detail explanation regarding growth and development of mandible. help full for pg students.

1. 29 July 20141

2. Dr. Akash Ardeshana
1st MDS
Department of paedodontics & Preventive
2
The Mandible
(Growth And Development)
29 July 2014

3. Contents
3
Introduction
History and background
Prenatal development of mandible
Postnatal development of mandible
Development of mandible in relation to various theory of
growth
Anatomy of mandible
Muscle attachment
Age changes
Developmental anomalies
29 July 2014

4. 4
MANDIBL
E
Largest and
strongest bone of
the face
1st pharyngeal
arch
Articulation with
skull
shape and
Function
INTRODUCTION
29 July 2014

5. Some historical
events
• JOHN HUNTER (1771) compared a series of
dried mandibles and concluded that in order to
attain space for permanent molar teeth the
mandible must grow by posterior apposition of
ramus accompanied by anterior ramus
resorption.
• HUMPHRY (1866) studied growth of mandible
by inserting metal wires in the mandible of young
pigs.
• Belchie (1936) fed pigs the madder plant root
which labeled appositional growth
29 July 20145

6. • BJORK (1955): conducted implant studies on jaws
to determine the growth pattern & rotation ,when
subjected to serial cephalometric methods.
• DONALD ENLOW : proposed the V principle of
growth and counterpart principle.
29 July 20146

7. The Evolution of Human Jaw
7
The jaws and teeth of Homo sapiens have evolved,
from the last common ancestor of chimpanzee.
Many factors such as the foods eaten and the
processing of foods by fire and tools have effected
this evolution course.
ON THE EVOLUTION OF HUMAN JAWS AND TEETH: A REVIEW, YUSUF
EMES , BUKET AYBAR, SERHAT YALCIN , BULL INT ASSOC PALEODONT.
2011;5(1):37-47
29 July 2014

8. 8 29 July 2014

9. PRENATAL DEVELOPMENT OF
MANDIBLE
9
Start abouth 4th week of
intara- uterine life.
Developing brain and the
pericardium form two
prominent bulges on the
ventral aspect of the
embryo.
These bulges are
separated by primitive oral
cavity or stomodaeum
The floor of the
stomodaeum is formed by
the bucco-pharyngeal
membrane, which
separates it from the
29 July 2014

10. 10
Mesoderm of foregut comes to arranged in the
form of six bars that run dorsoventrally in the side
wall of the foregut.
These are called pharyngeal arches.
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11. 11
Coronal section through cranial part of foregut
before formation of pharyngeal arches.
29 July 2014
(Human embryology- Inderbir Sing Eight edition)

12. 12
Formation of pharyngeal arches
29 July 2014
(Human embryology- Inderbir Sing Eight edition)

13. 13
First Branchial arch called MANDIBULAR ARCH.
Mandibular arch gives off a bud from its dorsal
end called maxillary process.
It grows ventro-medially cranial to main part of
the arch which is called mandibular process.
.
29 July 2014

14. 14
Mandibular process of each side grow towards
each other.
fuse in midline give rise to mandible.
First structure develop in lower jaw :
- Mandibular division of Trigeminal nerve.
- Neurotrophic factor produced by nerve
induce osteogenesis.
29 July 2014
(Ten Cate’s Oral Histology – Sixth Edition)

15. MECKEL'S CARTILAGE
15
It is the cartilage of the first arch
In human beings the Meckel's cartilage has a
close positional relationship to the developing
mandible but makes no contribution to it.
At 6 weeks of development this cartilage extends
as a solid hyaline cartilaginous rod, surrounded
by a fibrocellular capsule, from the developing ear
region to the midline of the fused mandibular
processes.
29 July 2014

16. 16
The Mandibular branch of trigeminal nerve has
close relationship to Meckel’s cartilage
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17. 17
On lateral aspect of Meckel’s cartilage, during the
6th week of embryonic development, a condensation
of mesenchyme occurs in the angle formed by the
division of the inferior alveolar nerve and its incisor
and mental branches.
(Ten Cate’s Oral Histology – Sixth Edition) 29 July 2014

