FACTORS AFFECTING GROWTH AND DEVELOPMENT
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“ WHAT IS THE MOST RIGOROUS LAW OF OUR BEING? GROWTH . NO SMALLEST ATOM OF OUR MORAL, MENTAL, OR PHYSICAL STRUCTURE CAN STILL A YEAR. IT GROWS/IT MUST GROW, NOTHING CAN PREVENT IT” --- MARK TWAIN
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Contents 1. 2. 3. 4. 5.
Definition Classification Prenatal factors Natal factors Postnatal factors
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GROWTH
It is the quantitative aspect of biologic development and is measured in units of increase per units of time.--- MOYERS Change in any morphological parameter which is measurable– MOSS Increase in size, change in proportion and progressive complexity-- KROGMAN
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DEVELOPMENT
Progress towards maturity– TODD All naturally occurring unidirectional changes in the life of an individual from its existence as a single cell to its elaboration as a multifunctional unit terminating in death– MOYERS Characterized by changes in complexity, a shift to fixation of function, and more independence, all of which is under genetic control, yet modified by the environment. DEVELOPMENT=GROWTH+DIFFERENTIATIO N+TRANSLOCATION www.indiandentalacademy.com
Why to assess growth of an individual? 1.
2.
3. 4.
Identification of grossly abnormal pathologic growth. Recognition and diagnosis of significant deviations from normal growth. Planning of therapy. Determination of the efficacy of therapy.
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MOYER’S CLASSIFICATION NATURAL
DISRUPTIVE FACTORS
GENETICS
ORTHODONTIC FORCES
NEUROTROPISM
SURGERY
FUNCTION
MALNUTRITION GENERAL BODY GROWTH
GROSS CRANIOFACIAL ANOMALIES MALFUNCTION
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VAN LIMBORGH’S CLASSIFICATION 1.
2.
3.
INTRINSIC FACTORS EPIGENITIC FACTORS a) Local b) General ENVIRONMENTAL FACTORS a) Local b) General www.indiandentalacademy.com
Pre natal Natal Post natal
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Pre-natal factors 1. 2. 3. 4. 5. 6. 7.
Developmental anomalies. Teratogens. Congenital infections. Maternal health. Socioeconomic status of parents. Multiple births. Congenital defects. www.indiandentalacademy.com
Natal causes 1. 2.
Trauma during birth. e.g. forceps delivery Intrauterine moulding.
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Post natal factors 1. 2. 3.
Hereditary Epigenitic Environmental
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PRENATAL FACTORS
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DEVELOPMENTAL ANOMALIES 1. 2. 3. 4. 5. 6. 7.
PIERRIE ROBIN SYNDROME TREACHER COLLINS SYNDROME CLEFT LIP AND PALATE CROUZON’S SYNDROME ECTODERMAL DYSPLASIA APERT SYNDROME HEMIFACIAL HYPERTROPHY www.indiandentalacademy.com
Pierrie robin syndrome
Retrognathia or micrognathia Glossoptosis Airway obstruction Crying child Management- prone position, relief of airway, mandibular lengthening process
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Treacher collins syndrome
Autosomal dominantmutation in tracheal gene Diminished neural crest cell migration Avian like faces with colobamata of lower eyelids, slanting palpebral fissures, malar defficiencies, microstomia, auricular defects. Severe conditions show malformed ears, cleft palate. Enlarged antigonial notch. www.indiandentalacademy.com
Crouzon syndrome
Maxilary hypoplasia with reduced dental arches and crowding Prenatal fusion of superior and posterior sutures of maxilla Short upper lip, widely spaced eyes, protruding eyeballs Unilateral or bilateral crossbite www.indiandentalacademy.com
Apert syndrome
Premature fusion of skull bonesmalformed head shape protruding eyes, fused fingers and toes, cleft palate, airway problems, ear infections and hearing loss, etc Management- multidisciplinary approach.. Orthodontist play a role in correction of facial form.
