The document discusses postnatal growth and development of the maxilla and mandible. It describes how the maxilla grows through displacement, growth at sutures, and surface remodeling, with the maxillary tuberosity, palate, and sinus undergoing specific changes. The mandible grows primarily through remodeling at the condyle, ramus, and alveolar process. Various theories of craniofacial growth are also summarized, along with clinical implications such as cleft lip/palate and space maintenance for orthodontic treatment.

1. POST NATAL
GROWTH & DEVELOPMENT OF
MAXILLA AND MANDIBLE
PRESENTATION BY:
DR.SHEHNAZ JAHANGIR
FIRST YEAR MDS
DEPT OF ORTHODONTICS & DENTOFACIAL ORTHOPAEDICS
NICDS

2. ANATOMY OF MAXILLA

3. BODY (CORPUS MAXILLAE) :

4. ANTERIOR SURFACE :

5. POSTERIOR/ INFRATEMPORAL SURFACE :

6. SUPERIOR / ORBITAL SURFACE :

7. NASAL / MEDIAL SURFACE :

8. PROCESSES :
1. Zygomatic : Marks the division between anterior and
infratemporal surface.
2. Frontal : Forms the lateral boundary of the nose.
3. Palatine : Forms considerable part of the floor of the nose
and roof of the mouth.
4. Alveolar process : Houses roots of teeth.
Ref : B.D Chaurasia, Vol. 3, Pg - 38

9. AGE CHANGES :
At Birth :

10. In Adults :

11. In Old Age :

12. ARTICULATIONS OF MAXILLA
 Superiorly, it articulates with three bones, the
nasal, frontal and lacrimal.
 Medially, it articulates with five bones, the ethmoid,
inferior nasal concha, vomer, palatine and opposite
maxilla.
 Laterally, it articulates with one bone, the zygomatic
bone.
Ref : B.D. Chaurasia,Vol. 3, Pg - 39

14. FUNCTIONS OF MAXILLA
 Mastication.
 Provides path of airway.
 Separate nasal from oral cavity.
 Houses olfactory nerve endings.
 Encloses the eyes.
 Adds resonance to voice because of sinuses.

15. DEFINITION :
 Profitt – Growth is defined as an increase in size or
number and development is in complexity.
 Todd – Growth is an increase in size &
Development is progress towards maturity.
 JX Huxley – The self multiplication of living
substance
 Moss – Change in any morphological parameter,
which is measurable.

17. POSTNATAL GROWTH OF MAXILLA
 Just as the mandible remodels in a
predominantly posterio-superior manner as
it simultaneously becomes displaced in an
opposite antero-inferior direction the naso-
maxillary complex also grows in a
generally comparable way.
Ref : Enlow’s Facial Growth

18.  The growth of nasomaxillary complex is produced
by following mechanism:
1. Displacement
2. Growth at sutures
3. Surface remodelling

19. 1.DISPLACEMENT
 Maxilla is attached to the cranial base by means of
a number of sutures.
 Thus the growth of cranial base has a direct bearing
on the nasomaxillary growth.

20.  A passive or secondary displacement of the
nasomaxillary complex occurs in a downward and
forward direction as the cranial base grows.
 Primary type of displacement is also seen in the
forward direction by growth of the maxillary
tuberosity.

22. 2.GROWTH AT SUTURES
 The maxilla is connected to the cranium and cranial
base by a number of sutures.
 These includes
1. Fronto-nasal suture
2. Fronto-maxillary suture
3. Zygomatico-temporal suture
4. Zygomatico-maxillary suture
5. Pterygo-palatine suture

24. 3.SURFACE REMODELLING
 Massive bone remodelling by deposition and
resorption occurs to bring about :
1. Increase in size
2. Change in shape of bone
3. Change in functional relationship

25. ORBIT

26. MAXILLARY TUBEROSITY AND ARCH
LENGTHENING
 Remodeling at the maxillary tuberosity causes
horizontal lengthening. It is a depository field, hence
causes lengthening and widening of the arch and
provides space for the eruption of molars.
 Allows the clinician to “expand the arch” by
distalization of molars into an area of bone
deposition.
Ref : Enlow’s Facial Growth

28. LACRIMAL SUTURE
 The lacrimal bone is a bony island with its entire
perimeter bounded by sutural connective tissue
contacts separating it from many other surrounding
bones.
Ref : Enlow’s Facial Growth

29. KEY RIDGE
 Major change in surface contour occurs along the
vertical crest just below the malar protuberance
called the key ridge.

