Prenatal growth /certified fixed orthodontic courses by Indian dental academy


Published on

The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit ,or call

Published in: Education
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Prenatal growth /certified fixed orthodontic courses by Indian dental academy

  1. 1. PRENATAL FACIAL GROWTH INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. INTRODUCTION Orthodontists are heavily involved in the development of not just dentition but the entire dentofacial complex. . The terms growth and development though closely related are not synonymous. Growth is largely an anatomic phenomenon, whereas development is physiologic and behavioral Development = Growth + Differentiation + Translocation
  3. 3. THEORIES OF GROWTH The Genetic theory Brodie noting the persistent pattern of facial configuration assumed it was under tight genetic control. The assumption was made that the cartilages, facial sutures were under genetic control and that the brain determined the vault dimensions. Wendell Wylie termed this thinking “Orthodontic Calvinism”
  4. 4. Scott’s hypothesis Scott noting the prenatal importance of cartilaginous portions of the head, nasal capsule, mandible and cranial base and feeling that this development was under intrinsic genetic control, held that they continued to dominate facial growth postnatally.
  5. 5. Sicher’s hypothesis Sicher deduced from the many studies using vital dyes that the sutures were causing most of the growth. Infact he said “The primary event in sutural growth is the proliferation of connective tissue between the two bones”.
  6. 6. Moss’ hypothesis ( Functional matrix) Moss felt that bone and cartilage lack growth determination and grow in response to intrinsic growth of associated tissues. Moss divides the skull into a series of discrete functional components each comprised of a functional matrix and an associated skeletal unit. Moss identifies two large, enveloping capsular matrices the cerebral and the facial,” The effect is a passive translation of skeletal components in space.
  7. 7. PRENATAL CRANIO-FACIAL GROWTH  Events leading to organization of face in its normal form are critical and starts during first 4 weeks in utero.  Till 4th prenatal weeks, the embryo is isolated from external environment, utilizing its yolk sac for nourishment and growth.  The increase in cellular proliferation enhances the potential for teratogenic (adverse environmental) factors to alter development.
  8. 8. PRE NATAL PERIOD The prenatal life period is divided into Three periods for the purpose of understanding : Period of ovum ( 0- 14 days ) Embryo period ( 15- 56 days ) Fetal period ( 16 – till birth )
  9. 9. Preorganogenesis. Anomalies produced by teratogens acting during this period usually result in death of the embryo. The time table of the events described above is as follows: 2 days after fertilization embryo is at 2 cell stage. 3 days after fertilization embryo has become a morula. On 4th day, the blastocyst has formed. By 8th day, bilaminar disc has been established. A round the 14th day, procordal plate and primitive streak are seen
  10. 10. PERIOD OF OVUM Fertilization of sperm and ovum results in formation of zygote (1 cell ) .  Zygote undergoes a series of subdivisions called cleavage to form 2 cell stage then 4 cell stage so on till 16 cell stage .This 16 cell mass is called morula .It has inner cell mass and outer cell mass .  It thus forms a cyst called blastocyst.
  11. 11. GASTRULATION Formation of three layered disc is termed gastrulation . First germ layer is endoderm. Second germ layer is ectoderm . Third germ layer is mesoderm . Neural crest cells are termed fourth germ layer.
  12. 12.
  13. 13.
  14. 14.
  15. 15.
  16. 16.
  18. 18. TIME TABLE OF THE EVENTS on the 15th day , the primitive streak appears & definitive yolk sac is formed on 16th day embryonic disc is three layered due to formation of intra embryonic mesoderm . on 17th day notochordal process and heart tube can be seen. On the 21st day neural groove is seen and head fold begins to form .
  19. 19. On the 23rd day closure of the neural tube is seen. On around 22nd day first branchial arch appears . On 24th day bucco-pharyngeal membrane ruptures & foregut communicates with stomatodaeum By 29th day four arches can be seen.
  20. 20. FORMATION OF NEURAL TUBE  The ectoderm overlying the notochord undergoes changes that result in formation of neural tube.  The neural tube gives rise to the brain and spinal chord.  The neural tube is formed from ectoderm overlying notochord and therefore extends from prochordal plate to primitive knot.  In early embryo, the developing brain forms a large conspicuous mass on the dorsal aspect.
  21. 21. INTRA EMBRYONIC MESODERM The intraembryonic mesoderm becomes subdivided into 3 parts: The mesoderm on either side of the notochord , becomes thick and is called the paraxial mesoderm. More laterally, the mesoderm forms a thinner layer called lateral plate mesoderm Between these 2, there is a longitudinal strip of mesoderm called the intermediate mesoderm.
  22. 22.
