Basics to advance about the Temporomandibular Joint with respect to dentistry, Easy guide for dental students with reference and credentials

1. Development of Temporomandibular
Joint (TMJ)
By: Dr. Kanchan Sahwal
Department of Prosthodontics
RDC, Loni
1

2. CONTENTS
 Introduction
 Definition
 Development
 Anatomic Components
 Vascular Supply of TMJ
 Innervations of TMJ
 Movements
 Prosthodontic Implications
 Temporomandibular Disorder
 Conclusion
 References
2

3. INTRODUCTION
 Joint: the place of union of two or more bones
(GPT-8).
 Fibrous Joint: Lack of intervening cartilage and
provide very restricted movement. E.g. suture,
gomphosis.
 Cartilaginous Joint: Intervening with cartilage and
permit some movement. E.g. postcranial bones
 Synovial joint: Bones are linked by fibrous capsule
by internal and external accessory ligaments.
Presence of synovial fluid. E.g. TMJ
3

4. DEFINITION
4
 The articulation between the temporal bone and the
mandible. It is a bilateral diarthrodial, bilateral
ginglymoid joint. (GPT-8)
 The articulation of the condylar process of the
mandible and the intraarticular disk with the
mandibular fossa of the squamous portion of the
temporal bone; a diarthrodial, sliding hinge
(ginglymus) joint. Movement in the upper joint
compartment is mostly translational, whereas that
in the lower joint compartment is mostly rotational.
The joint connects the mandibular condyle to the
articular fossa of the temporal bone with the
temporomandibular disk interposed (GPT-8)

5. Other Names
5
 Diarthrodial joint : A freely moving joint. (GPT-8)
 Ginglymus joint : A hinge joint.
 Ginglymoarthrodial Joint
 Compound joint : A joint involving three or more
bones. (GPT-8)
 Ellipsoid joint
 Synovial Joint
 Craniomandibular articulation

6. DEVELOPMENT of TMJ
6
 At 6th week : Articular disc first appears.
 At 7th week : Meckels cartilage extends from chin
to base of skull acts as scaffolding for mandible
development. Two ectomesenchymal condensation
appears.
 At 12th week : Condylar growth cartilage appears &
condyle begins to develop.
 At 22nd week : Articular capsule becomes
recognizable and merges peripherally with
condensation.

7. 7
 At 26th week : All components of joint appears
except articular eminence.
 At 31st week : Sphenomandibular ligament
appears.
 At 39th week : Ossification of bony components
starts and resembles the future joint.
 It is a last joint to develop.
 Rigid end point (Teeth)

8. 8
ANATOMICAL COMPONENT
Passive
Bony
components
Ligaments
Articular
Disc
Active
Muscles

9. Bony Components
9
1. GLENOID FOSSA
 The squamous portion of temporal bone (approx.
23mm)
 Anterior – articular eminence
 Posterior – Post glenoid plane (prevents forced
displacement)

10. 10
 The posterior roof is thin not designed to sustain
heavy force.
 The articular eminence consists of thick dense bone
to tolerate such forces.
 The steepness of the articular eminence surface
dictates the pathway of the condyle CONDYLAR
GUIDANCE
10

11. 11
2. CONDYLE
HEAD OF CONDYLE
 Mediolateral: 15-20mm
Anteroposterior: 7-10mm
 Anterior view : medial & lateral poles,
the medial pole more prominent

12. 12
 The articular surface lies on its
anterosuperior aspect, thus facing
the posterior slope of the articular
eminence of the temporal bone.
 The imaginary lines connecting the
medial and lateral poles of the
condyles are posteriorly and medially
directed toward the anterior border
of the foramen magnum.

13. 13
3. ARTICULAR EMINENCE
 Transverse bony bar that
forms the root of zygomatic
process.
 This articular surface have
dense bone and is most
heavily traversed by condyle
and disk during forward
and backward movements
of jaw.
Squamous part of
temporal bone
Articular eminence

14. 14
ARTICULAR DISC
 Dense fibrous connective tissue
with chondrification in areas of
maximum loading.
 Peripherally it is thick with the
central depression (Biconcave)
 Posteriorly: Attaches to loose
vascular and nervous tissue (the
bilaminar region) which provides
only attachment.

