Orthodontics- growth and development

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GROWTH & DEVELOPMENT
DEFINITIONS AND
TERMINOLOGIES

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Definition of Growth
 “Growth refers to increase in size” - Todd
 “Growth usually refers to an increase in size
and number” – Proffit
 “Self multiplication of living substance”-
J.S.Huxley.

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 “Growth may be defined as the normal change
in the amount of living substance
 “Change in any morphological parameter
which is measurable”- Moss.

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Definition of Development
Development is a progress towards
maturity” – Todd
“Development connotes a maturational
process involving progressive
differentiation at the cellular and tissue
levels” - Enlow

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“Development refers to all
naturally occurring
progressive, unidirectional,
sequential changes in the
life of an individual from it’s
existence as a single cell to
it’s elaboration as a
multifunctional unit
terminating in death” –
Moyers

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Definitions
 Morphogenesis – “A
biologic process having
an underlying control at
the cellular and tissue
levels”
 Differentiation – “It
is a change from
generalized cells or
tissues to a more
specialized kinds during
development”

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•Translocation –
“ It is a change in position”
•Maturation –
“It is the emergence of
personal characteristics and
behavioural
phenomenon through
growth processes”

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Timing and sequential change
a. Prenatal growth
b. Postnatal growth
c. Maturity
d .Old age

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Timing and sequential change
•Prenatal growth- rapid increase in cell no.
•Postnatal growth- 20 yrs- declining growth-
increasing maturation
•Maturity-period of stability
•Old age
•death

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Different types of growth
 Size change
 Positional change
 Proportional change
 Functional change
 Maturational change
 Compositional change

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Proportional change
Eg-Head of the infant
Functional change
Eg-Secretion , production of enzymes,
hormones

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Size change- height, weight, volume
Positional change-
•Migration of neural crest cells
•Eruption of teeth
•Dropping of diaphragm

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Maturational change
stability and adulthood
Compositional change
Eye pigmentation

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Major themes of development
 Changing complexity
 Shifts from competent to fixation
 Shifts from dependent to independent
 Ubiquity of genetic control modulated by
environment

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Changing complexity
 All level of organisation - sub-cellular to
whole organism
 Complexity development
 Orthodontics Mixed dentition period

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Shifts from competent to fixation
 Undifferentiated cells once differentiated become
fixed.
Shifts from dependent to independent
 Development brings greater independence at most
levels of organisation.

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Ubiquity of genetic control modulated
by environment
 Genetic control of development is
constantly being modified by
environmental interactions

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Growth
•Increase in size decrease in size
eg- thymus gland after puberty
Development process of inc complexity
Development=growth+differenciation+translocation

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Importance of growth and development to
orthodontist
 Etiology of malocclusion
 Health and nutrition of children
 comparison of growth

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 identification - abnormal occlusal
development at an earlier stage
 use of growth spurts
 Surgery initiation
 Planning of retention regime

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Normal features of
Growth & Development
 pattern
-Differential Growth
-cephalocaudal gradient of growth
 Variability
 Timing, rate & direction

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PATTERN
 Pattern in growth represents proportionality .It
refers not just to a set of proportional
relationships at a point in time but to change in
these proportional relationships over time
 The physical arrangement of the body at any
one time is a pattern of spatially proportioned
parts.

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DIFFERENTIAL GROWTH
Different organs grow at different rates
amount and at different times.
 Scammon’s curve of growth
-Richard scammon

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SCAMMON’S CURVE OF GROWTH
 LYMPHOID
 NEURAL
 GENERAL
 GENITAL

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CEPHALOCAUDAL GRADIENT
OF GROWTH
• Changes , part of normal growth pattern reflect
“Cephalocaudal gradient of growth”
• Axis of increased growth

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CEPHALOCAUDAL GRADIENT
OF GROWTH

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Growth of head and face

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•It illustrates the change in overall body
proportions during normal growth and
development.
•Imp aspect of pattern is its predictability.

