for students of Orthodontics

1. Presented By:
Dr. Smaraki Mahapatra
PG 1st Year ( MMCDSR)
Dept. of Orthodontics
Guided By:
Dr. Geetanjali Gandhi
Growth and Development and
Theories of Growth

2. CONTENTS
Introduction
Definitions of growth and development
Difference between growth and development
Factors affecting physical growth and development
Growth spurts
Terminologies related to growth
Difference between growth site and growth center
Growth; pattern, variability and timing
Methods of studying physical growth
Genetic influences on growth
Concepts of growth
Theories of growth
Conclusion
2

3. INTRODUCTION
 A sound knowledge of growth and development
is essential for successful orthodontic treatment.
 Understanding the growth of the oro-facial
region is vitally important when planning such
treatment procedures.

4. GROWTH AND DEVELOPMENT
o Growth usually refers to increase in size but
tends to be linked more to change than
anything else.
o Development denotes an increasing degree of
organization, often with unfortunate
consequences for the natural environment.
Proffit ; 6th edition; Contemporary orthodontics

5. DEFINITONS OF GROWTH

6. J . S. HUXLEY
 The self–multiplication of living substance

7. KROGMAN
 Increase in size, change in proportion and
progressive complexity.

8. TODD
 According to Todd- “Increase in size”.

9. DR. MELVIN MOSS
 Change in morphological parameter which is
measurable.

10. DEFINITIONS OF DEVELOPMENT

11. DEVELOPMENT
 According to Moyers, development refers to all
naturally occurring unidirectional changes in the
life of an individual from its existence as a
single cell to its elaboration as a multifunctional
unit terminating in death.

12. DEVELOPMENT
 According to Todd, ‘ it is
progress towards maturity.’

13. DIFFERENCE BETWEEN GROWTH AND
DEVELOPMENT
GROWTH DEVELOPMENT
1. It is largely anatomic.
2. Increase in size and number
3. Quantitative
4. Occurs at cellular level
5. Part of development
6. Brings changes in size, shape
form, and structure of the body
7. Stops at the maturation
8. It is unidirectional
1. Physiologic and behavioral
2. Improvement in circumstances
3. Qualitative
4. Occurs at organizational level
5. Includes growth, morphogenesis
and differentiation.
6. Brings changes in functions .
7. Continues throughout the life.
8. It is multidirectional.

14. FACTORS AFFECTING PHYSICAL GROWTH
 HEREDITY: - The genes play a major role in the
overall growth of a person.
 NUTRITION: - The growth process accelerates
when proper nutrition is provided. This is called
catch-up growth.
 ILLNESS: - Prolonged and debilitating illness can
have a marked effect on all aspects of growth.
 RACE:- AMERICAN Blacks, calcification and
eruption of teeth occurs almost a year earlier
than their white counterparts.
Op kharbanda ;2ND EDITION

15.  SOCIOECONOMIC FACTORS;-Affluent and favorable
socio-economic conditions show earlier onset of growth.
 FAMILY SIZE AND BIRTH ORDER -The smaller the family
size ,the better would be the nutrition and other
conditions. The first newborn babies tend to weigh less at
birth and have smaller stature but higher I.Q.
 SECULAR TRENDS -Changes in size and maturation in a
large population can be shown to occur with time .e.g-
fifteen year old boys are approximately 5 inches taller
than the same age group 50 years back.
 OP Kharbanda; 2nd edition

16.  CLIMATIC AND SEASONAL EFFECT:- Climatic changes
seem to have little direct effect on rate of growth.
Seasonal variations affect adipose tissue content and
weight of newborn babies.
 PSYCHOLOGICAL DISTURBANCES- Psychological
disturbances of prolonged duration can hence markedly
retard growth.
 EXERCISE:- It is essential for a healthy body but,
strenuous and regular exercises have not associated
with more favorable growth.
Op kharbanda;2nd edition

17. GROWTH SPURTS
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18. GROWTH SPURTS
 Growth does not take place uniformly at all times.
There seems to be periods when a sudden
acceleration of growth occurs. This sudden acceleration
of growth is termed as ‘growth spurts’.
 The physiological alteration in hormonal secretion is
believed to be the cause for such accentuated growth.
 The timing of the growth spurts differ in boys and
girls.

