Temporomandibular joint/ fellowships in orthodontics

2,207 views

Published on



Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.

Published in: Education
0 Comments
7 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
2,207
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
47
Comments
0
Likes
7
Embeds 0
No embeds

No notes for slide

Temporomandibular joint/ fellowships in orthodontics

  1. 1. 1 TEMPOROMANDIBULAR JOINTTEMPOROMANDIBULAR JOINT INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. 2 Temporomandibular joint Types of joints Embryology Functional anatomy Muscles of mastication Biomechanics of TMJ Evolution www.indiandentalacademy.com
  3. 3. 3 Types of jointsTypes of joints Depending on the types of tissues involved 1. Fibrous joints 2. Cartilaginous joints 3. Synovial joints www.indiandentalacademy.com
  4. 4. www.indiandentalacademy.com 4
  5. 5. 5 Fibrous jointsFibrous joints 1. Sutures 2. Gomphosis 3. syndesmosis www.indiandentalacademy.com
  6. 6. 6 Cartilaginous jointsCartilaginous joints 1. Primary 2. secondary www.indiandentalacademy.com
  7. 7. 7 Synovial jointsSynovial joints Permits significant movement Synovial cavity Synovial membrane  Synovial fluid hyaline cartilage capsule www.indiandentalacademy.com
  8. 8. 8 Synovial jointsSynovial joints • Uniaxial/biaxial /multiaxial • Planar /ginglymoid /pivot/condyloid/saddle/ball and socket • Hiltons law • Muscles acting upon a joint have same nerve supply as joint www.indiandentalacademy.com
  9. 9. 9 TMJTMJ GINGLYMOID DIARTHROIDAL SYNOVIAL TRUE COMPOUND www.indiandentalacademy.com
  10. 10. 10 TMJ OTHER SYNOVIAL JOINTS 2 BLASTEMA -Temporal -Condylar Cavity formation within a single blastema Fibrous cartilage at the articular surfaces Hyaline cartilage at the articular surfaces. Cartilage acts as growth centre Does not www.indiandentalacademy.com
  11. 11. 11 Temporomandibular joint Types of joints Embryology Functional anatomy Muscles of mastication Biomechanics of TMJ  Evolution www.indiandentalacademy.com
  12. 12. 12 EmbryologyEmbryology  Primary Jaw joint Homologous reptiles.  -maeckels cartilage functions as the primary joint.mouth opening begins  Persists till 4 months IUL 6 weeks iu.-Membranous bone forms lateral to meckels cartilage at-body and ramus www.indiandentalacademy.com
  13. 13. 13  10th week-the joint forms both malleo- incudal and Definite jaw joint move together in synchrony for 8 weeks in fetal life. The accessory mandibular condylar cartilage develops as 1st blastema..  Grows towards the later developing temporal blastema. EmbryologyEmbryology www.indiandentalacademy.com
  14. 14. 14  -Lateral pterygoid develops medial to future condyle and causes movement at through the primary meckelian joint.  Fossa  Interposed connective tissue becomes thinner.  Two clefts develop in the fibrous connective tissue forming two joint cavities. EmbryologyEmbryology www.indiandentalacademy.com
  15. 15. 15 1st inferior compartment 2nd superior compartment. Invading synovial membrane compartment. Cavitation. Early immobilization Early functional activity EmbryologyEmbryology www.indiandentalacademy.com
  16. 16. 16 EmbryologyEmbryology Clefting and formation of joint cavity Formation of condylar + temporal blastema and ossification www.indiandentalacademy.com
  17. 17. 17 Articular disc-biconcave. Ventarally –lpm Dorsally –the superior laminae,inferior laminae EmbryologyEmbryology www.indiandentalacademy.com
  18. 18. 18 EmbryologyEmbryology Fossa – flat Articular tubercle  Absent condyle,no fossa/tubercle www.indiandentalacademy.com
  19. 19. 19 Temporomandibular joint Types of joints Embryology Functional anatomy Muscles of mastication Biomechanics of TMJ Evolution www.indiandentalacademy.com