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Predictability
 Predictability of growth pattern is a specific
kind of proportionality that exists at a
particular time and progresses towards another,
at the next time frame with slight variations.
 Change in growth pattern indicates some
alteration in the expected changes in body
proportions.

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Variability
 No two individuals with the exception of
siamese twins are like.
 Hence it is important to have a “normal
variability” before categorizing people as
normal or abnormal

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Normality
 Normality refers to that which is usually
expected, is ordinarily seen or typical – Moyers
 Normality may not necessarily be ideal.
 Deviation from usual pattern can be used to express
quantitative variability
 This can be done by using “growth charts”
•

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TYPES OF NORMALITY
 STATISTICAL
 EVOLUTIONARY
 FUNCTIONAL
 ESTHETICAL
 CLINICAL

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Growth chart

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Applications of growth charts.
 Location of an individual relative to the group
can be established.
 Can be used to follow a child over time and
note for any unexpected change in growth
pattern.

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Timing of Growth
 One of the factors for variablity in growth.
 Timing variations arise because biologic clock of
different individuals is different.
 It is influenced by:
 genetics
 sex related differences
 physique related
 environmental influences

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Distance curve Vs
Velocity curve
Distance
curve
Velocity
curve
Age
Height
Distance Curve (cumulative curve): In this curve growth
can be plotted in height or weight recorded at various
ages.
Velocity Curve(incremental curve): In this by amount
of change in any given interval that is growth increment
is plotted.

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Growth spurts
 Defined as periods of growth acceleration
 Sex-linked
 Normal spurts are
 Infantile spurt – at 3 years age
 Juvenile spurt – 7-8 years (females); 8-10 years (males)
 Pubertal spurt – 10-11 years(females); 14-15 years
(males)
 Growth modulation can be done

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GROWTH STUDIES AND METHODS OF
STUDYING GROWTH.

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 “If I have seen further, it is by standing on the
shoulders of giants”
_ SIR ISAAC NEWTON , ENGLISH MATHEMATICIAN
1643- 1727

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• Longitudinal growth studies
• Methods of studying bone growth
• Types of growth data
• Methods of gathering growth data

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.
Opinion
Observations.
Ratings and
rankings.
Quantitative
measurements.
direct data.
indirect data.
derived data.
Types of growth data

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Types of growth data.
• Opinion
clever guess based on experience.
crudest form of scientific knowledge.
• Observations:
for studying all or none phenomenon
limited way use
quantitative data is must.

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 RATING
comparison
RANKING
value

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Quantitative measurements:
Includes expressing an idea or fact as a
meaningful quantity or numbers.
• Direct data: measurements ,living persons or
cadaver -measuring device.
• Indirect data: images or reproductions of
actual person.
• Derived data comparing at least two
measurements.

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Methods of gathering growth
data.
• Longitudinal studies .
• Cross sectional studies.
• Overlapping or semi longitudinal studies.

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Longitudinal studies.
• measurements of same person or group-
regular intervals through time.
• Advantage: problems are smoothed with time,
Variability,serial comparison makes study of
specific developmental pattern of individual
possible.
Disadvantages: time consuming, expensive,
sample loss or attrition,averaging.

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Cross sectional studies
ADVANTAGES
 repeating Quicker
 Less costly
 Statistical treatment made easier
DISADVANTAGES
 Variation amongst individuals cannot be studied

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Semi longitudinal studies.
Merger of either studies

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LONGITUDINAL GROWTH
STUDIES.

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Longitudinal growth studies
 Bolton brush growth study
 Burlington growth study
 Michigan growth study
 Denver child growth study
 Iowa child welfare study
 Forsyth twin study
 Meharry growth study

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 Montreal growth study
 Krogman philadelphia growth study
 Fels growth study
 Implant studies
 The mathews implant collection
 The hixon oregon implant study
 Cleft palate study

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Bolton Brush growth study.
• Prof T Wingate Todd - 1926
• skeletal development .
• Dr Holly Broadbent Sr- 1929.
• development of facial skeleton.
• 5000 normal healthy children.
• Records

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• merged in 1970.
• 1975 - published - Dr Holly Broadbent jr.
• standards of averages that represent optimum
facial and developmental growth baseline for
understanding and assessing craniofacial
growth.
Bolton Brush Growth Study

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Burlington growth study
• AIM
• Malocclusion
• preventive and interceptive orthodontic treatment.
• growth records as a database for future studies.
• Sample size:1632 .