19. TIMINGS OF GROWTH SPURTS
 Childhood/Infantile growth spurts
Up to 3yrs in both sexes.
 Mixed dentition/juvenile growth spurts
 BOYS - 8-11YRS
 GIRLS - 7-9YRS
 Pre-pubertal/Adoloscent growth spurts
 BOYS -14-16YRS
 GIRLS -11-13YRS

20. FACTORS AFFECTING GROWTH SPURTS
 Growth modification by means of functional
and orthopedic appliances elicit better
response during growth spurts. e,g-chin cup
 Surgical correction involving the maxilla and
mandible should be carried out only after
cessation of the growth spurts.e.g-
orthognathic surgery

21. TERMINOLOGIES RELATED TO
GROWTH
 Growth site
 Growth centre
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22. GROWTH SITE
 It is the location at where the actual growth
occurs.
 BAUME defined the growth site.
 Growth sites are dependent on growth
centers for growth.
• e.g.- Sutures of cranial vault, lateral cranial base, and sutures of
maxilla.
• Condyle of mandible.

23. GROWTH SITES
Condyle
 E.g;-

24. GROWTH CENTERS
It is a location at which growth occurs
independently that is they are genetically
programmed sites of growth.
(proffit)
All growth centres are special growth site but the
reverse is not true.
e.g.- spheno-occipital synchondrosis.

25. DIFFERENCE BETWEEN GROWTH SITE
AND GROWTH CENTER
GROWTH SITE GROWTH CENTER
1. It has special significance in
growth of bone.
2. Growth occurs as a secondary
compensatory effect
3 Lacks direct genetic influence.
4 All growth sites are not
centres.
1. Special growth site which
control the overall growth of the
bone.
2. Growth is primary under the
control of heredity.
3. It has intrinsic growth potential
4. All growth centers are growth
sites
Contemporary orthodontics;Proffit;6th edition

26. Growth Site Growth Center
growth adjuster growth initiator
“pulled apart” “pushes apart”
no tissue separating
force
tissue separating
force
condyle, sutures spheno-occipital
synchondrosis,
nasal cartilage

27. GROWTH; PATTERN,
VARIABILITY AND TIMING
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28. PATTERN
 Pattern of growth in human body is allometric.
 There is a difference in the relative rates of
growth between one part of the body to another.
 Contemporary orthodontics;Proffit ;6th edition
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May
2021
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29. DIFFERENTIAL GROWTH
 The human body does not grow at the
same rate throughout life. Different organs
grow at different rates, to a different amount
at different times. This is termed differential
growth.
 Two important aspects of growth help us to
understand the concepts of differential growth
more clearly.
1. SCAMMON’S GROWTH CURVE
2. CEPHALO-CAUDAL GRADIENT OF GROWTH

30. SCAMMON’S GROWTH CURVE
 The body tissues can be broadly classified in
to 4 types. They are
1. LYMPHOID TISSUE
2. NEURAL TISSUE
3. GENERAL TISSUE
4. GENITAL TISSUE

31. LYMPHOID TISSUE
 Lymphoid tissue proliferates rapidly in late
childhood and reaches almost 200% of adult
size.
 This is an adaptation to protect children from
infection, as they are more prone to it.
 By about 18 yrs of age, lymphoid tissue
undergoes involution to reach adult size .

32. NEURAL TISSUE
 It grows very rapidly and almost reaches
the adult size by 6-7 yrs of age.
 Very little growth of neural tissue occurs after
6-7 yrs.

33. GENERAL TISSUE
 General tissue or visceral tissue consists of
the muscles, bones and the other organs.
 These tissues exhibit an ‘s’ shaped curve
with rapid growth up to 2-3 yrs of age
followed by a slow phase of growth between
3-10 yrs.
 After the tenth year, a rapid phase of growth
occurs terminating by the 18-20 yr.

34. GENITAL TISSUE
 It consists of the reproductive organs .
 They show negligible growth until puberty.
 However they grow rapidly at puberty reaching
adult size after which growth ceases.

36. CEPHALO-CAUDAL GRADIENT OF GROWTH

37.  Cephalo-caudal gradient of growth simply means
that there is an axis of increased growth
extending from head towards the feet.
 A comparison of the body proportion between
pre-natal and post-natal life reveals that post-
natal growth of regions of the body that are
away from the hypophysis is more.
CEPHALO-CAUDAL GRADIENT OF GROWTH

38. The growth concept can be illustrated as follows;
The head takes up about 50% of the total body
length around the 3rd month of intra-uterine life.
 At the time of birth , the trunk and the limbs
have grown more than the head, thereby
reducing the head to about 30% of body length.
 The overall pattern of growth continues with a
progressive reduction in the relative size of the
head to about 12% in the adult.

39. The lower limbs are rudimentary around the
2nd month of intra-uterine life.
 They later grow and represent almost 50%
of the body length at adulthood.
The increased gradient of growth is evident
even with in the head and face.
 At birth, the cranium is proportionally larger
than the face.
 Post-natally, the face grows more than the
cranium.