18. Centre of ossification
Intramembraneou
s Ossification
starts at the
division of mental
and incisive
branch of inferior
alveolar nerve
lateral to meckel’s
cartilage around
7th week IUL.
18 29 July 2014

19. .
19
From center of ossification bone formation spreads:
Anteriorly - midline
Posteriorly - where mandibular nerve divided into
lingual and inferior alveolar branch.
Bone formation spreads rapidly and surrounds the
inferior alveolar nerve to form mandibular canal.
Intra-membranous ossification spreads in anterior and
posterior direction forms the Body & Ramus of the
mandible.
29 July 2014
Gray’s Anatomy – Fortieth edition

20. 20
Anteriorly bone extends towards midline and comes
in approximation with similar bone forming on
opposite side.
These two bones remain separated by fibrous tissue
mental symphysis untill shortly after birth.
Continued bone formation increases size of
mandible with development of alveolar process to
surround the developing tooth germ.
29 July 2014

21. .
21
Ossification spread
posteriorly to form
ramus of mandible,
turning away from
meckel’s cartilage.
This point of
divergence is
marked by lingula in
adult mandible.
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22. 22
Thus by 10 weeks the rudimentary mandible is
formed almost entirely by membranous
ossification with little direct involvement of
Meckel’s cartilage
(Ten Cate’s Oral Histology – Sixth Edition)
29 July 2014

23. NOW….. What is the
fate of the Meckel’s
cartilage?
23 29 July 2014

24. 24
Incus and malleus
Spine of sphenoid bone
Anterior ligament of malleus
Spheno-mandibular ligament
29 July 2014

25. SECONDARY CARTILAGES IN
MANDIBULAR DEVELOPMENT
25
Further growth until birth influenced by appearance
of secondary cartilage
Condylar cartilage:
Coronoid cartilage:
Symphyseal cartilage:
29 July 2014

26. CONDYLAR CARTILAGE
26
appear during 12th week of IUL
Rapidly form cone shape mass which is
converted quickly to bone by endochondral
ossification.
At the end of 20th week only a thin layer remains
on the condylar head ,persist until the end of the
second decade of life ,providing a further growth
29 July 2014
(Ten Cate’s Oral Histology – Sixth Edition)

27. • Cartilage fuses with mandibular ramus around 4th month.
27 29 July 2014
(Contemporary orthodontics Williams R. proffit fifth edition)

28. CORONOID CARTILAGE
28
Appears at about 4 month of development.
Coronoid cartilage is transient growth cartilage
and disappears long before birth.
Cartilage grow as a response of developing
temporalis muscle.
Coronoid cartilage become incorporated into
expanding intra-membranous bone of ramus.
29 July 2014
(Ten Cate’s Oral Histology – Sixth Edition)

29. SYMPHYSEAL CARTILAGE
29
Two in number
Appear in between the two end of Meckel’s
cartilage.
They are obliterated within the first year after
birth.
29 July 2014
(Ten Cate’s Oral Histology – Sixth Edition)

30. POST NATAL DEVELOPMENT OF
MANDIBLE
30
Right & left mandibular body fuses at midline
symphysis one year after birth.
Mandible appears as single bone.
29 July 2014

31. 29 July 201431
(Contemporary orthodontics Williams R.
proffit fifth edition)

32. According to MOSS while mandible
appears in the adult as a single bone,
it is divisible into several skeleton
subunits
Condylar process
Coronoid process
Angular process
Ramus
Lingual tuberosity
Body of mandible
Alveolar process
chin.
29 July 201432
(Facial Growth – Donald H. Enlow third ed

