Development of maxilla & mandible

detailed description of craniofacial development of maxilla & mandible

1. GOOD MORNING DR. SWATI SAHU MDS FELLOW DEPT. OF ORAL & MAXILLOFACIAL SURGERY 4/14/2018 1

2. CRANIOFACIAL DEVELOPMENT OF MAXILLA & MANDIBLE & ITS SIGNIFICANCE 4/14/2018 2

3. MAXILLA 4/14/2018 3

4. Introduction Growth Development Prenatal growth & development of maxilla Prenatal growth & development of palate Postnatal growth & development of maxilla CONTENTS 4/14/2018 4

5. Development of Tongue Formation of Anterior 2/3 rd of the Tongue Formation of Posterior 1/3 rd of the Tongue Developmental defect of Tongue Developmental defect of maxilla 4/14/2018 5

6. Growth and development of an individual can be divided into pre-natal and the post-natal periods. Pre-natal period of development is a dynamic phase in the development of a human being. INTRODUCTION 4/14/2018 6

7. Stewart – It may be defined as a developmental increase in mass. In other words it is a process that leads to an increase in the physical size of cells, tissues, organs or organisms as a whole. Proffit – an increase in size or number. Pinkham – an increase, expansion or extension of a given tissue. GROWTH 4/14/2018 7

8. DEVELOPMENT Moyers – all the 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. Todd – development means progress towards maturity. Proffit – development is in complexity . 4/14/2018 8

9. Indicator of general health. Identify unusual growth patterns at an early stage. Etiology and development of malocclusion. Identify abnormal occlusion – early stage. Poorly timed eruptions - malocclusion Growth - effects stability of occlusion. Use of growth spurts. IMPORTANCE OF GROWTH 4/14/2018 9

10. Growth and development of an individual can be divided into PRENATAL & the POSTNATAL periods . The pre-natal period of development is a dynamic phase in the development of a human being. During this period, the height increases by almost 5000 times as compared to only a threefold increase during the post-natal period. The pre-natal life can be arbitrarily divided into three periods. 1. Period of the Ovum 2. Period of the Embryo 3. Period of the Fetus 4/14/2018 10

11. This period extends for a period of approximately two weeks from the time of fertilization . During this period the cleavage of the ovum and the attachment of the ovum to the intra-uterine wall occurs. PERIOD OF OVUM - 4/14/2018 11

12. PERIOD OF EMBRYO - This period extends from the fourteenth day to the fifty sixth day of intra-uterine life. During this period the major part of the development of the facial & the cranial region occurs. 4/14/2018 12

13. PERIOD OF FETUS - This phase extends between the fifty sixth day of intra-uterine life till birth. In this period ,accelerated growth of the cranio -facial structures occurs resulting in an increase in their size. In addition, a change in proportion between the various structures also occurs 4/14/2018 13

14. PRENATAL DEVELOPMENT OF MAXILLA 4/14/2018 14

15. Around fourth week of intra uterine life a prominent bulge appears on ventral aspect of the embryo corresponding to the developing brain . Below the bulge the shallow depression , which corresponds to the primitive mouth appears called stomatodaeum . Floor of stomatodaeum is formed by buccopharyngeal membrane , which separates it from foregut . 4/14/2018 15

16. Pharyngeal arch During 4 th week, lateral plate mesoderm of ventral foregut, segments to form 5 bilateral mesenchyme swellings– pharyngeal arches 4/14/2018 16

17. Each PHARYNGEAL ARCH consists of 4/14/2018 17 A central cartilage rod that form the skeleton of the arch. A muscular component termed as bronchomere A vascular component. A neural element.

18. 4/14/2018 18

19. M esoderm covering the developing forebrain proliferates, and forms a downward projection that overlaps the upper part of the stomatodeum this downward projection is called the frontonasal process The first branchial arch is called the mandibular arch and plays an important role in the development of the naso maxillary region . The stomodeum is overlapped superiorly by frontonasal process & laterally by mandibular arches of both sides . 4/14/2018 19

20. 4/14/2018 20 The ectoderm overlying the Fronto -nasal Process shows bilateral localized thickenings above the stomatodeum . These are called the Nasal Placodes . These Placodes soon sink and form the Nasal Pits .

21. Formation of nasal pits divides frontonasal process into 2 parts : - The medial nasal process - The lateral nasal process The mandibular arch gives off a bud from its dorsal end called the maxillary process which grows ventro - medio -cranial to the mandibular process. 4/14/2018 21

22. 4/14/2018 22 At this stage the stomodeum is overlapped from above by the frontal process, below by the mandibular process & on either side by the maxillary process. The two mandibular processes grow medially & fuse to form the lower lip & the lower jaw.

