Temperomandibular joint /certified fixed orthodontic courses by Indian dental academy

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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 www.indiandentalacademy.com ,or call
0091-9248678078

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Temperomandibular joint /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. PRESENTED BYDR.PANKAJ JUNEJA P.G. IN ORTHODONTICS COLLEGE OF DENTAL SCIENCES www.indiandentalacademy.com
  3. 3. INTRODUCTION CLASSIFICATION OF JOINTS EVOLUTION OF TMJ EMBRYOLOGY OF TMJ TMJ ANATOMY soft tissue components  skeletal components  vascular & nerve supply HISTOLOGY MUSCLES OF MASTICATION EXAMINATION OF TMJ DIAGNOSTIC IMAGING BIOMECHANICS OF TMJ EFFECTS OF AGING www.indiandentalacademy.com CONCLUSION
  4. 4. INTRODUCTION TEMPEROMANDIBULAR JOINT IS A COMPOUND, BICONDYLAR, GINGLIMO-ARTHROIDAL, ELIPSOIDAL, SYNOVIAL JOINT. The TMJ influences the function, esthetics, & structural harmony of the teeth, dentition, face and thus a person in total. Therefore an understanding of the anatomy , physiology, biomechanics etc., of the masticatory system is very much necessary. www.indiandentalacademy.com
  5. 5. Classification of Joints •FIBROUS •CARTILAGENOUS •PRIMARY •SECONDARY •SYNOVIAL www.indiandentalacademy.com
  6. 6. Hence the tmj is --------• Bilateral • Diarthrodial------bcz joint has two articulting bone ,the mandibular condyle inferiorly ans the articular eminance superiorly • Ginglymoid-----bcz the joint has a hinge like movememnt component • Synovial • Freely movable joint SYNOVIAL SLIDING-GINGLYMOID JOINT www.indiandentalacademy.com
  7. 7. www.indiandentalacademy.com
  8. 8. • It is said that change is only thing which is permanent in life….that mean every thing is changing in this world according to its function requirement.TMJ is not exception of this evolutionary history. This joint has changed a lot from our primitive ancestor to present level. In this process it has gradually develop from rudimentary form to very well developed structure. www.indiandentalacademy.com
  9. 9. • When the first vertebrates make its appearance in the process of evolution, the TMJ also made its appearance. And the appearance of TMJ in the primitive vertebrates was an important evolutionary step which was related to development of various other structures like middle and internal ears and other related structures . • It is said that the evolutionary history of TMJ is very old….and some researchers has traced back the evolutionary history and concluded that it make its appearance some 450 millions years ago. www.indiandentalacademy.com
  10. 10. Amphibians & Primitive reptiles Ventured on land Increased food intake Variety in diet Increasing efficiency of the feeding mechanism - critical factor in vertebrate evolution Adaptive modifications in1. Tooth morphology 2. Jaw architecture 3. Muscular anatomy www.indiandentalacademy.com 4. TMJ articulations
  11. 11. AGNATHA Slits Gill arches Slits  Slits – respiration , food filtration  Gill arches (cartilage) - Co-ordinated movement of slits with mouth  Internal bend – turning point ‘synarthrosis’ Earliest form of jaw joint www.indiandentalacademy.com EPICERATOBRANCHIAL JOINT in SHARK
  12. 12. GNATHOSTOMES Jaw apparatus  Highly evolved than agnatha  1st and 2nd gill arches – disappeared into the skull.  3rd and 4th gill arches – prey capture first ‘jaw apparatus’ – ‘CEPHALIZATION’ www.indiandentalacademy.com
  13. 13. OSTEICHTHYES Cartilaginous jaw Bony dermal plates  Gill arches – cartilaginous jaws  2nd jaw – bony dermal plates Teeth  Bone, dentine and enamel – first appeared in fossil www.indiandentalacademy.com records as constituents of dermal plates.