40. VARIABILITY
 It is the law of nature and human growth is no
exception.
 Some children are average growers. Some are
genetically tall, while others are genetically short.
 Cause of variability in growth include heredity,
sex, nutrition,racial differences, exercise, climate,
and socioeconomic and psychological factors.
 Girls gain maximum length earlier than boys.
40

41. TIMING
 The third and most important factor of growth
in terms of clinical applications is the timing of
growth.
 One important factor in timing of growth is
sex of individual. Girls mature earlier than boys .
 Some girls mature faster than others.
41

42. METHODS OF STUDYING GROWTH

43. MEASUREMENT APPROACHES
 Craniometry
 Anthropometry
 Radiographic method
 Biometric test
Ref.Proffit;6th edition

44. EXPERIMENTAL APPROACHES
 Vital staining
 Implants
 Radioisotopes

45. MEASUREMENT APPROACHES

46. CRANIOMETRY
 Measurement of skull.
 ADVANTAGES:-
 Precise measurements.
 Information of extinct
population.

47. ANTHROPOMETRY
Measured in living individual directly.

48.  RADIOGRAPHIC TECHNIQUES - The most
commonly used techniques are CEPHALOMETRY and
HAND-WRIST RADIOGRAPHY.
 CEPHALOMETRY;-It is standardized radiographic
technique of the craniofacial region. It makes it possible
to take serial radiographs of a patient’s skull in order to
study the growth changes taking place. It is also a
valuable aid in orthodontic diagnosis, treatment planning,
evaluation of treatment results and for growth prediction.
 HAND-WRIST X-RAYS: - Radiographs of the hand-wrist
region are used to study the biological or skeletal age of
a person.

49. CEPHALOMETRY

50. HAND-WRIST RADIOGRAPH

51. OPG

52. CT SCAN

53. CBCT

54. MRI
 Magnetic resonance imaging more clearly shows
soft tissue .

55. BIOMETRIC TEST
 They are tests in which physical characteristics
are:
1. weight
2. height,
3. skeletal maturation
4. ossifications are measured and compared with
standards based upon the examinations of large
groups of healthy subjects. 55

56. EXPERIMENTAL APPROACHES
Vital staining

57. IMPLANTS

58. RADIOISOTOPES
 They are injected into the growing bone by auto
radiographic technique.
 E.g;-Calcium-45

59. GENETIC INFLUENCES ON GROWTH
 Homeobox , Msx gene and Dix genes are known
to be critically important in the establishment of body
plan, pattern formation, and morphogenesis are
expressed differentially not only in the development of
teeth but also in growth of mandible.
 Dlx-1 and Dlx-2 are expressed in the dental
mesenchyme and in the epithelium of the maxillary and
mandibular arch mesenchyme and other homeobox gene
groups have been shown to play a role in dental and
facial development.
 Msx-1 predominates in tooth formation and is
expressed in basal bone but not in alveolar process,
whereas Msx-2 is strongly expressed there.

60.  CONCEPTS OF GROWTH

61. CONCEPT 1
 Facial growth and development is a morphogenic process
working toward a composite state of aggregate structural
and functional balance among all of the multiple , regional
growing and changing hard & soft tissue parts

62.  The same underlyning process then continues to work in
order to sustain ongoing equilibrium throughout adulthood
and old age in response to changing internal and external
conditions

63. CONCEPT 2
 Bone grows by adding new tissue on
one side of bony cortex (deposition+)
and taking it away from the other side
(resorption- )
 Deposition + resorption drift
 Drift produces a direct growth
movement of any given area of bone

64. CONCEPT 3
 Bone surfaces are completely blanketed by a mosaic
like pattern of growth fields
 If a given periosteal area has a resorptive type of
field , the opposite inside (endosteal) area has a
depository field.

65. CONCEPT-4
 Bone is covered by both - a covering membrane
(periosteal bone) which constitutes about half of the
cortical bone ,
 And by lining membrane (endosteal bone) which makes
up the other half

66. CONCEPT-5
 Bone formation is actually carried out by osteogenic
membranes and other surrounding tissues rather than
hard part of bone
 Growth is produced by soft tissue matrix , that encloses
each whole bone

67. CONCEPT 6
 The resorptive and depository growth fields throughout
bone donot have the same rate of growth activity
 Some grow more rapidly and some less than others
 Fields that have some special significance in in growth
process are often called as GROWTH SITES

68.  E.g Mandibular condyle
(endochondral bone
formation) – growth by
regional tension related
mechanism – specific
response to local
circumstance- no genetic
programming

69. CONCEPT 7- BONE REMODELLING
 Remodelling involves deposition of bone on any
surface pointed towards the direction of enlargement
of a given area ; resorption usually occurs on the
opposite side of the particular bony cortex.