23. Maxillary process undergoes growth, frontonasal process becomes narrower so that 2 nasal pits come closer. Line of fusion of maxillary process & the medial nasal process corresponds to the nasolacrimal duct . 4/14/2018 23

24. 4/14/2018 24 Each maxillary process now grows medially and fuses , first with the lateral nasal process and then with the medial nasal process . Medial and lateral process also fuse with each other in this way the nasal pit(external nares) are cut off from the stomatodeum . As the Maxillary Process undergoes growth the Fronto -nasal process becomes narrow so that the two Nasal Pits come closer. Mesodermal basis of the median part of the lip(called philtrum )is formed from the frontonasal process.

25. DEVELOPMENT OF NASAL CAVITY Nasal cavity are formed by extension of nasal pits . S oon the medial and lateral processes fuse , and form a partition between the pit and the stomatodeum this is called primitive palate and is derived from the frontonasal process. The nasal pits now deepen to form the nasal sac . 4/14/2018 25

26. 4/14/2018 26 The dorsal part of this sac is , at first , separated from the stomatodeum by thin membrane called the bucconasal membrane or nasal fin this soon breaks down. N asal sac now has a ventral orifice that opens on the face (anterior or external nares) and dorsal orifice that open into stomatodeum ( primitive posterior nasal aperture) .

27. Frontonasal process becomes progressively narrower . This narrowing of the frontonasal process and the enlargement of the nasal cavities themselves being closer together the intervening tissue becomes much thinned to form the nasal septum ventrally attached to below the primitive palate and dorsally bucconasal membrane . 4/14/2018 27

28. PRENATAL DEVELOPMENT OF PALATE 4/14/2018 28

29. The palate is formed by contributions of the- Maxillary process Palatal shelves given off by the maxillary process Fronto nasal process The frontonasal process gives rise to the premaxillary region while the palatal shelves grows medially , their union is prevented by the presence of the tongue, thus initially the developing palatal shelves grow vertically downward the floor of the mouth 4/14/2018 29

30. PRIMARY PALATE By the fusion of the maxillary and nasal processes in the roof of the  stomodeum , the primitive palate  (or  primary palate ) is formed, and the  olfactory pits  extend backward above it . It consists of the  maxillary process  and  medial nasal process . The lip and primary palate close during the 4th to 7th weeks of gestation 4/14/2018 30

31. Primitive palate of a human embryo of thirty-seven to thirty-eight days . 4/14/2018 31

32. SECONDARY PALATE The development of the  secondary palate  commences in the sixth week of  human embryological development . It is characterised by the formation of two palatal shelves on the  maxillary prominences 4/14/2018 32

33. As the palatal shelves grow medially their, their union is prevented by the presence of tongue Initially the developing palatal shelves grow vertically toward the floor of mouth 4/14/2018 33

34. During 7 th week of intrauterine life, a transformation in the position of the palatine shelf occurs They change from a vertical to a horizontal position 4/14/2018 34

35. Various reasons are given to explain how this transformation occurs. They are: Alteration in biochemical and physical consistency of the connective tissue of the palatal shelves Alteration in vasculature and blood supply to the palatal shelves Apperance of an interensic shelf force Rapid differential mitotic activity Muscular movements 4/14/2018 35

36. The 2 palatal shelves, by 8 ½ weeks of intra uterine life are in close approximation to each other Initially the 2 palatal shelves are covered by an epithelial lining. As they join the epithelial cells degenerate The connective tissue of the palatal shelves intermingle with each other resulting in their fusion 4/14/2018 36

37. The entire palate doesnot contact and fuse at the same time. Initially the contact occurs in the central region of the secondary palate posterior to the premaxilla From this point, closure occurs both anteriorly and posteriorly 4/14/2018 37

38. 8 th week IUL Stomodeum enlarge Tongue drops Vertically inclined palatal shelves -horizontal Shelves contact each other in midline By 12 th week, fusion of palatal processes is complete 4/14/2018 38

39. 4/14/2018 39

40. 4/14/2018 40

41. Elevation of palate Histological section 4/14/2018 41

42. Theories of palatal shelf elevation EXTRINSIC FORCES Descent of tongue Myoneural activity with in tongue Shelves pushed up by tongue Mouth opening reflexes 4/14/2018 42

43. INTRINSIC FORCES Hydration and polymerisation of intercellular substance Differential growth on one side of palatal shelf Turgor produced by build up of HYALURONIC ACID SEROTONIN release from neural tissue. Mesenchymal cell biosynthetic activity Changing amounts of GLYCOSAMINOGLYCANS(GAG) 4/14/2018 43

44. Palatal fusion 4/14/2018 44

45. FUSION OF PALATAL SHELVES 9-10 Week. Epethlium Thickens And Contacts. Role Of Glycoproteins And Desmosomes Degeneration Of Epithelium. Conective Tissue Penetration And Intermingling. Entire Palate Does Not Fuse At Same Time, Intial Contact ,Central Region Of Secondary Palate, Then Closure Continues Both Anterior And Posteriorly. 4/14/2018 45

46. OSSIFICATION OF PALATE Ossification of the palate occurs from the 8 th week of intra- uterine life. This is an intramembranous type of ossification The palate ossifies from a single centre derived from the maxilla The most posterior part of the palate does not ossify. This forms the soft palate The mid palatal suture ossifies by 12-14 yrs 4/14/2018 46