  20. 20. 20 3 components that make up the masticatory system 1. Maxillae 2. Mandible 3. Temporal bone www.indiandentalacademy.com
  21. 21. 21 TMJTMJ GINGLYMOID DIARTHROIDAL SYNOVIAL TRUE COMPOUND www.indiandentalacademy.com
  22. 22. 22 FUCTIONAL ANATOMYFUCTIONAL ANATOMY SQUAMOUS PART OF TEMPORAL BONE ARTICULAR DISC CONDYLE www.indiandentalacademy.com
  23. 23. 23 FUCTIONAL ANATOMYFUCTIONAL ANATOMY condylecondyle  Poles of condyle  Convex articulating surface  Articulating surface –ant and post www.indiandentalacademy.com
  24. 24. 24 FUCTIONAL ANATOMYFUCTIONAL ANATOMY Temporal boneTemporal bone  Squamous part  Concave-Glenoid fossa  Squamotympanic fissure  Articular eminence  Roof - thin www.indiandentalacademy.com
  25. 25. 25 ARTICULAR DISCARTICULAR DISC ANTERIOR BORDER INTERMEDIATE ZONE POSTERIOR BORDER SAGITTAL VIEW ANTERIOR VIEW www.indiandentalacademy.com
  26. 26. 26 ARTICULAR DISCARTICULAR DISC Devoid of blood vessels and nerve Flexible and adaptable to functional demands www.indiandentalacademy.com
  27. 27. 27 Attachments of the articular disc-Attachments of the articular disc- Retrodiscal tissue-  Loose connective tissue  Rich blood and nerve supply  Bilaminar zone Superior retrodiscal lamina(elastic fibres) Inferior retrodiscal lamina(collagenous fibres) www.indiandentalacademy.com
  28. 28. 28 Retrodiscal tissue Temporal bone condyle Capsular ligament + superior LPM Medially + laterally attached to the capsule which divides joint cavity Attachments of the articular discAttachments of the articular disc -- www.indiandentalacademy.com
  29. 29. 29 ARTICULAR DISCARTICULAR DISC  Articulating surfaces are covered with fibrous tissue  Synovial lining /fluid Upper joint cavity Lower joint cavity www.indiandentalacademy.com
  30. 30. 30 Functions of synovial fluidFunctions of synovial fluid I. Nutrition II. Lubrication 1. Boundary lubrication (moving joint) 2. Weeping lubrication(compressive forces) • Minimizes friction www.indiandentalacademy.com
  31. 31. 31 Ligaments of TMJLigaments of TMJ  Limit joint movement 1. Collateral ligaments 2. Capsular ligaments 3. Temporomandibular ligaments 4. Sphenomandibular ligaments 5. Stylomandibular ligaments Functional ligaments Accessory ligaments www.indiandentalacademy.com
  32. 32. 32 Collateral (discal) ligamentCollateral (discal) ligament 1. Medial discal 2. Lateral discal  Divide joint medio laterally  Allows passive movement of the disc  Permits anterior + posterior rotation of disc on condyle  Blood vessels + nerves  Proprioception www.indiandentalacademy.com
  33. 33. 33 Capsular ligamentCapsular ligament Surrounds the TMJ Resists forces that separate the articulating surfaces proprioception www.indiandentalacademy.com
  34. 34. 34 Temporomandibular ligamentTemporomandibular ligament 1. Outer oblique portion 2. Inner horizontal portion  Reinforces capsular ligament  OOP- Prevents excessive dropping of condyle / limits extent of mouth opening IHP www.indiandentalacademy.com
  35. 35. 35 Temporomandibular ligament-Temporomandibular ligament- actionaction • Limits rotational opening • Seen only in humans – erect posture • Prevents damage to submandibular / retromandibular structures www.indiandentalacademy.com
  36. 36. 36 Temporomandibular ligamentTemporomandibular ligament  IHP-  Limits posterior movement of condyle and disc  Prevents damage to the retrodiscal tissue www.indiandentalacademy.com
  37. 37. 37 Sphenomandibular ligamentSphenomandibular ligament Extents from spine of sphenoid to lingula No significant limiting effects on mandibe www.indiandentalacademy.com
  38. 38. 38 Stylomandibular ligamentStylomandibular ligament Extends from the styloid process to the angle + post border of ramus Limits excessive protrusive movement www.indiandentalacademy.com