33. The Mandibular Condyle
It is a major site of growth
Historically, the condyle has been
regarded as a kind of cornucopia
from which the whole mandible
itself pours forth.
The condyle functions as regional
field of growth that provides an
adaptation for its own localized
growth circumstances
29 July 201433

34. The condylar growth mechanism itself is a clear-cut
process. Cartilage is a special non-vascular tissue and
is involved because variable levels of compression
An endochondral growth mechanism is required for this
part of the mandible
Endochondral growth occurs only at the articular contact
part of the condyle
In Figure the endochondral bone tissue (b)
formed in association with the condylar cartilage (a)
The enclosing bony cortices (c) are produced by
periosteal-endosteal osteogenic activity
29 July 201434

35. The lingual and buccal sides of neck
characteristically have a resorptive surface. This is
because condyle is quite broad and neck is narrow
29 July 201435

36. The neck is progressively relocated into areas
previously held by the much wider condyle
What used to be condyle in turn becomes the
neck as one is remodeled from the other . This is
done by periosteal resorption combined with
endosteal deposition.
29 July 201436

37. Explained another
way, the endosteal
surface of the neck
actually faces the
growth direction; the
periosteal side points
away from the course
of growth. This is
another example of the
V principle, with the V-
shaped cone of the
condylar neck growing
toward its wide end.
29 July 201437

38. The condylar question
What is the physical force that
produces the forward and
downward primary
displacement of mandible ?
proliferation of cartilage
towards its contact thereby
pushes the whole mandible
away from it.
bilaterally condyle lacking
mandibles occupy an
essentially normal anatomic
position.
29 July 201438

39. These observations suggested conclusions.
• First the condyles may not play the kingpin role
of a “master center”.
• Second the whole mandible can become
displaced anteriorly and inferiorly into its
functional position without a "push" against the
basicranium
29 July 201439

40. Functional matrix
Mandible is carried forward and downward, in
conjunction with the growth expansion of the
soft tissue matrix associated with it
It is a passive type of carrying
The condyle and whole ramus secondarily
remodels toward it thereby closing the
potential space without an actual gap being
created
29 July 201440

41. Role of condyle
It is directly involved as a unique, regional growth site.
It provides an indispensable latitude for adaptive growth.
It provides movable articulation.
It is pressure tolerant and provides a means for bone growth
(endochondral) in a situation in which ordinary periosteal
(intramembranous) growth would not be possible
It can also, all too frequently, become involved in TMJ
pathology and distress.
29 July 201441

42. Clinical Implication
42
Condylar cartilage dose have some measure of
intrinsic, genetic programming,
This , however, appears to be restricted to
capacity for continued cellular proliferation .
Cartilage cells are coded and geared to divide
and continue to divide by extra condylar
biomechanical forces.
So overall mandibular length be clinically increase
or decrease for class II and class III individuals if
this were done during the period of active
condylar growth.
29 July 2014
(Facial Growth – Donald H. Enlow third edition)

43. Coronoid process
43
The coronoid process
has propeller like twist,
so that its lingual side
faces three general
directions all at once
posteriorly, superiorly
and medially.
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44. When bone is added onto the lingual side of the
coronoid process , growth thereby precedes
superiorly and this part of ramus increased in
vertical direction.
29 July 201444

45. The same deposits of bone
on the lingual side also bring
about a posterior direction of
growth movement .
produces backward
movement of two coronoid
process even though
deposits on the inside
(lingual) surface.
29 July 201445

46. These same deposits on
the lingual side also bring
about medial direction of
growth in order to lengthen
corpus
area occupied by anterior
part of ramus in mandible 1
becomes relocated and
remodeled into posterior
part of corpus in mandible
2.
29 July 201446
(Facial Growth – Donald H. Enlow third edition)

47. Growth at Ramus
47
Resorption occurs on the
anterior part of the ramus
while bone deposition
occur on posterior region.
This results in a drift of the
ramus in a posterior
direction.
29 July 2014