  23. 23. PARAXIAL MESODERM The paraxial mesoderm now becomes segmented into cubical masses, called somatomeres, which give rise to somites. The first somites are seen on the either side of midline, a little behind prochordal plate. More somites are formed caudally on either side of the developing neural tube.
  24. 24. The lateral plate mesoderm splits into: Somatopleuric or parietal mesoderm, which is in contact with ectoderm. It gives rise to peritoneal, pleural, pericardial cavities. Splanchnopleuric or visceral mesoderm in contact with endoderm. The heart is formed in the floor of coelom called cardiogenic area.
  25. 25. FOLDING OF THE EMBRYO Progressive increase in the size of embryonic disc. Head and tail ends are still close together the increase in length causes it to bulge upward With further enlargement, embryonic disc becomes folded on itself Parts of the yolk sac become enclosed within embryo . In this way a tube lined by endoderm is formed called primitive gut .
  26. 26.
  27. 27. EFFECT OF FOLDING ON OTHER STRUCTURES After the folding following changes are seen Developing pericardial cavity comes to lie on ventral side of embryo , ventral to the foregut .. Septum transversum now lies caudal to the heart. The bucco-pharyngeal membrane closes the foregut cranially Enlarged cranial part of the neural tube later forms the brain.
  28. 28.
  29. 29.
  30. 30. BRANCHIAL ARCHES:Six arches are formed bounded by clefts and grooves. The mid and lower facial regions develop from first two arches named mandibular & hyoid arch. The third arch also contributes to base of tongue. Each branchial arch has skeletal , muscular, vascular, epithelial, neural element that develop in to systems supplying face & neck.
  31. 31. ARCH NERVE MUSCLUAR ELEMENTS First Mandibular Nerve Second Facial Nerve Tensor tymani, tensor palati, medial and lateral pterygoid, masseter, temporalis, mylohyoid. Ant.Diagstric stapedius, stylohyoid, post. digastric facial muscles, occipito-frontalis. Third Glossopharyngeal Stylo pharyngeus Fourth Superior laryngeal Muscles of pharynx Sixth Recurrent Soft palate and larynx laryngeal
  32. 32.
  33. 33. ARCH First Derivatives Cartilage MECKELS . Malleus, incus, ant. Ligament of malleus, sphenomandibular ligament Second REICHERTS . Stapes, styloid process, stylohyoid, ligament, superior part of body of hyoid,smaller corner of hyoid Third Greater corner of hyoid, lower part of body of hyoid. Fourth Cartilages of larynx Sixth Cartilages of larynx
  34. 34. ARTERIAL ARCH: : A series of arches connecting dorsal aorta and ventral aorta. One such arterial arch lies in each pharyngeal arch.
  35. 35. FETAL PERIOD
  37. 37. FETAL SKULL AT 2ND MONTH CONSISTS OF THREE PARTS : CHONDROCRANIUM : which is cartilaginous & made up of base of skull with otic & nasal capsules. DESMOCRANIUM :which is membranous , forms lateral walls & roof of braincase APPENDICULAR (visceral part) : which is cartilaginous , consists of skeletal rods of branchial arches .
  38. 38.
  39. 39. DEVELOPMENT OF CHONDROCRANIUM The brain is given support by cartilage forming along its base, the chondrocranial elements The chondrocranium also is important to the growing face and supports both areas through the developments of a bar of cartilage extending uninterrupted along the midline from the anterior nasal region to the foramen magnum.
  40. 40.
  41. 41. The cartilaginous septum functions in anterior facial growth as well as in support According to Scott, it doubles its length from 10-14th week, trebles by 17th weeks, and is six times as large by 36weeks. Anteriorly, this cartilage forms a capsule related to olfactory nerve endings – Nasal capsule.
  42. 42. Posteriorly, the cartilage supports the pituitary-Hypophyseal capsule. Laterally otic capsules develop around the middle and internal ear structures. Most posteriorly, it forms the occipital cartilages around foramen magnum– parachordal cartilage The cartilages establish cranial base by 8th week and are transformed into bones
  43. 43. Future ethmoid arises from nasal capsule. Mastoid and petrous part of temporal bone from otic capsule. Parachordal cartilage forms part of sphenoid, temporal and occipital bone. As each of these bones develops, cartilaginous centers remain between them, forming the cranial base synchondroses.
  44. 44. Nasal capsule is large and important cartilage to developing face and consists of medial septum components the mesethmoid and two lateral cartilaginous wings
  45. 45. BRAIN ENLARGEMENT, BASICRANIAL FLEXURE At 5 weeks the face appears crowded between the rapidly growing forebrain and heart, Even at this stage growth pattern of face is downward and forward as it grows out from between these two organs. Flexures that occur during 4th week in region of future neck result in brain flexed ventrally, then dorsally and as a result head becomes erect (Cranial flexure).