47. APPLIED ANATOMY Cleft lip  ( cheiloschisis ) and  cleft palate  ( palatoschisis ) , which can also occur together as  cleft lip and palate , are variations of a type of clefting   congenital deformity  caused by abnormal facial development during  gestation . 4/14/2018 47

48. CLEFT PALATE Cleft palate  is a condition in which the two plates of the  skull  that form the  hard palate  (roof of the mouth) are not completely joined Palate cleft can occur as complete or incomplete (a 'hole' in the roof of the mouth, usually as a cleft soft palate). When cleft palate occurs, the  uvula  is usually split. It occurs due to the failure of fusion of the lateral palatine processes, the nasal septum, and/or the median palatine processes (formation of the  secondary palate Incomplete cleft palate Unilateral complete lip and palate Bilateral complete lip and palate 4/14/2018 48

49. COMPLICATIONS Cleft may cause problems with feeding, ear disease, speech and socialization. An infant with a cleft palate will have greater success feeding in a more upright position. Gravity will help prevent milk from coming through the baby's nose if he/she has cleft palate. 4/14/2018 49

50. TREATMENT STAGE ONE Often a cleft palate is temporarily closed, the cleft isn't closed, but it is covered by a  palatal obturator . Cleft palate can also be corrected by  surgery , usually performed between 6 and 12 months.  If the cleft extends into the maxillary alveolar ridge, the gap is usually corrected by filling the gap with bone tissue. The bone tissue can be acquired from the patients own chin, rib or hip. 4/14/2018 50

51. STAGE TWO Carried out from 18 th month to 5 th year of life, generally corresponds to primary dentition phase STAGE THREE Spans from 6 th to 11 th year of life, generally corresponds to mixed dentition phase STAGE FOUR Include the treatment done during the permanent dentition stage, 12-18 yrs of age 4/14/2018 51

52. POSTNATAL DEVELOPMENT OF MAXILLA 4/14/2018 52

53. Postnatal growth of maxilla is a multifactorial process According to Moss- Translation (displacement) Transposition (surface remodeling) 4/14/2018 53

54. Translation / dislocation Dislocation comprises of movement of the whole bone as it simultaneously expands Displacement can be Primary Secondary SCHOOLS OF THOUGHT Sutural theory Nasal septal theory Functional matrix 4/14/2018 54

55. Sutural theory Sicher believed that craniofacial growth occurs at sutures. Maxilla is attached to the cranium by frontomaxillary , zygomaticomaxillary , zygomaticotemporal and pterygopalatine suture, which are more-or-less oblique and parallel to each other Thus growth in these areas will push the maxilla downward and forward But??? Suture is a tension adapted tissue Suture doesn’t grow when transplanted Growth takes place in untreated cases of cleft palate Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 55

56. Nasal septum theory James Scott He viewed cartilaginous sites throughout the skull as primary centres of growth cartilage is a pressure-adapted tissue Pressure (of the growing brain) accommodating growth of the nasal septum provides a source of physical force that displaces the whole maxilla anteriorly and inferiorly. This sets up field of tension for the sutures, at which bone deposition may now take place. But??? Experiments are not decisive Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 56

57. Functional matrix theory Melvin moss Researches suggest that if there is no primordium for the eye, the orbit does not develop Acc to him, the functional soft tissue matrix is the epigenic governing determinant of skeletal growth process and all skeletal growth is secondary, compensatory and mechanically obligatory to it. In achondroplastic dwarfs, the midface shows marked concavity and retardation owing to deficient cartilage growth Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 57

58. Transposition / remodelling If you see in the picture, The area previously occupied by the ramus has now been converted into mandibular body of the adult This is REMODELLING It is a sequence of differential deposition and resorption that results in reshaping and resizing of bone into its adult form The surface that faces the direction of movement is depository and that away from it is always resorptive Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 58

59. Lacrimal suture Lacrimal bone is a flake of bony island with its entire perimeter surrounded by sutures, separating it from many bones The lacrimal bone acts a key traffic control , providing for slippage of multiple bones along its perimeter In itself, the lacrimal bone undergoes remodelling rotation Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 59

60. Maxillary tuberosity and key ridge Maxillary arch grows in 3 directions Posteriorly deposition on posterior surface of maxillary tuberosity Laterally- deposition on buccal surface of tuberosity Downward- deposition along alveolar ridge Endosteal surface is resorptive for growth of maxillary sinus Reversal occurs at key ridge, where most of the external surface becomes resorptive Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 60

61. Zygomatic arch Resorption at anterior surface and deposition at the lateral and posterior surfaces As a result the zygomatic arches move posteriorly and bilaterally outwards Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 61

62. Orbital growth To compensate for resorption in the endocranial side To compensate for the downward growth of nasomaxillary complex To make the supraorbital rim more prominent V PRINCIPLE= Anterior – lateral- superior relocation of orbit Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 62