70. Relocation –
 Is the sequential movement of component parts as the
bone enlarges
 E.g – The whole ramus is relocated posteriorly, thus the
posterior part of lengthening corpus becomes relocated in
the area of ramus
 And in maxilla – Palate is relocated inferiorly

71. CONCEPT-8 CORTICAL DRIFT
 Most bones grow by interplay of bone deposition
and resorption resulting in a growth resulting in
growth movement towards the deposition surface
called ‘cortical drift’.

72. CORTICAL DRIFT IN MAXILLA
14 May 2021 72

73. CORTICAL DRIFT IN MANDIBLE
14 May 2021 73

74. CONCEPT-9 DISPLACEMENT
 It is a separate movement of the whole bone by
some physical force that carries it,away from its
contacts with other bones, which are growing and
increasing in overall size at the same time.
 Displacement is two types;-
1.Primary displacement
2.Secondary displacement

75. DISPLACEMENT
14 May 2021 75

76. PRIMARY DISPLACEMENT
 As the bone enlarges , it is simultaneously carried away from
other bones in direct contact .- bone’s own enlargement
 This creates a space within which the bony enlargement
takes place .
 This is called as PRIMARY DISPLACEMENT OR
TRANSLATION

77. SECONDARY DISPLACEMENT-
 Movement of the whole bone caused by separate
enlargement of other bones
 One of the several basic factors involved in the
developmental basis of malocclusions and other types of
facial dysplasias

78. CONCEPT 10
 Facial growth is a process that requires morphogenic
INTER RELATIONSHIPS among all its component
growing ,changing and functioning soft and hard tissue
parts.
 No part is developmentally independent and self contained

79. CONCEPT-11 ROTATION
 According to Enlow, growth rotation is due to
diagonally placed areas of deposition and
resorption.
 Two types;-
 1.Remodelling rotation
 2.Displacement rotation
 Ref Essentials of facial growth;Enlow and Hans

80. DISPLACEMENT
ROTATION
REMODELLING
ROTATION

81. CONCEPT-12 ‘V’ PRINCIPLE
 Deposition occurs on the innerside and
resorption occurs on the outerside of the bones
causing enlargement and displacement.
 This displacement is towards wide end of ‘ V’.
 Examples-
 1.Neck of condyle
 2.Palatal process of maxilla

83. THEORIES OF GROWTH

84. THEORIES OF GROWTH
 Bone remodelling theory
 Genetic theory
 Sutural theory
 Cartilaginous theory
 Funtional matrix theory
 Van-limborgh’s theory
 Enlow’s expanding ’v’ principle
 Servosystem theory
 Growth relativity theory

85. BONE REMODELLING THEORY

86. REMODELLING THEORY
 It is given by Brash in 1930.
 According to this theory craniofacial skeletal
growth takes place by bone remodelling.
 Bone remodelling is selective deposition and
resorption of bone at its surface.
 There are 3 fundamentals of the theory;-
1.Bone grows by apposition at the surface.
2.Growth of jaws takes place by deposition of bone at
the posterior surfaces of the maxilla and mandible.
This is called Hunterian growth.
3. Calvarium grows through bone deposition on the
ectocranial surface of the cranial vault and
resorption of bone on the endocranial surface.

88. DISADVANTAGE
 The theory created doubt about the role of unique
stuructures like sutures, cranial base
synchonrosis, and mandibular condylar cartilage.
 The doubt was that if these sites are not essential
for normal craniofacial growth then why they are
present at all.?

89. GENETIC THEORY

90. GENETIC THEORY
 All growth is controlled by genetic influence
and preplanned.
 It is one of the earliest theories put forward.
 By Brodie in 1941.

91. SUTURAL THEORY

92. SUTURAL THEORY
 Sicher believed that craniofacial growth occurs
at the sutures.
 According to him paired parallel sutures that
attach facial areas to the skull and the cranial
base region push the naso-maxillary complex
forwards to pace its growth with that of the
mandible.

93. 14 May 2021 93

94. DISADVANTAGES
 When an area of suture is transplanted to
another location ,the tissue does not continue to
grow. This clearly indicates a lack of innate
growth potential of the sutures.
 Growth takes place in untreated cases of cleft
palate even in the absence of sutures.
 Micro cephaly and hydrocephaly raised doubts
about the intrinsic genetic stimulus of sutures.

95. CONCLUSION OF THIS THEORY
 Sutures are growth sites .
 It has no tissue separating force .
 So , they are not considered as growth centers.

96. CARTILAGINOUS THEORY

97. CARTILAGINOUS THEORY
 The theory was put forward by James Scott.
 According to him intrinsic growth controlling factors are
present in cartilage and periosteum with sutures being
only secondary.
 He viewed that cartilaginous sites throughout the skull
as primary centres of growth.
 Example-Growth of maxilla is attributed to nasal septal
cartilage.
 According to Scott , the nasal septal cartilage is the
pacemaker for the growth of the entire naso-maxillary
complex.

