Growth and development /certified fixed orthodontic courses by Indian dental academy


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Growth and development /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  4. 4. Every pedodontist should keep in mind that the patient on whom he works are in the state of growth and development , which is a dynamic and continuously changing process. He almost never find a static picture in pediatric patient. So a thorough understanding of complex craniofacial growth is of great importance for pedodontist Understanding of developing craniofacial skeleton represents, sum of growth of its separate parts in which growth is highly differentiated and occurs in different rates ,dimension and time.So keeping all these in mind we start with seminar topic 
  5. 5.  Growth and development can be seen in three aspects a) b) c) change in dimension change in proportion maturation
  6. 6. DEFINATION OF GROWTH  STEWERT(1982) : growth is increase in mass physical size of cell ,tissues , organ ,or organisms as a whole PROFIT (1986): growth refers to increase in size or number MOYERS (1988) : growth is normal change in the amount of living substance PINKHAM(1994) :growth is increase expansion or extension of any given tissue
  7. 7. DEFINATION OF DEVELOPMENT  TODD(1931) :development is increase in complexity  LOWREY(1951) :development indicates increase in skill and complexity of function  MOYER(1988) :development is the unidirectional change in the life of an individual from its existence as a single cell to terminating in depth .  PINKHAM(1994) :development addreses the progressive evolution of a tissue
  8. 8.  DIFFERENTIATION :The change from a generalized cell to one that is more specialized .it is change in quality and kind .  As we see that many of times growth and development are used synonymously, but they are not. In simple words,  * Growth is increase in size or number of things .It is numerical .can be easily measured with a specified scale. Ex. Height , weight of persons.  *development is increase in skill and complexity of fuction.  But, practically growth and development are inseparable entities and are simultaneous on
  10. 10. GENETIC GROWTH (Brodie) It says, growth is cantrolled by genetic influence in all aspect. But it cannot be accepted in all cases. As it has been shown that the external factor have significant modifying effect on growth 
  11. 11. SUTURAL THEORY (sicher)  It says that the proliferation of sutural mesanchyme causes apposition of bone . It is seen in membranous bone.  Limitation :- lack of growth of suture if it is transplanted .  gowth occurs in cleft lip and cleft palate pts.even if suture not present  Suture also respond to external influence 
  12. 12. CARTILAGENOUS THEORY (James Scott) :  It says that cartilage acts as primary growth center and has a innate growth potential  Ex ; condylar cartilage for mandible  Nasal cartilage for maxilla (nasomaxillary complex)  If it is transplanted it grows independently
  13. 13. FUNCTIONAL MATRIX THEORY (Melvin Moss –1968) It says that body has two element  a) skeletal element b) functional matrix  functional matrix comprised of  1)periosteal camponent  2)capsural camponent  (neuro cranial),(orofacial)  functional matrix has primary control on growth of skeletal unit and bone respond in passive manner  but it can not explain all aspects of growth 
  14. 14. MULTY FACTORIAL THEORY (Van Limborgh) It says bone growth is controlled by  a) intrinsic genetic factor  b) local epigenetic factor (nerves, brain ) – C)general epigenetic factor (harmones, secondary messengers ) – d) local environmental factor (habit, muscular force ) – e) general environmental factor ( oxygen, nitrogen)  It is most satisfactory theory that explains all aspect  It says growth is polygenic and multifactoral 
  15. 15. NEUROTROPISM (recent theory )  It includes epithelial , visceral , muscular component for these component nerve impulses which are transmitted has growth potential for bone .It also has indirect effect by influencing soft tissue growth  but by experiments it has proved that neurotropism has negligible effec
  16. 16. PETROVICS HYPOTHESIS It says that the interaction of serves of casual changes and feedback mechanism which determines craniofacial growth  ie brain---- cranium. 