15. 15
 The ARTICULAR DISC is a roughly oval, firm,
fibrous plate.
PARTS:
1. Anterior Band = 2 mm
2. Posterior Band = 3 mm
3. Intermediate Band =1 mm

16. 16
 Larger upper compartment
and
Smaller lower compartment.
 Hinging movements take
place in the lower
compartment and gliding
movements take place in the
upper compartment.

17. 17
ATTACHMENT OF DISC
ANTERIORLY:
 Anterior region: to the capsular
ligament, tendonious fiber of the
SLP
 Anterio-Superior : anterior
margin of the articular surface of
the temporal bone
 Anterio-Inferior : anterior margin
of the articular surface of the
condyle

18. 18
POSTERIORLY:
 RETRODISCAL TISSUE : It is a loose connective
tissue region that is highly vascularized and
innervated.

19. 19
 Superior : upper lamina
(Contains mainly elastic
fibers)
 It attaches the disc
posteriorly to the tympanic
plate & prevents slipping of
the disc while yawning.
 Inferior : lower lamina
(composed chiefly
collagenous fibers )
 It prevents excessive
rotation of the disc over the
condyle.

20. 20
FUNCTIONS
 To accommodate a hinge as well as the gliding
actions.
 Stablize the condyle within TMJ.
 Articular disc may also reduce wear.
 Aid lubrication of the joint by storing fluid
squeezed out from loaded area.

21. 21
SYNOVIALFLUID
 The synovial fluid comes from two sources: first, from
plasma by dialysis, and second, by secretion from type
A and B synoviocytes
 Upper: 1.2mL of synovial fluid and is responsible for
the translational movement of the joint.
 Lower: 0.9mL and allows rotational movements.
 It is clear, straw-colored viscous fluid.
 It diffuses out from the rich capillary network of the
synovial membrane.
 Hyaluronic acid which is highly viscous
 May also contain some free cells mostly macrophages.

22. 22
FUNCTIONS:
 Lubricant for articulating surfaces.
 Carry nutrients to the avascular tissue of
the joint.
 Clear the tissue debris caused by normal
wear and tear of the articulating surfaces.
Two MECHANISMS of the lubrication :
 Boundary lubrication: Prevents friction
in the moving joint.
 Weeping lubrication: Eliminates friction
in the compressed but not moving joint.

23. Ligaments
23
PRIMARY:
1. Fibrous Capsule
2. Collateral
3. Temporomandibular
SECONDARY:
4. Sphenomandibular
5. Stylomandibular

24. 24
1. CAPSULAR LIGAMENT/ FIBROUS CAPSULE
Thin sleeve of fibrous tissue surrounding the
entire TMJ
Superior attachment
 The borders of the articular surface of the glenoid
fossa and anterior edge of preglenoid plane of
articular tubercle
Inferior attachment
 Periphery of neck of
mandibular condyle

25. 25
 This capsule is reinforced more laterally by an
external Temporomandibular ligament, which also
limits the distraction and the posterior movement of
the condyle.

26. 26
 Anteriorly, the capsule has an orifice through which
the tendon of lateral pterygoid muscle passes.
 This area of relative weakness in the capsular lining
becomes a source of possible herniation of intra-
articular tissues
 May allow forward displacement of the disk.

27. 27
FUNCTION
 To resist any lateral or downward forces that tends
to separate or dislocate the articular surface.
 To retain the synovial fluid.
 Proprioception

28. 28
2. COLLATERAL ( DISCAL )
LIGAMENTS
 From medial and lateral
borders of the disc to the
poles of the condyle
Medial discal ligament
Lateral discal ligament
 Dividing the joint
mediolaterally into superior
and inferior joint cavities

29. 29
FUNCTION:
 Allow the disc to move passively with the condyle
as it glides and rotated A – P.
 These ligaments are responsible for the hinging
movement between the condyle and the articular
disc.
 They have a vascular supply and are innervated

30. 30
 It lies at the lateral aspect of the
capsular ligament
Attached above to articular tubercle
Below attached to lateral and
posterior surface of neck of condyle
FUNCTION
 Resists excessive dropping of the
condyle so limits the extent of
mouth opening
3. TEMPOROMANDIBULAR LIGAMENT

31. 31
4. SPHENOMANDIBULAR LIGAMENT
 From the spine of the sphenoid bone
& extends downward to lingula of mandible

32. 32
 Second accessory
ligament.
 This is a specialized
dense, local concentration
of deep cervical fascia
 From the styloid process &
extends downward and
forward to the angle and
posterior border of the
ramus of mandible
5. STYLOMANDIBULAR LIGAMENT

33. 33
FUNCTION:
 It limits excessive protrusive movements of the
mandible
 This ligament becomes tense only in extreme
protrusive movements.