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Hereditary ectodermal dysplasia
X linked recessive disorder… Hypohydrosis , hypotrichosis and hypodontia Decreased vertical dimension of face, protruding lips, thin sparse hair over the head. Very few teeth, malshaped or peg shaped teeth, caries Severe cases may be associated with cleft of lip or palate www.indiandentalacademy.com
Hemifacial hypertrophy
One half of face enlarged F>M Unilateral teeth size, tongue increased Eruption of teeth on affected side is hastened
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Cleft lip and palate
1 in 700 Most common congenital anomaly Due to nonfusion of medial nasal, lateral nasal and maxillary process Oronasal communication, facial deformity, malposition of teeth, speech problems, breathing problems, frequent infections www.indiandentalacademy.com
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TERATOGENS
Agents which are capable of producing embryological defects in critical doses.
Can be physical , chemical or biological agents.
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Other prenatal factors 1. 2. 3. 4. 5. 6.
Poor maternal health Mother’s nutritional status Placental insufficiency Multiple births Socioeconomic conditions Congenital infections
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Poor maternal health
E.g systemic diseases like renal failure, cardiac failure, diabetes, hypertension Affects fetus due to altered blood flow, altered diet of mother, drugs Also complications during delivery
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Mother nutritional status
Balance diet Alcohol and cicarettes Depends on financial condition, culture, society, emotional status of mother Fetal alcohol syndrome- due to defficiency of midline tissue of neural plate www.indiandentalacademy.com
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Placental insufficiency- may occur due to poor nutrition of mother, maternal health, etc
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Multiple births- 1st child is less in weight and more in I.Q when compared to subsequent children. Too many children- difficult to concentrate
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Socioeconomic conditions- children with unfavorable conditions lag in growth and development when compared to children with favorable conditions
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Congenital infections- CMV, Rubella, toxoplasmosis, syphilis, HSV, HIV
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NATAL FACTORS
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Intrauterine moulding 1.
2.
3.
Pressure of arm against face– maxillary defficiency.
Flexion of head against chest– mandibular deffiency. Forceps delivery www.indiandentalacademy.com
4.
Sometimes head distortion during passage through the birth canal
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Childhood fractures
# of condyle is most common Reduced development on the affected side Jaw deviated to affected side. Management- early mobilisation and symptomatic treatment
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GENETIC FACTORS
Actual outcome of growth= genetic potential+ environmental influences. Mutations- inherited by offspring Genetic studies make use of twin and family data. N.b:- difference between growth before and during adolescence. www.indiandentalacademy.com
ď Ž a) b) c)
Genes control:Size of body parts Rate of growth Onset of growth events e.g menarche, calcification of teeth, eruption of teeth, ossification of bones and start of adolescent growth spurt. www.indiandentalacademy.com
Genetic influences on malocclusion
Malocclusion runs in families– e.g Hapsburg jaw Primitive humans– genetic isolation– uniform malocclusion Urban population– e.g U.S.A c/a Genetic melting point have highest rate of malocclusion.
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Stockard study
Crossbreeding of boston terrier with collie Results showed malocclusions due to jaw discrepancies than from tooth size- jaw imbalances. Results were misleading as malocclusions were due to the extent to which achondroplasia was expressed.
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Twin study by Lundstorm(1963)
100 pair of twins 50 monozygotic & 50 dizygotic Skeletal and dental overjets measured More variations in dizygotic Skeletal problems were more variable Disadv– environmental and climatic conditions may not be the same for both the twins www.indiandentalacademy.com
Epigenetic factors
Genetically determined but manifest influence on associated structures– GRABER Sum total of all biochemical, biomechanical and biophysical events produced by the functioning of cells, tissues and the organs– RAKOSI AND PETROVIC
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Primary genetic control determines certain initial features like tooth buds calcify in jaws,etc. But there are inductive local feedback and inner communication mechanisms between cells and tissues- e.g teeth talk to bone. If face is under genetic control then it should be possible to predict 100% features of children from cephalometric data of parents. www.indiandentalacademy.com
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1. 2.