  46. 46. The human cerebrum similarly expands around a much smaller enlarging midventral segment (medulla, pons, hypothalamus). This causes a bending of whole under side of brain. The flexure of cranial base appears.
  47. 47. The expansion of frontal lobes displaces the frontal bone upward and outward. This results in bulbous, upright “forehead” of human face, although it is really part of neurocranium and not the face proper.
  48. 48. The frontal lobes also relate to a rotation of the human orbits into new position. As forehead is rotated into a vertical plane by the brain behind it, superior orbital rim is carried with it. The eye now point at a right angle to the spinal cord. The spine is vertical and orbit is horizontal. Vision is directed toward forward body movement Expansion of frontal and particularly, the temporal lobes of the cerebrum relates to a rotation of orbits towards midline. The eyes come closer together.
  52. 52. Mandible: Condyle ossifies by endochondral ossificaiton Body and ramus by intramembranous ossification Small part of symphysial cartilage may form mental tubercles by endochondral ossification
  53. 53. Sphenoid: Endochondral ossification forms:Body, lesser wings, basal parts of greater wings lateral plate of pterygoid process. Intramembranous ossification forms:Parts of greater wings, medial plate of pterygoid process
  54. 54. Temporal Endochondral ossification:- petrous part of bone Intramembraneous ossifications: Squamous and tympanic parts of temporal.
  55. 55. Occipital Endochondral ossification: lower part of squamous portion . Intramembranous ossification: Upper part of squamous portion.
  56. 56. MAXILLARY COMPLEX Until bone formation occurs , the nasal capsule is the only skeletal support of upper face The nasal ,premaxillary,maxillary, lacrimal, zygomatic , palatine,& temporal ossification centers appear as bones seperated by sutures only.
  59. 59. PALATAL SHELVES Two palatal processes . The primitive palate formed from frontonasal process. The definitive palate forms from fusion of these three processes During 9-10th week palatine shelves come in contact & fusion begins . Initial contact occurs just post. to primary palatine process & closure continues both anteriorly and posteriorly .
  60. 60.
  61. 61. MANDIBLE Rod shaped cartilage known as Meckels cartilage supports lower face It extends from midline to otic capsule where it forms malleus & incus. Center of ossification appears at around 6th week Carrot shaped cartilage appears at 10th week at site of future condyle
  62. 62.
  63. 63.
  64. 64. Coronoid process starts ossifying at around 14th week Coronoid process develops from accesory cartilage appearing at around 10-14th week It grows as a response to developing temporalis Alveolar bone starts developing as a response to developing tooth buds.
  65. 65. TEMPOROMANDIBULAR JOINT Malleus & incus function to provide a movable joint untill temporomandiblar joint articulation occurs. From 8-18th this joint is functional . TMJ develops at around 10th week and takes over by 19th week
  67. 67. FACE, NOSE ,LIPS Face at 5th week is only about one & half mm wide. Two small , ovoid raised areas appear just above the lateral aspects of future nostrils . These represent future nostrils . The tissue b/w nasal pits is medial nasal process & lateral to pits are called lateral nasal processes
  68. 68.
  69. 69.
  70. 70.
  71. 71.
  72. 72.
  73. 73.
  74. 74.
  75. 75.
  76. 76.
  77. 77.
  78. 78. The raised anterior edges of these pits form the shape of minute horseshoes with open sides below. Contact b/w medial border of maxillary process & lateral border of medial nasal process forms a lamina nasal fin. „NF‟ represent a potential site for formation of cleft lip. Upper lip is formed by fusion of these processes Lower lip is formed by mandibular processes fusion
  79. 79. In 6th weeks ,upper face appears flat & broad with nasal pits representing 90% of width of face. Auricle of ear arises from hillocks of tissues that cirumscribe the branchial cleft. At 6 ½ week the facial proportions change , due to increase in dimensions laterally to nasal pits. Eyes are now rotated to 90 degree from side to front of face.
  80. 80. In early 7th week face appears recognizably human as a result of frontal location of eyes, differentiation of nose and enlargement of mandible. At 7th week, furrows separating the mandibular, maxillary and nasal areas are les marked. External ears are also visible at this stage. Ears are well differentiated by 16th week.
  81. 81. TONGUE The tongue musculature originates from the occipital myotomes at beginning of 4th week. Develops into oral part (body) and pharyngeal part (base). The body arises in part, from contributions of first arch and base arises from 2nd, 3rd, 4th arches.
  82. 82.
  83. 83. Body of tongue is indicated by paired lateral lingual swellings and a centrally located tuberculum impar. At 5th week base of tongue is indicated by a median elevation, copula. During 6th and 7th week lateral lingual swellings enlarge and size of tuberculum impar‟s size reduces.
