This document discusses principles of craniofacial growth and development. It defines key terms like growth, development, pattern, and mechanisms of bone growth. Growth occurs through deposition and resorption on bone surfaces. The craniofacial skeleton grows through mechanisms like cortical drift, displacement, and V-shaped bone expansion. Several theories try to explain craniofacial growth, including the genetic, sutural, cartilaginous, and functional matrix hypotheses. Overall growth follows cephalocaudal and Scammon's gradients, while the maxilla and mandible grow through posterior expansion and anterior displacement.

1. GROWTH AND DEVELOPMENT AND
PRINCIPLES OF CRANIOFACIAL
GROWTH MODIFICATION
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS
Presented by:
Dr. Deeksha Bhanotia
Resident, Department of
Orthodontics and
Dentofacial Orthopaedics
NIMS Dental College and
Hospital

2. DEFINITIONS OF GROWTH
JS Huxley “The self multiplication of living substance.”
Krogman “Increase in size, change in proportion and progressive complexity.”
Todd “An increase in size.”
Meridith “Entire series of sequential anatomic and physiologic changes taking place from
beginning of prenatal life to senility.”
Moyers “Quantitative aspect of biologic development per unit of time”
Moss “Change in any morphological parameter, which is measurable.”
Profitt “Growth refers to an increase in size/number.”

3. DEFINITIONS OF DEVELOPMENT
Todd “Development is progress towards maturity.”
Profitt “Development is in complexity.”
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 multifunctional
unit terminating in death.”

4.  Development = Growth + Differentiation + Translocation, where differentiation means change in
quality, and translocation means change in position.
 Profit differentiates the term growth and development as follows. The basic difference between
growth and development is growth can be considered an "anatomic phenomenon" whereas
development is a “physiological and behavioural phenomenon”
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5.  Differentiation is the change from generalized cells or tissues to more specialized kinds during
development.
 Differentiation is change in quality or kind.
 Translocation is change in position.
 Translocation of chin point downward and forward is far more than any growth at the chin itself.
 Maturation is the qualitative changes which occur with ripening or aging.
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6. Kharbanda OP. Orthodontics: Diagnosis of & Management of Malocclusion & Dentofacial Deformities,(third edition).

7. GROWTH PATTERN
 Pattern refers to the way in which the various parts of the body are arranged in a proportional
relationship.
 It represents the set of proportional relationships and not a single proportional relationship.
 The relationships are not only represented at a particular point of time but also portray the
change in relationship over time.
 Moyers defines pattern as a set of constraints operating to preserve the integration of parts
under varying conditions or through time.
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8. CEPHALOCAUDAL GROWTH
 Cephalocaudal growth gradient is an example of change in the body proportions that occurs in
normal growth and development.
 In the third month of intrauterine life, head constitutes 50 percent of the total body length. The
cranium is large, relative to the face and represents more than half of the total head.
 Limbs are underdeveloped.
 At the time of birth the trunk and the limbs have grown faster than head and face, so that the
portion of the head is decreased to 30 percent.
 In the adult, there is progressive reduction in relative size of head which is 12 percent of the
total head body length.
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9.  Thus there is always an increase in the gradient of growth towards the caudal direction right from
the intrauterine life. We could also figure out that greater proportion of head which is seen
during birth is reduced in the adult.
 Even in the head and face at the time of birth, there is a larger cranium and a much smaller face.
 This increased axis of growth inthe caudal direction is called as cephalocaudal growth gradient.
Cephalocaudal growth is evident in the face also.
 At birth, jaws and face are less developed when compared to skull, maxilla being closer to head,
grows faster and growth is completed before mandibular growth. Mandible being away from the
brain grows more and growth completes later than maxilla.
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11. SCAMMON’S GROWTH GRADIENT
 Human body is comprised of four major tissues. They are neural, somatic—includes muscles and
bone, lymphoid and genital/sexual tissue.
 Not all the tissue systems of the body grow at the same rate.
 Growth of the neural tissues is complete by 6 or 7 years of age.
 General body tissues, including muscle bone and viscera show an ‘S’ shaped curve, with a definite
slowing down of the rate of growth during childhood and acceleration at puberty.
 Lymphoid tissues proliferate far beyond the adult amount in late childhood and then undergo
involution at the same time when growth of the genital tissues accelerates rapidly.
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13. VARIABILITY
 Another important concept of growth is variability.
 According to Moyers, variability is the law of nature.
 No two individuals grow in the same manner.
 Variations can be attributed to both genetic and environmental factors.
 Variations in growth can be expressed by statistics as range of differences found in a population
containing people of similar age, sex, socioeconomic background and race.
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14. MECHANISM OF BONE GROWTH
Deposition and Resorption
 Bones grow by addition of new bone tissue on one side of the bony cortex and taking it away from
the other side.
 The surface facing towards the direction of progressive growth receives new bone deposition.
 The surface facing away undergoes resorption.
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15.  The outside and the inside surfaces of a bone are covered by irregular patterns called growth
fields.
 It is comprised of various soft tissue osteogenic membranes or cartilages. Bone does not grow by
itself.
 Bone growth is influenced by this soft tissue growth fields.
 The genetic program of the bone growth is not contained within the hard tissue. But it resides in
the surrounding tissue growth fields.
 All bones have got both resorptive and depository fields.
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16. ENDOSTEAL AND PERIOSTEAL BONE GROWTH
 Approximately half of the cortical plate of the facial and cranial bones is formed by the outer
surface, i.e. the periosteum, and the other half by the inner surface, the endosteum.
 Appositional layers of cortical bone can originate entirely from the periosteum or the endosteum.
 In some cases, the same cortex is composed of periosteal and endosteal bone layers which are
separated by reversal lines.
 This type of bone growth indicates that there has been a change in the direction of growth at
some time.
 As new cortical bone is always deposited on the surface facing toward the direction of growth,
bones revert to a type of periosteal bone formation from endosteal bone formation or vice versa.
 The reversal line represents the interface between endosteally and periosteally produced bone
layers.
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17. (A) If the direction of the growth remains
constant, the right cortical is formed periosteally and left
formed endosteally. Both shift in unison in the direction of
the growth. (B) The direction of bone can change during
development of bone. In the area marked with an asterisk
bone formation initially occurs endosteally (above) and at
a later date after reversal of the direction of growth,
periosteally(below)
(A) Reversal line: The interface between
periosteally and endosteally formed bone is termed the
reversal line. Line drawing of the histological section: AK—
alveolar bone; P—periodontal space; Z—tooth root. (B)
Section through an alveolar bone. The yellow staining shows
endosteal bone formation in upper section of the surface
facing the tooth and periosteal formation in the lower section.
This leads to rotation of the bone structure (fluorescent
microscopic view after tetracycline staining)