  18. 18. ENLOWS EXPANDING “V” PRINCPLE  It says that most of craniofacial bones especially intramembranous have v shape eg:maxilla , mandible , palate ,nasal etc. And growth movement occurs towards wide end of V deposition of bone is seen in inner side and resorption is seen in outer surface.
  19. 19. ENLOWS COUNTERPART PRINCIPLE  It explains that, growth of one bone has influence on its adjuvant bone which is called counter part, and this controls the growth and proportional relationship with its counterpart.  E.g.:   nasomaxillary complex—cranialfossa Maxilla ----------mandible Tuberosity areas of upper/lower jaw Pharyngeal space -------- middle cranial fossa
  20. 20. FACTORS AFFECTING PHYSICAL GROWTH Heredity  Nutrition  Illness  Race  Socioeconomic states  Family size  Psychogenic disturbance  Exercise  Pharmacological 
  21. 21. characteristic properties of growth  concept of normality growth states are always accessed in normality value ie. in range but can not be explained as ideal with a definite value  Normality differs from age to age 
  22. 22.  Different growth : Different organs grow at different rate , different amount, and different time .  It can be best explained by SCAMMONS GROWTH CURVE 
  23. 23.  CEPHALOCUADAL GRADIENT OF GROWTH Axis of growth increases extending from head to feet  ie. 3 months intra uterine life head size--50%, birth head size---30%, adult head size---12% of whole body    Cranial growth 70% completed at birth to 1st year  limbs 3month IUL-1% by birth-50% of body
  24. 24. GROWTH SPURTS In spite growth is continuous process there occurs a period when a sudden acceleration of growth occurs called growth spurts .  It is due to physiological alteration in hormonal secretion  They differ in boys and girls This period is good for functional and orthodont appliance use Surgical correction involving jaws should carried out after cessation of growth spurts . 
  25. 25.  Timings of growth spurts  A)just before birth  B)one year after birth  C) mixed dentition  growth spurts ….girl—7-9yrs  boys- 8-11yrs  c) pre pubertal – growth spurt ……girls ----11-13 yrs  boys -----14-16yrs
  26. 26. METHODS OF STUDING GROWTH  a)measurement approach  bimanual test height and weight  b) experiment al approach : vital staining- alzirine blue  alzirine red  lead acetate  Rdioisotopes-------- te 33 ,ca*45 , k*32 injected in bone  c)Implants  d)radiographs
  27. 27. Mechanism of bone development   1)endochondral bone 2)intramemebranes  endochondral bone this type of bone is proceded by formation of cartilaginous model  intramembranes bone – bone is directly laiddown in fibrous membrane
  28. 28. prenatal growth {day1 to 266 day} It is divided into 3 periods 1) period of ovum (ferti. to 14th day) 2)period of embryo (14th day to 56th day) 3)period of fetous(56th day to birth)
  29. 29.  period of ovum(fertilization to 14th day)  In this period oocyte get fertilized with spermatozoa to form zygote which is a diploid cell. After this process cell division starts within 24 to36 hours. Cleavage continues to form , 2,4,8,cells. In 8th cell stage process of compaction occurs to get 1st embryo shape. 16th cell stage called morual . Next stage called blastula which is 150 cells stage. It is of 1.5mm in length and 3 to 5 days old it has inner cell mass which forms fetus & outer cell mass which forms yolk sack. On 5th day blastocyte starts penetrating endometrium & at 14th day it get implanted it self into uterine wall.
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  32. 32. or embryoblast utenne epithelium Uterine stroma ~,~~",". Trophoblast cells
  33. 33. Timeo! DNA duplicatiof Endometrium (progestational stage) ., ,.< ---I. ,I
  34. 34. Period of embryo th (14 day to 56th day)  It is the period where major development of organ specifically craniofacial structure occur. on 17th day process of gastrulation occurs to form different germ layers. Ectoderm above notochord thickens to form neural plate which forms nervous system . On 21st day embryo is of 3mm now primordial of brain eye are seen in prosenceophalon. On 3rd day otic &optic plocodes are seen. In the same period most inferior part of prosencephalon starts growing to from front nasal process which overhangs future oral cavity which is wide & shallow.