  14. 14. AMPHIBIANS Quadrate bone Dentary bone Articular bone  Definitive upper & lower (compound) jaws – • Quadrate bone • Dentary – teeth-bearing • Articular – from posterior part of Meckel’s cartilage www.indiandentalacademy.com
  15. 15. REPTILES Dentary enlarged to accommodate stronger masticatory movements  Extended backwards to brace and support primitive joint forming bones www.indiandentalacademy.com
  16. 16. MAMMAL -LIKE REPTILES Coronoid process Temporal fossa  Dentary bone - increased in size & function - CORONOID PROCESS - TEMPORAL FOSSA www.indiandentalacademy.com  Quadrato-articulate joint – sound-transmitter
  17. 17. MAMMALS Dentarysquamosal joint Quadratearticular joint  ‘DENTARY- SQUAMOSAL JOINT’  Reduction in size and weakening of post-dentary part of jaw  Dismissal of Quadrate-articular joint. www.indiandentalacademy.com
  18. 18. ROLE OF MUSCLE ACTIVITY IN TMJ DEVELOPMENT www.indiandentalacademy.com
  19. 19. Increased functional demand 1. Increase in muscle mass 2. Increase in size of dentary Reattachment of muscles to toothbearing bone Alterations in direction of pull Relieved the primary joint Decline of primary joint with evolution of new secondary joint www.indiandentalacademy.com
  20. 20. • QUADRATE-ARTICULAR JOINT • “Primitive jaw joint “ • “Reptilian jaw joint” • Primary vertebrate joint Present INCULOMALLEOLAR JOINT • DENTARY- SQUAMOSAL JOINT • “Mammalian jaw joint” • Secondary joint Early stages of TEMPOROMANDIBULAR articulation www.indiandentalacademy.com
  21. 21. Bone homologues of jaw joint: Reptiles Mammals Squamosal Squamous part of temporal bone Dentary Mandible Angular Tympanic plate Articular Malleus Surangular Ant. Process of malleus Quadrate Incus Columella (hyomandibular) Stapes None Mandibular condyle www.indiandentalacademy.com
  22. 22. EVOLUTION OF CONDYLAR CARTILAGE • Absent in Quadrate-articular joint • Dentary-squamosal joint – intervening periosteum developed into “Secondary Condylar Cartilage.” www.indiandentalacademy.com
  23. 23. Dentary-squamosal joint New site of articulation with basicranium Ectopic presence of pressure,Anoxia, ischemia Metaplastic change in undifferentiated stem cells of periosteum CHONDROBLASTS instead of osteoblasts www.indiandentalacademy.com Cartilage formation
  24. 24. EVOLUTION OF INTER-ARTICULAR DISK • Primitive jaw joint – no cartilage intervention between articular surfaces of quadrate and articular bones • Secondary jaw joint – as dentary enlarged and approached squamosal bone,lateral part of a muscle (from pterygoid region to posterior end of Meckel’s cartilage) was incorporated in the developing articulation. www.indiandentalacademy.com
  25. 25. www.indiandentalacademy.com
  26. 26. • Meckel’s cartilage – skeletal support for lower jaw • Terminates dorsally into MALLEUS – “ARTICULARE” • Articulates with INCAL cartilage (=Quadrate; in nonmammals) • Movement of early jaw – between these 2 cartilages – primary joint www.indiandentalacademy.com
  27. 27. • 3 months IUL – secondary joint • 2 distinct mesenchymal condensations – 1. Temporal blastema 2. Condylar blastema • Temporal blastema appears first • Condylar blastema grows rapidly to decrease intervening gap www.indiandentalacademy.com
  28. 28. • Cleft appears above mesenchymal condylar blastema – INFERIOR JOINT CAVITY • Differentiates into CONDYLAR CARTILAGE • 2nd cleft i.r.t. temporal ossification - SUPERIOR JOINT CAVITY PRIMITIVE ARTICULAR DISK www.indiandentalacademy.com
  29. 29. NEONATE TMJ  JOINT – stabilized by capsule  Most mobile  Flat glenoid fossa  Articular eminence – absent  Develops on eruption of permanent dentition www.indiandentalacademy.com
  30. 30. • Phylogenetically , the developing middle ear in primates & especially the humans was the initial jaw joint of the vertebrates • In the middle ear region that the malleus & probably the incus develop as posterior extensions of Meckels cartilage. • The intermediate portion of Meckels cartilage disappears, but its sheath remains to persist in the form of anterior malleolar ligament & the sphenomandibular lig. www.indiandentalacademy.com
  31. 31. • 24mm stage of embryo, the pterygoid & masseter muscles have differentiated. • At the superior border of the external pterygoid muscle & just below to the masseter muscle, a layer / bulk of mesenchyme tissue is seen which is the analogue of articular disc. • 28mm stage the middle ear ossicles are fully formed in true cartilage & malleus is continuous with the Meckels cartilage. -Articular disc & external pterygoid tendons are attached to the malleus. www.indiandentalacademy.com
  32. 32. • 11th week – condylar cartilage becomes evident, located at the upper end of the posterior border of developing mandible. • 30mm stage embryo – articular surface faces directly lateral, it is parallel to the articular disc as well as to the articular surface of the zygomatic process of the temporal bone. • 50mm stage – condylar cartilage shapes the articulating surface of the condyle in a hemisphere. www.indiandentalacademy.com
  33. 33. - Articular disc has flattened & the plane of the articular surfaces has undertaken a shift of 45 0 - 55mm stage – condylar head produces an osseous head which matures into condylar cartilage by 65mm stage. - 85mm stage – ossification of the cartilage begins, growth center of the mandible. - joint cavity formation is evident as the loose connective tissue on either side of the future articular disc becomes less dense. www.indiandentalacademy.com
  34. 34. • Inferior portion of the joint cavity takes the shape of a distinct cleft. • 13th week – the lower joint cavity is well formed around the superior surface of the condyle, so as the upper part. • 15th week – vascular mesenchyme of the condylar cartilage can be seen breaking down. - both joint cavities are formed. www.indiandentalacademy.com
  35. 35. • At 155mm stage – differentiation continues anteriorly to arrive at a point of full articulation. • 190mm stage – all the elements of the joint are fully formed. • Full differentiation of all articular elements occurs by 4th fetal month. www.indiandentalacademy.com
  36. 36. Temporomandibular joint proper www.indiandentalacademy.com