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 Records
 original concept - Robert Moyers
 records-Frank Popovich.
BURLIGTON GROWTH STUDY

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Burlington growth study
• 247 investigations & 322 studies - based on this
growth study
• Longitudinal studies by Thompson & Popovich to
derive cephalometric norms of a representative
sample was based on 210 children followed for 15
years at the Burlington growth center.
• age sex and growth type specific craniofacial
templates were derived and static and dynamic
analysis were proposed on the basis of this study.

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The Iowa child welfare study.
• Sample size: 20 males and 15 female 4 year
old subjects.
• Followed till 17 years of age. Non –
orthodontical-European
• Records:lateral and PA views and dental
casts.
• Samir Bishara.

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• changes in facial dimensions ,standing height
• The dentofacial relationships of 3 normal facial
types (long, average, short) from 5-25 yrs of
age was described & compared.

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CLEFT PALATE STUDIES.
• LANCASTER PA: 850 record sets - birth to 15
years/annually
• HOSPITAL FOR SICK CHILDREN(Toronto):over
4000 - 5-20 years
• .CENTER FOR CRANIOFACIAL
ANOMALIES(Chicago); 1000 subjects.
• Records: x-ray films, casts, medical and orthodontic
treatment records.
• All subjects: surgical repair, minor - extensive ortho
treatment.

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METHODSMETHODS
OFOF
STUDYING GROWTHSTUDYING GROWTH

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Ancient Greek Studies
On Growth
-- According to “Galen et al”.
-- Pattern – Intelligence /
Specific areas of Skull – Specific
Growth
Perfection / Dumbness etc.....

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Greek Mythology
on
Growth Studies
-- Constellations, Sun,
Moon etc... determine
the growth of the body.

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Methods of studying Growth
c e p h a lo m e tr y .
a n th r o p o m e tr y .
c r a n io m e tr y .
m e a s u r e m e n t a p p r o a c h e s .
a u to r a d io g r a p h y .
n u c le a r v o lu m e m o r p h o m e tr y .
r a d io is o to p e s .
p o la r is e d lig h t.
flu o r e s c e n t la b e ls .
m ic r o r a d io g r a p h y .
m in e r a lis e d s e c tio n s .
a t m ic r o s c o p ic le v e l.
fin ite e le m e n t m o d e lin g .
im p la n t m a r k e r s
a t m a c r o s c o p ic le v e l.
n a tu r a l m a r k e r s .
c o m p a r a tiv e a n a to m y .
v ita l s ta in in g .
a t b o th le v e ls .
e x p e r im e n ta l a p p r o a c h e s .

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CRANIOMETRY.
measurements of skull
Neanderthal and Cro-magnon
skull.
information of extinct
population ,growth pattern
Advantages: Precise measurements.
Disadvantages:All growth data must be cross sectional.

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ANTHROPOMETRY:
• soft tissue pts over bony landmarks- living
individuals.
• variation in soft tissue thickness - different rslts
• individual growth directly measured

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• CEPHALOMETRIC RADIOGRAPHY:
• direct measurement - bony skeletal dimensions
follow up same individual over time .
• Disadvgs
•precise orientation of head ,precise control of
magnification.
• 2D of 3D structure

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Mineralized sections.
• less processing distortions , both organic and inorganic
matrix- studied simultaneously.
• Cellular details , resolutions - enhanced –reduce
thickness of the sections.
• Special stains
• Thin sections- quench- rapidly

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Microradiography.
• High resolution of images of bone sections
• Differential density btwn pri and seco bone.
• Bone strength -proportional to degree of
mineralisation.
• seco bone more strength than pri bone.
• Seco mineralisation process- 8 months to form
minimum retention : 6-8 months.

