POST NATAL GROWTH AND DEVELOPMENT OF MAXILLA ANDmand (2).ppt

post natal growth and development of maxilla
post natal growth and development of mandible

2. Facial Growth and Development is a
morphogenic process working towards a
composite state of aggregate structural and
functional balance among all of the
multiple,regional growing and changing hard
and soft tissues part.

4. DEF:-
According to Salzman:
According to Scott:
According to Todd:first definition in 1931
A.D.
According to Moss:

5. According to Tanner:
According to Krogman:given in 1943A.D.
According to J.S. Huxley:
According to Moyers:
According to meridith(most accepted):-
Entire
series of sequential anatomic and
physiologic changes taking place from the
beginning of prenatal life to senility

6. DEF:-
 According to Todd: Development is
progress towards maturity.
 According to Moyers: Development
refers to all the naturally occurring
unidirectional changes in the life of an
individual from its existence as a single cell
to its elaboration as a multifactorial unit
terminating in death.

7. BASIC KINDS OF GROWTH MOVEMENT
REMODELING DISPLACEMENT

9. The progressive, sequential ,movement of
component parts as a bone enlarges is
termed relocation

10. Bony cortex moves away from A to B by CORTICAL
DRIFT.(combination of deposition and resorption results
in growth movement toward the depository surface.)
Surface towards the direction of movement is
deposition, away from growth direction is resorptive.
If rate of deposition is more than resorption thickness
of cortex remains same.

11. If increases overall size and thickness and
size increases.
Actual bone tissues present in B is not same
as present in A.(because of deposition and
resorption of bone respectively).
Example:-metallic implants(tiny pieces of
tantalum)

12. DRIFT-Bone grows by adding new bone tissue on
one side of a bony cortex and removing it from the
other side.The surface facing towards direction of
growth receives new bone deposition,the surface
facing away undergoes resorption. This composite
process is DRIFT.

13. Direction of growth sequentionaly undergoes REVERSAL.
Crossover between the resorptive(-) and
depository(+) growth fields(can be seen under
microscope)
Interface between the layers of bone that were
produced first on one side and then on the
other as the direction of growth turned about.

15. Biochemical remodeling:-
constant deposition
and removal of ions to maintain blood
calcium levels and cary out other mineral
homeostasis function.
Secondary reconstruction:-
it is by haversion
systems and also the rebuilding of cancellous
trabeculae.

16. Regeneration and reconstruction:-
This type of
remodeling is seen in trauma and diseases.
Growth remodeling:-
In order for a bone to grow
and enlarge, it must also undergo process of
remodeling.

17. PRIMARY DISPLACEMENT
SECONDARYDISPLACEMENT

18. It is a physical movement of whole bone and occurs
while the bone grows and remodels by resorptionand
deposition.
This type of enlargement is associated with a bone’s own
enlargement.

19. This is a movement of whole bone caused by
separate enlargement of other bones, which can b
nearby or distant.

20. As bone enlarges it simultaneously drifts away from other
bones in direct contact with it.
This creates space within which bony enlargement takes
place.
As the bone grows by surface deposition in given direction , it
is simultaneously displaced in the opposite direction.

21. In both Bones of face and cranium about
half of total amount of cortical bone tissues
is of ENDOSTEAL origin and half of
periosteal which are depository and
resorptive respectively.
ENLARGEMENT and REMODELING of each
bone is provided by this function.

22. Bone has fields of resorptive(dark area)depositry
activityover its inside and outside cortical surface.The
DIFFERENTIAL GROWTH process that produces the
irregular shape of a bone.
Shape is irregular because of attachments of many
different soft tissues masses and their diverse growth
patterns and functional actions, articulation with other
bones, support of teeth and so on.

23. Bone produced by the
covering memebrane
(periosteal bone)
constitute about half
of all the cortical bone
tissues present; bone
led down by the lining
membrane (endosteal
bone) makes up the
other half.

25. Resorptive and depository fields of growth
cover or blanket all the outside and inside
surfaces of a bone.
As the perimeter of these growth fields
enlarges, the parts of bone associated with
them increase correspondingly.
During remodeling the extent of bone
deposition usually exceeds that of
resorption, thus allowing regional parts of a
bone to enlarge.

