 Deposition occurs in the ANS to make it make
prominent
36
ANTERO-POSTERIOR DEPTH

37.  Resorption anterior region &
Apposition posterior region
of zygomatic bone –result Translation
of zygomatic bone posteriorly
37

38. 38

39.  In vertical direction maxillary bones increase in height by
apposition along the alveolar process
This increase is seen as long as the teeth erupt
This contributes early increase in height
of maxilla
39
MAXILLARY HEIGHT

40.  40% of the maxillary height is achieved by this.
 Resorption Palatal surfaces &
Deposition Palatal roof
End result Downward shift of palate
40

41.  Follows the concept of expanding ‘V’ by Enlow
41
POSTNATAL GROWTH OF PALATE
Bone deposition inner aspect of ‘V’
Direction of growth Wide end of ‘V’
Periosteal surface lined by Osteoclasts
Endosteal surface lined with Osteoblasts

42. 42

43. Growth in width is completed first then length &
height
Growth in width of Jaws & Dental arches completed
before adolescent growth spurt
43
TIMING OF GROWTH IN WIDTH,
LENGTH & HEIGHT

44.  As the jaws grow in length posteriorly, they also
increase in width
 for the mandible, both molar & bicondylar widths
shows small increase until end of growth in length
Growth in length & height of jaws continues through
the puberty .
44

45. In both sexes , growth in vertical height of face
continues longer than growth in length, with the
late vertical growth in mandible.
 Increase in facial height & concomitant eruption
of teeth continue throughout the life, but decline
to adult life
45

46. POSTNATAL GROWTH OF
MANDIBLE
 Mandible at birth is much smaller in size & there is
slight variation in shape from the adult form
 Infant mandible has a short more or less horizontal
ramus with Obtuse Gonial angle
 Mandibular growth continues at relatively steady
rate before puberty.
46

47. The condyles are low & at the position along the
occlusal plane .
 Symphyseal suture has not yet ossified
47

48. 48

49. o Growth in the first year involves growth at the
symphyseal suture & lateral expansion in the
anterior region to accommodate the erupting the
teeth .
o Mental foramen is directed at right angles to the
surface of the corpus.
o There is increased deposition in the posterior
surface of ramus of mandible.
49
GROWTH IN THE FIRST YEAR

50. MANDIBLE IN THE ADULT
 Mandible in the adult is different from the mandible
of an infant.
 Ramus is longer & gonial angle is less obtuse.
50

51. 51

52.  All those changes taking place with the growth of
mandible is in the form of expanding V.
 It’s easier to visualize mandible as V-shaped bone
than maxilla because of it’s horseshoe shape.
52
V- PRINCIPLE OF GROWTH

53. 53
Fig. showing
Mandibular
growth in the
form of ‘V’

54. 54
FUNCTIONAL MATRICES OF
MANDIBLE

55.  Lateral of ramus Deposition &
Lingual surface Resorption
of mylohyoid ridge
 Coronoid process Apposition
its Lateral surface Resorption
 Condyle Resorption at
lateral aspect
55
GROWTH IN WIDTH

56.  Thus Inter-ramal distance is efficiently increased by
the growth of mandible following the V- Principle
 The growth of mandible in length A-P is by the
deposition of bone at the posterior surface of the
Ramus &
 Resorption at the Anterior surface
56
GROWTH IN LENGTH

57.  This helps lengthen the mandible
anterior part of the ramus is occupied by posterior
part of the body in the future to Accommodate
permanent molars
57
Deposition - +
Resorption - -

58. Alveolar process height correlates well with the
eruption of teeth
 Bone deposition taking place in the lower
border of mandible also contributes to increase
in height of the mandible
58
GROWTH IN HEIGHT

59.  Arne Bjork et.al , Dept. Of Orthodontics, Royal
dental college , Copenhagen, Denmark performed
longitudinal Radiographic study by Implant method
for studying Jaw rotations
 Longitudinal study involved about 110 Danish
children of 7 yrs. to 18 yrs old.
59
GROWTH ROTATIONS

60. 60
Instruments used by Bjork
for inserting metallic
implants in mandible

61. 61
3 types of metallic
implants tested
A)
Kirschner
wire
B)
Cr-Co
Alloy
C)
Tantalum
Wire

62. 62
For the radiographic profile analysis of mandibular growth, one implant was
inserted in the mid-line of the symphysis, and three on the right side nearest the
film: under the first and second premolars, and in the external aspect of the
ramus on a level with the occlusal lines.