Hence from investigations so far, two conclusions are inescapable:Inheritance of facial dimensions is polygenic Not more than 25% of any variability of any dimension in children can be explained by consideration of that dimension in parents.
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2. 3.
1. 2.
Local epigenetic factors– Muscles “ what is environment to bone is genetic to muscles and teeth” Neurotropism Function General epigenetic factors– Hormonal General body growth www.indiandentalacademy.com
Muscles
Influences both initiation and formation of bone
Decreased contraction– underdevelopment of that part of face
Excessive contraction– restricts the growth e.g torticollis or wry neck. www.indiandentalacademy.com
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Neurotropism ď Ž
It is the nervous control of skeletal growth by transmission of a substance through the axons
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TypesNeuromuscular Neuroepithelial Neurovisceral
1. 2. 3.
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Axoplasmic transport Efferent- muscle www.indiandentalacademy.com Afferent-epithelial cell
Neuromuscular trophic relationships 1. 2. 3. 4. 5.
Muscle development Muscle denervation- reinnervation Cross- innervation Hyperneuralization Control of genetic activity
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Muscle development
Myoblast stage of differentiation- neural innervation is established
If muscle is not efferently innervated- motor end plates will never develop.
Also muscle spindles, receptors and tendon organs require afferent innervation. www.indiandentalacademy.com
Muscle denervation and reinnervation
Ventral root section- muscle degeneration
Denervation atrophy or disuse atrophy of innervated but inactive muscles?
Studitsky et al(’62)— Autotransplanted mince muscle fragments– if supplied by motor nerve– reform to functioning muscle www.indiandentalacademy.com
Cross innervation
Demonstrates neurotrophic relationship between neuron and uninnervated tissue.
Motor nerve to fast and slow muscles cut- fast nerve + slow muscle and vice versa
Results- fast muscle becomes slow and vice versa. www.indiandentalacademy.com
Hyperneuralisation ď Ž
It is seen when neurotrophic substance were released in quantal amounts.
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Nerve crushed and 2nd nerve implanted- will form new end plate but if implanted
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Neurotrophic control of genetic activity
Protein synthesis in oral epithelial cells
Specific enzymes synthesis in epithelium
Mechanism- direct control on the synthesis of DNA, RNA and Protein synthesis
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General body growth
Rate, pattern, timing of peak growth is different for different individual
Affected by many factors like genetic, hormonal, climate, racial, nutritional
Height– 2 spurts 6-7 yrs- small but inconsistent Pubertal spurt- 12 yrs in girls and 14 in boys www.indiandentalacademy.com
1. 2.
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Hormones
I excite or arouse
Specific stimulus– endocrine glands release hormones into circulation in small amounts--acts on target cells
2nd great controlling system of our body after nervous system
Most mysterious and elegant of all systems of the body. www.indiandentalacademy.com
Hormones responsible for growth 1.
2.
3.
Group I- responsible for influencing skeletal growth .e.g GH, Insulin, Thyrotrophic hormones Group II- responsible for ossification of long bones. E.g Parathormone Group III- responsible for pubertal growth spurts .e.g Androgens, Progesterone, Estrogen www.indiandentalacademy.com
4.
Group IV- prolactin
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Growth hormone
Infancy- growth due to thyroid hormone and GH.
Permissive action
Excess GH- Gigantism and Acromegaly
Decrease GH- Dwarfism www.indiandentalacademy.com
Summary of effects of growth hormones Ant pitutary GH
Negative feedback mechanism Indirect growth promoting action
Direct anti insulin action
cortisol
Liver and other organs somatomedians Skeletal chondrogenesis Skeletal growth
extraskeletal Protein synthesis
fat lipolysis
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carbohydrate Blood sugar
GIGANTISM
Increased production of GH before the closure of the epiphyseal plate- grows at rapid pace .