  37. 37. TMJ BONY COMPONENTS 1. Glenoid fossa 2. Condylar head 3. Articular eminence www.indiandentalacademy.com SOFT-TISSUE COMPONENTS 1. Articular disk 2. Joint capsule 3. Ligament
  38. 38. BONY COMPONENTS www.indiandentalacademy.com
  39. 39. GLENOID FOSSA Single layer of cortical bone separates fossa from middle cranial fossa – Temporal lobe of brain   Covered by thin fibrous layer www.indiandentalacademy.com
  40. 40. CONDYLAR HEAD • Oval – mediolaterally • 15-20 mm long (M-L); 8-10 mm wide (A-P); 8-120 mm thick • Medial pole more prominent than lateral pole. • Posterior surface is greator than anterior surface • Articulating surface is convex a-p & only slightly convex mediolaterally. www.indiandentalacademy.com Anterior view Posterior view
  41. 41. 1450 • line drawn through the centers of the poles of the condyles, usually extends medially & posteriorly towards the anterior border of the foramen magnum. www.indiandentalacademy.com
  42. 42. ARTICULAR EMINENCE Sigmoid shape, Anterior & posterior slopes  Saddle – shaped in coronal section – concave mediolaterally – path of condyle  With disc, guides mandibular movement during jaw opening  www.indiandentalacademy.com
  43. 43. SOFT-TISSUE COMPONENTS www.indiandentalacademy.com
  44. 44. • Articular disc - Composed of dense fibrous connective tissue - Extreme periphery of the disc , is innervated Sagittal plane – AB- anterior border PB- posterior border IZ- intermediate zone www.indiandentalacademy.com
  45. 45. Anterior view – the disc is slight thicker medially than laterally. LP- lateral pole MP- medial pole www.indiandentalacademy.com
  46. 46. • The articular disc is attached to the capsular lig. ,not only anteriorly & posteriorly, but also medially & laterally; this attachment divides the joint into ; a) the upper cavity [superior cavity] b) the lower cavity [inferior cavity] • Upper is bordered by, the mandibular fossa & the superior surface of the disc. • Lower is by, the mandibular condyle & the inferior surface of the disc. www.indiandentalacademy.com
  47. 47. • Specialized endothelial cells forms a synovial lining surrounding the internal surface of the cavities. • This lining along with a specialized synovial fringe located at the anterior border of the retrodiscal tissues, produce synovial fluid. Synovial Fluid – i) metabolic requirements to the non-vascular articular surfaces of the joint. ii) lubrication during function, reducing friction. www.indiandentalacademy.com
  48. 48. • Lubrication – i) Boundary lubrication ii) Weeping lubrication • Boundary lubrication – -when the joint moves, the synovial fluid is forced from one area of the cavity to another. -prevents friction & is the primary mechanism of joint lubrication • Weeping lubrication – -the ability of the articular surfaces to absorb a small amount of fluid. -forces during function drive a small amount of fluid in & out of the articular tissues, helps in metabolic www.indiandentalacademy.com exchange.
  49. 49. • Compressive forces - release fluid & prevents sticking of articular tissues. • Weeping eliminates friction in compressed but not moving joint. • But prolonged compressive forces will exhausts this supply leading to deleterious effects. www.indiandentalacademy.com
  50. 50. LIGAMENTS • Non-elastic collagenous structures which restrict and limit the movements a joint can make • Restrict the distance by which articulating bones can be separated from each other without causing tissue damage • According to this definition– joint capsule is also a ligament • True ligaments: 1. COLLATERAL / DISCAL LIGAMENTS 2. CAPSULAR LIGAMENT 3. TEMPOROMANDIBULAR / LATERAL LIGAMENT • Accessory ligaments: 1. SPHENOMANDIBULAR LIGAMENT www.indiandentalacademy.com 2. STYLOMANDIBULAR LIGAMENT
  51. 51. • Collateral (discal ligaments) : - Attaches the medial & lateral borders of the articular disc to the poles of the condyles. - Divides the joint mediolaterally into the superior & inferior cavities. - True ligs , do not stretch & restricts movement of the disc away from condyle. - Responsible for hinging movement of the TMJ. - Have both vascular as well as innervation , providing movement information regarding joint position . - Strain on these ligs produces pain. www.indiandentalacademy.com
  52. 52. Capsular ligament- - surrounds & encompasses the entire TMJ. - attached superiorly to the temporal bone along the borders of the articular surfaces of the mandibular fossa & articular eminence. - attached inferiorly – neck of the condyle - resist any medial, lateral / inferior forces that tend to separate / dislocate the articular surfaces. - helps to retain synovial fluid & provides proprioceptive www.indiandentalacademy.com feedback.
  53. 53. Temporomandibular (Lateral) ligament • IHPInner horizontal portion • OOPOuter oblique portion Oblique portion – resists excessive dropping of the condyle - aids in normal opening of the mouth. - wider mouth opening- the condyle moves downwards & forward across the articular eminence. - unique limited rotational opening is found only in www.indiandentalacademy.com humans.
  54. 54. - in erect postural position & with a vertically placed vertical column, continued rotational opening movement would cause the mandible to impinge on the vital sub-mandibular & retro-mandibular structures of the neck. Inner horizontal portion ; - limits the posterior movement of the condyle & disc. - protects the retrodiscal tissues from trauma. - also protects the lateral pterygoid muscle from over-lengthening / extension - in case of trauma to the mandible – neck of the condyle will fracture before the retrodiscal tissues are severed / before the condyle enters the middle www.indiandentalacademy.com cranial fossa.
  55. 55. • Accessory ligs ; i) the sphenomandibular lig ii) the stylomandibular lig www.indiandentalacademy.com
  56. 56. • Innervation of TMJ – - The trigeminal nerve , that provides both motor & sensory innervation to the muscles that control it. - Afferent innervation – branches of the mandibular nerve. - Also by auriculo-temporal nerve as it leaves the mandibular nerve behind the joint & ascends laterally & superior to wrap around the posterior region of the joint. www.indiandentalacademy.com - Additional nerves – temporal & masseteric .