18. REMODELING
 Facial bones undergo resizing and reshaping simultaneous to bone deposition and resorption.
 The reshaping of bone occurs not due to generalized deposition and resorption. Bone shaping
requires differential growth activity, known as remodeling.
 Remodeling is a part of growth process, provides regional changes in shape, dimensions and
proportions.
 It also provides regional adjustments that adapt to the developing function of the bone and its
various growing soft tissues.
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19. GROWTH MOVEMENTS
Drift and Displacement
 All bones have one common growth principle, that is drift, which was termed by Enlow(1963).
 Drift is growth movement (relocation or shifting) of an enlarging portion of a bone by the
remodeling action of its osteogenic tissues, while displacement is a physical movement of a whole
bone.
 The cortical plate can be relocated by simultaneous apposition and resorption processes on the
opposing periosteal and endosteal surfaces (cortical drift).
 The bony cortical plate drifts by depositing and resorbing bone substance on the outer and inner
surfaces respectively, in the direction of growth.
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20. Process of cortical drift:
(A) Cortical plate of bone;
(B) increase in thickness due to apposition on one of
the surfaces;
(C) When the resorption process on one side
of the bone exceeds the apposition process on the
opposing side, the thickness of the bone will be
reduced;
(D) When resorption on one side of the bone
corresponds in magnitude to apposition on the opposing
side, the bone will drift without changing its size;
(E) The cortical plate has drifted completely to the right
when compared to its original position in ‘A’ by the
process of remodelling

21. DISPLACEMENT
 Displacement is movement of the whole bone as a unit.
 It is a translatory movement of the whole bone caused by the surrounding physical forces, and is
the second characteristic mechanism of skull growth.
 The entire bone is carried away from its articular interfaces (sutures, synchondroses, condyle)
with adjacent bones.
 Displacement is of two types namely primary displacement and secondary displacement.
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22.  Primary displacement:
 As a bone enlarges, it is simultaneously carried away from the other bones in direct contact with
it.
 This creates space within which bony enlargement takes place. This is termed as primary
displacement.
 It is the physical movement of the whole bone, as the bone grows and remodels by resorption and
apposition.
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23. Primary displacement. Bone moves from one position to another not only because
of deposition and resorption but also because of space created by enlarging bones

24.  Secondary displacement:
 It is the movement of a whole bone caused by the separate enlargement of other bones, which
may be nearby or quite distant.
 It is the movement of bone related to enlargement of other bones.
 For example, growth in the middle cranial fossa results in the movement of the maxillary complex
anteriorly and inferiorly.
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25. Secondary displacement. Bone moves from one position to another not because
of deposition and resorption but because of surrounding physical forces

26.  Genetic theory (Brodie 1941) : This theory simply states that genes determine and control the
whole process of craniofacial growth. Genetic concept suggests that the genes supply all the
information in growth and development. This originated with classical Mendelian genetics.

27.  The Sutural Theory (Sicher and Weinnman 1952) Acc. to this theory, sutures, cartilage and
periosteum are all responsible for facial growth. Sutures are the main contributor of growth in
craniofacial region. The craniofacial skeleton enlarges due to the expansible forces exerted by
the sutures as they separate

28.  Cartilaginous Theory (Scott) z Also known as Scott hypothesis / Nasal septum theory /
Nasocapsular theory. Essence of theory: According to this theory, sutures play little role or no
direct role in the growth of the craniofacial skeleton . Sutures are considered as merely passive,
secondary and compensatory sites of bone formation and growth ,Intrinsic growth controlling
factors were present only in cartilage and periosteum.