48. Ramus is important as
it positions the lower arch in occlusion
It is continuous adaptive to the multitude of
changing craniofacial conditions.
increasing mass of masticatory muscle inserted
into it.
Bridges the pharyngeal compartment.
determines the anteroposterior positioning of
lower arch.
accommodates the vertical of face.
give space to accommodate erupting permanent
molar.
29 July 201448
(Facial Growth – Donald H. Enlow third edition)

49. Body of the mandible
49
The displacement
of former ramal
bone into the
posterior part of the
body of mandible.
In this manner the
body of mandible
lengthens.
29 July 2014
(Contemporary orthodontics Williams R.
proffit fifth edition)

50. Angle of mandible
50
Buccal surface
Bone deposition - postero-inferior surface
Bone resorption - antero-superior surface
Lingual surface
Bone deposition – antero-superior surface
Bone resorption – postero-inferior surface
29 July 2014

51. MANDIBULAR FORAMEN
The mandibular foramen
likewise drift backward and
upward by deposition on the
anterior and resorption on
the posterior part of its rim.
The foramen presents a
constant position about
midway between the
anterior and posterior
border of ramus.
29 July 201451
(Facial Growth – Donald H. Enlow third edition

52. 52
Title Relative position of the mandibular foramen in different age groups
of children: A radiographic study.
Author Poonacha, K. S. Shigli, A. L. Indushekar, K. R.
Journal Journal of the Indian Society of Pedodontics & Preventive Dentistry. Jul-
Aug2010, Vol. 28 Issue 3, p173-178. 6p. 2 Diagrams, 4 Charts.
Level of
evidence
III
Objectives: To assess the relative position of the mandibular foramen (MF) and to
evaluate the measurement of gonial angle (GoA) and its relationship with
distances between different mandibular borders in growing children
between 3 and 13years of dental age
Materials
and
Methods
: The radiographs were traced to arrive at six linear and two angular
measurements from which the relative position of the MF was assessed
and compared in different age groups to determine the growth pattern of
the mandible and changes in the location of the MF.
Result The distances between the MF and the anterior plane of the ramus were
greater than that between MF and posterior plane of the ramus through all
stages. There was a maximum increase in the vertical dimensions of the
mandible compared with the horizontal dimensions, particularly in the late
mixed dentition period.

53. ANTEGONIAL NOTCH
A single field of surface resorption is present on the
inferior edge of mandible at the ramus corpus
junction. This forms the antegonial notch
In vertical growth it is deep and
horizontal growth shallow
29 July 201453
(Facial Growth – Donald H. Enlow third edition)

54. The lingual tuberosity
Grows posteriorly by deposits on the posterior
facing surface.
The prominence of tuberosity is increased by
presence of large resorptive fields just below it
which produces a sizable depression, the lingual
fossa.
29 July 201454
(Facial Growth – Donald H. Enlow third edition

55. The alveolar process
55
As teeth erupt the alveolar process develops and
increase in height by bone deposition at the
margins.
29 July 2014

56. The chin
56
In infancy, the chin is usually under developed.
As age advances the growth of chin become
significant.
The mental protuberance formed by bone deposition
during childhood.
Its prominence is accentuated by resorption that
occrus in the alveolar region above it.
29 July 2014
(Facial Growth – Donald H. Enlow third edition)

57. Development of mandible in relation
to various theory of growth
57
Genetic theory - BRODIE (1941)
Cartilaginous theory- JAMES SCOTT
Functional matrix concept- MELVIN MOSS
Enlow’s expanding ‘V’ principle
29 July 2014

58. GENETIC THEORY:-
This theory states that all growth is compelled
by genetic influence ie: genetic encoding of
mandible determines its growth.
29 July 201458
(Contemporary orthodontics Williams R. proffit fifth
edition)

59. CARTILAGENOUS THEORY
This theory states that the cartilage is the
primary determinant of skeletal growth while
bone responds secondarily & passively.
According to this theory, the condyle by
means of endochondral ossification deposits
bone, which tends to grow the mandible.
29 July 201459
(Contemporary orthodontics Williams R.
proffit fifth edition)