  57. 57. • In addition to the above mentioned nerves the tmj capsule also contains three types of mechanoreceptors. mechanoreceptor Nature of the receptor Ruffini proprioception Golgi tendon Static mechanoreceptor Pacinian receptor Dynamic mechanoreceptor www.indiandentalacademy.com
  58. 58. The neural innervation was greatest at the periphery of the disc,with the greator concentration being posteriorly & progressively decreased towards the centre. (J Oral maxillofac Surg 1992,50:334-337) www.indiandentalacademy.com
  59. 59. • Vascularization – - predominantly ; i) from posterior- superficial temporal artery ii) from anterior- middle meningeal artery iii) from inferior- internal maxillary artery iv) others ; - the deep auricular - anterior tympanic - ascending pharyngeal arteries - condyle, receives supply through its marrow spaces by “feeder vessels” from inferior alveolar artery. www.indiandentalacademy.com
  60. 60. Lymphatic drainage AREA OF TMJ DRAINING LYMPH NODE Anterior surface parotid lymph nodes Posterior surface submandibular nodes Lateral surface preauricular lymph node Medial surface submandibular nodes www.indiandentalacademy.com
  61. 61. HISTOLOGY OF TMJ www.indiandentalacademy.com
  62. 62. • HISTOLOGY OF TMJ - Histologically the appearance varies with age, due to presence of secondary cartilage. - This cartilage appears about 10th month IU & remains as a zone of proliferating cartilage until about the later half of the second decade of life. - The condyle of the young child is not lined by a distinct layer of compact bone as is that of the adult. - The organisation of collagen fibrils in articular cartilage shows a 3D network with a special system in each zone. www.indiandentalacademy.com (J Oral Maxillo Surg1984,42:306-313)
  63. 63. CONDYLE 4 Zones – 1. Articular 2. Proliferative 3. Fibrocartilaginous 4. Calcified cartilage www.indiandentalacademy.com
  64. 64. Articular zoneMost superficial found adjacent to the joint cavity and forms the outermost functional surface. Made up of dense connective tissue rather than hyaline cartilage. Has a much better ability to repair. Proliferative zoneMainly cellular consisting of undifferentiated mesenchyme which is responsible for the proliferation of articular cartilage in response to the functional demands placed on the articular surface during loading. www.indiandentalacademy.com
  65. 65. Fibrocartilagenous zoneThe collagen fibrils are arranged in bundles in a crossing pattern. It appears in a random orientation providing a 3D network that offers resistance against compressive and lateral forces. Calcified cartilage zoneDeepest zone made up of chondrocytes and condroblasts distributed throughout the articular cartilage. In this zone the chondrocytes become hypertrophic,die and have their cytoplasm evacuated,forming bone cells www.indiandentalacademy.com from within the medullary cavity.
  66. 66. MUSCLES OF MASTICATION - MASSETER - TEMPORALIS - LATERAL PTERYGOID -MEDIAL PTERYGOID www.indiandentalacademy.com
  67. 67. INTRODUCTION  These are SKELETAL, VOLUNTARY muscles.  Moves the mandible during chewing and speech. - Masseter - Temporalis - Lateral Pterygoid - Medial Pterygoid - Buccinator (accessory /5th muscle) - Ant. belly of digastric, geniohyoid,mylohyoid, www.indiandentalacademy.com
  68. 68. DEVELOPMENT • It develops from the mesoderm of the 1st PHARANGIAL ARCH. www.indiandentalacademy.com
  69. 69. MASSETER • Has 3 layers: superficial, middle & deep. • Multipinnate arrangement of fibers • Quadrilateral muscle that covers lateral surface of the mandible. www.indiandentalacademy.com
  70. 70. LAYERS ORIGIN FIBERS INSERTION SUPERFICIAL: ANT.2/3 OF LOWER BORDER ZYGOMATIC ARCH & ZYG. PROCESS OF MAXLLLA. - PASS DOWNWARDS & BACKWARDS AT 45º LOWER PART OF LATERAL SURFACE OF MAND. MIDDLE:   ANT. 2/3 OF DEEP SURFACE & POST. 1/3 OF LOWER BORDER OF ZYG. ARCH.   - VERTICALLY & DOWNWARDS.   MIDDLE PART OF RAMUS DEEP:   DEEP SURFACE OF ZYG. ARCH UPPER PART OF -   LAYERS ARE 3 SEPERATED BY AN RAMUS AND CORONOID www.indiandentalacademy.com NERVE ARTERY & A