34. 34
* DISCO MALLEOLAR
LIGAMENT
 The disco malleolar ligament
(PINTO LIGAMENT) was
described by pinto(1962) as a
connection between the
malleus & the medial wall of
joint capsule.
 However, a separate ligament
can be demonstrated here in
only 29% of
temporomandibular joints .

35. 35
MUSCULAR COMPONENT

36. Muscles
36
PRIMARY MUSCLES OF MASTICATION
 Masseter
 Temporalis
 Lateral Pterygoid
 Medial Pterygoid

37. 37
SECONDARY MUSCLES OF MASTICATION
 Suprahyoid Muscles
 Infrahyoid Muscles

38. 38
SUPRAHYOID MUSCLES
 Digastric
 Mylohyoid
 Geniohyoid
 Styohyoid

39. 39
INFRAHYOID MUSCLES
 Sternohyoid
 Sternothyroid
 Thyrohyoid
 Omohyoid
 Sternocleiodomastoid and Trapezius

40. 40
1. MASSETER
 Voluntary
 Multipennate
 Quadrilateral
 Antigravity
 Elevator

41. 41
ORIGIN
 SUPERFICIAL LAYER: From
maxillary process of the
zygomatic bone. The anterior
2/3rd of the inferior border of the
zygomatic arch.
 MIDDLE LAYER: The medial
aspect of the anterior 2/3rd of
the zygomatic arch. The lower
border of the posterior third of
this arch.
 DEEP LAYER: The deep surface
of the zygomatic arch

42. 42
INSERTION
 SUPERFICIAL LAYER: The
angle and lower posterior half
of the lateral surface of the
mandibular ramus
 MIDDLE LAYER: The central
part of the ramus of the
mandible.
 DEEP LAYER: The upper part
of the mandibular ramus &
into its coronoid process.

43. 43
 Elevation of mandible and
teeth in contact.
 Protraction and Retraction
 Electrical activity in the
resting position is minimal.
FUNCTION of MASSETER MUSCLE

44. 44
VASCULAR SUPPLY
 By the masseteric branch of
the maxillary artery,
the facial artery and
the transverse facial branch
of the superficial temporal
artery
INNERVATION
 The masseteric branch of the
anterior trunk of the
mandibular nerve.

45. 45
2. TEMPORALIS
 Fan Shaped
 Bipennate
 Voluntary

46. 46
ORIGIN
 The whole of the temporal
fossa up to the inferior
temporal line and from the
deep surface of the
temporal fascia.
INSERTION
 The coronoid process and to
the anterior border of the
mandibular ramus

47. 47
FUNCTION
 Elevates (Anterior fiber) the
mandible to close the
mouth.
 Side to side grinding
movements.
 Retraction (Posterior Fiber)
after the protrusion.

48. 48
VASCULAR SUPPLY
 The deep temporal branches
from the second part of the
maxillary artery.
INNERVATION
 The deep temporal branches
from the anterior trunk of
mandibular nerve

49. 49
3. MEDIAL PTERYGOID
MUSCLE contains deep and
superficial head.
 Thick muscle
 Quadrilateral
 Multipennate
 Voluntary

50. 50
ORIGIN
 Large deep head: From the medial
surface of the lateral pterygoid
plate of the sphenoid bone.
 Small superficial head : Maxillary
tuberosity and the pyramidal
process of the palatine bone
INSERTION
 Postero-inferior part of the medial
surface of the ramus and angle of
the mandible

51. 51
FUNCTION
 Elevation
 Protrusion with the
lateral pterygoid
 Side to side movements
to triturate the food.

