Factors affecting growth and development

FACTORS AFFECTINGFACTORS AFFECTING
GROWTH ANDGROWTH AND
DEVELOPMENTDEVELOPMENT
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SIMPLE CLASSIFICATIONSIMPLE CLASSIFICATION
• INTRINSIC FACTORS
• EXTRINSIC FACTORS

VAN LIMBORGH’SVAN LIMBORGH’S
CLASSIFICATIONCLASSIFICATION
• INTRINSIC GENETIC FACTORS
• LOCAL EPIGENETIC FACTORS
• GENERAL EPIGENETIC FACTORS
• LOCAL ENVIRONMENTAL FACTORS
• GENERAL ENVIRONMENTAL FACTORS

EPIGENETICSEPIGENETICS
Definition:
1. An outside genetic control – Proffit
2. Epigenesis includes the sum total
of all bichemical, biomechanical
and biophysical events produced by
the functioning of cells, tissues
and organs – Rakosi and Petrovic

•Epigenetics provides an internal environment
•Acts upon the products of genome to regulate
all developmental processes leading to the
production, increase, and maintainance of
biologic structural complexity.

LOCAL EPIGENETIC FACTORS
MUSCLES
GENERAL EPIGENETIC FACTORS
HORMONES

VARIOUS FACTORS AFFECTINGVARIOUS FACTORS AFFECTING
GROWTH AND DEVELOPMENTGROWTH AND DEVELOPMENT
1. GENETICS AND HERIDITY
2. HORMONAL FACTORS
3. NEUROTROPHSIM
4. FUNCTION
5. ENVIRONMENTAL FACTORS
• LOCAL
• GENERAL
6. MISCELLENIOUS

GENETICSGENETICS
(MOYERS)(MOYERS)1) Van Limborgh’s Experiments on Chick
Embryos
2) Inter Communication Mechanisms
Between Cells and Tissues:
TEETH
BONEMUSCLES

HERIDITY
Growth is largely inheritable
• If both parents are alike in respect to a
Particular trait ,the chances of sibiling
Showing that particular trait are more.
• If one parent is unlike the other with
respect to a particular trait the chances of
the sibling showing either trait vary.

CHROMOSOMALCHROMOSOMAL
DEFECTSDEFECTS
1. Absence Of Inductor
2. Deficiency Of An Inductor
3. Excessive Action Of An Inductor
4. Seperation Of Single Inductor
5. Action Of An Inductor In Abnormal Site

Hormonal FactorsHormonal Factors
Various Hormones Concerned With
Regulation Of Growth:
1) Growth Hormone
2) Thyroxine
3) Parathyroid Hormone
4) Thyrocalcitonin
5) Insulin
6) Glucocorticoidswww.indiandentalacademy.com

GROWTH HORMONEGROWTH HORMONE
SECRETED BY ADENOHYPOPHYSIS
Actions:
1) Increases Anabolism Of Protien
2) Increases size & number of cells
3) Converts chondrocytes into
oseogenic cells
4) Enhances RNA translation to
cause protein synthesis

ACROMEGALY

SOMATOMEDINSSOMATOMEDINS
Definition:
An intermediary group of insulin
like peptides – mediates the growth
Hormone action
Site Of Origin:
Liver
Kidney
Adrenal Cortex

THYROXINETHYROXINE
Secreted By:Thyroid Gland
FUNCTIONS:
1. Cotrolling metabolism by regulating the
catabolic anabolic processes.
2. Controlling effect on protein metabolism.
3. Organ differetiation.
4. Regulate the rate of secretion of other
hormones.

EXOPHTHOLMUS

MYXEDEMA

PARATHYROID HORMONEPARATHYROID HORMONE
SECRETED BY:
Parathyroid Gland
FUNCTIONS:
1. Increasesblood calcium levels by increasing
the number and activity of the osteoclasts.
2. Increases absorption of calcium & phosphate.
TETANY

THYROCALCITONINTHYROCALCITONIN
SECRETED BY:
PARA FOLICULAR CELLS OF
THYROID GLAND
ACTIONS:
1) Increases buildup of proteins in cells.
2) Controls morphologic differentiation of fetal
and post natal tissues.
3) Decreasing the calcium levels by inhibiting
Osteoclastic activity.
.

INSULININSULIN
SECRETED BY:
ISLETS OF LANGERHANS
ACTIONS:
1) Increases glucose entry into the tissues of
skeletal muscle, smooth muscle, liver etc.
2) Decreases protein breakdown, by decreasing
the enzymes, which induces gluconeogenesis.
3) Insulin promotes amino acids uptake.
.