30. ALVEOLAR RIDGES
 It occurs by bone deposition at alveolar margins.
 It is termed as vertical drift.
 This increases the maxillary height and depth of
palate

31. PALATAL REMODELLING
 The external labial side of the whole anterior part of
the maxillary arch is resorptive with bone being
added into the inside of the arch, the arch increases
in width and the palate becomes wider.
 (V Principle)
Ref : Enlow’s Facial Growth, Pg - 119

32. NASAL CAVITY
 The lining surface of the bony walls and floor of the
nasal chambers are predominantly resorptive,
which produces a lateral and anterior expansion of
the nasal chambers.

33. ZYGOMATIC BONE

34. MAXILLARY SINUS
 The lining cortical surface of the sinus are all
resorptive except the medial nasal wall which is
depository as it remodels laterally to accommodate
nasal expansion.

35. EXPANSION OF MAXILLARY SINUS
At birth - 7 mm length
- 4 mm height
- 4 mm width
Expands at
rate of - 2 mm vertically yearly
- 3mm A-P yearly
Expansion by - bone resorption
- by tooth eruption
(as vacated bone become
pneumatized)

36. GROWTH ROTATION OF MAXILLA
 Maxilla undergoes extensive remodeling and
displacements when subjected to various functional
demands.
 Generally, the vector of maxillary growth is in
anterior and inferior direction (downward and
forward displacement).

37. BJORK AND SKEILLER INTRODUCED VARIOUS
TERMINOLOGIES TO DESCRIBE THE GROWTH
ROTATION OF MAXILLA.
 Internal rotation
 This is the rotational pattern that occurs in the core
of the maxilla. This is also called intramatrix
rotation. The internal rotation is similar to intramatrix
rotation of mandible.
 External rotation:
 Simultaneous to internal rotation of maxilla, varying
degrees of resorption of bone on the nasal side and
apposition of bone on the palatal side in anterior
and posterior parts of the palate also takes place.

38.  This external rotation is usually opposite in direction
and equal in magnitude to the internal rotation, so
that the two rotations cancel each other and the net
change in jaw orientation, as evaluated by the
palatal plane is zero.
 Depending upon the different degrees of
combination of internal and external rotations, Bjork
and Skeiller observed two types of rotational
growth.
 The terminologies they used are forward and
backward rotations.

39.  Forward growth rotation: This condition occurs
either due to excessive internal rotation or lack of
normal compensatory external rotation or a
combination of both.
 Here, the maxilla is inclined upward and forward,
that is, the anterior end is tipped up.
 This is also called ante inclination as coined by
Schwarz.
 He also named this condition as pseudo-protrusion.
 This forward rotation also tends to tip the incisors
forward, increasing their prominence.

40.  Backward rotation: Backward rotation of maxilla is
exactly opposite to that of forward rotation where
there is downward and backward tipping of the
anterior end of the palatal plane and the maxillary
base.
 This is otherwise called as retroinclination, a term
coined by Schwarz.
 In this type of maxillary displacement, the jaw
bases are translated posteriorly and the upper
incisors appear to tip lingually.

41. DOWNWARD MAXILLARY DISPLACEMENT
 The primary displacement of the whole
ethmomaxillary complex in an inferior direction is
accomplished by simultaneous remodelling in all
areas, inside and out throughout the entire
nasomaxillary region.

42. MAXILLARY HEIGHT
 Classic implant studies of Bjork and Skiellerlo
confirm that maxillary height increases because of
sutural growth towards the frontal and zygomatic
bones and appostional growth in the alveolar
process.

43. MAXILLARY WIDTH
 Growth in the median suture is more important for
appositional remodeling in the development of
maxillary width.
 Growth increase at the median suture mimic the
general growth curve for body height.