63. POSTNATAL DEVELOPMENT OF PALATE 4/14/2018 63

64. Enlow’s ; Essentials of Facial Growth, 4 th Edition 4/14/2018 64

65. In early pre natal life the palate is relatively long but from the 4th month it widens as a result of mid palatal suture growth and appositional growth along the lateral alveolar margins. Growth of the mid palatal suture occurs between 1 and 2 years of age.it is large in its posterior than in its anterior part, so that the posterior part of the nasal cavity widens more than the anterior part. Lateral appositional growth continues until 7 years of age by this time the palate achieves its maximum anterior width. Posterior appositional growth continues after the lateral growth has ceased, so that the palate becomes longer and wider during late childhood. 4/14/2018 65

66. The appositional growth of the alveolar processes contributes to deepening as well as widening of the vault of the bony palate at the same time adding to the height and breadth of maxilla Ossification does not occur in the posterior part of the palate, giving rise to the region of soft palate. Myogenic mesenchymal tissues of the I, II and IV branchial arch migrates into this facial region supplying the musculature of facial and palate. 4/14/2018 66

67. DEVELOPMENTAL ANOMALIES AFFECTING MAXILLA Cleft palate. Agnathia Micrognathia . Macrognathia . Treacher collins syndrome (first arch syndrome) Cleidocranial dyplasia Craniofacial dysostosis 4/14/2018 67

68. 4/14/2018 68 A GNATHIA Synonyms – otocephaly , holoprosencephaly agnathia Lethal anomaly characterised by hypoplasia or absence of mandible with abnormally positioned ears having an autosomal recessive mode of Inheritance. Due to failure of migration of neural crest mesenchyme into the maxillary Prominence at fourth to fifth week of gestation.

69. 4/14/2018 69 MICROGNATHIA Small jaw Either maxilla / mandible may be affected. Two types – true / Pseudo Congenital /acquired Occasionally follows hereditary pattern Occurs due to deficiency in premaxillary area and patient with this deformity appear to have the middle third of the face retracted.

70. 4/14/2018 70 MACROGNATHIA Condition of abnormally large jaws May be associated with certain other conditions Pagets disease of bone Acromegaly Leontiasis ossea , a form of fibrous dysplasia

71. 4/14/2018 71 TREACHER COLLINS – FRANCESCHETTI SYNDROME Synonym - Mandibulofacial dysostosis Autosomal dominant The gene of treacher Collin was mapped to chromosome 5q32-q33.1 Clinical manifestations – Antimangoloid palpebral fissure with a coloboma of outer portion of lower eyelids Hypoplasia of facial bones especially malar and mandible Malformation of external ear Macrostomia , high palate Blind fistulas between the angles of ear and angle of mouth Atypical hair growth Facial clefts Bird like or fish like face

72. 4/14/2018 72 CLEIDOCRANIAL DYSPLASIA Synonyms – Marie and sainton’s disease, scheuthauer - marie - sainton syndrome, mutational dysostosis A congenital disorder of bone formation manifestated with c lavicular hypoplasia with a norrow thorax, which allows a pproximation of shoulders in front of the chest. Delayed ossification of skull, excessively large fontanels a nd delayed closing of sutures are prominent features Arnold head – characteristic skull abnormalities Etiology – mutation in core binding factor alpha – 1 (CBFA-1) gene, located on chromosome 6p21

73. 4/14/2018 73 CRANIOFACIAL DYSOSTOSIS (CROUZONS SYNDROME) Caused by premature obliteration and ossification of two or more sutures, More often coronal and sagittal sutures Etiology – mutation of fibroblast growth factor receptor (FGFR-2) gene The mutation in transmembrane region of FGFR3 Clinical features – Obliteration of coronal and sagittal sutures Flattening of acromium , growing only at vertical axis Forehead is wide and high Wide face Hypoplastic maxilla ( pseudoprognathism ) Deviation of nasal septum Narrowed or obliterated anterior nares Wide beaked nose Hypertelorism Divergent squint Antimongoloid eyelids Upper eyelid mimicking “frog face” Malocclusion, malposed teeth and dysphasia

74. 4/14/2018 74 THANK YOU

75. DEVELOPMENT OF TONGUE 4/14/2018 75

76. What is Tongue? Largest single muscular organ inside the oral cavity, which lies relatively free. Tongue develops in relation to the pharyngeal arches . It develops from two parts , they are formation of anterior 2/3 rd of the tongue formation of posterior 1/3 rd of the tongue 4/14/2018 76

77. Formation of anterior 2/3 rd of the tongue: Tuberculum Impar : first a swelling arises in the midline of the mandibular process. And is flanked by two other swellings Lingual Swelling: The lateral part of the mandibular process mesenchymal thickening develops to form two lingual swellings . Develops from mesenchyme of 1 st pharyangeal arch . (text book of Inderbir Singh ,8 th edition,G P Pal,HUMAN EMBRYOLOGY) 4/14/2018 77