  35. 35. P rimitive pit and neurenteric canal Amnion Wallo! yolk sac Cloacal plate (membrane) A Not ochordal plat e c E ndoderm Int raembry onic mes oderm Ex t raembry onic mes oderm E Notochord - ,u :1 I "e+r ~ t;n a for ,
  36. 36. I ~. ,f/,'~ M. W,'. :~:i: :> "-'.~ ,
  37. 37. on 3-4week oral groove starts deepening. Same time bud for max and man process show their presence lat to oral groove. Deepened oral cavity is now called stomodium and is separated by hind gut with a membranes formed by endoderm and ectoderm called buccopharyngeal membranes . on 4th week the embryo is 5mm . Now frontal elevation shows some ectodermal proliferation which form future nasal placode and olfactory epithelium optic placodes which are formed are placed very widely apart
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  39. 39. Otic placode Lens placode Limb ridge B 28 days
  40. 40.  Front nasal process show more growth mesially than laterally which forms medial nasal process. As medial nasal process grows faster, in future it unites with maxillary process to form part of upper lip specifically along line of philtrum . lateral nasal process mainly contribute formation of columella .on 5th week caudal to frontonasal and maxillary process brachial arches show their development they are totally six with 5th one turning to be rudimentary. 2nd brachial arch develop faster than other and covers other brachial arches
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  42. 42. ; Pharyngeal pouch Endoderma! epithelium Nerve 1 st pharyngeal arch Cartilage cleft Ectodermal epithelium. 2nd arch with ner ve, artery, and c<1rtllage Mesenchymal tissue in 4th arch A
  43. 43. Auditory tube Primitive tympanic cavity Ventral side of phary nx External auditory meatus - Foramen cecum f , f I f ! I f Palatine tonsil , I , '¥ Superior parathy roid gland (f rom 4th pouch) Thy roid gland Inf erior parathy roid gland (f rom 3rd pouch) Ultimobranchial body Foregut
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  46. 46.  same time between and around primordial of brian and eye Mesenchymal condensation appears which gives a shape of skull. Mesenchyma of brachial arch also appears by 5th week. 1st brachial grows faster to become distant .In 6th week mandibular arch show accentuated growth to divide in maxillary and mandibular process both process grows medially . medial nasal process from above also grows downwards and towards midline as a result by the 7th week fusion between maxillary and frontonasal process occurs and this time embryo is 14.5mm in length
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  50. 50.  Now eye starts migrating towards midline Mesenchymal of cranial and brachial arch differentiates into cartilage (CHONDRIFICATION)  cartilage in the base of skull thins to join with nasal and optic capsules. same time centers for endochondral ossification appears in the cartilage of base of skull, also Mesenchymal condensation in intramembranous bone is seen. At 8th week nasal septum further narrows to become a prominent structure ,also external ear starts its development. nasal pit breaks down to form nostrils. Demarcation seen between lateral nasal and maxillary to form nasolacrimal groove
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  53. 53.  primary palat starts its development at 8 th week .so till this time their occurs a direct communication between oral and nasal cavity . lidless eyes increase their movement towards midline .both lateral halves of mandibular process fuse by 8 th week. at this time embryo is 18mm in length .  Rough head and face shape is almost completed by 8th week . By end of 8th week embryo increases in length almost by 4 times to that of 7th week
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  55. 55.               main structures formed in the embryonic period are neural plate -2 buccopharyngeal membrane -2 mandibular arch –3 hypoglossal muscle—5 median and lateral nasal process-5 lens of eye-5, retina—5 external carotid artery-6 middle ear-6 larynx -6 maxillary process -6 external ear -7 nasal septum-8 palatal shelves-8 *IN WEEKS OF IUL