29.  Growth in sutures was permissive, secondary and entirely dependent on the growth of the
cartilage and adjacent soft tissues. The cranial base synchondroses cause the growth of the
cranial base and Scott compared the condylar cartilage to the cranial base cartilage. Histologic
research validates much of the Scott hypothesis Nasal septum is most active and important part
for craniofacial skeletal growth at late prenatally and early postnatally

30.  Functional Matrix Hypothesis (Moss’ Hypothesis) /(FMH) The concept of this theory was
introduced first by Vander Klaaw (1948-52). Melvin L. Moss developed the form and function
concept into the functional matrix hypothesis.(1960s). The origin, growth and maintenance of all
the skeletal tissues and organs are always secondary, compensatory and obligatory responses to
temporally and operationally prior events or processes that occur in specifically related non
skeletal tissues, organs or functioning spaces.

31.  One function Functional cranial component
 Skeletal unit Functional matrix
 1. Micro skeletal 2. Macro skeletal 1. Periosteal matrix e.g.. muscles, blood,
 2. Capsular matrix e.g.. Skin and mucosa

32.  The periosteal matrices stimulation causes growth of the microskeletal units. They act to alter
the size or shape or both of the bones.
 Temporalis – coronoid process, temporal line .
 Tooth - alveolar bone The growth process that occurs due to periosteal matrix stimulation is
called Transformation

34. V PRINCIPLE
 The V principle is an important facial skeleton growth mechanism, since many facial and cranial
bones have ‘V’ configuration or ‘V’ shaped regions.
 The areas grow by bone deposition on the inner side due to the concept of surface growth
depending on growth direction.
 Resorption takes place on the external surface of the ‘V’.
 The ‘V’ moves away from its tip and enlarges simultaneously.
 Thus an increase in size and growth movement takes place in a unified process. Hence it is also
called expanding ‘V’ principle.
 The movement of the bone is towards the broad end of the ‘V’
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35. Expanding V principle—vertical expansion. Bone
is deposited on the inner surface of ‘V’ shaped bone and
resorbed on the outer surface. Thus, the ‘V’ moves away from
its narrow end (direction of the arrow) and enlarges in overall
size

36.  Longitudinal section through the right and left coronoid processes of a mandible reveals that the
 processes are enlarged during growth.
 In accordance with the ‘V’ principle, bone is deposited on the lingual surfaces and resorbed from
the opposing buccal surfaces.
 The structures increase in height, the tips of the coronoid processes diverge further, and their
bony bases converge
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37. The ‘V’ principle—horizontal expansion. Mandibular
configuration of a five year old and an adult viewed from
above.
The mandible is viewed from above, including a
horizontal section through the base of the coronoid
process.
Bone is deposited on the lingual side of the mandibular
structures up to the ramal surface. Thus, the coronoid
process move—despite bone deposition on the inner
surfaces in backward direction and the posterior parts of
the mandible widen (Enlow 1982)

38. POSTERIOR GROWTH AND ANTERIOR DISPLACEMENT
 The overall growth pattern of maxilla and mandible can be explained in two different ways.
 If the cranium is considered as the reference area, the maxilla and mandible moves downward and
forward.
 On the contrary, findings from vital studies have shown particularly in the mandible the posterior
surface of the ramus, the condylar and coronoid processes are the principal sites of growth with
little changes along the anterior part of the mandible.
 This proves the concept that the jaw bones are translated downward and forward while it grows
upward and backward in response to the translation.
 This helps to maintain spatial contact with the skull.
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39. Comparison of posterior growth—anterior
displacement with a swimmer who dives from the
board
(A) Mandible grows downward and forward
if cranial base is taken as reference and
(B) Vital studies have shown that the concept B is correct
and the mandible grow backwards and upwards

40. GROWTH EQUIVALENTS CONCEPT/ENLOW
COUNTERPART PRINCIPLE
 According to Enlow, the growth activity in one region is invariably accompanied by complementary
growth in other regions.
 This complementary activity is essential for maintaining functional and esthetic balance. Enlow
pointed out, both the dimensions and alignment of the craniofacial components are important in
determining the overall facial balance.
 Thus if the anterior facial height is long, facial balance is preserved if the posterior facial height
and mandibular ramus height are also relatively large.
 On the other hand, short posterior facial height can lead to a skeletal open bite tendency and
disturbance in facial proportionality.
 Similarly, alignment would affect the vertical and anteroposterior position of the various skeletal
units and could compensate or worsen a tendency toward imbalance.
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41. SITE VS CENTER
 Baume had coined these two terminologies. According to him, “growth centers” are places of
endochondral ossification with tissue separating force, contributing to the increase in skeletal
mass.
 Growth site has been defined as a region of periosteal or sutural bone formation and modeling
resorption adaptive to environmental influences.
 Profitt defines growth site as merely a location at which growth occurs whereas center is a
location at which independent or genetically controlled growth occurs.
 All growth centers are also sites, whereas all growth sites are not centers.
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