  39. 39. 39 Temporomandibular joint Types of joints Embryology Functional anatomy Muscles of mastication Biomechanics of TMJ Evolution www.indiandentalacademy.com
  40. 40. 40 Muscles of masticationMuscles of mastication Masseter Temporalis Medial pterygoid Lateral pterygoid Digastric Muscles of masticationMuscles of mastication www.indiandentalacademy.com
  41. 41. 41 The masseterThe masseter Origin insertion & direction Function –elevation www.indiandentalacademy.com
  42. 42. 42 The temporalisThe temporalis Origin & insertion Function – elevation retrusionwww.indiandentalacademy.com
  43. 43. 43 The medial pterygoidThe medial pterygoid  Origin & insertion Function - elevation Protrusion Muscle sling with Masseter U/l - mediotrusive www.indiandentalacademy.com
  44. 44. 44 The lateral pterygoid- inferiorThe lateral pterygoid- inferior portionportion Origin & insertion Function-protrusion U/l – mediotrusive With depressors – downward+forward www.indiandentalacademy.com
  45. 45. 45 The lateral pterygoid- superiorThe lateral pterygoid- superior portionportion Infratemporal surface of greater wing of sphenoid – capsule ,disc ,neck Active during power stroke Closure with elevators www.indiandentalacademy.com
  46. 46. 46 The lateral pterygoidsThe lateral pterygoids Exert medial pull on disc & condyle www.indiandentalacademy.com
  47. 47. 47 The digastricusThe digastricus Function– b/L contraction depression of mandible with fixed hyoid bone Raises hyoid –swallowingwhen mandible is fixed www.indiandentalacademy.com
  48. 48. 48 Other muscles coordinatingOther muscles coordinating Mandibular movementsMandibular movements Coordinated movements of- Supahyoid Infrahyoid Posterior neck muscles www.indiandentalacademy.com
  49. 49. 49 Summary ofSummary of mandibularmandibular movements &movements & musclesmuscles involvedinvolved www.indiandentalacademy.com
  50. 50. 50 Temporomandibular joint Types of joints Embryology Functional anatomy Muscles of mastication Biomechanics of TMJ Evolution www.indiandentalacademy.com
  51. 51. 51 Biomechanics of TMJBiomechanics of TMJ  Based on structure and function can be divided into 2 systems  First joint system -Inferior joint cavity • Second joint system -Superior joint cavity www.indiandentalacademy.com
  52. 52. 52 Biomechanics of TMJBiomechanics of TMJ  Articular disc as meniscus 1. Not a determinant of joint movement 2. Attached on one side and unattached on the other. 3. Freely extends into the joint space www.indiandentalacademy.com
  53. 53. 53 Biomechanics of TMJBiomechanics of TMJ TMJ - no attachment Yet stable due to muscles Resting stage – tonus Increase muscle activity - increase interarticular pressure Absence of pressure - dislocate www.indiandentalacademy.com
  54. 54. 54 Biomechanics of TMJBiomechanics of TMJ Disc space varies with pressure  Increased – disc space narrows  Decreased – space widens Condyle on anterior / posterior zone www.indiandentalacademy.com
  55. 55. 55 Biomechanics of TMJBiomechanics of TMJ Mandibular opening and closingMandibular opening and closing SRL –retract the disc Closed joint position – relaxed Stretched – during opening www.indiandentalacademy.com
  56. 56. 56 Biomechanics of TMJBiomechanics of TMJ Mandibular opening and closingMandibular opening and closing  SLP – protractor of the disc  ILP – protractor of condyle  So forward movement – articular cartilage – disc morphology. opening closing www.indiandentalacademy.com
  57. 57. 57 Biomechanics of TMJBiomechanics of TMJ closed mouth restingclosed mouth resting positionposition SLP - tonus  SLP > SRL  Resting position-interarticular pressure reduced,disc space wide. Disc rotated anteriorly  Condyle contacts intermediate & post zone  Open mouth –SRL stretches , SRL > SLP Disc rotated posteriorly www.indiandentalacademy.com