  71. 71. TEMPORALIS  FAN shaped muscle. Fills the Temporal Fossa. MUSCLE TEMPORALIS ORIGIN FIBERS CONVERGE & PASSES THROUGH GAP DEEP TO ZYG. ARCH www.indiandentalacademy.com TEMPORAL BONE AND FASCIA INSERTION MARGIN & DEEP SURFACE OF CORONOID - ANT. BORDERS OF RAMUS OF MAND. -
  72. 72. LATERAL & MEDIAL PTERYGOID LATERAL PTERYGOID: It is a short & conical muscle. Has upper & lower head. MEDIAL PTERYGOID: Quadrilateral muscle Has superficial & deep head www.indiandentalacademy.com
  73. 73. LATERAL PTERYGOID ORIGIN FIBERS INSERTION UPPER (SMALL) FROM INFRATEMPORAL SURFACE & CREST OF G.WING OF SPHENOID RUN BACKWARDS & LATERALLY. CONVERGE FOR INSERTION PTERYGOID FOVEA (CONDYLAR NECK)   LOWER (LARGER) LATERAL SURFACE OF LATERAL PTERYGOID PLATE   ANT. MARGIN OF ARTICULAR DISC & CAPSULE OF TMJ. MEDIAL PTERYGOID ORIGIN FIBERS INSERTION SUPERFICIAL (SMALL) TUBEROSITY OF MAXILLA & ADJOINING BONE DOWNWARDS, BACKWARDS & LATERALLY MEDIAL SURFACE OF ANGLE & RAMUS OF MANDIBLE DEEP (LARGE) MEDIAL SURFACE OF   LATERAL PTERYGOID   PLATE & ADJ.   PROCESS OF   PALATINE BONE   www.indiandentalacademy.com   BELOW & BEHIND MAND. FORAMEN & MYLOHYOID GROOVE
  74. 74. • The relationship between the disk & the lateral pterygoid muscle--The foot of the anterior part of disc blends with the capsule and provides a mechanism by which the foot is attached to the roof of the superior head of the lateral pterygoid muscle.. (J Prosthet Dent 1988,60:715-724) www.indiandentalacademy.com
  75. 75. SUPPLIES: MUSCLE ARTERY VEIN NERVE MASSETER MASSETRIC.A. (II PART OF MAXILLARY A.) RESPECTIVE VEIN MASSETRIC NR. (BR.OF ANT. DIV.OF MAND.NR) TEMPORALIS SUP. TEMPORAL A. LATERAL PTERYGOID LAT. PTERYGOID. (II PART OF MAXILLARY A.) MEDIAL PTERYGOID MED. PTERGOID. (II PART OF MAXILLARY A.) PTERYGOID VENOUS PLEXUS DEEP TEMPORAL (BR.OF ANT. DIV.OFMAND.NR) MAXILLARY VEIN LAT. PTERYGOID (BR.OF ANT. DIV.OF MAND.NR) RETROMANDIBULAR VEIN MED. PTERYGOID (BR. OF MAIN TRUNK OF MAND. NR.) www.indiandentalacademy.com
  76. 76. www.indiandentalacademy.com
  77. 77. AUSCULTATION PALPATION OBJECTTMJ SYMPTOMSCREPITUS CLICKING FUNCTIONAL ANALYSIS TMJ TMJ MUSCULATURE MANDIBULAR EXCURSIONS OCCULUSION REST POSITION PREMATURE CONTACTS DYSFUNCTIONS PALPATORY PAIN RADIOGRAPHIC EXAMINATION TMJ DISLOCATION DISLOCATION HYPERMOBILITY LIMITATION CHANGES IN www.indiandentalacademy.com SHAPE AND DEVIATION
  78. 78. Examination of TMJ in ORTHODONTIC CLINICS  Palpation – in closed, at rest & various open position  Deviation should be noted  Crepitus / abnormal sound  Palpation of the neck & sub mandibular area  Speech evaluation  Facial asymmetry  Pain in head & neck region  Opening movement  Examination of soft tissues www.indiandentalacademy.com  Examination of occlusion
  79. 79. Path of opening Alterations 1. Deviation 2. Deflection DEVIATION is any shift of the midline during opening that disappears with continued opening (i.e. returns to midline) www.indiandentalacademy.com
  80. 80. DEFLECTION is shift of midline to one side that becomes greater with opening and is maintained in that position at maximum opening (i.e. does not return to midline) www.indiandentalacademy.com
  81. 81. Causes of altered path Extracapsular – elevator muscle spasm Direction of deflection depends on location of muscle i.e. mesial or lateral to the joint If Lateral – deflection ipsilateral side If mesial – deflection contralateral side Intracapsular – disc derangements Deflection is toward the ipsilateral side www.indiandentalacademy.com
  82. 82. Lateral movements < 8mm is recorded as restricted movement www.indiandentalacademy.com
  83. 83. MAXIMUM JAW OPENING • The distance between the incisal edges of the upper and lower central incisors is measured with a Boley gauge. • Extent of max jaw opening between the incisal edges is 40-45mm. • In overbite cases this amount is added to the obtained value whereas in open bite it is www.indiandentalacademy.com subtracted.