78. These lateral s welling quickly enlarge and merge with each other and the tuberculum impar to form a large mass from which mucous membrane of the anterior 2/3 rd of the tongue is formed. (text book of Inderbir Singh ,8 th edition,G P Pal,HUMAN EMBRYOLOGY) 4/14/2018 78

79. Formation of posterior 1/3 rd of the tongue: Root of the tongue arises from large midline swelling develops from mesenchyme of 2 nd ,3 rd and 4 th arches. Consist of , Copula (associated with 2 nd arch) A large hypobranchial eminence (associated by 3 rd and 4 th arch) (text book of Inderbir Singh,8 th edition, G P Pal, HUMAN EMBRYOLOGY) 4/14/2018 79

80. Hypobranchial eminence overgrows the copula The tongue separates from the floor of the mouth by a down-growth of ectoderm around its periphery, which degenerates to form lingual sulcus and gives the tongue mobility. (text book of Maji Jose,1 st edition, ORAL BIOLOGY) 4/14/2018 80

81. Muscle of the tongue have a different origin, they arises from the occipital somites , which have migrated forward in to the tongue area, carrying with them their nerve supply hypoglossal nerve (text book of Ten Cate’s,7 th edition,ORAL HISTOLOGY) 4/14/2018 81

82. 4/14/2018 82 NERVE SUPPLY OF TONGUE

83. Papillae: Small hair-like structure on the upper surface of the tongue that give the tongue its characteristics rough texture. Types: Fungiform Papillae Filliform Papillae Foliate Papillae Circumvallate Papillae 4/14/2018 83

84. Fungiform Papillae: Anterior portion of the tongue (look like fungi) Scattered between the numerous filifom papillae at the tip of the tongue Smooth, round structure appears red(because of highly vascular connective tissue core, visible through a thin, non keratinized covering epithellium ) 4/14/2018 84

85. Filiform Papillae: covers entire anterior part of the tongue Cone shaped structures each with a core of connective tissue covered by a thick keratinized epithelium Together form a tough abrasive surface that is involving in compressing and breaking food when tongue is opposed to the hard palate 4/14/2018 85

86. Foliate papillae: Sometimes present on the lateral margins of the posterior part of the tongue Pink,consist of 4 to 11 parallel ridges that alternate with deep grooves in the mucosa and few taste buds are present in the epithelium of the lateral walls of the ridges 4/14/2018 86

87. Cirumvallate Papillae: Adjacent and anterior to the sulcus terminalis are 8 to 12 papillae Large structure, each surrounded by a deep, circular groove in to which open the duct of minor salivary gland Have connective tissue core that covered on the superior surface by a keratinized epithelium The epithelium covering lateral walls is non-keratinized and contains taste buds 4/14/2018 87

88. Taste Bud – A specialized receptor that occurs only in the oral cavity and pharynx is called taste bud. Most of them found in fungiform papilla, foliate and circumvallate papilla. Barrel shaped structure composed of 30 to 80 spindle shaped cells Communicate with surface through a small opening called taste pore 4/14/2018 88

89. 4/14/2018 89

90. DEVELOPMENTAL DEFECTS OF TONGUE 4/14/2018 90 Aglossia 2 . Microglossia 3 . Macroglossia 4 . Ankyloglossia 5 . Cleft tongue 6 . Fissured tongue 7 . Median rhomboid glossitis 8 . Benign migratory glossitis 9 . Hairy tongue 10 . Lingual varices 11 . Lingual thyroid nodule

91. 4/14/2018 91 AGLOSSIA - Complete absence of tongue at birth-very rare MICROGLOSSIA - A rare congenital anomaly -presence of small or rudimentary tongue Aglossia-microglossia with extreme glossoptosis Etiology-fetal cell traumatism in the first few weeks of gestation

92. 4/14/2018 92 MACROGLOSSIA - An enlarged tongue TYPES:- 1 . Congenital/ primary 2. Secondary Congenital macroglossia :- Due to overdevelopment of musculature which may or may not be associated with generalized muscular hypertrophy Secondary macroglossia : - May occur as a result of tumor of tongue such as, diffuse lymphangioma or haemangioma. CLINICAL FEATURES – Displacement of teeth / malocclusion. Crenation and scalloping of the lateral border of tongue Tips of the crenation fitting into the interproximal spaces between the teeth. ASSOCIATED SYNDROMES:- Beckwith’s Wiedemann syndrome & Down syndrome Beckwith’s Weidemann syndrome includes -Neonatal hypoglycemia , Mild micro cephaly , Umbilical hernia , Fetal visceromegaly TREATMENT - No particular treatment Removal of cause Surgical trimming 

93. 4/14/2018 93 ANKYLOGLOSSIA - CLASSIFIED AS - Partial Complete Partial ankyloglossia / Tongue tie: - results of a short lingual frenum / one which is attached near to the tip of the tongue. Complete ankyloglossia :- Fusion between the tongue and the floor of the mouth CLINICAL FEATURES - difficulty during speech TREATMENT - frenectomy

94. 4/14/2018 94 CLEFT TONGUE / BIFID TONGUE - Complete & Partial Complete cleft / bifid tongue - A rare condition Is due to lack of merging of the lateral lingual swelling of this organ Partially cleft tongue - Common condition Is due to incomplete merging and failure of groove obliteration by underlying mesenchymal proliferation. Manifest as deep groove in the midline of dorsal surface . Associated syndrome – Oro facial digital syndrome- Thick fibrous band in the lower anterior mucobuccal fold eliminating the sulcus & with clefting of the hyperplastic mandibular alveolar process. Clinical considerations - Microorganisms &food debris may collect in the base of the cleft & cause irritation.  

