FACTORS AFFECTING GROWTH AND DEVELOPMENT
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SIMPLE CLASSIFICATION • INTRINSIC FACTORS • EXTRINSIC FACTORS
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VAN LIMBORGH’S CLASSIFICATION • INTRINSIC GENETIC FACTORS • LOCAL EPIGENETIC FACTORS • GENERAL EPIGENETIC FACTORS • LOCAL ENVIRONMENTAL FACTORS • GENERAL ENVIRONMENTAL FACTORS www.indiandentalacademy.com
EPIGENETICS 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 www.indiandentalacademy.com
•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. www.indiandentalacademy.com
LOCAL EPIGENETIC FACTORS MUSCLES
GENERAL EPIGENETIC FACTORS HORMONES
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VARIOUS FACTORS AFFECTING GROWTH AND DEVELOPMENT 1. 2. 3. 4. 5.
GENETICS AND HERIDITY HORMONAL FACTORS NEUROTROPHSIM FUNCTION ENVIRONMENTAL FACTORS • LOCAL • GENERAL 6. MISCELLENIOUS www.indiandentalacademy.com
GENETICS (MOYERS) 1) Van Limborgh’s Experiments on Chick Embryos 2) Inter Communication Mechanisms Between Cells and Tissues: TEETH MUSCLES
BONE
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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. www.indiandentalacademy.com
CHROMOSOMAL DEFECTS 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 www.indiandentalacademy.com
Hormonal Factors Various Hormones Concerned With Regulation Of Growth: 1) Growth Hormone 2) Thyroxine 3) Parathyroid Hormone 4) Thyrocalcitonin 5) Insulin 6) Glucocorticoids www.indiandentalacademy.com
GROWTH 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 www.indiandentalacademy.com
ACROMEGALY
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SOMATOMEDINS Definition: An intermediary group of insulin like peptides – mediates the growth Hormone action Site Of Origin: Liver Kidney Adrenal Cortex
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THYROXINE 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. www.indiandentalacademy.com
EXOPHTHOLMUS
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MYXEDEMA
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PARATHYROID 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 www.indiandentalacademy.com
THYROCALCITONIN 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. www.indiandentalacademy.com
INSULIN 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. www.indiandentalacademy.com
GLUCOCORTICOIDS SECRETED BY ADRENAL CORTEX FUNCTIONS: 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. www.indiandentalacademy.com
NEUROTROPHISM 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 www.indiandentalacademy.com
AXOPLASMIC 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. www.indiandentalacademy.com
A SCHEMATIC REPRESENTATION OF AXOPLASMIC TRANSPORT
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NEURO – 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.
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EFFECTS OF NEURO MUSCULAR TROPHISM • MUSCLE DENERVATION – REINNERVATION » STUDITSKY ET AL
• CROSS INNERVATION • LIMB REGENERATION » SINGER www.indiandentalacademy.com
NEURO EPITHELIAL TROPHISM EXERIMENTS DONE ON ADULT RATS - FRANK & KARLI
Epitelial changes include lingual ulcers, atrophy of palatal epithelium,sclero hyperplastic lesion on the cheek.
NEURO VISCERAL TROPHISM www.indiandentalacademy.com
EVIDENCES NOT FAVORABLE FOR NEURO TROTHISM • GUTMANN – EXPERIMENTS ON MOTOR NEURON CONDUCTION • FRANK AND KARLI’S EXPERIMENTS ON TRIGEMINAL GANGLION
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FUNCTION Origin of bones is determined by intrinsic genetic factors, but thereafter, all morphological changes are influenced by extrinsic factors, which includes function - Moss
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ROLE OF MUSCLE AND BONE INTERACTION 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 www.indiandentalacademy.com
ANTERO-POSTERIOR ADAPTATIONS JAMES McNAMARA
TRANSPLANTATION STUDIES -DUTERLOO & WOLTERS
– Implantation of condylar and angular cartilages – Replaement of condylar cartilage with angular cartilage www.indiandentalacademy.com
ALTERING MANDIBULAR GROWTH • INTERMAXILLARY ELASTICS Exps. On juvenile resus monkeys done by PAYNE suggested that changes occuring in the joints not of magnitude. • ALTERED FUNCTION www.indiandentalacademy.com
STUDIES OF MUSCULO SKELETAL 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 www.indiandentalacademy.com
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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 www.indiandentalacademy.com
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ENVIRONMENTAL FACTORS LOCAL: • MUSCLES • HABITS • ORTHOPEDIC FORCES • TRAUMA GENRAL • NUTRITION • MATERNAL DIET & METABOLISM
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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. www.indiandentalacademy.com
HABITS • Definition: Tendency towards an act, and that has become a repeated performance, relatively fixed, consistent and easy to perform by an individual. www.indiandentalacademy.com
VARIOUS HARMFUL HABITS 1. 2. 3. 4. 5.
MOUTH BREATHING TONGUE THRUSTING THUMB SUCKING BRUXISM LIP BITING etc.
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MOUTH BREATHING CAUSES: 1) DEVIATED SEPTUM 2) NARROW NASAL PASSAGE 3) RECURRENT RESPIRATORY INFECTIONS 4) ALLERGIES 5) AIR HUNGER
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FREQUENT RESPIRATORY INFECTION
NASAL SEPTAL DEVIATION
SWOLLEN NASAL MUCOSA
CONTRACTED MAXILLARY ARCH
DECREASE IN NASAL WIDTH REDUCED NASAL BREATHING
ENLARGED ADENOIDS
MOUTH BREATHING
LOWER TONGUE POSITION
EXTENDED HEAD POSTURE
LOWERED MANDIBULAR www.indiandentalacademy.com POSTURE
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. www.indiandentalacademy.com
ADENOID FASE
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ORTHOPEDIC FORCES MILWAUKEE BRACE THERAPY • 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. www.indiandentalacademy.com
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CONTROVERSY – BIOLOGIC JUSTIFICATION OF ORTHOPAEDIC FORCE Can the orthodontist influence mandibular condylar growth? Mandible is the bone involved in skeletal malocclusion (Class I, II & III). -Riedel (1960). www.indiandentalacademy.com
EFFECTS ON MANDIBULAR GROWTH 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 www.indiandentalacademy.com
CLINICAL IMPLICATIONS: External Forces Can Be Used In The Treatment Of – Mandibular Prognathism – Open Bite Malocclusions – Maxillary Prognathism www.indiandentalacademy.com
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 www.indiandentalacademy.com
TREATMENT OF OPENBITE MALOCCLUSIONS A Palatal splint Intrusive effect on molars Eruption of anterior teeth correction of open bite www.indiandentalacademy.com
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 www.indiandentalacademy.com back.
TRAUMA • 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 www.indiandentalacademy.com
GENERAL ENVIRONMENTAL FACTORS NUTRITION: VITAMIN DEFICIENCIES - RICKETS - SCURVEY - BERI BERI DEPRIVED OXYGEN SUPPLY www.indiandentalacademy.com
MISELLANEOUS • TERATOGENS – DEFINITION: Substances which interferes with the normal morphogenesis
– Glucocorticoid Teratogenecity
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TERATOGENS AFFECTING THE EMBRYO: 1. Infectious agents 2. Drugs – Thalidomide 3. Irradiation 4. Alcohol And Smoking 5. Retinoids www.indiandentalacademy.com
CLINICAL IMPLICATIONS • PRENATAL:
Nutritional intake of the mother Influence of drugs & medication • POSTNATAL:
Size & position of the tongue Respiratory obstruction syndrome (RICKETTS)
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“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. www.indiandentalacademy.com
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