  56. 56. FETAL PERIOD (56days--9 months ) Eye lid formation occurs .eyes get close . nostrils are formed. This period shows accelerated rate of craniofacial growth resulting in an increase size and proportion In 8th to 12 weeks fetus increases in length by 22—60mm . mandible increases in size and anteroposterior relationship of both jaws develop as it is seen at birth
  57. 57.  Development of tongue  Appears in embryo at 4th week of IUL . in the form of two lateral swellings and one median swelling that is tubercular impar .all are from 1 st pharyngeal arch  Another median swelling copula (hypobranchial eminance) from 2,3 and 4th arch .posterior part of 4th arch gives rise to epiglottis  Two lateral swellings grows medially and anteriorly and overgrows on TI . both half meet each other to form anterior two third of tongue  Muscles of tongue develop from occipital myotomes
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  60. 60.  Thyroid gland :   Thyroid appears as epithelial proliferation of in the floor of tongue between TI and HE  Then it descends in front of pharyngeal gut and forms bilobed diverticulum's which forms two lobes  
  61. 61. GROWTH OF CRANIAL BASE  As we have seen that by 4th to 8th week of IUL evidence of cranial base formation is seen .the Mesenchymal form is derived from primitive streak of neural crest and occipital schlerotomes.  condensed mesanchyma forms capsule around brain called ectomenix basal portion of this capsule gives rise future cranial base. The process by which ectomeningeal capsule get convert into cartilage is called chondrification .  it mainly occurs in 4 regions
  62. 62. Para chordal—around cranial end of notochord  Hypophyseal—it occurs in 4 centers  post sphenoid—body of sphenoid  pre sphenoid –body of sphenoid  mesethmoid---plate of ethmoid  cristagalli    Nasal-nostril  Otic-mastoid orbito sphenoid---lesser wing ali sphenoid – greater wing
  63. 63. OCCIPITAL BONE It ossifies both endochondrally and intramembranously. It has 2 intra membranous centers and 5 endochondral centers • supra nuchal sq. part – one pair ---8th week • infra nuchal sq.part --1 pair -------10th week • basilar part –single median center -11thweek • foramen magnum occipital condyle ---1 pair –12th week 
  64. 64.       TEMPORAL BONE It has 11 centers of ossification Sq, part –1 center (IM)—8TH week Tympanic ring 4 centers (IM)------12th week Petrous temporal bone ---4 centers (EC)-----5th month Styloid 2 centers (EC) 5th month   ETHMOID    BONE Its an endochondral bone with 3 centers Median floor of anterior cranial fossa –1 centers Nasal capsule 2 lateral centers
  65. 65.  SPHENOID BONE It has 15 centers of ossification  Lesser wing –2 orbito sphenoidal cartilage  Greater wing ,lateral pterygoid plate2(IM)1alisphenoid  Median pterygoid plate -2 secondary cartilage of hamular process  Anterior part of body of sphenoid- 5 (EC)  Posterior part body of sphenoid - 4 (EC)  Cranial base chndrocraniam is relatively stable during growth compared to cranial vault and face so cranial base is taken as bases against which cranial vault and facial skeleton can be compared in cephalometric studies 
  66. 66.  FLEXURE OF CRANIAL BASE  In early fetal period cranial base becomes flexed in the region between pituitary fossa and sphenooccipital junction this is accompanied by developing brain stem so that spinal chord and foramen magnum directed downwards from their initial position of backwards this adaptation only seen in human beings  It increases neurocranial capacity  It facilitates predominant downward growth of face  At 10th week of intrauterine life flexure angle is 65 degrees with then flattens. anterior and posterior part of cranial base grows at different rates that is between 10th to 40th week anterior cranial base increase in width 7 times but posterior increase by 5 times
  67. 67.  Development of palate  Main part of palate arise from maxillary process & small premaxilla is formed by deeper part of medial nasal process. initially medial nasal process gives rise to small triangular projection which forms futer premaxilla .then from maxillary process lateral segments arise which are placed vertically. In this period mandible is small & already formed tongue is pushed upwards in nasal cavity so lateral segments of maxillary process grow vertically .