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THERMOGRAPHYTHERMOGRAPHY

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Scintigraphy
“Hot Spots”.

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M R IM R I
Magnetic Resonance Imaging
Depicts- soft tissue growth
contrast with hard tissue.

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Fluorescent labels.
• in vivo calcium binding labels
• anabolic time markers of bone formation.
• Mechanism of bone growth determined by
analysis of label incidence and interlabel distance.
• Sequential use of different colored labels assess
bone growth,healing and functional adaptation.
• Tetracycline,calcein green,xylenol orange,alizarin
complexone,demeclocycline and oxytetracycline

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Radioisotopes.
• Radioisotopes of certain elements or compounds
are often used as in vivo markers
• labeled material injected and located within
the growing bone by autoradiographic
techniques.
1. Technetium 99
2. Calcium 45
3. Potassium 32

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RADIOISOTOPES

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Autoradiography.
• Histological sections are coated with a nuclear track
emulsion to detect radiographic precursor for
structural and metabolic material.
• Specific radioactive labels for protein carbohydrates
or nucleic acids are injected.

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• Quantitative and qualitative assessment of the label uptake
is a physiologic index of cell activity.
• Commonly used autoradiographic labels are:
• A. 3
H thymidine.
• B. 3
H proline.
• C. Bromodeoxyuridine.

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Polarized light.
• indicates the orientation of collagen fibers within
the bone matrix.
• Most lamellar bone consists of collagen fibers
oriented at right angles.
• However 2 other configurations can also be
noted:longitudinally aligned(L osteons).

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• And mixed fiber pattern.
• Loading condition at the time of bone formation
dictate the orientation of collagen fibers . Thus
bone formation can adapt to different loading
conditions by changing the internal lamellar
organization of bone tissue.

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Nuclear volume morphometry.
• cytomorphometric procedure to measures the
nuclear size for assessing the stages of
differentiation of osteoblastic precursor cells.
• Pre osteoblasts have significantly larger nuclei
than their precursors.
• used in determining the relative differentiation of
PDL and other bone living cells.

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Teleradiology.
 Introduced in 1982 at international conference
of PACS.
 Universal method of storing and transporting
digital images .
 Currently American college of radiology have
developed DICOM to allow the transmisssion
of images over the internet.

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Vital staining
• reported by Belchier in 1796
• John Hunter- alizarin dye
• Other dyes : tetracyline
trypon blue
lead acetate
procion

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• Vital staining aids in studying:
Manner in which bone is laid down
site of bone growth
the direction and amount of growth
and the timing and relative duration
of growth at different sites.

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Natural markers.
• developmental features - serial radiography.
• trabaculae,nutrient canals, lines of arrested
growth
• cephalometric landmarks.

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Implant markers.
• Bjork- tantalum or biologically inert alloys into
growing bone –
• radiographic reference markers for serial
cephalometric study.
• The method allows precise orientation of serial
cephalograms and information on the amount and
sites of bone growth.

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B O N E :- L : ost Gr : osteonB O N E :- L : ost Gr : osteon
Definition : Modified connective tissue.
Elements comprising bone tissue.
Cells of Bone –
1. osteoprogenitor
2. osteoblast
3. osteocytes
4. osteoclasts
5. bone lining cells

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Osteoprogenitor Cells
-- Stem cells of mesenchymal origin.
Osteoblast cells
-- Bone forming cells.
-- varied shape
- oval
- triangular
- cuboidal
-- increased RER, golgi apparatus
-- Lay down organic matrix and calcification.