44. MAXILLARY LENGTH
 Length increases in the maxilla after about the
second year, occurs by apposition on the maxillary
tuberosity and by sutural growth toward the palatine
bone.
 Bjork and Skieller’s implant studies show that
anterior surface to be rather stable sagitally, but the
maxillary arch is remodeling as it grows downward,
which is why the anterior region is resorptive.

45. RELEVANT THEORIES OF GROWTH
1) Remodelling theory by Brash (1930’s) :
 First general theory of craniofacial growth.
 Postulated that all the growth occurs exclusively by
bone remodelling and that sutures and cartilages have
little or no role in growth of craniofacial skeleton
 Growth of jaw is characterized by deposition of bone at
the posterior surface of maxilla and mandible.

46. 2) Sutural Dominance Theory by Weinmann and Sicher
(1940’s) :
 According to this theory, the nasomaxillary complex is
attached to the cranial base by a number of sutures
which push the nasomaxillary complex downward and
forward.

47. 3) Nasal Septal Theory by Scott (1950’s) :
 Also known as Cartilagenous theory.
 It considers that the nasal septum is the most active
and important for the craniofacial skeleton’s growth
prenatally and early post natal period.
 During which time, the antero-inferior growth of nasal
septal cartilage which is buttressed against the cranial
base posteriorly drives the midface downward and
forward.
 But the consensus today is that the nasal septum
functions essentially to support the roof of the nasal
chamber, but does not actively participates in the
displacement of palate.

48. 4) Functional matrix Hypothesis by Moss (1962) :
 “The origin, form, position, growth and maintenance of
all skeletal tissues and organs is always secondary,
compensatory and mechanically obligatory, necessary
response to chronologically and morphologically prior
events or processes that occur in specifically related
non-skeletal tissues, organs or functioning spaces.”
 Hence the growth of maxilla and mandible is due the
enlargement of the nasal and oral cavities which grow
in response to functional needs such as breathing,
mastication.etc

49. 5) Enlows ‘V’ Principle :
 Many facial and cranial bones or their parts have a V-
shaped configuration.
 Bone deposition occurs on the inner side of V and
resorption occurs on the outer side, hence bone
moves in the direction of the wide end of the V and at
the same time, increases in overall dimension.
 Eg- Palatal and orbital growth.

50. 6) Enlows Counter Part Principle :
 Growth in any one region of the skull necessarily
influences growth in other and consequently a
functional equilibrium is maintained.
 Growth of certain skeletal parts of the craniofacial
region are related specifically to other structural and
geometric counterparts in the face and cranium.
 Balanced equilibrium occurs if the regional parts and
counterparts enlarge to the same extent.

51. ANOMALIES AND CLINICAL IMPLICATIONS
1. Cleft lip & Palate :

52. 2) Microstomia and Macrostomia :
Merging of the maxillary and mandibular
prominences beyond or short of the site for
normal mouth size results in a mouth that is too
small (microstomia) or too wide (macrostomia)

53. MICROSTOMIA

54. MACROSTOMIA

55. 3) Oblique facial cleft :
An oblique facial cleft results from persistence
of the groove between the maxillary prominences
and the lateral nasal prominences running from the
medial canthus of the eye to the ala of the nose.

57. 4) Craniofacial development cyst :
Developmental cysts arise along the lines of facial
cleft and their lining epithelia appear to be derived
from residues or “rests” of the covering epithelia of
the embryonic prominences that merges to form the
face.

58. 5) Medial palatal rest cysts :
The entrapment of epithelial rests or pearls in
the lines of fusion of the palatal shelves (particularly
the midline raphe of the hard palate) may give rise
later to median palatal “rest” cysts

59. CLINICAL SIGNIFICANCE :
1. Maxilla is formed from the first branchial arch and
ectomesenchymal cells. Any etiological factors
which interfere with the function of this structure
may give rise to under developed maxilla.
2. Maxilla forms the middle 1/3rd of the face, hence
underdevelopment leads to midface deficiency
especially in cases of trauma to the nose.