63. condition Bjork Proffit
Rotation of
mandibular core
relative to
Cranial Base
Total rotation Internal rotation
Rotation of
Mandibular
plane relative to
Cranial base
Matrix rotation Total rotation
Rotation of
Mandibular
plane relative to
Intramatrix
rotation
External
rotation63
TERMINOLOGY OF ROTATIONAL CHANGES OF JAWS

64. 
 Total Rotation = Internal Rotation - External Rotation
Relationship b/w Matrix, Total & Intramatrix
Rotation (Bjork)
Matrix Rotation = Total Rotation – Intramatrix
Rotation
64
Relationship b/w Total , Internal &
External rotation (Proffit)

65.  Bone that surrounds the inferior alveolar nerve
& the rest of the mandible consists of its
functional processes
 Functional processes incl. muscular processes
, the condylar process, functions incase being
the articulation of the jaw with the skull.
65
CORE OF THE MANDIBLE

66. 66

67.  If implants are placed in areas of stable bone
away from the functional processes, it can be
observed that In most individuals , the core of
the mandible rotates during growth in a way
that tend to decrease the mandibular plane
angle
(i.e up anteriorly & down posteriorly)
67

68.  Bjork & Skieller distinguished 2 contributions to Internal rotation(
Total rotation) of the mandible
Matrix Rotation/rotn around Condyle
Intramatrix Rotation/rotn centered
within the body of the mandible
68
Total
rotation

69.  Variation of internal rotation of mandible b/w
individuals, ranging up to 10 to 15 degrees.
 For an average individual with normal vertical
facial height there is about -15 degrees internal
rotation from age 4 – adult life
25% - Matrix rotation &
75% - Intramatrix rotation69

70.  When the core of the mandible rotates forward an average
of 15degrees, orientation of jaw from outside
decreases only 2 – 4 degrees(av..)
 Internal rotation is not expressed in jaw orientation , surface
changes tends to compensate i.e. ,posterior part of lower
border of mandible may be the area of resorption, while
anterior aspect of lower border is unchanged / little
apposition
70
Reason

71. 71

72. SHORT FACED INDIVIDUALS/
FORWARD ROTATORS
 These individuals are characterized by short anterior
lower facial height
 Excessive forward rotation of mandible, due to an
increase in normal internal rotation & a decrease in
external compensation
72

73.  Square type jaw + Low mandibular plane
angle+ Square Gonial angle +skeletal Deep bite
malocclusion + crowded Incisors
Muscles much stronger they mature early
Space closure is very difficult .
73

74. 
74
Facial height ratio (upper : lower ) – 50 : 50 / 50 :
45

75.  Characterized by excessive lower anterior face height.
 Palatal plane rotates down posteriorly.
Creates a negative rather than the normal
positive inclination to the true horizontal
75

76.  Mandible shows an opposite ,backward rotation
with an increase in mandibular plane angle
Weak musculature & mature late , so avoid mechanics
which increase vertical height of patient
 facial height ratio (upper: lower) is exaggerated
76

77. Avoid bite planes
 Avoid anchor bends
 Avoid class II elastics
77
In these patients we should avoid :-

78.  This type of rotation is normally associated
with Skeletal Anterior Open Bite
malocclusion(because chin rotates back well as
down)
Backward rotation of mandible also occurs in
patients with abnormalities/pathological changes
affecting the TMJ
In TMJ patients growth of condyle is restricted
78

79. 79

80. Rotation pattern of jaw growth obviously influences
tooth eruption
 It can also influence the direction of eruption &
ultimate antero-posterior position of incisor teeth .
80
INTERACTION BETWEEN JAW ROTATION
& TOOTH ERUPTION

81.  Path of eruption of Maxillary teeth is downward
& forward
 Normally maxilla rotates slightly few degrees
forward & frequently backward
 Forward Rotation tends to tip
incisors forwards & increasing their prominence.
 Backward Rotation directs ant.
teeth more posteriorly than normal, up righting them
& decreasing their prominence
81

82.  Movement of teeth relative to cranial base obviously
could be produced by
 Translocation bring about ½ of the total maxillary
tooth movement during adolescent growth
82

83.  Eruption path of mandibular teeth is upward &
forward.
Normal Internal rotation of the mandible carries
the jaw upward in front
This rotation alters the eruption path of incisors,
tending to direct them more posteriorly than
would other wise have been the case.
83