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Osteocytes
-- imprisoned osteoblast
--keep intact lacunae & canaliculli
-- keep open channel for diffusion
-- removal or deposition of matrix and calcium when reqd.
Osteoclasts
-- Bone removing cells
-- resorption bay or Howship’s lacunae
-- 2-100 um
-- nuclei-20 or more
-- acid phosphatase and lizosomes

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Bone Lining Cells
-- present on ndosteal and periosteal layer
-- can form bone when called for
-- dual function - resorption and deposition.
Periosteum
-- outer layer-fibrous
-- inner layer-cellular
Function– nutritive
-- supportive-sharpey’s fibers
-- reparative-protective-osteoprogenitor cells
-- protective-limiting membrane
-oldage exostosis due to
tear of periosteum

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Ossification → Intramembraneous
↓
endochondral
Intramembranous Ossification

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Endochondral ossification

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Comparison of physiologic properties of bone
and cartilage
 Characteristic cartilage bone
 Calcification Non calcified Calcified
 Vascularity Avascular Vascular
 Surface membrane Nonessential Essential
 Pressure resistance Tolerant Sensitive
 Rigidity Flexible Inflexible
 Modes of growth Interstitial Appositional
and appositional

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TYPE OF BONES
 Lamellar bone
 Non lamellar bone
 Fine cancellous bone
 Coarse cancellous bone
 Woven bone
 Bundle bone
 Composite bone

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Clinical significance
 Full strength of lamellar bone supporting an
orthodontically moved tooth is not attained
for upto a year after completion of active
treatment.

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Non Lamellar bone
 Makes up fine cancellous bone tissue
 No distinct stratification in fibre orientation

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Woven bone
 Type of non lamellar bone
 Weak , disorganised, poorly mineralised
 Not found in adult human skeleton under
normal conditions
 First bone formed in response to orthodontic
loading.

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Bundle bone
 Present adjacent to periodontal ligament
 Presence of perpendicular striations called
sharpey’s fibres.
 Formed on depository side of socket, laid
dowm in the direction toward the moving tooth
root.

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Composite bone
 Predominant bone type during early retention
phase
 Most rapid means of producing strong bone
 Formed by deposition of lamellar bone within a
woven bone lattice.

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Fine cancellous bone tissue
 Formed by periosteum and endosteum
 Marrow spaces are fine
 It is located in cortex e.g. posterior border of a
growing ramus in a child
 Fastest growing of all bone types

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Coarse cancellous bone
 Produced by endosteum only
 Irregular marrow spaces containing red or
yellow marrow
 Irregularly arranged trabeculae
 Present in medulla

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Mechanisms of bone growth
 Deposition and resorption
 Growth fields
 Modelling
 Remodelling
 Growth movements
drift
displacement

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Deposition and resorption
 Bone sides which face the
direction of growth are
subject to deposition (+)
and those opposite to it
undergo
resorption(-)
…surface principal

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Deposition and resorption
 Bone produced by
covering membrane-
periosteal bone comprises
about half of the cortical
bone tissue: bone laid
down by the lining
membrane-endosteal
bone makes up the other
half.

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Transverse histologic section of bone:
A.Periosteal surface reorptive,endosteal
surface depository.
B.New endosteal bone addedon inner
surface.
C.Endosteal layer produced covered by
periosteal layer following outward
reversal.
D.Cortex made entirely of periosteal
bone….outer surface depository and
inner surface resorptive.

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Growth fields
 Inside and outside of
every bone is covered
by growth fields which
control the bone growth.
 They are both resorptive
and depository types..

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 About one half of the
bone is periosteal and the
other half endosteal.If
endosteal surface is
resorptive then periosteal
surface would be
depository.
 Provides two growth
functions:
Enlargement of any
given bone
Remodelling of any
given bone

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Growth sites
 Growth fields having
special role in the
growth of the particular
bone are called growth
sites
 e.g. mandibular condyle,
maxillary tuberosity,
synchondrosis of the
basicranium, sutures and
the alveolar process.

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Growth sites
 Such special sites do
not out the entire
carry growth
process but the
entire bone takes
part

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Growth centers
 Special areas which are
believed to control the
overall growth of the bone
e.g.mandibular condyle.
 Force, energy or motor for a
bone resides primarily
within its growth centre.
 Now believed that these
centers do not control the
whole growth process.

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MODELING
 Bone modeling involves
independent sites of resorption and
formation that change the size and
shape of a bone.