  68. 68.  Nasal septum from above starts growing downwards & backwards by 7th week of IUL . Mandible shows accelerated growth so tongue falls back & transformation of position of palatal selves occurs from vertical to horizontal this transformation takes place within hrs .  Both palatal selves properly approximate by 8 ½ to form hard palate & posterior part use to form sot palate entire palate does not close at once . initial contact occurs in central region of secondary palate posteriorly to pre maxilla from this point closure occurs both anteriorly &posteriorly also from above end of nasal septum fuses with palate .  Palatal ossification (IM) 1 center 8th week  mid palatal suter ossifies at 12 to 14 years
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  73. 73. development o maxillary sinus  It is formed around at 3rd month of IUL It develops by expansion of nasal mucous membrane into maxillary bone  It enlarges later by internal resorption of wall of maxilla
  74. 74. meckels cartilage it derived from first brachial arch on 41st to 45th day of IUL .extends from cartilaginous otic capsule to sysmphysis .it acts as template and guide for growth of mandible . a major portion of this disappears and remaining part develops in to  mental ossicle  incus, malleus  spine of sphenoid  ant. Ligament of malleus  sphenomandibular ligament  1st structure that develops in promordia of man. Is mandibular division of 5th nerve this is followed by osteogenesis (neurotropic theory ) 
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  77. 77.  on 6th week of IUL single ossification center for each man. Arise in the region of bifurcation of inferior alveolar nerve in to mental and incisive. ossifying membrane is located lateral to meckels cartilage .IM ossification spreads dorsally and ventrally to form body and ramus of man. Ossification continues till region of future linguala. meckels cartilage continues into middle ear and develops in to auditory ossicle that is malleus and incus and SML
  78. 78.  Endochondral bone formation in man. Seen in3 areas  condylar process  mental region  coronoid process  condylar process; at 5th week of IUL mesanchymal condensation seen above ventral part of man. By 10th week it develops into cone shaped cartilage. by 14th week it starts ossifying. it then migrates inferiorly and fuse with man. Ramus by4th months . by 6-7 th month of IUL much of cartilage ossifies except upper end which ossifies at adult hood
  79. 79.  mental region  on either of symphysis 2 small cartilage appears in 7th month of IUL .it then incorporates into body . symphysis ossifies after 1yr after birth coronoid  process it is formed by secondary cartilage. appears at 10-14th week of IUL. it grows as response to temporalis muscle. it then join with ramus
  80. 80. TMJ  In IUL it develops in three phases Blastamic stage (7—8th week) corresponds with organization of condyle ,articular disc and capsule  Cavitations stage (9—11th week) initial formation of inferior joint cavity  Maturation stage (from 12thweek)  At birth articular disc is flat but it then transforms into S shape  Articular disc at birth is 1.5mm thick. it then thins down and replaced by endochondral ossification  It grows in post . sup. Lat. Direction 
  81. 81. POST NATAL DEVELOPMENT AND GROWTH  Maxilla and mandible are attached to cranial base by means of sutures and TMJ respectively. so any growth change in CB affect growth of jaw
  82. 82.  cranial base  CB grows post natally by complex interaction between  1) cortical drift and remodeling  2) elongation at synchondrosis  3) sutural growth  cortical drift and remodeling ; remodeling is apposition or resorption of bone which bring about change in size shape and relationship of bone  cranial base is divided into many components by bony elevations called ridges .These ridges show bony deposition and other part show resorption by this process CB develops  in the area where blood vessels and nerves pass CB ,show cortical drift ie by bone deposiotion and resorption and maintain constant position
  83. 83.  elongation of synchondrosis  cartilage at various junction of bone called SY  they act as important growth sites as they are primary cartilages  main synchondrosis are  sphenooccipital  sphenoethmoid  intra sphenoid  intra occipital 