  58. 58. 58 Biomechanics of TMJBiomechanics of TMJ www.indiandentalacademy.com
  59. 59. 59 Biomechanics of TMJBiomechanics of TMJ Power stroke / chewingPower stroke / chewing  pressure reduced on biting side  Fulcrum around food  Pressure increased on contralateral side  Same side – separation – dislocation  SLP - active ,positions disc anteriorly on condyle  Stabilizes joint  Teeth approach intercuspation –pressure increases  Mechanical post rotation – intermediate zone- resting positionwww.indiandentalacademy.com
  60. 60. 60 Biomechanics of TMJBiomechanics of TMJ  Points to remember 1. Ligaments do not actively participate in function of TMJ 2. Ligaments do not stretch 3. Articular surfaces must maintain constant contact www.indiandentalacademy.com
  61. 61. 61 Temporomandibular joint Types of joints Embryology Functional anatomy Muscles of mastication Biomechanics of TMJ Evolution www.indiandentalacademy.com
  62. 62. 62 Adaptive morphology is dependent upon-  Locomotion  Feeding www.indiandentalacademy.com
  63. 63. 63 EVOLUTION OF T.M.JEVOLUTION OF T.M.J Primitive vertebrates Collection of food led to dev of jaws along with fins Amphibians and reptiles  Greater demand on jaw mechanics to adjust to new habitat www.indiandentalacademy.com
  64. 64. 64 Mammals  Greater benefit from food source  Modification in jaws, joint, dentition Humans  Upright posture  Bipedal locomotion  Shrinkage of human face www.indiandentalacademy.com
  65. 65. 65 1.Prehension 2.Control size of mass of food entering alimentary tract -sharp cusps -force in a direction effective -sharp cutting edges Earliest functional activity ofEarliest functional activity of TMJTMJ www.indiandentalacademy.com
  66. 66. 66 Jaw joint has been classified into-Jaw joint has been classified into- 1.Primitive jaw jointreptilian jaw jointquadrate-articular occlusion 2.Mamalian type of jaw jointdentary squamosal articulationearly TMJ www.indiandentalacademy.com
  67. 67. 67 Primitive jaw joint –reptilian joint Maxillae  Palatoquadrate bar Mandible  Hyomandibular(stapes)  Quardate(incus)  Articulare(malleus)  Dentary Dentary –squamosal joint/mammalian jaw joint www.indiandentalacademy.com
  68. 68. 68 Most primitive jaw Flexible plate of fibrocartilage connects the upper and lower cartilagenous jaws(shark) -1st arch no longer forms the gill and grows under the brain as palatoquadrate bar.It extends front to back under the base of the skull to join the lower jaw(maeckels cartilage )at the epiceratobranchial joint. The second arch modified to support the first arch in its function-hyomandibular cartilage. www.indiandentalacademy.com
  69. 69. 69 AMPHISTYLIC SUSPENSION Upper jaw connected to cranium-2 places Behind eye Hyomandibular cartilage attached to cranium Relationship of primitive jaw andRelationship of primitive jaw and cranial basecranial base www.indiandentalacademy.com
  70. 70. 70 Relationship of primitive jaw andRelationship of primitive jaw and cranial basecranial base HYOSTYLIC SUSPENSION . Hyomandibular element was the only articulation between the jaws and the cranial base www.indiandentalacademy.com
  71. 71. 71 Autostylic suspension Upper jaws are firmly fused to the cranial base.eg chimera Relationship of primitive jaw andRelationship of primitive jaw and cranial basecranial base www.indiandentalacademy.com
  72. 72. 72 STREPTOSTYLIC SUSPENSION Great degree of movement between jaws and cranial base Assists in swallowing  Reptiles and modern snakes The pterygopalatine component can remain clamped onto the animal while other parts shifted their grip Relationship of primitive jaw andRelationship of primitive jaw and cranial basecranial base www.indiandentalacademy.com