52. 52
VASCULAR SUPPLY
 Pterygoid branches of the maxillary artery.
INNERVATION
 Medial pterygoid branch of the mandibular nerve

53. 53
4. LATERAL PTERYGOID
contain Superior Head
and Inferior Head.
 Thick
 Short
 Non-pennate

54. 54
ORIGIN:
 The Superior head: Infratemporal surface and crest
of the greater wing of the sphenoid bone.
 The Inferior head: the lateral surface of lateral
pterygoid plate.
INSERTION
 Pterygoid fovea
 A part of the superior head attached to the capsular
ligament and to the anterior and medial borders of
articular disc.

55. 55
FUNCTION :
 When left and right muscles contract together in
protrusive movement
 If only one lateral pterygoid contracts, the jaw
rotates around a vertical axis passing through the
opposite condyle and is pulled medially toward the
opposite side.
 During powerful clenching of teeth ,temporalis
muscle pulls the condyle backwards which is
limited by superior head of lateral pterygoid muscle

56. 56
VASCULAR SUPPLY
 Pterygoid branches from the MAXILLARY ARTERY
 Ascending Palatine branch of FACIAL ARTERY
INNERVATION
 The superior head & the lateral part of the inferior
head: a branch from BUCCAL NERVE.
 The medial part of the lower head : a branch
arising directly from the anterior trunk of
MANDIBULAR NERVE..

57. VASCULAR SUPPLY OF TMJ
57
ARTERIES:
 Anteriorly: Masseteric Artery
 Posteriorly: Branches from
Maxillary Artery
Superficial temporal Artery
VEINS:
 Maxillary vein and pterygoid
venous plexes

58. INNERVATION of TMJ
58
 Branches of the mandibular division of the fifth
cranial nerve supply the TMJ.
 Anterioly by Auriculotemporal
and Masseteric Nerve.
 Posteriolrly by Deep temporal Nerve.
 Parasympathetic fibers of the otic ganglion stimulate
the synovial production.
 Sympathetic neurons from the superior cervical
ganglion reach the joint along the vessels and play a
role in pain reception and the monitoring of the blood
volume.

59. LYMPHATIC DRAINAGE
59
 Lymphocytes are located in many sites in the body
which are liable to infection e.g. Oropharynx

60. MOVEMENTS
60

61. Classification
61
HABITUAL
 Speech
 Mastication
 Deglutition
 Breathing
 Sucking, whistling etc.
BASED ON AXIS OF ROTATION
 Transverse
 Sagittal
 Vertical

62. 62
BASED ON TYPE OF MOVEMENT
 Hinge
 Protrusive
 Retrusive
 Lateral
BASED ON EXTENT OF MOVEMENT
 Border movements
Extreme movements in all planes
Envelope motion
 Intra border
Functional
Parafunctional

63. 63
AXIS OF MOVEMENTS
 Transverse or hinge axis: Opening and
closing movements takes place in sagittal
plane.
 Vertical axis: lateral movements takes
place through this axis which condyle
twists laterally and backward in horizontal
plane.
 Antero-posterior or Sagital axis: lateral
movements takes place through this axis
at which condyle twists while rotating in
frontal plane

64. 64

65. 65

66. 66
DEPRESSION OF MANDIBLE
 Digrastric
 Geniohyoid
 Mylohyoid
 Lateral Pterygoid
ELEVATION OF MANDIBLE
 Temporalis
 Masseter
 Medial Pterygoid

67. 67
PROTRUSION OF
MANDIBLE
 Medial Pterygoid
 Lateral Pterygoid
RETRUSION OF MANDIBLE
 Posteroir fibers of
Temporalis

68. 68
ENVELOPE MOTION
 Every tooth in the mandible (the
only moving jaw) has an envelope
of motion that outlines the outer
limits to which each lower tooth
can be moved. These limits of
movement are imposed on the
mandible.
 The envelope of motion can be
altered in a limiting way by teeth
that interfere with physiologic
masticatory muscle function.