98. ADVANTAGES
 In many bones, cartilage growth occurs , while bone
merely replaces it.
 If a part of epiphyseal plate is transplanted to a
different location , it will continue grow in the new
location. This indicates the innate growth potential of
the cartilage.
 Nasal septal cartilage also shows innate growth
potential on being transplanted to another site.
 Experiments on rabbits involving removal of the nasal
septal cartilage demonstrated retarded mid-face
development.

99. TWO DIFFERENT TYPES OF STUDIES WERE
CARRIED OUT TO PROVE THIS THEORY:
 Transplantation
 Surgical removal

100. FUNCTIONAL MATRIX THEORY

101. FUNCTIONAL MATRIX THEORY
 In 1962 Melvin Moss introduced the functional matrix
hypothesis in to the orthodontic world.
 It was developed complimentary to the original
concept of functional cranial component by Van der
klaau (1952).
 According to this theory, bone growth within the
craniofacial skeleton is influenced primarily by function.

102.  This hypothesis claims that the origin, form,
position, growth and maintenance of all skeletal
tissues and organs are always secondary,
compensatory and necessary responses to
chronologically and morphologically prior events
or processes that occur in specifically related
non-skeletal tissues, organs or functioning
spaces.

103. TYPES OF FUNCTIONAL MATRICES
• Periosteal
Matrix
 Active growth
 Deposition &
Resorption
 Affect size
&/shape
• Capsular
matrix
Passive growth
×Deposition
×Resorption
Affect location

104. FUNCTIONS THAT ARE CARRIED OUT IN THE
CRANIO-FACIAL REGION OF THE HUMAN
BODY:
1. Respiration
2. Chewing
3. Olfaction
4. Vision
5. Hearing
6. Balance
7. Digestion
8. Swallowing
9. Speech
10. Neural integration

105. Skeletal unit Functional matrices
Macroskeletal
eg-skull
Microskele
tal
eg-maxilla and
mandible
Perioste
al
eg-teeth
and
muscles
Capsular
Matrix.
e.g.orofacial
capsule and
neurocranial
capsule

106. FUNCTIONAL CRANIAL COMPONENT
 It is divided into:
1. Functional matrix
2. Skeletal unit
 The functional matrix consists of muscles, glands,
nerves, vessels,fat, teeth and the functioning spaces. It
is divided in to following two:
1.Periosteal matrix
2.Capsular matrix

107. SKELETAL UNIT
 Bony structures that support the functional matrix and
these are necessary or permissive for that function.
 The skeletal unit does not refer to the individual bone
directly , but to the function it supports.
 They are two types of skeletal units.
1. microskeletal
2. macroskeletal
 Micro skeletal unit are parts of the bone whose growth is
modulated by the periosteal matrices.
 Macroskeletal units are made up of the core of maxilla,
mandible and neurocranium.

108. SKELETAL UNIT
MACRO-SKELETAL
MICRO-SKELETAL

109. PERIOSTEAL MATRICES
 It includes:
1. Muscles
2. Blood vessels
3. Nerves
4. Glands

110. PERIOSTEAL MATRIX

111. CAPSULAR MATRICES
 Example:- NEUROCRANIAL CAPSULE AND OROFACIAL
CAPSULE.
 Neurocranial capsule is made up of skin ,connective
tissue, aponeurotic layer, loose connective tissue layer,
periosteum, base of the skull and two layers of dura
mater.
 The oro-facial capsule surrounds and protects the
oro-naso-pharyngeal spaces that constitute the oro-
facial capsular matrix.

112. CAPSULAR MATRIX
ORO-FACIAL CAPSULE
NEURO-CRANIAL CAPSULE

113. NEURO-CRANIAL CAPSULE

115. FUNCTIONAL MATRIX AND FRANKEL
APPLIANCE
 Frankel appliance works based on the functional matrix
theory.
 The functional regulator provides a larger functional
matrix than the teeth.
 The buccinator mechanism will grow and adapt to
whichever functional matrix (soft tissue capsule) present
in the mouth.
 The adaptation occurs primarily during growth.

116. FUNCTIONAL MATRIX THEORY
REVISITED

117. FUNCTIONAL MATRIX HYPOTHESIS REVISITED
1997: 1.THE ROLE OF MECHANOTRANSDUCTION
 The FMH postulates two types of functional matrices. This
new version deals only with the responses to periosteal
matrices. It now includes the molecular and cellular
processes underlying the triad of active skeletal growth
processes
1. DEPOSITION
2. RESORPTION
3. MAINTENANCE

118.  FMH – revisit presents seamless description between
several level of bone structure and operation from genomic
to organ level.
It does so by the inclusion of two complementary concepts-
1) Mechanotransduction occurs in single bone cells.
2) Bone cells are computational elements that function
multicellularly as a connected cellular network.