60. 3. Mid palatine suture closes around 15-19 years
until this age the transverse growth continues
and can be utilized for expansion of narrow arch
by RME or SME.
4. Maxilla is surrounded by an envelope of facial
muscles whose restricted growth can eventually
retard the growth of maxilla.
Eg: Scarring after CLP repair

61. 5. Vertical lengthening of maxilla is equal in both anterior
and posterior regions and any discrepancies can
cause open bite or deep bite.
6. Development of dentition is directly related to
development of alveolar bone which in turn is related
to vertical height.

62. MANDIBLE
 ANATOMY

64. FUNCTIONS OF MANDIBLE
 (i)providing mobility to jaws by the TMJ;
 (ii) mastication by teeth and are the site for insertion
of muscles of mastication;
 (iii) maintenance of airway, ramal width coinciding
with pharyngeal width.

65. POST NATAL GROWTH OF THE MANDIBLE

66. GROWTH OF MANDIBLE ACCORDING TO V
PRINCIPLE

67. MAIN SITES OF POST NATAL GROWTH IN THE
MANDIBLE
 Condylar cartilage
-Height
 Posterior border of the Rami
-width
 Alveolar ridges
-height & length

68. ALVEOLAR PROCESS
 Adds to the height and thickness of the mandibular
body
 Teeth absent - fails to develop
 Teeth extracted - resorbs
 Acts as buffer zone
 Maintains vertical height
 Adaptive remodeling makes orthodontic tooth
movement possible

70. CONDYLE
 It is an important growth site
 The head is covered by condylar cartilage
 Secondary cartilage
 Important contribution to the overall length of the mandible

71. CONDYLE AS AN EXPANDING V WITH DEPOSITION ON
THE INNER ASPECT AND RESORPTION ON THE OUTER
ASPECT OF V

72.  Condylar cartilage was once thought to be the soul of
mandibular growth, as the responsible growth center.
 It is now a known fact that the condylar cartilage is not
a primary cartilage but just a secondary cartilage.
 According to Petrovic, the secondary cartilage is more
open to external forces.
 It can be manipulated by external environmental
influences.
 This is used to advantage in functional treatment.
 Condylar cellular arrangement also is to the
orthodontist's advantage.

73. CONDYLAR NECK
BOTH RESORPTION AND DEPOSITION OCCURS ON
THE BUCCAL AND LINGUAL SURFACE

74. RAMUS
 Increase in the length of mandibular corpus occurs by
resorption in the anterior border of ramus.
 This allows the growth in length of dental arch to
accommodate the permanent molars.

75. RAMAL REMODELING: HUNTERIAN CONCEPT

76. REMODELING ASSOCIATED WITH RAMAL
UPRIGHTING

77. RAMUS: UPRIGHTING AND DIRECTION OF
ROTATION

78. MANDIBULAR FORAMEN

79. CORONOID PROCESS
 Coronoid process as an expanding V Grows
medially and vertically

80. SYMPHYSIS
 Deposition on the chin to accentuate the
prominence

81. LINGUAL TUBEROSITY
 Lingual tuberosity is a very important anatomic site in
mandible at the junction of corpus and ramus at the
medial aspect.
 Lingual tuberosity is the counterpart of maxillary
tuberosity.
 Deposits on the tuberosity will cause a definitive
posterior growth of the posteriorly facing tuberosity

82.  When viewed from the lateral aspect, the lingual
and maxillary tuberosity appear to be positioned
along the same vertical line called the posterior
maxillary plane or PM plane.
 This key anatomic plane forms the reference basis
for Enlow's counterpart principle or principle of
growth equivalents .
 This plane extends from the junction of anterior and
middle cranial fossa and extends downward in a
direction perpendicular to the vertical axis of the
orbit.

83. GROWTH ROTATIONS OF MANDIBLE
 Mandibular rotations assume an important role in
orthodontic treatment planning because mandibular
rotations are more common than maxillary
rotations.
 Bjork has classified rotation of mandible into
forward and backward rotations.

84. FORWARD ROTATION HAS THREE TYPES
AND OCCURS IN THE FOLLOWING WAYS:
 Type I.
 In this type (the one that is usually considered)
 there is forward rotation about centers in the joints
which gives rise to a deep-bite, in which the lower
dental arch is pressed into the upper, resulting in
underdevelopment of the anterior face height.