84.  When excessive rotation occurs in short face type of
development, the incisors tend to carried into an
overlapping position even if they erupt very little;
hence the tendency for Deep Bite Malocclusion
The rotation also progressively upright’s incisors,
displacing them lingually & causing a tendency
towards Crowding
84

85.  In long face growth pattern anterior open bite will
develop as the anterior face height increases unless
incisor erupt for an extreme distance
 Rotation of jaw also carries the incisor forward ,
creating a dental protrusion
85

86. Change in
soft tissues
like Nose&
Lips
Change in
Eruption –
Active &
Passive
Alignment
changes &
changes in
Occlusion
86
AGE CHANGES IN GROWTH
PATTERN

87.  Changes in soft tissue not only continues with
aging, they are much larger in magnitude than
changes in hard tissue .
 The Lips &other soft tissues of face , sag downward
with aging.
 The result is a decrease in exposure of upper
incisors, & an increase in exposure of lower
incisors , both at rest & on smile
87
CHANGES IN FACIAL SOFT
TISSUE

88.  With aging , Lips also become progressively thinner,
less vermillion display.
88

89. 89

90. Active Eruption
 Active eruption has been described as the eruption
process of a tooth and their alveoli through the
gingival tissues (Moshrefi 2000). This phase ends
when the tooth makes contact with the opposing
dentition but may continue with occlusal wear or loss
of opposing teeth (Dolt 1997).
90
CHANGES IN ERUPTION

91.  Passive eruption begins once active eruption has
completed. This takes place as the dentogingival unit
migrates in the apical direction until it is adjacent to
the cemento-enamel junction (CEJ) (Evian et al. 1993).
 In contrast to active eruption, passive eruption is the
apparent lengthening of the crown due to the loss of
attachment, or recession of the gingiva, also due to
inflammation.
91
PASSIVE ERUPTION

92. 92
Passively
erupted
teeth
After
surgical
Correctio
n

93.  Its due to
93
CHANGES IN ALIGNMENT &
OCCLUSION
Lack of
Attrition
Pressure
from 3rd
Molars
Late
mandibul
ar Growth

94.  Raymond Begg ,a pioneer Australian orthodontist noted his
studies of Australian aborigines that malocclusion is
uncommon but large amounts of interproximal & occlusal
attrition occurred
 He concluded that in modern populations the teeth became
crowded when attrition didn’t occur with soft diets, &
advocated wide spread extraction of premolar teeth to
provide equivalent of the attrition he saw in aborgines
94
LACK OF ATTRITION

95. a) Late incisor crowding coincides with the time of
eruption of 3rd molars
b) So one school of thought says that the pressure
from the erupting 3rd molars, causes mesial
migration of teeth,which is the reason for late
incisor crowding
c) But the amount of pressure from 3rd molars is not
sufficient to cause pressure effect & changes in
lower incisors
95
PRESSURE FROM THIRD MOLARS

96.  Mandibular growth continues even after the
cessation of the maxillary growth in late teens
 When mandible grows forward relative to maxilla,
in late teens mandibular incisors tends to move
lingually, particularly if any excess rotation is
present.
 Due to the mandibular growth, if there where any
tight anterior occlusion before the late mandibular
growth occurs one of the 3 of the following can
occur 96
LATE MANDIBULAR GROWTH

97. Mandible is displaced distally & can cause TMJ
distortion & displacement of Articular disc
Upper incisors may flare forward, opening
space b/w the teeth
Lower Incisors may displace distally & become
crowded
97

98.  Malocclusions & Dentofacial deformity arises through variations
in normal developmental process
 A thorough background in craniofacial growth & development is
necessary for every dentist
 A thorough knowledge is also necessary because orthodontic
treatment involves the manipulation of skeletal growth & dental
growth .
 So once alteration/modification is been done, its done for ever
98
CONCLUSION

99.  Contemporary Orthodontics - William R Proffit
 Relationship b/w - Open Anatomy Journal
synchondrosis & craniofacial gth 2010/ Vol 2
 Journal of Dental Research - http//jdr.Sagepub.com
 Sutural Growth by Implant - http//ejo.oxfordjournals.org
method
 Morphogenic analysis of facial
growth - Enlow
 Orthodontics (Art & Science) - S I Balaji
 Orthodontics - Sridhar Premkumar
 Textbook of orthodontics - Gurkeerat Singh
99
BIBILIOGRAPHY

100.  THANK U
100