119. MECHANOTRANSDUCTION
 Mechanosensing process enable a cell to sense and to
response to extrinsic loading by using the process of
mechanoreception and mechanotransduction.
mechanoreception: transmits an extra cellular physical
stimulus into a receptor cell, the mechanotransduction
transforms the stimulus into an intra cellular signal.

120. Mechanotransduction: Transducing or transforming the
stimulus's energetic and/or informational content into an
intracellular signal. Mechanotransduction is one type of
cellular signal transduction.
There are 2 mechanotransductive process-
1) Ionic or electric
2) Mechanical - through physical continuity of the
transmembrane molecule integrin

121. mechanical
Ionic/electrical

122. Extracellular Collagen
INTEGRIN
Intracellularly with Cytoskeletal ACTIN
Nuclear Membrane
Intranuclear Process
Regulate Genomic Activity

123. OSSEOUS MECHANOTRANSDUCTION
Osseous mechanotransduction is unique in 4 ways:
1) Not cytologically specialized.
2) Evoke three adaptational responses
3) Osseous signal transmission is aneural.
4) Evoked bone adaptational response are confined with
in each ‘bone organ’ independently.

124. FUNCTIONAL MATRIX HYPOTHESIS REVISITED 1997: 2.
THE ROLE OF AN OSSEOUS CONNECTED CELLULAR NETWORK
 Bone as an osseous connected cellular network
(CCN): All bone cells, except osteoclasts, are
extensively interconnected by GAP-junction that form an
osseous CCN.
 Each osteocyte enclosed with in its mineralized lacunae

125.  Gap-junction exhibit both electrical and
fluorescent dye transmission, in addition to
permitting the intercellular transmission of ions
and small molecules.

Mechanotransductively activated bone cells, e.g.
osteocyte, can initiate membrane action potentials
capable of transmission through interconnected
Gap-junction.

126. Loading of bone
stimulate initial cells
( loading exceeds
threshold value)
Intracellular signals generated
transmitted to intermediate or hidden
layer cells (osteocyte)
( when exceeds
threshold value)
transmission to final layer cells
(osteoblasts)
Adaptive response

127.  A skeletal CCN displays the following attributes:
1) Developmentally: untrained
self-organized, self-adaptive and
epigenetically regulated system.
2) Operationally: stable, dynamic system that
exhibits oscillatory behavior permitting feed back.
3) Structurally, an osseous CCN is nonmodular.

128. CCN

129. FUNCTIONAL MATRIX HYPOTHESIS REVISITED1997:
3. THE GENOMIC THESIS
 The initial version of the functional matrix hypothesis
claiming epigenetic control of morphogenesis was based on
macroscopic (gross) experimental, comparative and clinical
data.
 Recently revised it now extends hierarchically from gross to
microscopic (cellular & molecular) levels and identifies
some epigenetic mechanisms capable of regulating genomic
expression.

130.  The epigenetic /genomic problem is a dichotomy and
dialectics is one analytical method for its resolution. The
method consists of the presentation of two opposing
views-
• The genomic thesis
• An epigenetic antithesis and a
resolving synthesis.
 The genomic thesis :
The genomic thesis holds that the genome from the
moment of fertilization, contains all the information
necessary to regulate (cause, control, direct)---
1) The intranuclear formation and transcription of mRNA.
2) All (phenotypic) feature are ultimately determined by
the DNA sequence of the genome.

131. Genomic thesis is denied because it is both
reductionist and molecular, that is description of the
causation (control, regulation) of all hierarchically
higher and structurally more complex
morphogenetic processes are reduced to
explanation of mechanisms at the molecular (DNA)
level.

132. THE FUNCTIONAL MATRIX HYPOTHESIS
REVISITED :4. THE EPIGENETIC ANTITHESIS
AND THE RESOLVING SYNTHESIS
 The epigenetic antithesis :
Its Goal is to identify and describe comprehensively the
series of initiating biological process and their related
underlying (biochemical, biophysical) responsive
mechanisms that are effective at each hierarchical level of
increasing structural and operational complexity.

133. Craniofacial epigenetics:
 Broadly speaking, epigenetics refers to the entire series of
interaction among cells and cell products which leads to
morphogenesis and differentiation. thus all cranial
development is epigenetic.
 In terms of clinical orthodontics, all therapy is applied
epigenetics and all appliances acts as prosthetic functional
matrices.
 Clinical therapeutics includes a number of epigenetic
processes, whose processes of tissue adaptation by both
skeletal unit and functional matrices.