95. 4/14/2018 95 FISSURED TONGUE / SCROTAL TONGUE - Manifests as small furrows or grooves 2-6mm in depth on the dorsal surface often radiating from central groove on the midline of the tongue Associated with chronic trauma or vitamin deficiency/hereditary Painless except in cases when food debris tends to collect in the grooves & produce irritation . Associated with Melkersson -Rosenthal syndrome ( traid of recurring facial paralysis, cheilits granulomatosis and fissured tongue )

96. 4/14/2018 96 MEDIAN RHOMBOID GLOSSITIS - Congenital anomaly which is due to failure of the tuberculum impar to retract or withdraw before fusion of the lateral halves of the tongue Etiological agent - candida albicans CLINICAL FEATURES - it appears as an ovoid ,diamond, rhomboid shaped reddish patch or plaque on the dorsal surface of the tongue, immediately anterior to circumvallate papillae 

97. 4/14/2018 97 BENIGN MIGRATORY GLOSSITIS - Geographic tongue, wandering rash of tongue , glossitis areata exfoliative Areas of desquamation of the filiform papillae in an irregular circinate pattern Central portion – inflamed white with borders may be outlined by a thin, yellowish white line or band. F ungiform papillae persist &appear as elevated dots. The area of desquamation remain for a short time in one location & then heal & appear in another location i.e ; migration TREATMENT - Empirical since its etiology is not known. Reassurance to the patient.

98. 4/14/2018 98 HAIRY TONGUE - Hypertrophy of the filiform papillae of the tongue with lack of normal desquamation which may be extensive and form a thick matted layer on the dorsal surface. Color of the papillae varies, yellowish white to brown or even black. Etiology - Candida albicans TREATMENT - Brush the tongue to promote desquamation and remove the debris.

99. 4/14/2018 99 LINGUAL VARICES - Lingual or sublingual varicosities Varix - is a dilated , tortuous vein, most commonly a vein. Mostly involved -sublingual varix Common in older adults Red or purple elevated blebs of vessels on the ventral surface and lateral borders of the tongue as well as floor of the mouth. No treatment needed 

100. 4/14/2018 100 LINGUAL THYROID NODULE - In this anomalus condition, the follicle of thyroid tissue are found in the substance of the tongue, possibly arising from thyroid that failed to migrate to its original position/ from enlarge remnants that became detached and were left behind. ETIOLOGY - functional insufficiency of the chief thyroid gland in the neck. CLINICAL FEATURES - nodular mass in or near the base of the tongue. Dysphagia , dysphonia, dyspnoea, hemorrhage with pain or feeling of tightness or fullness in the throat. TREATMENT -Careful physical examination to demonstrate the thyroid gland location. 

101. 4/14/2018 101 MANDIBLE

102. 4/14/2018 102 Introduction Anatomy of mandible Prenatal development of mandible Postnatal development of mandible Development of mandible in relation to various theory of growth Age changes Developmental anomalies CONTENTS

103. 103 MANDIBLE Largest and strongest bone of the face 1 st pharyngeal arch Articulation with skull shape and Function 14 April 2018 INTRODUCTION

104. 4/14/2018 104 ANATOMY OF MANDIBLE It has horseshoe shaped body which lodges the teeth, and pair of rami which project upwards from the posterior ends of the body and provide attachment to muscle.

105. 4/14/2018 105

106. 4/14/2018 106

107. 4/14/2018 107 PRENATAL DEVELOPMENT OF MANDIBLE Start abouth 4th week of intra- uterine life . Developing brain and the pericardium form two prominent bulges on the ventral aspect of the embryo . These bulges are separated by primitive oral cavity or stomodaeum . The floor of the stomodaeum is formed by the bucco -pharyngeal membrane, which separates it from the foregut.

108. 4/14/2018 108 Mesoderm of foregut comes to arranged in the form of six bars that run dorsoventrally in the side wall of the foregut . These are called pharyngeal arches.

109. 4/14/2018 109 First Branchial arch called MANDIBULAR ARCH . Mandibular arch gives off a bud from its dorsal end called maxillary process . It grows ventro -medially cranial to main part of the arch which is called mandibular process.

110. 4/14/2018 110 Mandibular process of each side grow towards each other. fuse in midline - give rise to mandible. First structure develop in lower jaw : - Mandibular division of Trigeminal nerve. Neurotrophic factor produced by nerve induce osteogenesis .