  84. 84. Palpation of T.M.J. • Pain or tenderness of TMJ is determined by digital palpation when the mandibular is in both stationary and dynamic movements. • The examiners finger tips are placed over the lateral aspect of joint areas simultaneously on both sides. www.indiandentalacademy.com
  85. 85. Lateral palpation • The finger tips should feel the lateral poles of condyles passing down towards across articular eminence. • Once position is verified, the medial force is applied to the joint area to check for any pain www.indiandentalacademy.com
  86. 86. Posterior palpation: • Position the little finger in the external auditory meatus and palpate the posterior surface of condyle during opening and closing of the mandible. • Palpation is done in such a way that the condyle displaces the little finger when in full occlusion. www.indiandentalacademy.com
  87. 87. AUSCULATION OF THE T.M.J. • Sounds made by the TMJ can be examined with a stethoscope. Also the timing of clicking during opening and closure can be noted . www.indiandentalacademy.com
  88. 88. Crepitation • This is a grating or scalping noise that occurs on jaw movements . Sound like when sand paper is rubbed against a surface. • Crepitation is very uncommon in asymptomatic joint and may be an early sign of degenerative joint disease. • Crepitus is caused by roughened, irregular anterior surface. www.indiandentalacademy.com
  89. 89. Clicking • It occurs due to the uncoordinated movement of condylar head and T.M.J disc. • Joint clicking is differentiated as: Initial Intermediate Terminal Reciprocal www.indiandentalacademy.com
  90. 90. • Initial clicking : It is a sign of retruded condyle • Intermediate clicking : Is a sign of unevenness of the condylar surfaces and articular disc • Terminal clicking : is an effect of the condyle being moved too far anteriorly in relation to the disc on maximum jaw opening. • Reciprocal clicking : is an expression of incoordination between displacement of the condyle & the disc. www.indiandentalacademy.com
  91. 91. Joint sounds Single click during opening– internal derangement www.indiandentalacademy.com
  92. 92. Reciprocal clicking- advanced derangement www.indiandentalacademy.com
  93. 93. MUSCLE EXAMINATION MUSCLES PALPATED     TEMPORALIS MASSETOR LATERAL PTERYGOID MEDIAL PTERYGOID FUNCTIONALLY ASSESED  INFERIOR BELLY OF LATERAL PTERYGOID  SUPERIOR BELLY OF LATERAL PTERYGOID  MEDIAL PTERYGOID www.indiandentalacademy.com
  94. 94. TEMPORALIS Anterior region – above the zygomatic arch & anterior to the TMJ Middle – directly above the TMJ & superior to the zygomatic arch Posterior – above & behind the ears www.indiandentalacademy.com
  95. 95. With the index finger intraorraly Palpate tha cheek laterally at the Retromolar fossa. www.indiandentalacademy.com
  96. 96. MASSETER Palpated bilaterally at its Superior and inferior attachments Started anterior to TMJ and then dropped down to the inferior border of the ramus www.indiandentalacademy.com
  97. 97. Masseter (intra oral) With the index finger intraorally Press laterally inside the cheek. www.indiandentalacademy.com
  98. 98. • Inferior lateral pterygoid should no longer be considered as a standard clinical procedure bec it is nearly impossible to palpate it anatomically & bec the risk of false +ve findings by palpation of the medial pterygoid muscle is high.. (J Prosthet Den 2000;83:548-554) www.indiandentalacademy.com
  99. 99. For years intraoral technique was suggested for palpating the pterygoids But this has not been proven effective. Bec these muscles reside deep within the skull,originating on the lateral wing Of the sphenoid bone ,location of this muscle made palpation immpossible. Therefore a second method for evaluating muscle symptoms,called FUNCTIONAL MANIPULATION ,was developed. www.indiandentalacademy.com
  100. 100. FUNCTIONAL ANALYSIS OF MUSCLES • Lateral pterygoid • Medial pterygoid • Principle A muscle which is fatigued & symptomatic elicits pain on further function and is painful both on contraction and stretching www.indiandentalacademy.com
  101. 101. Inf. belly of Lateral pterygoid Contraction – mandibular protrusion, mouth opening or both FM – protrude against resistance Stretching – maximum intercuspation of teeth FM – clench the teeth Differentiation test – place tongue blade in b/w posterior teeth. This prevents the teeth from reaching max. intercuspal position. Hence lat ptery. does not stretchwww.indiandentalacademy.com
  102. 102. SUPERIOR BELLY OF LATERAL PTERYGOID Contraction – clenching ; POWER STROKE (along with other elevator muscles) FM – clenching Differential test – tongue blade is placed bilaterally & ptn asked to bite. This increases the pain if it is symptomatic while the stretching pain of inf. Belly of lat. Ptery is relieved Stretching – also produces clenching FM- clenching Differential test – ptn is asked to open mouth widely. www.indiandentalacademy.com If pain is elicited
  103. 103. Medial pterygoid Contraction – clenching FM – clenching Differential test – tongue blade is placed bilaterally & ptn asked to bite. This increases the pain if it is symptomatic bec elevators are still contracting. Stretching-mouth opening FM-opening www.indiandentalacademy.com
  104. 104. FM either by Opening widely Protrude against resistance Clench the teeth together Clench and bite on separator “ TRUE SOURCE” Only site of pain and not exact source can be found out since these muscles are working in unison “DIAGNOSTIC ANAESTHETIC NERVE BLOCKING” www.indiandentalacademy.com
  105. 105. www.indiandentalacademy.com
  106. 106. Two dimensional imaging Panoromic radiographs Transcranial view Transpharyngeal view Transorbital view Reverse Towne’s view Submento-vertex (SMV) view Conventional tomography Arthrography Three dimensional imaging Computed tomography (CT) Magnetic resonance imaging (MRI) New Tom scanner www.indiandentalacademy.com