69. 69
EXAMINATION OF TMJ
1. History taking
2. Measuring maximum interincisal opening
3. Palpation of pretragus area ; the lateral aspect of
TMJ
4. Intra – auricular palpation ; the posterior aspect of
TMJ
5. Palpation of masseter muscle
6. Palpation of lateral pterygoid muscle
7. Palpation of medial pterygoid muscle
8. Palpation of temporalis muscle

70. 70
2. The maximum opening distance
between the incisal edges of upper
and lower incisor is measured using
scale , Boley gauge or ruler
 Normal opening – 40 to 55 mm
 Normal opening can also be
estimated by patient’s own finger
 Normal : three finger end on end
 Two finger opening reveals
reduction in opening but not
necessarily reduction in function
 One finger opening indicates
reduced function

71. 71
 Normal lateral range of movement is >7-10mm
 PROTRUSIVE: 10-14mm

72. 72
DEVIATION ON OPENING
 The opening pathway
deviates from the
straight opening, but the
midline returns to
normal at maximum
opening.

73. 73
3. Palpation of pretragus area ; the lateral aspect of
TMJ

74. 74
4. Intra – auricular palpation ; the posterior aspect of
TMJ

75. 75
5. PALPATION OF
MASSETER MUSCLE
 Palpate multiple areas of
the masseter muscle
 As with temporalis
muscle,it can be located
when patient’s jaw are
opened maximum

76. 76
6. PALPATION OF LATERAL PTERYGOID MUSCLE
 The muscle is palpated by using the little or index
finger and placing it lateral to maxillary tuberosity
and medial to coronoid process.The finger presses
upwards and inwards and a painful response can
be determined .

77. 77
7. PALPATION OF MEDIAL PTERYGOID MUSCLE
 Anterior part of insertion can be palpated by
placing the finger at 45 degrees in the floor of the
patients mouth near base of the relaxed tongue.
 The opposite hand can be used to extraorally to
palpate posterior and inferior portions of insertion.
 Body of the muscle can be palpated by rotating the
index finger upwards against the muscle to near
its origin on the tuberosity.

78. 78
8. PALPATION OF TEMPORALIS MUSCLE
 Temporalis muscle can be seen and readily
palpated throughout entire length and breadth
when the patient’s teeth are firmly clenched.

79. 79
EXAMINATION FOR HEALTHY
TMJ
1. Screening History
2. Load Test
3. Range and Path of
Movement test
4. Doppler analysis
5. Radiograph/Imaging
6. Anterior bite plane for
muscle deprogramming

80. 80
 The changes in mandible
and maxilla occurs slowly
over a period of time
 Articular surfaces of TMJ undergo slow
but continuous remodelling throughout
life
PROSTHODONTIC IMPLICATIONS

81. 81
 Neuromuscular harmony depends on structural
harmony between the occlusion and
temporomandibular joints. - DAWSON

82. 82
VERTICAL DIMENSION
 The distance between two
selected anatomic or marked
points (usually one on the tip
of the nose and the other upon
the chin), one on a fixed and
one on a movable member.
(GPT-8).
 Dictated by repetitious
position of contracted length of
elevators

83. 83
 The vertical dimension determined by contracted length
of elevators, sets the limit of jaw separation to which
teeth erupts

84. 84
CENTRIC RELATION
 The maxillomandibular relationship in which the
condyles articulate with the thinnest avascular
portion of their respective disks with the complex in
the anterior-superior position against the shapes of
the articular eminencies. This position is
independent of tooth contact. This position is
clinically discernible when the mandible is directed
superior and anteriorly. It is restricted to a purely
rotary movement about the transverse horizontal
axis (GPT-5)

85. 85
Triad of strong elevator muscles
moves the condyle-disk assembly
up on posterior slopes of the
articular tubercle
The LATERAL PTERYGOID
relaxes and stays relaxed during
complete closure
Complete seating of the condyles
in superior most position
CENTRIC RELATION

86. 86
 A: SUPERFICIAL MASSETER moves
the condyle up against the posterior
slope
 B: The MEDIAL PTERYGOID
moves THE CONDYLES UP from
the lingual side of the mandible
 C: The TEMPORALIS attach to the
coronoid process between the teeth
and the TMJs and moves THE
CONDYLE up

87. 87
Age changes of the TMJ:
 Arrticular Disc:
 Its steepness is variable (initially 25 degree) and becomes flatter in
edentulous subjects.
 Condyle:
 Becomes more flattened
 Fibrous capsule becomes thicker.
 Osteoporosis of underlying bone.
 Thinning or absence of cartilaginous zone.
 Disc:
 showing fraying, thining and perforation
 Shows hyalinization and chondroid changes.
 Synovial fold:
 Become fibrotic with thick basement membrane.