60. 29 July 201460
Gilhuus-Moe and Lund k. demonstrated that after
fracture of mandibular condyle in a child ,there
was an excellent chance that condylar process
would regenerate to approximately its original
size and a small chance that it would overgrow
after the injury.
(Gilhuus-Moe , fractures of the Mandibular condyle in the Growth
period.stockholm: Scandinavian university book,Universitatsforlaget 1969
Lund k. Mandibular growth and remodling process after mandibular
fracture , odontol Scand 32(64):3-117, 1974)

61. THE FUNCTIONAL MATRIX
CONCEPT
61
If neither bone nor cartilage was the determinant
for growth of the craniofacial skeleton, it would
appear that the control would have to lie in the
soft tissue.
View was introduced formally in the 1960s by
moss.
He theorized that growth of the face occurs as
response to functional needs and neurotrophic
influences and is mediated by the soft tissue in
which the jows are embedded.
29 July 2014

62. 62
Which means the muscles, connective tissues
etc. carries the entire mandible away from the
cranial base . The bone follows secondarily at the
condyle to maintain constant contact with the
glenoid fossa.
29 July 2014
(Contemporary orthodontics Williams R.
proffit fifth edition)

63. 63
FUNCTIONAL MATRIX - carries out functions.
ex : muscle, nerve , gland , vessels
- There is periosteal capsule and capsular matrices.
SKELETAL UNITS - supports & protects the
relative functional matrices
- divided in to macroskeletal & microskeletal units.
29 July 2014

64. 29 July 201464

65. ENLOW’S EXPANDING ‘V’
PRINCIPLE
This theory states that many facial bones or a
part of the bone follows a ‘v’ pattern of
enlargement.
Deposition is in the inner surface of of ‘v’ .
Resorption is seen along the outer surface of
‘v’.
CORONOID PROCESS: Deposition –lingual
surface, Resorption-buccal
CONDYLE PROCESS: Deposition-ant. & post.
Margins, Resorption-buccal & lingual surfaces.
29 July 201465
(Facial Growth – Donald H. Enlow third edition)

66. COUNTERPART PRINCIPLE
This principle states that growth of any given
facial or cranial part relates specifically to
other structural & geometric counterpart in the
face & cranium
Eg;- The maxillary arch is the counter part of
the mandibular arch.
29 July 201466

67. Anatomy of the mandible
67
It has horseshoe shaped
body which lodges the
teeth, and pair of rami
which project upwards
from the posterior ends of
the body and provide
attachment to muscle.
29 July 2014

68. 68
The body:
Body has outer and inner surfaces and upper and
lower border.
The ramus:
Quadrilateral in shape, has two surfaces, lateral
and medial, four borders and the coronoid and
condyloid process.
29 July 2014

69. LATERAL SURFACE PRESENTS THE FOLLOWING
FEATURES
69
1. Symphisis menti
2. Mental foramen
3. Mental protuberance
4. Mental tubercle
5. The oblique line
6. Condylar process
7. Coronoid process
8. Mandibular notch
9. Alveolar process29 July 2014

70. The Medial surface presents the following features
1. Mental spine
2. Mylohyoid line
3. Submandibular
fossa
4. Sublingual fossa
5. Mylohyoid
groove
6. Mandibular
foramen
70 29 July 2014

71. 71
(Gray’s Anatomy – Fortieth edition)
29 July 2014

72. 72
Attachments and relations of the mandible
29 July 2014

73. 73
Lateral surface
(Gray’s Anatomy – Fortieth edition)
29 July 2014

74. 74
Medial surface:
(Gray’s Anatomy – Fortieth edition)29 July 2014

75. TMJ
75 29 July 2014

76. 29 July 201476
Lateral Aspect Medial aspect

77. AGE CHANGES IN THE
MANDIBLE
77 29 July 2014
Human anatomy-BD Chaurasia Forth Edition

78. At birth
78
At the birth the mental foramen, opens below the
sockets for the two deciduous molar teeth near the
lower border.
The mandibular canal runs near the lower border.
The angle is obtuse. It is 175.
29 July 2014