  107. 107. Panoramic view Used as screening projection Provides non corrected tomographic view of the condyles on one film Non corrected – beam does not pass through the long axis of www.indiandentalacademy.com 0 condyle aligned at 20 to coronal plane
  108. 108. Transcranial projection - modified Schuller method Provides sagittal view of lateral aspects of condyle and temporal component Indication Gross changes on the lateral aspect of joint Displaced joint fractures Range of motion (open view) www.indiandentalacademy.com
  109. 109. Transpharyngeal projection Provides sagittal view of the medial pole of the condyle Limitations Temporal components are not imaged well Indications www.indiandentalacademy.com To visualize gross erosive changes of the condyle
  110. 110. Transorbital projection Transmaxillary, antero posterior view Provides an anterior view of the TMJ perpendicular to the transcranial and transpharyngeal views Indication It provides images of entire mediolateral dimension and the articular eminence , condylar neck and condylar head are imaged Range of motion cannot be assessed Mainly for detection of condylar neck fractures www.indiandentalacademy.com
  111. 111. Reverse Towne’s view Similar to transorbital view Useful for viewing medial displacements of the condyle www.indiandentalacademy.com
  112. 112. Submentovertex (SMV) projection Provides view of the base of the skull with condyles superimposed on the condylar neck and rami www.indiandentalacademy.com
  113. 113. Conventional tomography Provides the most definitive diagnostic information about the osseous structures of the TMJ Provides visualization of anatomic stc’s free from superimposition Exposure can be done either in sagittal (lateral) plane or coronal (frontal) plane The x-ray source and film move parallel to each other with the patient in b/w Image thickness obtained varies from 1-2mm and above www.indiandentalacademy.com
  114. 114. Arthrography Provides information regarding soft tissue of the joint Technique – intra- articular administration of radio-opaque iodinated contrast agent is done under fluoroscopic guidance After both the joint spaces are filled with the the contrast agent the disk function is studied using fluoroscopy supplemented by tomography Adv – it is adv over MRI in identifying any perforations b/w the superior and inferior joint compartments Disadvs – 1. expensive 2. ptn may develop allergy to contrast medium www.indiandentalacademy.com 3. invasive
  115. 115. Arthrography www.indiandentalacademy.com
  116. 116. www.indiandentalacademy.com
  117. 117. Computed tomography Incorporates the principles of direct digital (computed) electronic imaging & cross sectional radiography (tomography) Provides visualization in all 3 planes Sagittal (lateral) Coronal (frontal) www.indiandentalacademy.com Axial
  118. 118. Computed tomography www.indiandentalacademy.com
  119. 119. Magnetic resonance imaging (MRI) Used to image soft tissues of the TMJ to visualize Joint effusion Disk position Disk shape Inflammatory changes www.indiandentalacademy.com
  120. 120. New Tom scanner – Diagnosis goes digital (David C.Hatcher, Cameron L. Aboudara AJO-DO Apr 2004) New Tom QR 9000 (Verona, Italy) It uses the principle of tomosynthesis or cone – beamed CT Entire maxillo facial volume (13 cm dia. Of field of view) is imaged Dosage – equivalent to that of a periapical survey of dentition Provides axially corrected tomographic image of the TMJ www.indiandentalacademy.com
  121. 121. BIOMECHANICS OF TMJ www.indiandentalacademy.com
  122. 122. BIOMECHANICS OF TMJ – Can be divided into two system: 1) One joint system; • Tissues surrounding the inferior synovial cavity (condyle & the articular disc) • Only physiologic movement is rotation of the disc on the articular surface of the condyle – condyledisc complex. • Responsible for rotational movement in the TMJ. www.indiandentalacademy.com
  123. 123. 2) condyle-disc complex functioning against the surface of mandibular fossa; • Free sliding movement possible, in the superior cavity. • This movement occurs when the mandible is moved forward – translation. www.indiandentalacademy.com
  124. 124. • The articular surfaces of the joint is maintained by constant activity of the muscles that pull across the joint, primarily the elevators. (even in resting stage in a mild tonus) • Increase in intra articular pressure holds the joint. • Width of the disc varies with the intra articular pressure. - low (closed rest position) – widens. - high (clenced) – space narrows. www.indiandentalacademy.com
  125. 125. TYPES OF MOVEMENTS • ROTATIONAL MOVEMENTS (within the inferior cavity of the joint) • TRANSLATIONAL MOVEMENTS (within the superior cavity of the joint) • HORIZONTAL AXIS • FRONTAL AXIS • SAGITTAL AXIS www.indiandentalacademy.com
  126. 126. ROTATIONAL MOVEMENT AROUND THE HORIZONTAL AXIS www.indiandentalacademy.com
  127. 127. ROTATIONAL MOVEMENT AROUND THE FRONTAL AXIS www.indiandentalacademy.com
  128. 128. ROTATIONAL MOVEMENT AROUND THE SAGITTAL AXIS www.indiandentalacademy.com
  129. 129. BASIC SAGITTAL PLANE POSITIONS OF MANDIBLE 1. Postural resting position 2. Centric relation 3. Initial contact 4. Centric occlusion 5. Terminal hinge position/Most retruded position 6. Most protruded position www.indiandentalacademy.com 7. Habitual occlusal position
  130. 130. POSTURAL RESTING POSITION • Earliest postural positions to develop • Postural position of mandible determined largely by neuromuscular activity & viscoelastic properties of muscles 1. Body & head posture 2. Sleep 3. Emotional factors influencing muscle tonus 4. Age 5. Proprioception from dentition & muscles 6. Occlusal changes 7. Pain 8. Muscle disease 9. TMD www.indiandentalacademy.com