  73. 73. 73 Amphibians and higher vertibrates Maxillary palatine , pterygoid elements attached to the cranium,but hyomandibular (stapes) ,quadrate (incus) and articulare (malleus) continued to form movable joint. Mobility of upper and lower jawsMobility of upper and lower jaws www.indiandentalacademy.com
  74. 74. 74 Bones dentine and enamelBones dentine and enamel Bones dentine and enamel first appeared in fossil records as-dermal plates of primitive creatures. In primitive sharks the denticles extend into the jaws to give rise to teeth. The dermal bones sank into the skin . They gained attachment to muscles. www.indiandentalacademy.com
  75. 75. 75 ``  Pre maxillae-with ant teeth  Maxillae – with marginal teeth  Jugal bone-lower orbit  Quadrato-jugal  Quadrate  Squamosal bone The bones at the margin of upper jaw- www.indiandentalacademy.com
  76. 76. 76 Maeckels cartilage(core of the lower jaw)became invested in 8 separate dermal bony plates.  Dentary(with marginal row of teeth)  2 spenials  Angular  Surangular  Prearticular  2 coronoid bones Lower jawLower jaw www.indiandentalacademy.com
  77. 77. 77 Development of musclesDevelopment of muscles Advanced reptiles – capitii mandibularis and pterygoid muscles. Well divided muscles Increased functional activity Size of dentary bone,heterodont dentition www.indiandentalacademy.com
  78. 78. 78 Development of musclesDevelopment of muscles Alteration in orientation of jaw muscles Forces directed away from the joint www.indiandentalacademy.com
  79. 79. 79 Development of inter-articularDevelopment of inter-articular discdisc  Primitive joint did not have any cartilage. Lateral part of the muscle that extended from the pterygoid region to the maeckels cartilage gives rise to the cartilage. www.indiandentalacademy.com
  80. 80. 80 Functional activity of theFunctional activity of the mamalian TMJmamalian TMJ Prehension Tearing Crushing www.indiandentalacademy.com
  81. 81. 81 Prehension  Condyle clamped by glenoid processes  Reptiles have enlarged teeth at corners www.indiandentalacademy.com
  82. 82. 82 PrehentionPrehention 1. Speed -temporalis muscle 2. Constant reproduction of jaw closure -interlocking canines -hinge like tmj www.indiandentalacademy.com
  83. 83. 83 TearingTearing  Combination of – muscles controlling the dentition and movement of the jaws –neck muscles  Carnivore dentition  Grazing activity of the ungulate www.indiandentalacademy.com
  84. 84. 84 CrushingCrushing 1. Slicing (carnivores) 2. Gnawing (rodent incisors) 3. Grinding (herbivores) www.indiandentalacademy.com
  85. 85. 85 Slicing in carnivoreSlicing in carnivore  Well dev canines  Condyle encircled in fossa at level of occlusal surface of mandibular teeth  Coronoid – large  Disc present  Right and left halves are not united at the symphysis. www.indiandentalacademy.com
  86. 86. 86 Slicing in carnivoreSlicing in carnivore  Masseter +temporalis –well dev  Zygomatic arch-strong  No forward  Minimum lateral www.indiandentalacademy.com
  87. 87. 87 Rodent - gnawingRodent - gnawing Incisors chisel shaped Continuous erruption Differential wear Ant –post oriented glenoid fossa No side to side movement www.indiandentalacademy.com
  88. 88. 88  Well dev molars  Ascending ramus increased height  Condyle oval  No articular eminence  Slight post glenoid process  Capsule is present.  Anisognathous-do not occlude simultaneously. Herbivore - grinding www.indiandentalacademy.com
  89. 89. 89  Disc & capsule present  Masseter + temporalis well dev but not as much as the carnivores.  Lat pterygoid  Lateral movements prominent Herbivore - grinding www.indiandentalacademy.com
  90. 90. 90 ReferencesReferences JEFFEREY P OKESON GUNNAR E CARLSSON  RICHARD TEN CATE GRAYS ANATOMY www.indiandentalacademy.com
  91. 91. www.indiandentalacademy.com 91

×