111. 4/14/2018 111 MECKEL'S CARTILAGE It is the cartilage of the first arch In human beings the Meckel's cartilage has a close positional relationship to the developing mandible but makes no contribution to it . At 6 weeks of development this cartilage extends as a solid hyaline cartilaginous rod, surrounded by a fibrocellular capsule, from the developing ear region to the midline of the fused mandibular processes.

112. 4/14/2018 112 The Mandibular branch of trigeminal nerve has close relationship to Meckel’s cartilage

113. 4/14/2018 113 On lateral aspect of Meckel’s cartilage, during the 6th week of embryonic development, a condensation of mesenchyme occurs in the angle formed by the division of the inferior alveolar nerve and its incisor and mental branches.

114. 4/14/2018 114 Centre of ossification Intramembraneous Ossification starts at the division of mental and incisive branch of inferior alveolar nerve lateral to meckel’s cartilage around 7 th week IUL.

115. 4/14/2018 115 From center of ossification bone formation spreads: Anteriorly - midline Posteriorly - where mandibular nerve divided into lingual and inferior alveolar branch. Bone formation spreads rapidly and surrounds the inferior alveolar nerve to form mandibular canal. Intra-membranous ossification spreads in anterior and posterior direction forms the Body & Ramus of the mandible. Gray’s Anatomy – Fortieth edition

116. 4/14/2018 116 Anteriorly bone extends towards midline and comes in approximation with similar bone forming on opposite side. These two bones remain separated by fibrous tissue mental symphysis untill shortly after birth. Continued bone formation increases size of mandible with development of alveolar process to surround the developing tooth germ.

117. 4/14/2018 117 Ossification spread posteriorly to form ramus of mandible, turning away from meckel’s cartilage. This point of divergence is marked by lingula in adult mandible. Thus by 10 weeks the rudimentary mandible is formed almost entirely by membranous ossification with little direct involvement of Meckel’s cartilage

118. 4/14/2018 118 NOW….. What is the fate of the Meckel’s cartilage? Incus and malleus Spine of sphenoid bone Anterior ligament of malleus Spheno -mandibular ligament

119. 4/14/2018 119 SECONDARY CARTILAGES IN MANDIBULAR DEVELOPMENT Further growth until birth influenced by appearance of secondary cartilage Condylar cartilage Coronoid cartilage Symphyseal cartilage

120. 4/14/2018 120 CONDYLAR CARTILAGE Appear during 12 th week of IUL Rapidly form cone shape mass which is converted quickly to bone by endochondral ossification . At the end of 20 th week only a thin layer remains on the condylar head ,persist until the end of the second decade of life ,providing a further growth . (Ten Cate’s Oral Histology – Sixth Edition)

121. 4/14/2018 121 Cartilage fuses with mandibular ramus around 4 th month . (Contemporary orthodontics Williams R. proffit fifth edition)

122. 4/14/2018 122 CORONOID CARTILAGE Appears at about 4 month of development . Coronoid cartilage is transient growth cartilage and disappears long before birth . Cartilage grow as a response of developing temporalis muscle . Coronoid cartilage become incorporated into expanding intra-membranous bone of ramus. (Ten Cate’s Oral Histology – Sixth Edition)

123. 4/14/2018 123 Two in number Appear in between the two end of Meckel’s cartilage . They are obliterated within the first year after birth. SYMPHYSEAL CARTILAGE (Ten Cate’s Oral Histology – Sixth Edition)

124. 4/14/2018 124 POSTNATAL DEVELOPMENT OF MANDIBLE Right & left mandibular body fuses at midline symphysis one year after birth. Mandible appears as single bone. (Contemporary orthodontics Williams R. proffit fifth edition)

125. 4/14/2018 125 According to MOSS while mandible appears in the adult as a single bone, it is divisible into several skeleton subunits Condylar process Coronoid process Angular process Ramus Body of mandible Alveolar process chin. (Facial Growth – Donald H. Enlow third edition)

126. 4/14/2018 126 MANDIBULAR CONDYLE It is a major site of growth Historically, the condyle has been regarded as a kind of cornucopia from which the whole mandible itself pours forth . The condyle functions as regional field of growth that provides an adaptation for its own localized growth circumstances

127. 4/14/2018 127 The condylar growth mechanism itself is a clear-cut process. Cartilage is a special non-vascular tissue and is involved because of variable levels of compression An endochondral growth mechanism is required for this part of the mandible. Endochondral growth occurs only at the articular contact part of the condyle In Figure the endochondral bone tissue (b) formed in association with the condylar cartilage (a) The enclosing bony cortices (c) are produced by periosteal- endosteal osteogenic activity

128. 4/14/2018 128 The lingual and buccal sides of neck characteristically have a resorptive surface. This is because condyle is quite broad and neck is narrow The neck is progressively relocated into areas previously held by the much wider condyle What used to be condyle in turn becomes the neck as one is remodeled from the other . This is done by periosteal resorption combined with endosteal deposition.