26. Growth changes that occur are such that the
same craniofacial form and pattern are
maintained throughout; that is the
proportion, shape, relative sizes, and angles,
are not altered as each separate region
enlarges.
The geometric form of the face in the first
and last stages is the same only the size
changes.

27. The facial and cranial enlargement in which
the form and proportion remain constant
constitutes balanced growth.
But imbalances always occur in the
development process.

28. It states that the growth of any given facial
or cranial part relates specifically to other
structural and geometric counterparts in
the face and cranium.
Example-Maxillary arch is a counter part of
mandibular arch.
The effective horizontal
dimensions of the ramus and middle cranial
fossa are direct counterparts to each other.
If each regional part and its particular
counter part enlarges to the same extent,
BALANCED GROWTH occurs between them.

29. Apposition of bone in the cranial sutures
accounts for growth after birth.
Pressure from the growing brain promotes
resorption of bone in the inner surfaces of the
cranial vault=remodeling allows for changes in
the contour.

30. GROWTH OF
NASOMAXILLARY
COMPLEX

31. PRIMARY DISPLACEMENT :-
1.It includes both the bodily movement with
bone’s own enlargement.
2.Two growth vector in maxilla are posterior
and inferior direction.
3.As this takes place whole bone is dispalced
in opposite anterior and inferior direction.

32. Secondary displacement:-
1.maxillary growth and enlargementitself are not involved in
this particular kind of displacement movement.
2.the anterior direction of growth by the middle cranial fossa and
the temporal lobe of the cerebrum dispalces the maxilla
anteriorly and inferiorly.

33. Mechanism for growth in the
nasomaxillary complex are the-
1.Sutures
2.Nasal septum
3.Periosteal and endosteal surfaces
4.Alveolar process
5.According to MILLS the maxilla is increased
in size by subperiosteal activity during
postnatal growth.

34. Horizontal lengthening
of the bony maxillary
arch is produced by
deposition at the
backward periosteal
surface of maxillary
tuberosity. Responsible
for most of postnatal
lengthening of arch
after about 2-3 years
of age.

35. Vertical lengthening of nasomaxillary complex
involves-
i) remodeling
ii)displacement
The overall growth changes are a result of both
downward and forward translation of maxilla and a
simultaneous surface remodeling.
CLASSIC IMPLANT Studies by Bjork and Skiller
confirm that maxillary height increases by-
sutural growth toward frontal and
zygomatic
bone appositional growth in alveolar
process.

36. Growth of the bony maxillary arch-it is moving in three
directions.
1.Lengthens posteriorly-by deposition on posterior facing maxilary tuberosity.
1.Grows laterally-by deposits on buccal surfaces. It also widens the posterior
part of the arch.
1.Grows downward-by deposition along the alveolar regions and on lateral
side.
Bone deposition on external surface and resorption on the endosteal surface.

37. It is an island of bone with its entire
perimeter bounded by sutural contacts
separating it from the ethmoid , maxillary
and frontal bones.
As these separate bones enlarge or become
displaced, the sutural system of lacrima
bone make it possible for the maxilla to
slide downward along the contact with
medial orbital wall as whole maxilla
becomes displaced inferiorly.

38. This is due to the presence of abundant
population of actively contractile fibroblasts
‘m’ cells within the linkage zones of the
sutural membrane. This exerts a contractile
force that exerts tension on the fibrous
framework.
This pulls one bone along its sutural interface
with another bone

40. Whole maxilla undergoes a process of
primary displacement in an anterior direction
as it grows and lengthens posteriorly.
Earlier it was assumed that the addition of
bone on the posterior surface of elongating
maxillary tuberosity “push” the maxilla
against the adjacent muscle-supported
pterygoid plates.

41. Nasal septum theory by SCOTT
Cartilage is a specifically adapted to certain
pressure-related growth sites. It provides
linear growth by endochondral proliferation.
Pressure accomodating expansion of the
nasal septal cartilage provides a source for
physical force that displaces the maxilla.

42. Another theory held that bone growth
within maxillary suture produced a pushing
apart of bones, with a resultant thrust of
the maxilla anteriorly and inferiorly.
Since suture is a tension adapted tissue,
presence of any unusual pressure on suture
triggers resorption.
It is believed that stimulus for sutural bone
growth is tension produced by
displacement of that bone.