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CONTROL FACTORS FOR BONE
MODELING
– Mechanical Peak load in
Micro strain.
1. Disuse atrophy <200.
2. Bone Maintenance 200—2500.
3. Physiological Hypertrophy 2500—4000.
4. Pathological Overload >4000.
•

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• Endocrine.
1. Bone metabolic hormones-PTH,Vit D,Calcitonin.
2. Growth Hormones-Somatotropin,IGF 1,IGF 2.
3. Sex steroids-Testosterone,Estrogen.

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Remodelling
 Required differential growth activity required for bone
shaping.
 It involves deposition and resorption occuring on opposite ends
 Four types
 Biochemical remodelling
 Haversian remodelling
 Pathologic remodelling
 Growth remodelling

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 E.g. The ramus moves
posteriorly by the
combination of deposition
and resorption.
 so the anterior part of the
ramus gets remodeled into
a new addition for the
mandibular corpus.

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Functions of Remodeling
1. Progressively change the size of whole bone
2. Sequentially relocate each component of the
whole bone
3. Progressively change the shape of the bone to
accommodate its various functions

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1. Progressively change the
size of whole bone
2. Sequentially relocate each
component of the whole
bone
3. Progressively change the
shape of the bone to
accommodate its various
functions
Functions of Remodeling

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4. Progressive fine tune fitting of all the separate
bones to each other and to their contiguous
,growing, functioning soft tissues
5. Carry out continuous structural adjustments to
adapt to the intrinsic and extrinsic changes in
conditions .

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Drift
 It is remodeling process
and a combination of
deposition and
resorption.
 If an implant is placed
on depository side it
gets
embedded.eventually
marker becomes
translocated from one
side of cortex to other.

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Displacement
 Displacement is a physical movement of the
whole bone as it remodels
 Two types:
primary displacement
secondary displacement

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Primary displacement
 It is a physical
movement of a whole
bone and occurs while
the bone grows and
remodels by resorption
deposition
 E.g. in maxilla

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Secondary displacement
 It is the movement of a
whole bone caused by
the separate enlargement
of other bones

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Combination of remodeling &
displacement
 Both these mechanisms carries out two
general functions
 Positions each bone
 Designs and constructs each bone

130. 130
Balloon Anology

131. 131
Hand Anology

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Tripod Chair Anology

133. 133
Rotation
 According to Enlow,
growth rotation is due to
diagonally placed areas
of deposition and
resorption
 Two types
 Remodelling rotations
 Displacement rotations

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Principle of ‘Area relocation’
Both remodeling and
displacement together
cause a shift in existing
position of a particular
structures with reference
to
another
.

135. 135
Growth equivalent principle
This principle proposed by Hunter & Enlow
relates the effects of cranial base growth on
the facial bone Growth.

136. 136

137. 137
Counter Part Principle
Donald H Enlow

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Regional Change (Stage 1)
 Two reference line
Horiz
Verti
 P T M

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Stage 2
°Displacement.
°Amt of forward displacement
equals the amt of post length.
°PTM returns to same line.
°Class 2 position of maxilla.

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Stage 3
 What are counterparts of maxillary
arch.
- NMC
- ACF
- Palate
- Corpus of
mandible.
mandible described.
- Corpus
- Ramus
Why separate bcoz has separate
counterparts.

141. 141
 Bony mandi arch cp of
max arch.
 Body of max arch cp of
max arch.
 Corpus remodels, what
was ramus at once
becomes body.
 however still cl 2.

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Stage 4
 remodelling and disp of
mandi.
 condyle and post part of
ramus remodels.
 process not to increase
width of ramus.
 but to relocate it postly
for lengthening the
corpus.

143. 143
stage 5
 whole mandible displaced
ant by amt ramus has
relocated.
 post- primary displ.
 ramus lengthening remains
same.
 only corpus horizontal
dimension change.
 cl 1 returned.
 separation of occlusion.

144. 144
stage 6
 dimension of temporal
lobe and MCF.
 Spheno-occipital
synchondroses- maj
growth site.