88. 88
These age changes lead to:
 Decrease in the synovial fluid formation
 Impairment of motion due to decrease in the disc
and capsule extensibility
 Decrease the resilience during mastication due to
chondroid changes into collagenous elements
 Dysfunction in older people

89. 89

90. 90
CLASSIFICATION OF TMD
1. Occluso-muscle disorder
2. Intracapsular disorders
3. Disorder that mimic TMDs

91. 91
OCCLUSO MUSCLE PAIN
Occlusal Interferences causes
Displacement of TMJ to achieve
maximum intercuspation
Leading to incordination of
masticatory musculation
Muscle Hyperactivity and Pain

92. 94
MOST COMMON CONDITIONS AFFECTING TMJ IN A
PROSTHETIC SET UP
 Occlusal discrepencies
 Dysharmony between centric relation & occlusion
 Bruxism
 Emotional stress (mostly in edentulous patients)

93. 95
OTHER FACTORS AFFECTING TMJ
 Trauma
 Mal-alignment of the occlusal surfaces of the teeth
due to defective crowns or other restorative
procedures.
 Excessive gum chewing or nail biting.
 Degenerative joint disease, such as osteoarthritis

94. 96
PRIMARY REQUIREMENTS
FOR SUCCESSFUL
OCCLUSAL THERAPY
 Stable TMJ
 Non interfering post. teeth
 Anterior teeth in harmony
with envelope of
function
 Masticatory muscle
function is affected by the
other 3 structures.

95. 97

96. 98
TREATMENT
 Restoration of the occlusal
surfaces of the teeth:
Selective reshaping of teeth
Crown & bridges , Implants
 Occlusal Splint (also called
night guards or mouth guards)
 Orthodontic treatment &
Orthognathic Surgery

97. 99
OCCLUSAL SPLINTS

98. 100
 An occlusal splint is a removable device made of
hard acrylic resin creating precise occlusal contact
with the teeth of the opposing arch.

99. 101
PRIMARY FUNCTION OF OCCLUSAL
SPLINTS
 Temporarily provide an
orthopedically musculoskeletal
stable joint position.
 Introduces an optimum occlusal
condition that prevents the
muscular hyperactivity.
 Used to protect teeth from
excessive tooth wear.

100. 102
SECONDARY FUNCTION OF OCCLUSAL SPLINTS
 Stablization of week teeth
 Distribution of occlusal forces
 Stablization of unopposed teeth

101. 103
1. The Permissive Splint
Stabilizing appliance are generally
used to treat muscle pain disorders.
(also called as Muscle De-
programmer)
2. The Directive Splint
Anterior positioning appliance are
used to position or align the condyle
disk assembly
TYPES OF OCCLUSAL SPLINT (COMMONLY USED)

102. 104
INSTRUCTIONS
 The patient is instructed how to properly seat the
appliance and the final seating is done by biting.
 Patients are instructed to wear it in night for
bruxism and in day time for disc problems.

103. 105
SPLINT MANAGEMENT
 A splint should be checked at least once during
the 1st week after delivery and adjustments are
done if required.
 Patients with occlusal splint should preferably be
recalled after 3 months months.

104. 106
CONCLUSION
 Dentist must assess the oral function of patients
prior to any treatment, since mastication is the
most important oral function and it is closely
associated with TEMPOROMANDIBULAR JOINT.
 Therefore, examination of TMJ & thorough
knowledge of its anatomy and functioning are the
keys for successful PROSTHODONTIC treatment.

105. REFERENCE
107
1. The Glossary of Prosthodontic Terms – 8; JPD, 2005,
volume 94, no. 1, 10-92.
2. Strandrings. Grays Anatomy. 40th ed., Elsiever, 2008.
3. Jefferey P. Okeson. Management of
Temporomandibular disorders and occlusion. 7th ed,
Elsiever.
4. Peter E. Dawson, Functional Occlusion from TMJ to
smile design.Elsiever.
5. Sharry JJ,Complete Denture Prosthodontics, 3rd ed,
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106. THANK YOU
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