  84. 84. SALIVARY GLAND The Parotid and submandibular salivary glands appear in the connective tissues of developing cheek in 6th week. Sublingual glands develops at around 8th week
  85. 85. FACIAL MUSCLES The facial muscles mass, termed subcutaneous colli, appears in the 4th week in the ventral lateral position of the hyoid arch just beneath the surface of the skin. In the 5th week, it spreads out,muscle mass fans out and stylohyoid, diagastric and stapedial muscle masses appear.
  86. 86.
  87. 87. Advancing sheet then separates into superficial and a deep layer in 7th week The superficial form the spread of platysma muscle over the mandible to cheek, forehead, , temporal region. During 7-9th Sphincter colli further forms orbicularis, caninus and incisivuslabii. The quadratus labii inferiors and mentalis muscles of lower face appear in 8-9th week
  88. 88. The orbicularis oculi and buccinator muscles appear from deep fibers of sphincter colli whereas triangularis and platysma from superficial faci Overlying it buccinator & buccal pad of fat develop . By 14th week all facial muscles are in their definitive position
  89. 89. MUSCLES OF MASTICATION The muscles of mastication are developing in the mesenchyme of mandibular arch in seventh week and nerve fibers are apparent by 8th week. these muscle develop in close relation to Meckel‟s cartilage and cranial base cartilages Temporalis muscle begins lateral development in 8th week, occupying the space anterior to otic capsule.
  90. 90. Masseter muscle attaches along the zygomatic arch as it undergoes lateral growth, providing space for muscle development. The pterygoid muscles differentiate in 7th week Typically the fetal histologic structure of muscles of mastication appears by 22nd week.
  91. 91. Respiratory reflexes, jaw closure reflexes, suckling and infantile swallow are all developed in a patterned way between 14th –32nd week of intrauterine life. In human fetus by 8th week, generalized uniform reflex movement of entire body can be elicited by tactile stimulation. 14th week movements become much more individualized Gag reflex has been demonstrated in human fetus at about 18½ week
  92. 92. By 25 weeks, respiration is shallow but may support life for a few hours if established. By 29 weeks stimulation of mouth elicited suckling although complete suckling and swallowing are developed at around 32 week.
  93. 93. ORIGIN OF FACIAL MALFORMATIONS Malformation: morphologic defect of an organ or a larger area of body, resulting from intrinsically abnormal development e.g. clefts of lip or palate alone or as a part of syndrome.
  94. 94. Deformation: abnormal form or position of a part of body caused by non-disruptive mechanical forces e.g. club foot, congenital hip dislocation, congenital postural scoliosis.
  95. 95. Disruptions: morphologic defects of an organ or a larger region of body , resulting from a break down of ,or interferences with originally normal development . e.g. an amputation of a digit in utero because of amniotic band .
  96. 96. The importance of drug induced impairment in neural crest migration has been implicated in thalidomide induced congenital defects and antiacne drug isotretinoin induced defects.
  97. 97. Fetal alcohol syndrome (FAS): characteristics facies is due to deficiency of midline tissues of the neural plate very early in embryonic development caused by very high chronic intoxication in alcoholic mothers, maxillary and midface deficiency is seen.
  98. 98.
  99. 99. Mandibulofacial dysostosis (Treacher Collins), Pierre Robbin syndromes are defects of branchial arches. Altered neural crest development has been implicated. In treacher Collins syndrome – lack of development of malar bones, short curved mandible, lack of middle ear development which results in loss of hearing. .
  100. 100.
  101. 101. Hemifacialmicrosomia is primarily unilateral and characterized by a lack of tissues on affected side. Typically external ear is deformed and both the ramus of mandible and associated soft tissues are deficient or missing..
  102. 102.
  103. 103. Phenytoin when used during pregnancy also gives rise to characteristic defects called as fetalhydantoin syndrome characterized by hypo plastic phalanges, cleft palate, hare lip, microcephaly.
  104. 104. Clefting of lip occurs because of failure of fusion between median and lateral nasal processes and the maxillary prominence which is seen during 6th week of development in humans. Isolated clefts of palate occur when lip closure is complete and problem arises after that.
  105. 105.
  106. 106.
  107. 107. Synostosis syndromes occurs because of early closure of sutures between cranial and facial bones. From early in fetal life, normal cranial and facial development is dependent on growth adjustments at the sutures in response to growth of brain and soft tissues. Early closure of sutures leads to distortions depending on location of early fusion.
  108. 108. Crouzon‟s syndrome is the most frequently occurring member of this group. Characterized by underdevelopment of midface and eyes that seem to bulge from sockets. Their is prenatal fusion of superior and posterior sutures of maxilla, along the wall of orbit. The early fusion prevents downward and forward translation of maxilla as a result of under development of middle third of face.
  109. 109.
  110. 110. Thank you For more details please visit