145. 145
stage 7
 vertical line moves ant.
 forehead
 cheekbone
 ACF
 Palate
 Max arch
 all move in ant
direction.

146. 146
stage 8
 Effect of MCf on mandi.-
secondry disp.
 less than max effect.
 bcoz MCF grows in front and
between the condyle and maxi
tuberosity.
 SOS lies between condyle and ant
boundary of MCF.

147. 147
stage 9
 MCF counterpart ?
 ramus and pharyngeal
space.
 skeletol function of
ramus
 - bridge
pharyngeal space and
span of MCF.
 A-P breadth of ramus is
critical.
- too →
narrow- retrusive.
→
wide- protrusive.

148. 148
stage 9
 floor of ACF & forehead grow by endocranial
depostition & ectocranial resorption.
 nasal bone – ant displaced.
 enlarging bone displaces calvaria – by sutural growth.
 depositing new bone at contact edges.
1. frontal.
2. parietal.
3. occipital.
4. temporal.

149. 149
stage 10
 NMC – vertical
lengthening.
 remodelling → depo and
reso.
 prim disp.
 resorption of superior
(nasal side).
 deposition of inferior
(oral side).

150. 150
stage 11
 Downward mvmt of
palate & max arch.
2-3 → downward pri
disp & suture grow
1-2 → remodelling.
2-3 → downward
disp.
1-2 → teeth own

151. 151
Stage 12
 upward / superior drift
of each mandi tooth.
 max teeth drift more
than mandi teeth.
 less growth “to work
with” in mandi.
 curve of spee.

152. 152
stage 13
 remodelling also
- incisor
alveolar region.
- chin.
- corpus
of mandi.
differential growth timing.

153. 153
stage 14
 rationale of growth of
zygo process.
 zygo remodels → post
more deposition
→ ant less
resorption
 hence forward growth.

154. 154
Enlow’s V principal
 Most useful and basic
concept in facial growth as
many facial and cranial
bones have a V- shaped
configuration.
 Bone deposition(+) occurs
on the inner side and
resorption (-) occurs on
the outer surface.

155. 155
Example with V oriented vertically
 When bone added on
lingual side of coronoid
process,growth
proceeds and this part
of the ramus increases
in vertical dimension.

156. 156
Example of V oriented horizontally
 Same deposits of bone
also bring about a
posterior direction of
growth movement.
 This produces a
backward movement
of coronoid processes
even though deposit is
on the lingual side.

157. 157

158. 158
 Same deposits carry
base of bone in medial
direction as in fig 1.
 Hence, the wider part
undergoes relocation
into a more narrow part
as the whole v moves
towards the wide part
(fig 2)

159. 159
REFERENCES:
 Proffit:contemporary orthodontics.
 Moyers:handbook of orthodontics.
 An inventory of United states and Canadian
growth record sets.S.Hunter , Baumrind S
AJO 1993.
 Craniofacial imaging in orthodontics :S
Kapila et al AO 1999:69
 Essays in honour of Robert moyers
CFGS.monograph 24.

160. 160
References
 Bone biodynamics in
orthodontics:CFGS.27
 Atlas of craniofacial growth in Americans
of African descent CFGS.26
 Growth changes in the nasal profile from 7-
8 yrs AJO 1988:94 Meng H ,R Nanda
 Longitudinal changes in 3 normal facial
types .S Bishara,AJO1985:88
 S Bishara,J R Peterson, changes in the
facial dimensions & relationships between
the ages 5-25yrs.AJO 1984:85

161. 161
References
 Lewis A B, Roche AF pubertal spurts in
cranial base & mandible AJO 1985:55
 Popovich.Thompson. Craniofacial
templates for orthodontic case analysis.
 Baumrind S,Korn EL,quantitation of
maxillary remodeling. AJO 1987:91
 Atlas of craniofacial growth CFGS
monograph 2.
 Moyers,Van Der Linden standards of
human occlusal development CFGS:5
 B Grayson 3D cephalogram
theory,technique and clinical application.