85.  Type II.
 Forward growth rotation of the mandible about
a center located at the incisal edges of the lower
anterior teeth is due to the combination of marked
development of the posterior face height and normal
increase in the anterior height.
 The posterior part of the mandible then rotates
away from the maxilla.

86.  Type III.
 In anomalous occlusion of the anterior teeth, the
forward rotation of the mandible with growth
changes its character.
 In case of large maxillary overjet or mandibular
overjet, the center of rotation no longer lies at the
incisors but is displaced backward in the dental
arch, to the level of the premolars.
 In this type of rotation, the anterior face height
becomes underdeveloped when the posterior face
height increases.
 The dental arches are pressed into each other and
basal deep-bite develops.

87. BACKWARD ROTATION OF THE MANDIBLE IS LESS
FREQUENT
THAN FORWARD ROTATION
 Type I:
 Here, the center of the backward rotation lies in the
temporomandibular joints. This is the case when
the bite is raised by orthodontic means, by a
change in the intercuspation or by a bite-raising
appliance, and results in an increase in the anterior
face height.
 Backward rotation of the mandible about a center in
the joints also occurs in connection with the growth
of the cranial base.

88.  Type II.
 Backward rotation occurs about a center situated at
the most distal occluding molars.
 This occurs in connection with growth in the sagittal
direction at the mandibular condyles.
 As the mandible grows in the direction of its length,
it is carried forward more than it is lowered in the
face, and because of its attachment to muscles and
ligaments it is rotated backward.

89.  Bjork and Skeiller subsequently together carried out
extensive implant studies and introduced
variousterminologies to understand the rotational
pattern of mandible. They divided the rotation into
three components:

90.  Total rotation.
The rotation of the mandibular corpus measured as a
change in inclination of an implant line in the
mandibular corpus relative to the anterior cranial
base.

91.  Matrix rotation.
 This is the rotation of the soft-tissue matrix of the
mandible relative to the cranial base.
 The soft-tissue matrix is defined by the
tangentialmandibular line.
 The matrix rotation has its center at the condyles.

92.  Intramatrix rotation.
 The difference between the total rotation and the
matrix rotation is an expression of remodeling at the
lower border of the mandible.
 It is identified by the change in inclination of an
implant or reference line in the mandibular corpus
relative to the tangential mandibular line.
 The intramatrix rotation has its center Somewhere
in the corpus.

93. PROFFIT’S DESCRIPTION OF
ROTATION
 Proffit coined different terminologies to explain
growth rotation of mandible, namely total rotation,
internal rotation and external rotation.
 Total rotation is the net resultant rotation including
the internal and external rotation.

94.  The internal rotation is masked by surface changes
and alterations in the rate of eruption of teeth.
 There are two contributions to internal rotation,
namely matrix and intramatrix rotations.
 Matrix rotation occurs around the condyle while
intramatrix rotation is centered within the body of
mandible.
 Matrix rotation is also termed as hinge rotation.
This is the rotation of the mandibular plane related
to cranial base.

95.  Intramatrix rotation is the rotation of bony element
within its periosteal matrix which occurs in the
corpus or the core of the mandible.
 If there is no hinge movement, then the total
rotation and intramatrix rotation will be identical.

96.  External rotation is the result of surface changes. These
surface changes include resorption in the posterior
partof the lower border of the mandible, while the
anterior aspect of the lower border is unchanged or
undergoes slight apposition.
 This external compensation in an average growing adult
is about 11 to 12 degrees.
 The orientation of the jaw results from a combination of
both internal and external rotation.
 The difference between the internal and external
rotation accounts for 3 to 4 degrees reduction in
mandibular plane angle during growth in adolescence.

97. ANOMALIES & CLINICAL
IMPLICATIONS
 AGNATHIA

98.  MICROGNATHIA

99.  PIERRE-ROBIN SYNDROME
 Micrognathia, cleft palate, glossoptosis

100.  TREACHER COLLINS SYNDROME
 Micrognathia, hypoplasia of mandible, bird like
face.

101. THANK YOU