43. COPRAY JC-studied the growth of the nasal
septal cartilage of rats in vitro. Nasal septal
cartilage was found to grow nearly as well
in culture as in epiphyseal plate.
The surgery itself and accompanying
interference with blood supply to area, not
the loss of cartilage may cause the growth
changes. MOSS ML also studied the role of
nasal septal cartilage in midfacial growth.

44. SARNAT BG-conducted an experimental
surgery wherein he extirpated a young’s
rabbit septum. Deficiency occurred in
midfacial region.

45. According to LATHAM RA-nasal septum and
septomaxillary ligament act as an operative
force.( septomaxillary ligament arises from
side and anteroinferior border of nasal
septum and inserts into ANS)

46. CONCEPT OF MULTIPLE ASSURANCE By
“LATHAM and SCOTT-according to them the
process and mechanism that function to carry
out the growth are multifactorial in nature.
If any one determinant of growth process
becomes inoperative, other morphologic
components in the such instances have
capacity to compensate.

47. FUNCTIONAL MATRIX THEORY By MOSS
1960s.
The growth expansion of the facial muscles,
subcutaneous, submucosal connective tissue,
oral and nasal epithelia lining spaces vessels
and nerves, all combine to move facial bones
passively along with them as they grow.

48. The displacement movement of the complex
accompanies enlargement in all areas
throughout the entire nosomaxillary region.
New bone is added at frontomaxillary,
zygotemporal, zygoshenoid, zygomaxillary,
ethmomaxillary, ethmofrontal, nasofrontal,
frontolacrimal, palatine and vomerine
sutures.

49. Has a secondary displacement effect on
nasomaxillary complex.
The temporal and frontal lobes have fibrous
attachment to middle and anterior cranial
fossa.
As these expand these two are pulled apart.
This sets up tension fields in various
frontal, temporal, shenoidal and ethmoidal
sutures.
This triggers sutural bone growth.
Both fossa are thus enlarged and the
nasomaxillary complex is carried along
anteriorly with the anterior cranial fossa.

51. At birth breadth is equal to length.
The post natal increase in length is by
appositional growth in maxillary tuberosity
region and transverse maxillary-palatine
suture.
Increase in width of palate is by midpalatal
sutural growth and appositional growth along
lateral alveolar margins.

52. Growth at the mid-palatal suture ceases at 1-
2 years of age.
Growth in the width of the suture is larger in
its posterior part than in its anterior part.
Obliteration of growth starts in adolescence,
but complete fusion occurs usually till age of
30 years.

53. Lateral appositional growth continues till 7
years of age, by this time palate reaches its
ultimate anterior width.
Posterior appositional growth continues after
cesation of lateral appositional growth,
resulting in lengthening of palate.

54. The appositional
growth of alveolar
processes
contributes to
deepening and
widening of palate.

55. In childhood, the level of maxillary arch and nasal
floor lie very close to the inferior orbital rim.
Maxillary arch and Palate grows downward by
periosteal resorption on nasal side and periosteal
deposition on oral side.

56. Deposition occurs on the
downward facing surface
and resorption on the
superior facing surface
on the palate.
This results in downward
relocation of the whole
palate-maxillary arch on
lower level.
Arch comes down n lie
below the inferior orbital
rim.
This grows and remodels
the dimentions of nasal
chambers.

57. Half of the palate is resorptive and half is
depository.
Nasal mucosa provides the periosteum on
one side and oral mucosa provides it on the
other side.

58. Bony maxillary arch
and palate in early
childhood remodels
and become nasal
chamber of adult.

59. Downward and
forward
displacement seen
as bone deposition
takes place in an
opposite upward
and backward
direction.
Ref:-enlow

60. By the expansive force of soft tissues in the
midfacial region the whole maxilla displaced
downward and forward.
This helps new bone growth at the various
sutural contact surfaces between the
nasomaxillary composite and cranial floor.

62. Robin sequence

63. Triad of micrognathia and cleft palate
Prevalence: 1 of every 8,500 newborns
Syndromic 80%
Treacher Collins Syndrome
Velocardiofacial Syndrome
Fetal Alcohol Syndrome
Nonsyndromic 20%

64. Mandibular Deficiency
Hypo plastic and
Retruded Mandible
(Micrognathia)
Tongue Remains
Retruded and High in
Oropharynx
(Glossoptosis)
Failure of Fusion of
Lateral Palatal Shelves
Cleft Palate

67. Maxilla
Maxillary tuberosity is
a free surface that is
this surface grows
directly posteriorly.
Mandible
It has a ramus.
The posterior growth
of bony arch, thus has
to proceed into a
region already
occupied by ramus.
This requires a
remodelling conversion
from ramus to
mandibular corpus.