79. At Childhood
79
The two halves of the mandible fuse during the first
year of the life.
The body becomes elongated in its whole length, but more
especially behind the mental foramen, to provide space for
the three additional teeth developed in this part.
Mandibular foramen slightly above the occlusal plane
The angle becomes less obtuse around 140.
29 July 2014

80. In adult
80
The mental foramen opens midway between the
upper and lower borders.
The mandibular canal runs parallel with the
mylohyoid line.
Mandibular foramen 7 mm above the occlusal plane
The angle reduces about 110 or 120 degrees.
29 July 2014

81. In old age
81
Alveolar border is absorbed, so that height of the
body is markedly reduced.
The mental foramen and mandibular canal are close
to the alveolar border.
The angle again becomes obtuse about 140 degrees
.
29 July 2014

82. DEVELOPMENTAL DEFECTS OF
THE MANDIBLE
82 29 July 2014

83. Agnathia
83
Hypoplasia or absent of
mandible with abnormally
positioned ears.
Autosomal recessive .
It is probably due to failure of
neural crest mesenchyme into
the maxillary prominence.
29 July 2014
(Shafer’sTextbook of Oral pathology sixth edit

84. micrognathia
84
Small jow either the maxilla or the mandible may
be affected.
True or aqcuired.
Severe retrusion of chin , a steep mandibular
plane angle.
29 July 2014
(Shafer’sTextbook of Oral pathology sixth
edition )

85. Macrognathia
85
Abnormally large jow
E.g. paget’s disease of bone
Acromegaly
Fibrous dysplasia
29 July 2014
(Shafer’sTextbook of Oral pathology sixth
edition )

86. CORONOID HYPERPLASIA
86
Rare developmental anomaly
Result in limited mandibular movement
Unknown etiology.
M:F ratio 5:1
May be unilateral or bilateral
Bilateral is more common
29 July 2014
(Oral and maxillofacial Pathology- Neville third edition)

87. Condylar hyperplasia
87
Excessive growth of one of the condyles
Cause is unknown, but local circulating problems,
endocrine disturbances, and trauma have been
suggested as possible etiologic factors.
29 July 2014
(Oral and maxillofacial Pathology- Neville third
edition)

88. Condylar hypoplasia
88
Congenital or acquired
congenital:
mandibulofacial dysostosis
goldenhar syndrome
hemifecial microsomia
29 July 2014

89. 89
Acquired:
disturbances of the growth center of the condyle.
29 July 2014
(Oral and maxillofacial Pathology- Neville third
edition)

90. Bifid condyle
90
Rare
Most of have medial and lateral head
divided by an antero posterior
grooves.
Some condyles may be divided into
an anterior and posterior head
Cause is uncertain
Antero-posterior may be traumatic
origin.
29 July 2014
(Oral and maxillofacial Pathology- Neville third
edition)

91. Torus mandibularis
91
Develops along the
lingual aspect of the
mandible.
Probably multifactorial,
including both genetics
and environmental
influences.
29 July 2014
(Oral and maxillofacial Pathology- Neville third
edition)

92. Bibliography
29 July 201492
Ten Cate’s Oral Histology – Sixth Edition
Human embryology- Inderbir Sing Eight edition
Contemporary orthodontics Williams R. proffit
fifth edition
Facial Growth – Donald H. Enlow third edition
Gray’s Anatomy – Fortieth edition
Human anatomy-BD Chaurasia Forth Edition
Shafer’sTextbook of Oral pathology sixth edition
Oral and maxillofacial Pathology- Neville third
edition

93. 29 July 201493