Clinical features Extreme height (7 ft tall)
Oral changes Enlargement of facial soft tissues Enlargement of the mandible True generalized macrodontia www.indiandentalacademy.com
ACROMEGALY •Excess GH after the closure of the epiphyseal plate. •Clinical features Increased size of hands and feet coarse facial features •Oral changes cause or accentuate sleep apnea Mandibular prognathism -- Apertognathia www.indiandentalacademy.com (anterior open bite), spacing, macroglossia
Acromegaly www.indiandentalacademy.com
PITUITARY DWARFISM • Decreased production of GH Clinical features 1. Short stature 2. Face is small 3. skull size is usually normal
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Oral changes Smaller jaws Size of teeth is reduced with delayed eruption Shedding of deciduous teeth is delayed by several years Third molars absent www.indiandentalacademy.com
Thyroid hormones
T3 and T4(follicular cells)
Calcitonin (parafollicular cells)
Inc O2 consumption by cells
Key role in development of brain and nervous system in children. www.indiandentalacademy.com
Hyperthyroidism
Graves disease Enlarged thyroid CNS signs Cardiac signs Wasting of muscles, heat intolerance, osteoporosis (bone resorption) www.indiandentalacademy.com
Hypothyroidism
Myxoedema , Cretinism Inc sleep, dec memory, slow reflexes Yellowish discolouration of skin, cold sensitivity, nonpitting oedema Mental retardation Decreased sexual development www.indiandentalacademy.com
Parathormone
Chief cells Increases serum Ca levels. Hypoparathyroidism- Tetany Tingling and numbness Hyperparathyroidism- osteitis fibrosa cystica Bone fractures, decreased muscle tone, mental confusion www.indiandentalacademy.com
Adrenal glands Adrenal medulla Adrenaline Noradrenaline
Adrenal cortex Zona glomerulasasalt Zona fasciculatasugar Zona reticularissex www.indiandentalacademy.com
Glucocorticoids
Cortisol, corticosterone
Must in medical kit
Stimulates gluconeogenesis, protein catabolism, anti allergic and anti inflammatory
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Insufficiency of adrenal cortex Chronic form
Acute form Waterhouse friderichen syndrome
Addison's disease
-Primarily occurs in children
-Auto immune destruction of adrenal glands
-Fulminating septic course and death in 48-72 hrs
- leathergy, fatigue, muscular weakness
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Hyperfunctioning of adrenal cortex
Cushing syndrome Moon face, buffalo hump, muscular weakness Children- premature cessation of epiphyseal growth Adults- severe osteoporosis www.indiandentalacademy.com
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Sex hormones
Males- testosterone
Females- estrogen and progesterone
Growth spurts
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Girls- I- onset of spurt II- peak height velocity III- onset of menstruation
Boys- I-fat spurt (feminine fat distribution) II- height spurt III- peak height velocity www.indiandentalacademy.com IV- end of growth spurt
Environmental factors ď Ž
Local environmental factors- Habits
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General environmental factorsNutrition Illness Race
1. 2. 3.
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4. 5. 6. 7. 8. 9.
Climate and seasonal effects Exercise Family size and birth order Psychological disturbances Socioeconomic conditions Secular trends
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Habits
Eg. Tongue thrusting, mouthbreathing, thumbsucking
Alter functional equilibrium
Normal growth- abnormal growth
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Thumb sucking
Mainly to obtain- nutrients, feelings of euphoria, sense of security and feeling of warmth.