68. It is direct anatomic
equivalent of maxillary
tuberosity.
It grows posteriorly by
deposits on its
posterior facing
surface.
The lingual and
maxillary tuberosity
ideally have equal rates
and amount of
respective growth.

69. Lingual tuberosity
grows posteriorly by
deposits on its
posterior facing
surface.

70. It grows in an almost
directly posterior
direction, with only slight
lateral shift.
This occurs because the
bicondylar width does
not increase as much as
the mandibular length
during childhood period
(as most of the lateral
growth of cranial base
has occurred by about
2
nd
and 3
rd
year.

71. The part of ramus
just behind the
tuberosity grows
medially.
That is this area
later becomes the
part of the corpus
thus lengthening the
corpus.

72. Resorption on the anterior border of ramus is
involved in the direct relocation of the entire
ramus in a posterior direction.

73. A remodeling transition occurs at the junction
between the ramus and body. This is a key
process because it involves conversion of one
major portion of mandible directly into
another.
Bone deposition occurs on lingual surfaces,
anterior portion of the ramus, and posterior
portion of body.

74. The lingual side of coronoid process is
depository and buccal side is resorptive.
The lingual side of the coronoid process faces
three general directions all at once:
posteriorly, superiorly, medially.

75. When bone is added
on the lingual side
of the coronoid
process, its growth
thereby proceeds
superiorly, thus this
part of ramus
becomes increased
in vertical
dimension.

76. The same deposits
bring about a posterior
direction of growth
movement.
This produces a
backward movement of
the two coronoid
process.
Also results in
widening of the
posterior part of
ramus.

77. It also functions to
carry the base of the
corornoid process and
the anterior part of the
ramus in a medial
direction.
Thus the area occupied
by the anterior part of
the ramus in 1
becomes relocated and
remodeled into
posterior part of
corpus in 2.

78. The mandibular
foramen drifts
backward and upward
by deposition on
anterior and resorption
on posterior part of its
rim.
The foramen maintains
a constant posotion
about midway between
anterior and posterior
borders of the ramus.

79. It is major site of growth.
It is a secondary type of cartilage that is it
does not develop by differentiation from
established primary cartilages of the skull
(that is the cartilages of the pharyngeal
arches) and definitive cartilages of the cranial
base.

80. Another difference between primary and
secondary cartilages is that secondary
cartilages do not have a linear columns of
daughter cells.
As pointed out by KOSKI the arrangement of
daughter cells in condylar cartilages does not
reflect the direction in which the condyle is
growing.

81. The anterior and posterior edge of condylar
neck is depository.
The lingual and the buccal side of neck are
resorptive surfaces.
The endosteal surface of the neck faces the
course of growth.
The periosteal surface points away from the
growth direction.

82. Earlier concept-the growth of condylar
cartilage towards its contact presumably
pushes the whole mandible away from it

83. Two kinds of experiments were conducted to
test the idea that cartilage can serve as
growth centre-
transplanting cartilages
evaluation of effect on growth
of removing cartilages at an early age.

84. Transplantation experiments as conducted
by COPRAY JC and DUTERLOO HS
demonstrate that not all skeletal cartilages
act similarly when transplanted.
On transplanting the condylar cartilage
intracerebrally little or no growth was
observed (RONNING O )
According to study conducted by Jansen HW
and DUTERLOO HS condylar cartilage
showed significantly less growth than the
other cartilages.

85. Studies conducted by GILHUUS-MOE and LUND
demonstrated that after fracture of mandibular
condyle there was regeneration of condylar
process and at times there was overgrowth of
the process.
As mandible totally lacking condyle existed
with almost a normal morphology with the
absence of condyle and a part of condylar
neck.
Experiments conducted by COPRAY JC,
DIBBETS JM, KANTOMAA T also demonstrate
that the condylar cartilage is not a growth
center.

