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GROWTH & DEVELOPMENT

DEFINITIONS AND TERMINOLOGIES

Dr. Narayan H.Gandedkar

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Ancient growth and development concepts Garbha Upanishad “From the conjugation of the blood and

semen embryo comes into existence.during the period of conception, after the sexual inter course it becomes kalada (one day old embryo) after remaining seven nights it becomes a spherical mass, after two monthsthe head is formed, after three months limb region is formed”

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Greek scholars – Hippocrates of Los Aristotle of stagera Claudius Galen Talmud Leonardo da vinci

To present sheep cloning in 1997 by Ian Wilmut

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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 changeEg-Head of the infant

Functional changeEg-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 changeEye 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 GRADIENTOF GROWTH

• Changes , part of normal growth pattern reflect “Cephalocaudal gradient of growth”

• Axis of increased growth

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CEPHALOCAUDAL GRADIENTOF 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 VsVelocity 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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OpinionObservations.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 comparisonRANKING 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

cephalom etry.

anthropom etry.

craniom etry.

m easurem ent approaches.

autoradiography.

nuclear volum e m orphom etry.

radio isotopes.

po larised light.

fluorescent labels.

m icroradiography.

m inera lised sections.

at m icroscopic leve l.

finite e lem ent m odeling.

im plant m arkers

at m acroscopic leve l.

natura l m arkers.

com parative anatom y.

vita l sta ining .

at both levels.

experim enta l approaches.

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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 992. Calcium 453. 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 Remodeling1. 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

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Balloon Anology

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Hand Anology

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Tripod Chair Anology

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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 existingposition of a particular structures with reference to another

.

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Growth equivalent principle

This principle proposed by Hunter & Enlow

relates the effects of cranial base growth on

the facial bone Growth.

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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.

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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.

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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.

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stage 6

dimension of temporal lobe and MCF.

Spheno-occipital synchondroses- maj growth site.

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stage 7

vertical line moves ant. forehead cheekbone ACF Palate Max arch all move in ant

direction.

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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.

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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.

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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.

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stage 10

NMC – vertical lengthening.

remodelling → depo and reso.

prim disp. resorption of superior

(nasal side). deposition of inferior

(oral side).

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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 mvmnt

( vertical drift). can be clinically

influenced by appliances.

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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.

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stage 13

remodelling also - incisor

alveolar region. - chin. - corpus

of mandi. differential growth timing.

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stage 14

rationale of growth of zygo process.

zygo remodels → post more deposition

→ ant less resorption

hence forward growth.

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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.

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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.

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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.

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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)

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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.

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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

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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.