Till 3-4 years normal
Management- psychological Remainder therapies www.indiandentalacademy.com
Tongue thrusting
Tongue between ant teeth and against lower lip during swallowing
Skeletal open bite
Management- tongue crib
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Mouth breathing
Lowering of mandible and tongue with extension of head
Adenoid faces
Management- Removal of etiology
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THE NUTRIENTS
Essential nutrients
Non essential nutrients Cellulose,
Proteins, Fats,
Hemicelulose,
Carbohydrates,
Pectins
Vitamins, Minerals Water
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Proteins
Body building food Important in infancy and childhood
protein def- reduction in jaw size- new bone sensitive to protein
Delayed eruption of teeth. www.indiandentalacademy.com
VITAMINS Water soluble
Fat soluble Vit A Vit D
Non B complex
Vit E Vit K
B-complex
Vitamin C
Energy releasing
Hematopoietic
Thaimin B1,Riboflavi B2
Folic acid
Niacin B3,PyridoxineB6
Vit B12
Biotin B7,Pantothenic acid www.indiandentalacademy.com
Vit A in growth Malformed enamel Retardation of eruption Disturbances in calcification of teeth Disturbances of periodontal tissues
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www.indiandentalacademy.com Vitamin D metabolism
Vitamin D
Rickets and Osteomalacia
Retarded eruption of the deciduous and the permanent teeth
Jaw bones are thickened and the teeth irregularly arranged
Narrow maxilla and high arched palate. The mandible is shortened www.indiandentalacademy.com
Vitamin C
Scurvy
Collagen synthesis
Swollen bleeding gums, periodontal breakdown- mobile teeth
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Minerals 1. 2.
3.
4% human body weight Macro minerals (require in >100mg/day).Ca,P,Na,K,Mg Micro minerals (Trace elements) Fl,I,Cu,Co,Mn,Se,Cr,Zn.(.004-.00004% of body weight)
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Calcium
Function:-
Rigidity to bone and teeth
Blood coagulation n muscle contraction…
Necessary for release of neurotransmitter
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www.indiandentalacademy.com Calcium homeostasis
Phosphorous
FunctionsFormation of bone and tooth
Constituent of nucleotides and nucleic acid
Constituent of lipids
Regulation of acid-base balance www.indiandentalacademy.com
Illness
Minor illness- no effect
Major and prolong illness- marked effect
Catch up growth after recovery
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Race ď Ž
Due to climatic, nutritional or socioeconomic conditions
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Gene pool differences
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Climate and seasonal effects
Cold climates- more adipose tissue
Autum- inc height
Spring- inc weight
Growth inc during night www.indiandentalacademy.com
Exercise
Effect on linear growth not made in quantitative fashion-MOYERS
Exercise- increase in muscle mass
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Psychological disturbances
Due to reduction in GH levels
Catch up growth
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Socioeconomic factors ď Ž
Favourable conditions- children are larger, display different types of growth, show variation in timing of growth when compared with disadvantaged children.
ď Ž
Standard of living more imp than income
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Secular trends
15 yr boy 5” taller than boy 50 yrs ago
Onset of growth is earlier but growth also stops earlier
Menarche achieved earlier in girls when compared with 50 yrs ago
No satisfactory www.indiandentalacademy.com explanation for such trends
Summary Prenatal factors Developmental anomalies Teratogens Congenital infections Condition of mother During pregnancy
Natal factors Intrauterine moulding Forceps delivery Childhood #
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Post natal factors Genetic factors Epigenetic factors Environmental factors
References 1. 2. 3.
4.
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Hand book of orthodontics- MOYERS Contemporary orthodontics- PROFFIT Control mechanisms in craniofacial growthJAMES McNAMARA (monograph 3Craniofacial Growth Series) Orthodontic principles and practiceT.M.GRABER Essentials of physiology- A.K.JAIN www.indiandentalacademy.com
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Nature vs. nurture in dentofacial variationA. LUNDSTROM (Eu J Ortho, 1984) Textbook of orthodontics- BISHARA, I Ed Textbook of Oral Pathology-SHAFER’S Essentials of Biochemistry- T.N. PATABHIRAMAN Textbook of Pedodontics- SHOBHA TONDON www.indiandentalacademy.com
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