GLUCOCORTICOIDSGLUCOCORTICOIDS
SECRETED BY ADRENAL CORTEX
1. Promote DNA Synthesis And stimulate
mesenchymal growth.
2. Helps in normal metabolism in conjunction
with other hormones.
3. Decreases protein breakdown & synthesis
which leads to increase in cellular protein.
4. Stimulation of gluconeogenesis by liver.
FUNCTIONS:

NEUROTROPHISMNEUROTROPHISM
DEFINITION
Interaction between nerves and
cells which initiate or control molecular
modifications in other cells.
TYPES OF NEUROTROPHISM
1.Neuromuscular Trophism
2.Neuroepithelial Trophism
3.Neurovisceral Trophism

AXOPLASMIC TRANSPORTAXOPLASMIC TRANSPORT
Definition
It is the presumed pathway
by means of which neurotrophic
substances passes by utilising the
processes of axons from their sites
of synthesis in the neural cell body
to the innervated tissues.

A SCHEMATIC REPRESENTATION OF
AXOPLASMIC TRANSPORT

NEURO – MUSCULAR TROPHISMNEURO – MUSCULAR TROPHISM
MUSCLE DEVELOPMENT:
Embryonic myogenisis in vivo
and in vitro is independent of neural
innervation and hence of trophic control.
Approx. at the myoblast stage of
differentiation, neural innervation is
established.
- Studitsky Et Al.www.indiandentalacademy.com

• MUSCLE DENERVATION –
REINNERVATION
» STUDITSKY ET AL
• CROSS INNERVATION
• LIMB REGENERATION
» SINGER
EFFECTS OFEFFECTS OF
NEURO MUSCULAR TROPHISMNEURO MUSCULAR TROPHISM

NEURO EPITHELIALNEURO EPITHELIAL
TROPHISMTROPHISM
EXERIMENTS DONE ON ADULT RATS
- FRANK & KARLI
Epitelial changes include lingual ulcers,
atrophy of palatal epithelium,sclero
hyperplastic lesion on the cheek.
NEURO VISCERALNEURO VISCERAL
TROPHISMTROPHISM

EVIDENCES NOT FAVORABLEEVIDENCES NOT FAVORABLE
FOR NEURO TROTHISMFOR NEURO TROTHISM
• GUTMANN – EXPERIMENTS ON
MOTOR NEURON CONDUCTION
• FRANK AND KARLI’S EXPERIMENTS
ON TRIGEMINAL GANGLION

FUNCTIONFUNCTION
Origin of bones is determined by
intrinsic genetic factors, but thereafter,
all morphological changes are
influenced by extrinsic factors, which
includes function - Moss

ROLE OF MUSCLE AND BONEROLE OF MUSCLE AND BONE
INTERACTIONINTERACTION
Adaptation:- An alteration in the structure
or function of an organism which favors
it’s survival in an altered environment.
TYPES OF ADAPTATIONS:
– ANTERO – POSTERIOR
– VERTICAL

ANTERO-POSTERIORANTERO-POSTERIOR
ADAPTATIONSADAPTATIONS
JAMES McNAMARAJAMES McNAMARA
TRANSPLANTATION STUDIES
-DUTERLOO & WOLTERS
–Implantation of condylar and angular
cartilages
–Replaement of condylar cartilage
with angular cartilage

ALTERING MANDIBULARALTERING MANDIBULAR
GROWTHGROWTH
• INTERMAXILLARY ELASTICS
Exps. On juvenile resus monkeys
done by PAYNE suggested that changes
occuring in the joints not of magnitude.
• ALTERED FUNCTION

STUDIES OF MUSCULOSTUDIES OF MUSCULO
SKELETAL INTERACTIONSKELETAL INTERACTION
• PRIMATE STUDIES – McNAMARA
• The superior head of the lateral
Pterygoid muscle appeared to assume
an active role in the determination of
antero-posterior mandibular position.
• MAMMILIAN STUDIES –CHARLIER &
PETROVIC

VERTICAL ADAPTATIONS
• Adaptive changes with in the
muscle
• Adaptive alterations in the
central nervous system
• Adaptive changes at the muscle-bone
interface
• Adaptive chages with bone and
Cartilage

ENVIRONMENTAL FACTORSENVIRONMENTAL FACTORS
LOCAL:
• MUSCLES
• HABITS
• ORTHOPEDIC FORCES
• TRAUMA
GENRAL
• NUTRITION
• MATERNAL DIET & METABOLISM

MUSCLES
• Skeletal muscle comprising 40% of
mummalian body weight.
• Functional equilibrium :
There should be a balance between
the forces of the tongue and compensating
action of lips & cheeks musculature to
allow the jaws & dentition normally.

HABITSHABITS
• Definition:
Tendency towards an act, and
that has become a repeated
performance, relatively fixed,
consistent and easy to perform by
an individual.