134. A RESOLVING SYNTHESIS
 Morphogenesis is regulated (controlled, caused) by the
activity of both genomic and epigenetic processes and
mechanisms.
 Both are necessary, neither alone are sufficient cause and
only their integrated activities provides the necessary and
sufficient causes of growth and development.
 Genomic factors are considered as intrinsic and prior
causes, epigenetic factors are considered as extrinsic and
proximate cause.
 Epigenetic processes and events are the immediately
proximate causes of development and as such they are the
primary agencies.

135. VAN –LIMBORGH’S THEORY

136. VON –LIMBORGH’S THEORY
1. A multi-factorial theory was put forward by van-limborgh
in 1970.
2. This theory is conceptual, taking only the positive
aspects of Scotts cartilaginous theory, sutural
dominance theory by Sicherrand Moss functional matrix
theory.
3. He suggested 6 factors that controls growth.
4. Van Limborgh lists the essentials of all the 3 hypothesis.

138. 6 FACTORS THAT CONTROLS THE GROWTH
 Growth of synchondrosis and endochondrial growth
is exclusively under the control of intrinsic growth
factor.
 The intrinsic factors controlling intramembranous
growth ,that is growth at sutures , periosteum
(desmocranium) growth to a larger extend are
general in nature.
 Cartilaginous parts of the skull must be considered
as growth centres.
 Sutural growth is controlled by both cartilaginous
growth and growth of adjacent structures in the
head.

139.  Periosteal growth to a large extend depends on growth
of adjacent structures.
 Intramembranous bone formation is additionally
influenced by local non genetic environmental factors
inclusive of muscle forces.

140. THE CONTROLLING FACTORS JUDGED BY VAN
LIMBORGH IN CRANIOFACIAL GROWTH
 Intrinsic genetic factor-genetic factor inherent to the
skull tissues.
 Local epigenetic factor -capsular functional matrix
 General epigenetic factor -originating from distant
structure (sex hormone, growth hormone)
 Local environmental factors -periosteal matrix (habits,
muscle force etc)
 General environmental factors – originating from
external environment (nutrition, oxygen supply, etc)

141. ENLOW’S EXPANDING ‘ V’ PRINCIPLE

142. ENLOW’S EXPANDING V PRINCIPLE
 Many facial bones or parts of bone have v shaped
pattern of growth.
 The growth movements and enlargement of these
bones occur towards the wide ends of the v as a
result of differentiatial deposition and selective resorption
of the bone.
 Bone deposition occurs on the inner side of the wide end
of the v and bone resorption on the outer surface.
 Deposition also takes place at the ends of the 2 arms of
the V resulting in growth movement towards the
ends.

144.  The V pattern of the growth occurs in a no of regions
such as the mandible, ends of long bones, mandibular
body, palate etc.

145. ENLOW’S COUNTERPART PRINCIPLE
 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.

147. FEW COUNTERPARTS
 Nasomaxillary complex relates to the ant. cranial fossa.
 Horizontal dimension of the pharyngeal space relates to
the middle cranial fossa.
 Middle cranial fossa and breadth of ramus are
counterparts.
 Maxillary and mandibular arches are mutual counterparts.
 Bony maxilla and corpus of mandible are mutual
counterparts.
 Maxillary tuberosity and lingual tuberosity are
counterparts.

148. IMBALANCES ARE PRODUCED DUE TO VARIATION IN:
 Magnitude of growth between the counterparts.
 Timing of growth between the counterparts.
 Direction of growth between the counterparts.

149. NEUROTROPHISM
(Neuro +Trophism = Nerve + Nourish
 "Oro-facial growth is now capable of being conceived of
as a homeostatically controlled series of processes in
which the neural center regulates the peripheral tissues
and the periphery, in turn, regulates the center.'‘ Moss

151. NEUROTROPIC PROCESS IN ORO-FACIAL
GROWTH
 Neurotrophism is a non-impulse transmitting neural
function that involves axoplasmic transport and provides
for long term interaction between neurons and innervated
tissues that homeostatically regulates the morphological,
compositional and functional integrity of the tissues.
 The different types of neurotropic mechanisms are;
1. Neuro-epithelial tropism
2. Neuro-visceral tropism
3. Neuro-muscular tropism

152. SERVOSYSTEM THEORY
 A new system in understanding the process controlling
craniofacial growth.
 Given by Petrovic and Stutzman in 1980.
 Charlier and Petrovic in 1967 and Stutzman and Petrovic
in 1970 observed some basic dissimilarities between
growth of primary and secondary cartilages in their
investigations. Their observation leads to the servo
system theory.
 It is based on cybernetic concept. It states that the
everything affects everything and living organisms never
operate in open loop mechanism.
 In open loop mechanism , the input or stimulus leads to
a response and there is no feed back or regulation.
14 May 2021