86. Recent research studies by Mc NAMARA show
that stimulus of condylar cartilage is more
complex than simple forces acting directly on
the condyle, rather nerve-muscle-connective
tissue pathways are involved.
The current thinking is that condylar cartilage
does not have a measure of intrinsic genetic
programming

87. Mandible is carried forward and downward in conjunction with
the growth of soft tissue matrix associated with it.
Thos mandible is displaced away from its cranial base articular
contact, the condyle secondarily grows towards it.

88. It has secondary displacement effect on
mandible.
The amount of horizontal displacement for
mandible is less as the enlargement of middle
cranial fossa takes place anterior to
mandibular condyle.

89. It continues to take place after horizontal
ramus growth slows or ceases (that is the
horizontal growth of the middle cranial fossa
begins to stop).
Thus the condylar growth may become
more vertically directed, and
A different pattern of ramus
remodeling becomes operative.

90. Forward growth
direction on anterior
border in the upper part
of coronoid process.
Resorption occurs on
the upper part of the
posterior border.
A posterior direction of
remodeling takes place
in the lower part of
posterior border.
The result is more
upright alignment and a
longer vertical
dimension of ramus.

91. The ramus-corpus
angle (gonial angle)
is determined by the
growth direction of
ramus and condyle.

92. A single field of
resorption is present on
the inferior edge of the
mandible at the ramus-
corpus junction.
This forms the
antegonial notch by
remodeling from the
ramus just behind it as
ramus relocates
posteriorly.
The size of the notch
can be increased
whenever a downward
rotation of corpus
relative to ramus takes
place.

93. The mental protuberance of mandible is a
unique feature of man.
Chin formed in part of mental ossicles from
accessory cartilages and the ventral end of
meckel’s cartilage is poorly developed in
infants.
It develops as an independent subunit of
mandible, influenced by sexual as well as
specific genetic factors.

94. The skeletal unit of chin may be an
expression of functional forces exerted by
lateral pterygoid muscles.
Growth changes that bring about this involve
a differential combination of surface
resorption and deposition in different parts of
the mandibular archin general region forward
of the bicuspids.

95. The maturation of the chin
in shape and size proceeds
slowly through the
postnatal period of facial
growth.
The combination of
continued periosteal
deposition around the base
and apex of chin, together
with periosteal resorption
and endosteal deposition in
alveolar region above it,
progressively enlarges the
mental protuberance.

96. Growth in width length height.
Growth in width of jaws and dental arches tends to
complete before adolescent growth spurt and is
affected minimally by adolescent growth changes.
Growth in length of both jaws-
14-15 yrs in girls
18 or so in boys
Growth in height and concomitant eruption of teeth
continue throughout life, but decline to adult level-
17-18 yrs in girls
early twenties in boys

97. Metallic implants study conducted by BJORK
and coworkers in 1960s demonstrated the
rotation of the jaws during growth.
Internal rotation-rotation occurring in the
core of each jaw.
External rotation-rotation produced by the
surface changes.

98. MATRIX ROTATION
INTRAMATRIX ROTATION
FORWARD ROTATION( -)
BACKWARD ROTATION(+)
Skieller and Bjork showed that the total
rotation is sum of matrix and intramatrix
rotations.

99. The pattern of vertical facial development is
strongly related to rotation of both jaws.
The rotational patterns of growth are
different for individuals with short anterior
lower face height and with excessive lower
anterior face height. (Houstan WJ who
studied the mandibular growth rotations)
The rotational pattern also influences the
magnitude of tooth eruption. Both the
vertical and anteroposterior position of the
incisors are affected in short face and long
face individuals (as shown by studies
conducted by Nanda SK)

100. Individuals of short face types have excessive
forward rotation of mandible during growth
due to an increase in normal internal rotation
and a decrease in external compensation.
Thus the incisors are carried into an
overlapping position(even if they erupt very
less).

101. Individuals with long face the mandible shows
an opposite backward rotation due to either
lack of normal forward internal rotation
(which is primarily matrix rotation) or even a
backward rotation of jaw.
Anterior open bite develops as anterior face
height increases.
The jaw rotation also carries the incisors
forward creating dental protrusion.

102. CONTEMPORARY
ORTHODONTICS BY WILLIAM
R. PROFFIT with HENRY W.
FIELDS, Jr.
HANDBOOK OF
ORTHODONTICS BY ROBERT
E. MOYERS.