  84. 84.  spheno occipital SY ; it is active up to age 12—15years .these segments fuse in midline by 20yrs . it shows pressure adapted bone growth. direction of bone growth at SY is upwards so it carries ant. Part of cranium bodily forwards closure of this SY occurs at 13-15yrs  spheno ethmoid : it ossifies at 5-25yrs  intra sphenoid : it ossifies at birth  intra occipital:ossifies at 3–5yrs 
  85. 85. sutural  growth : -- growth seen sutures are spheno frontal  fronto temporal  sphenoethmoid  frontoethmoid  frntozygomatic  main timing of CB growth  by birth 55%-60%  4—7yrs 94%  8—1yrs 98% 
  86. 86. • post natal growth of maxilla – nasomaxillary complex grows by displacement  growth at suture  surface remodeling  displacement: as before discussed maxilla attached attached CB by sutures so as CB grows secondary displacement is seen in NMC in downwards and forwards direction . it mainly seen at 6—12yrs age. growth at tuberosity seen in postrior direction to shift maxilla in forwards direction 
  87. 87. growth at suture  main sutures at which growth seen are  frontonasal  frontomaxillary  zygomaticotemporal  zygomaticomaxillary  pterygopalatine  these sutures are obliquely placed and by this maxilla grows in forwards and downwards direction . soft tissues carry maxilla also in same direction
  88. 88.  surface remodeling ; the remodeling changes seen in NMC.  resorption occurs on lat. Surface of orbital region so that eye moves laterally .on medial rim deposition seen  floor of orbit due to remodeling grows in sup .lat. and ant. Direction  bone deposition occurs on posterior margin of maxillary tuberosity which causes lengthening of dental arch and enlargement of antero posterior dimension of entire maxilla  bone resorption seen on lateral wall of nose to increase size of nasal cavity  bone resorption seen in floor of nasal cavity and deposition in palatal side so net downward shift occurs leading to increase in maxillary height 
  89. 89.  zygomatic bone moves in posterior direction by resorption on anterior surface and deposition on posterior surface  face enlarges in width by formation of lateral surface of zygomatic arch and resorption on medial surface  anterior nasal spine increase in prominence by deposition  tooth eruption ,increase maxillary height by alveolar bone deposition  entire wall of sinus except mesial wall undergoes resorption by which maxillary sinus increase in size
  90. 90. post. Natal growth of man.  Of facial bone man. Has largest amount of growth post natally  Ramus : it moves posteriorly by bone remodeling  Resorption occurs in anterior part and deposition occurs in posterior region so it results in post . drift  Body of man.: its growth depends on remodeling growth of ramus so former ramus converts into posterior body
  91. 91.  Angle  On of mandible lingual side of angle resorption takes place on posteroinferior aspect and deposition occurs in anterosuperior aspect on buccal side exactly opposite process occurs this results in flaring of angle of mandible as age advances  Lingual tuberosity : it is vary similar to maxillary tuberosity grows posteriorly and lingually  Alveolar bone grows as tooth erupts in oral cavity  Chin in infancy is under developed due to position of head and precordial bulge its growth mainly influenced by sexual and specific genetic factor  Males have prominent chin  In childhood mental protuberance forms and ossifies its prominence is accelerated by bone resorption that occurs in alveolar region which creates concavity
  92. 92.  Condyle : it is main growth site its growth has 2 schools of thought  Earlier it was believed that growth occurs at surface of condyle by bone deposition so condyle grows towards CB condyle pushes against CB .so entire man. Is displaced forwards and downwards  Now it is believed that growth of soft tissue that is muscle and CT carry man. forwards away from CB ( carry away phenomenon) and bone grows secondarily to maintain contact with CB . condylar growth which peak at 12—14yrs and stops at 20yrs  Coronoid process : it follows enlows V principle , deposition occurs on lingual surface and with it vertical dimension also increase so it gets a characteristic twist that is sup. Post. Med.
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  97. 97. THANK YOU