VARIOUS HARMFUL HABITS
1. MOUTH BREATHING
2. TONGUE THRUSTING
3. THUMB SUCKING
4. BRUXISM
5. LIP BITING etc.

MOUTH BREATHINGMOUTH BREATHING
CAUSES:
1) DEVIATED SEPTUM
2) NARROW NASAL PASSAGE
3) RECURRENT RESPIRATORY
INFECTIONS
4) ALLERGIES
5) AIR HUNGER

FREQUENT RESPIRATORY
INFECTION
NASAL SEPTAL DEVIATION
CONTRACTED MAXILLARY
ARCH
SWOLLEN NASAL
MUCOSA
REDUCED NASAL
BREATHING
DECREASE IN
NASAL WIDTH
ENLARGED
ADENOIDS
MOUTH BREATHING
LOWER TONGUE POSITION
LOWERED MANDIBULAR
POSTURE
EXTENDED HEAD POSTURE

Features of Adenoid Facies:Features of Adenoid Facies:
• Increased Vertical Facial Height
• Lowered Mandibular Position
• Extended Head Position
• Open Bite
• Contracted Maxillary Arch
• Linder Aronson’s Studies on
adenoidectomy Patients.

ADENOID FASE

• Non dental application of orthopaedic force
• There are adjustable steel supports
transferring stress directly from the chin and
occiput to the iliac crest.
• Maxilla and mandible may be deformed by
growth guidance procedures aimed at the
endochondral spine.
MILWAUKEE BRACE THERAPY
ORTHOPEDIC FORCES

CONTROVERSY – BIOLOGICCONTROVERSY – BIOLOGIC
JUSTIFICATION OFJUSTIFICATION OF
ORTHOPAEDIC FORCEORTHOPAEDIC FORCE
Can the orthodontist influence mandibular
condylar growth?
Mandible is the bone involved in skeletal
malocclusion (Class I, II & III).
-Riedel (1960).

EFFECTS ON MANDIBULAREFFECTS ON MANDIBULAR
GROWTHGROWTH
Mandibular condyle responds differently from
other cartilaginous growth sites
- Koski et al
Mandibular condyle has a unique fibrous
covering, under which the proliferating
fibroblasts provide a storehouse of building
blocks for the orthodontist.
- Sarnat

CLINICAL IMPLICATIONS:CLINICAL IMPLICATIONS:
External Forces Can Be Used In The
Treatment Of
– Mandibular Prognathism
– Open Bite Malocclusions
– Maxillary Prognathism

TREATMENT OF
MANDIBULAR PROGNATHISM
Lee GRABER has analised the effects of
orthopedic guidance on 38 patients of
mandibular prognathism.
CHANGES OBSERVED:
1) SNA increased 1-2 degrees
2) SNB decreased or not changed
3) Overjet increased 4mm on average
4) Overbite increased

TREATMENT OF OPENBITE
MALOCCLUSIONS
A Palatal splint
Intrusive effect on molars
Eruption of anterior teeth
correction of open bite

TREATMENT OF MAXILLARY
PROGNATHISM
• With heavy, continuous force on the teeth
with combined head gear we can reduce the
maxillary growth.
• The best time for for initiating therapy is the
transitional dentition perod.
• The unfavourable effect of heavy
continuous force is that the mandible is
rocked open and the chin moved down and
back. www.indiandentalacademy.com

TRAUMATRAUMA
• BIRTH TRUAMA
Damage to the temporo mandibular
joint due to forceps delivery
• ACCIDENTAL TRUAMA
Condylar neck of the mandible is
more vulnerable to the fractures

GENERAL ENVIRONMENTALGENERAL ENVIRONMENTAL
FACTORSFACTORS
NUTRITION:
VITAMIN DEFICIENCIES
- RICKETS
- SCURVEY
- BERI BERI
DEPRIVED OXYGEN SUPPLY

• TERATOGENS
– DEFINITION: Substances which interferes
with the normal morphogenesis
–Glucocorticoid Teratogenecity
MISELLANEOUS

TERATOGENS AFFECTING THE
EMBRYO:
1. Infectious agents
2. Drugs – Thalidomide
3. Irradiation
4. Alcohol And Smoking
5. Retinoids

CLINICAL IMPLICATIONS
• PRENATAL:
Nutritional intake of the mother
Influence of drugs & medication
• POSTNATAL:
Size & position of the tongue
Respiratory obstruction syndrome
(RICKETTS)

“Form of an object is its diagram
of forces”-THOMPSON
American Association of Orthodontists’public
information programme advocates a dental
examination at age 3 and an orthodontic
examination at age 7.This is obsolete.The
orthodontist’s interest should begin pre
natally with the developing fetus &
continue until need for treatment has been
removed.

Factors affecting growth and development

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