129. 4/14/2018 129 Explained another way, the endosteal surface of the neck actually faces the growth direction; the periosteal side points away from the course of growth. This is another example of the V principle, with the V-shaped cone of the condylar neck growing toward its wide end.

130. 4/14/2018 130 ROLE OF CONDYLE It is directly involved as a unique, regional growth site . It provides an indispensable latitude for adaptive growth. It provides movable articulation . It is pressure tolerant and provides a means for bone growth ( endochondral ) in a situation in which ordinary periosteal (intramembranous) growth would not be possible . It can also, all too frequently, become involved in TMJ pathology and distress.

131. 4/14/2018 131 CLINICAL IMPLICATION Condylar cartilage dose have some measure of intrinsic, genetic programming , This , however, appears to be restricted to capacity for continued cellular proliferation . Cartilage cells are coded and geared to divide and continue to divide by extra condylar biomechanical forces . So overall mandibular length be clinically increase or decrease for class II and class III individuals if this were done during the period of active condylar growth. (Facial Growth – Donald H. Enlow third edition)

132. NERVE SUPPLY OF MANDIBLE 4/14/2018 132

133. 4/14/2018 133 AGE CHANGES IN THE MANDIBLE AT BIRTH At the birth the mental foramen, opens below the sockets for the two deciduous molar teeth near the lower border. The mandibular canal runs near the lower border. The angle is obtuse. It is 175.

134. 4/14/2018 134 AT CHILDHOOD The two halves of the mandible fuse during the first year of the life. The body becomes elongated in its whole length, but more especially behind the mental foramen, to provide space for the three additional teeth developed in this part. Mandibular foramen slightly above the occlusal plane The angle becomes less obtuse around 140.

135. 4/14/2018 135 IN ADULT The mental foramen opens midway between the upper and lower borders. The mandibular canal runs parallel with the mylohyoid line. Mandibular foramen 7 mm above the occlusal plane The angle reduces about 110 or 120 degrees.

136. 4/14/2018 136 IN OLD AGE Alveolar border is absorbed, so that height of the body is markedly reduced. The mental foramen and mandibular canal are close to the alveolar border. The angle again becomes obtuse about 140 degrees .

137. 4/14/2018 137 DEVELOPMENTAL DEFECTS OF THE MANDIBLE Agnathia Micrognathia Macrognathia Coronoid hyperplasia Condylar hyperplasia Condylar hypoplasia Bifid condyle Torus mandibularis

138. 4/14/2018 138 CORONOID HYPERPLASIA Rare developmental anomaly Result in limited mandibular movement Unknown etiology. M:F ratio 5:1 May be unilateral or bilateral Bilateral is more common (Oral and maxillofacial Pathology- Neville third edition)

139. 4/14/2018 139 CONDYLAR HYPERPLASIA Excessive growth of one of the condyles Cause is unknown, but local circulating problems, endocrine disturbances, and trauma have been suggested as possible etiologic factors. (Oral and maxillofacial Pathology- Neville third edition)

140. 4/14/2018 140 CONDYLAR HYPOPLASIA Congenital or acquired congenital : mandibulofacial dysostosis goldenhar syndrome hemifecial microsomia Acquired: disturbances of the growth center of the condyle. (Oral and maxillofacial Pathology- Neville third edition)

141. 4/14/2018 141 BIFID CONDYLE Rare Most of have medial and lateral head divided by an antero posterior grooves. Some condyles may be divided into an anterior and posterior head Cause is uncertain Antero-posterior may be traumatic origin.

142. 4/14/2018 142 TORUS MANDIBULARIS Develops along the lingual aspect of the mandible. Probably multifactorial, including both genetics and environmental influences. (Oral and maxillofacial Pathology- Neville third edition)

143. 4/14/2018 143 TMJ ANKYLOSIS Ankylosis of the Temporomandibular joint, an arthrogenic disorder of the TMJ, refers to restricted mandibular movements ( hypomobility ) with deviation to the affected side on opening of the mouth.

144. 4/14/2018 144

145. CLINICAL FEATURES - 4/14/2018 145 • Obvious facial deformity • Deviation of chin towards affected side • Inability to open the jaws, absent condylar movements on affected side • In unilateral ankylosis , the lower jaws shifts towards the affected side on opening of the mouth • Flatness or fullness on affected side • Cross bite on ipsilateral side • Class II malocclusion on affected side TREATMENT Surgical Non-surgical

146. 4/14/2018 146 Ten Cate’s Oral Histology – Sixth Edition Human embryology- Inderbir Sing Eight edition Contemporary orthodontics Williams R. proffit fifth edition Facial Growth – Donald H. Enlow third edition Gray’s Anatomy – Fortieth edition Human anatomy-BD Chaurasia Forth Edition Shafer’sTextbook of Oral pathology sixth edition Oral and maxillofacial Pathology- Neville third edition REFERENCES

147. 4/14/2018 147 THANK YOU