  131. 131. CENTRIC RELATION The most retruded relation of the mandible to the maxilla when the condyles are in most posterior unstrained position in the glenoid fossa from which the lateral movements can be made at an establised vertical Relationship…… Unstrained neutral position. (Glossary of prosthodontic terms) www.indiandentalacademy.com
  132. 132. INITIAL CONTACT • Maintains same centric relation position with fossa • Rotation of condyle in lower joint cavity • Synonymous with centric relation • Exception – Premature contacts www.indiandentalacademy.com
  133. 133. CENTRIC OCCLUSION It is the position of maximum intercuspation between the upper and lower teeth .. (Glossary of prosthodontic terms) • A state of balance – - maximal contact of opposing teeth - bilaterally symmetrical activity - harmonious & unstrained TM structures www.indiandentalacademy.com
  134. 134. TERMINAL HINGE POSITION (MOST RETRUDED POSITION) • Habitual, normal, bilaterally symmetrical, unstrained position of condyles in articular fossae • Centric relation movement, condyles rotate around a transverse axis through the condyles • Guide the jaw in opening & closing so that no www.indiandentalacademy.com
  135. 135. MOST PROTRUDED POSITION • Variations • Not used clinically • Dislocation in extreme protrusive position if capsular structures flaccid www.indiandentalacademy.com
  136. 136. BORDER MOVEMENTS • Movements to the limits of the region where mandible can physiologically exist • Mandibular movements i.r.t. a plane of reference • Recorded on a Pantograph, Kinesiograph • Termed as Border / Envelope of movements • Given by Posselt – 1952 www.indiandentalacademy.com
  137. 137. POSSELT DIAGRAM.COM www.indiandentalacademy.com
  138. 138. HORIZONTAL PLANE BORDER AND FUNCTIONAL MOVEMENTS  Left lateral border  Continued left lateral border with protrusion  Right lateral border  Continued right lateral border with protrusion www.indiandentalacademy.com
  139. 139. WORKING BITE Right condyle-rotating condyle(as mandible rotating around it) Left condyle-rotating condyle(as mandible rotating around it) Left condyle-orbiting condyle(as it is orbiting around the rotating condyle) Right condyle-orbiting condyle(as it is orbiting around the rotating condyle) Right condyle-working condyle(as it is on the working side) Left condyle-working condyle(as it is on the working side) Right condyle-non www.indiandentalacademy.com condyle(as Left condyle-non working it is located on non working side) working condyle(as it is located on non working side)
  140. 140. BENNETT MOVEMENT www.indiandentalacademy.com
  141. 141. FRONTAL(VERTICAL)BORDER AND FUNCTIONAL MOVEMENTS • Left lateral superior border • Left lateral opening border • Right lateral superior border • Right lateral opening border movements www.indiandentalacademy.com
  142. 142. MANDIBULAR BORDER MOVEMENTS IN THE FRONTAL PLANE www.indiandentalacademy.com
  143. 143. lateral moments.mov www.indiandentalacademy.com
  144. 144. EFFECTS OF AGING ON TMJ www.indiandentalacademy.com
  145. 145. • Stops growing at 20 yrs. of age • Continues adaptational responses due to physiological or functional changes in surrounding tissues • Factors affecting joint – Aging - decrease in muscle activity - loss of teeth - changes in occlusion - attrition of teeth • Remodeling according to functional & mechanical circumstances • Remodeling & no. of lost teeth www.indiandentalacademy.com • Condylar head > fossa, eminence
  146. 146.  Flattening of the articular fossa and decrease in prominence of the articular eminence. www.indiandentalacademy.com
  147. 147. CONCLUSION Orthodontists are constantly being challenged with the task of providing their patients with acceptable esthetics and masticatory function.Developing a sound functional masticatory system is a primary goal in orthodontic therepy.Only when the orthodontist understands how the system are designed to work ,he will know what's wrong with it and has to be treated.Thus a sound understanding of functional anatomy,biomechanics and dysfunction of T M J is essential to study of occlusion. www.indiandentalacademy.com
  148. 148. “ You cannot successfully treat dysfunction unless you understand function” www.indiandentalacademy.com
  149. 149. REFERENCES 1.Management of Temporomandibular disorders & occlusion. -JEFFREY P.OKESON 2.Orthodontic principles and practice. -T.M.GRABER 3.Grey’s anatomy. -PETER L.WILLIAMS 4.Oral radiology principles and interpretation -STUART C.WHITE,MICHAEL www.indiandentalacademy.com PHAROAH
  150. 150. REFERENCES 5.Burkit’s oral medicine and diagnosis. -MARTIN S GREENBERG,GLICK 6.Oral histology. -A.R.TENCATE 7.Colour atlas of dental medicine orthodontic diagnosis -THOMAS RAKOSI,IRMTRUD JONAS & THOMAS M. GRABER 8.Wheelers dental anatomy,physiology and occlusion -MAJOR M.ASH 9.Oral anatomy,histology & embryology -BERKOVITZ 10.David et al-diagnosis goes digital, www.indiandentalacademy.com -AJO-DO 2004Apr(512-515)
  151. 151. REFERENCES 11.Carrole S. Wink et al-Neural elementsin the human Temporomandibular articular disc,J Oral Maxillofac Surg 80:334-337,1992 12.Lambert et al-Spatial arrangement of collagen fibrils in the articular cartilage of the mandibular condyle,J Oral Maxillofac Surg 42:306-313,1984 13.T.M.Wilkinson-The relationship between the disk & the lateral pterygoid muscle in the human Temporomandibular joint,J Prosthet Dent 60:715-724,1988 14.Udo Statmann-Clinical anatomy and palpability of the inf lateral pterygoid muscle,J Prosthet Dent 2000;83:548-54 www.indiandentalacademy.com
  152. 152. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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