153.  Closed loop mechanism can be of two types:
1. Regulator system in which the the input is
constant
2. Servosystem / follow-up system in which the
main input varies rather than being constant.
14 May 2021 153

154. COMPONENTS OF SERVOSYSTEM THEORY
 Command;-A signal established independently of the feedback system
under scrutiny. It affects the controlled system without being affected
by the consequences of this behaviour. E.g;-Somatotropic hormone,
GH, testosterone, estrogen.
 Reference input elements ;-Establish relationship between the
command and reference input. It includes septal cartilage,
septomaxillary ligament and labionarinay muscles.
 Reference input;-It is the signal established as a standard of
comparision sagittal position of maxilla.
 Comparator;-The configuration between the position of the upper
and lower dental arch is the comparator of the servosystem .
 Actuating signal;-Retrodiscal pad and lateral pterygoid
 Controlled system;-It is between the actuator and controlled
variable,e.g;-growth of condylar cartilage through the retrodiscal pad
stimulation.
 Controlled variable;-It is the output signal of the servosystem e.g. -
sagittal position of the mandible. 154

155. 14 May 2021 155

156. HOW SERVOSYSTEM THEORY EXPLAINS THE
GROWTH OF JAWS?
 According to the theory, the influence of somatotropic
hormone on growth of primary cartilages, has a
cybernetic form of a command.
 Growth related hormones have a direct influence on
growth of primary cartilages.
 On the otherhand, these hormones have both direct
and indirect effects on the growth of secondary
cartilages.
 The growth of seconary cartilages corresponds to local
epigenetic and environmental factors.
 In the development of face and jaws, the upper arch
acts as a constantly changing reference input and the
lower arch is constant variable.
14 May 2021 156

157.  Any disturbance between the respective positions of
the upper and lower arch acts as the peripheral
comparator and sends activating signals through the
stimulation of retrodiscal pad and lateral pterygoid
muscles.
 This affects the output signal, i.e., the final sagittal
position of the mandible.
 The inference is that, the final saggital position of the
mandible depends on the modification of condylar
growth by the activity of retrodiscal pad and lateral
pterygoid muscle stimulation.
14 May 2021 157

158. GROWTH RELATIVITY THEORY
 By John Voudouris in 2000.
 Growth relativity - growth that is relative to the
displaced condyle from actively relocating fossae.
3 Main foundations -1. displacement
2. viscoelasticity
3. referred force

159.  It states that with orthopedically displaced condyle, the
bone architechture is influenced by the
neuromusculature, cartilages, non-muscular,
viscoelastic tissues anchored to the glenoid fossa and
the altered dynamics of the fluids enveloping bone.
 Viscoelasticity is conventionally applied to elastic tissue
primarily the muscles.
14 May 2021 159

160. GROWTH RELATIVITY HYPOTHESIS
Mandibular advancement(displacement)
Stretch of non-muscular
viscoelastic tissues
Engorged blood
vessels
transduction
New bone formation
Influx of nutrients
synovial fluid dynamics

161.  Glenoid fossa promotes condylar growth with the
use of mandibular advancement therapy.
Am J of Orthodontics and dento-facial orthopedics
;117,p-254
14 May 2021 161

162. CONCLUSION OF THE THEORY
 Identifying the primary trigger mechanism for the
growth of maxilla and mandible will help the
orthodontist to either to stimulate or retard the
growth of maxilla and mandible.
 This will prove to be the key to successful growth
modification treatment in skeletal malocclusion.

163. CONCLUSION
 Growth and development and theories of growth
have very much implications in orthodontics.
 It is very much necessary for orthodontists for the
successful orthodontic treatment.

164. BIBILOGRAPHY
 CONTEMPORARY ORTHODONTICS; South Asia Edition;6th edition
 Graber’s text book of orthodontics; 4th edition
 Am J OF ORTHODONTICS;1983-Elsevier
 OP Kharbanda.;2nd edition.
 Orthodontic principles and practice; Basavaraj Subhashchandra Phulari.
 Enlow handbook of facial growth.
 J anat.(1986),144,p-(99-111)
 Proceedings of royal society of medicine ;The growth of human face ;
James H .Scott. 47,p-(91-100)
 Am J Orthodontics, growth site n growth center facts or fallacy.
 Textbook of Craniofacial Growth ; Sridhar Premkumar
 Am J of orthodontics and dentofacial orthopedics;functional matrix
hypothesis revisited1,2,3,4.