This document provides information on temporomandibular disorders (TMD) including: - TMD is defined as abnormal, incomplete, or impaired function of the temporomandibular joint and muscles of mastication. - TMDs can be classified as masticatory muscle disorders, structural intracapsular disorders, or conditions that mimic TMD. - Etiological factors of TMD include occlusal factors, trauma, emotional stress, parafunction such as clenching or bruxism, and deep pain input. Protective muscle co-contraction, local muscle soreness, myofascial pain, and centrally mediated myalgia are some masticatory muscle disorders discussed.

1. PRESENTED BY,
Dr.SHARI.S.R
JUNIOR RESIDENT
DEPT.OF PROSTHODONTICS
GDC ,TVM

2. CONTENTS
TMD-Definition
Functional anatomy
Epidemiology
Etiology
Diagnosis
Treatment
Discussion
Classification
Review of literature
Conclusion

3. Functional anatomy

4. The area where the mandible articulates with the temporal
bone of the cranium is called the temporomandibular joint
(TMJ)

5. TYPE OF JOINT
TMJ is a Synovial joint between :
The condylar head of the mandible &
the mandibular fossa of squamous
part of temporal bone.
The joint cavity is filled with
Synovial fluid.
The articular surfaces are covered by
fibro cartilage.

6. SYNONYMS
Craniomandibular articulation
Ginglymus joint ( By function) allows Gliding movement
Diarthrodial joint (By function) allows rotational movements
Mandibular joint
Synovial joint ( By structure) contains Synovial cavity

7. 1. Condyle
2. Articular fossa
3. The Articular Eminence
4. Articular Disc
5. Capsule
6. Synovial linings
7. Ligaments
8. Muscles
9. Innervation
10. Vascularization

8. Trigeminal nerve
Auriculotemporal nerve
Deep temporal and masseteric nerves.
Innervation

9. Vascularization
The predominant vessels are :
The superficial temporal artery from the posterior,
The middle meningeal artery from the anterior and
The internal maxillary artery from the inferior
Other important arteries are :
the deep auricular,
anterior tympanic, and
ascending pharyngeal arteries.

10. TMD
Functional Occlusion: From TMJ to Smile Design- PETER E DAWSON

11. DEFINITION:“Temporomandibular disorders are
conditions producing abnormal, incomplete, or
impaired function of the temporomandibular
joint(s) and/or the muscles of mastication.”(GPT-9)
GPT 9

12. The dental profession generally was first drawn into the area of TM
disorders (TMDs) by Costen’s 1934 article. Costen was an otolaryngologist
who, based on 11 cases, first suggested that changes in dental condition
were responsible for various ear symptoms.
History of Temporomandibular Disorders
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
The most common therapies provided at that time were bite-raising
appliances first suggested and described by Costen.

13. CONTENTS
Epidemiology

14. 57 various epidemiological studies report :
• An average of 40% to 60% of the population as having at least one
detectable sign associated with TMD.
EPIDEMIOLOGICAL STUDIES
• Studies reveal that the most TMD symptoms are reported by people in the
20- to 40-year age group
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
• It is documented that occlusal contact patterns influence the function of
the masticatory system the occlusal contact pattern may also
influence functional disturbances.

15. CONTENTS
Definition
Functional anatomy
Epidemiology
Etiology
Treatment
Discussion
Diagnosis
Classification
Literature review
Conclusion

16. Classification

17. TMDs can be classified broadly as :
1. Masticatory muscle disorders
2. Structural intracapsular disorders
3. Conditions that mimic TMDs
Functional Occlusion: From TMJ to Smile Design- PETER E DAWSON

18. More specific classification [PETER E DAWSON ]
Category 1: Occluso-muscle disorders with no intracapsular defects.
Category 2 :Intracapsular disorders that are directly related to occlusal
disharmony and are reversible in re-establishing comfortable function
if the occlusion is corrected.
Category 3 :Intracapsular disorders that are not reversible, but because
of adaptive changes, can function comfortably if occluso-muscle
harmony is re-established.
Category 4 :Nonadapted intracapsular disorders that may be either
primary or secondary to occlusal disharmony or may be unrelated.
Functional Occlusion: From TMJ to Smile Design- PETER E DAWSON

19. Masticatory muscle disorders
Temporomandibular joint
(TMJ) disorders
Chronic mandibular hypomobility
Growth disorders
• Protective co-contraction
• Local muscle soreness
• Myofascial pain
• Myospasm
• Centrally mediated myalgia
• Derangement of the condyle-disc complex
• Structural incompatibility of the articular surfaces
• Inflammatory disorders of the TMJ
• Ankylosis
• Muscle contracture
• Coronoid impedance
• Congenital and developmental bone disorders
• Congenital and developmental muscle disorders
Classification System for Diagnosing Temporomandibular Disorders
[ OKESON JP ]
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

20. CLASSIFICATION
[American Academy of Orofacial Pain] – McNeil
Articular
•Developmental
Deviation of form.
•Disc displacement
With reduction.
Without reduction.
•Hypermobility.
•Dislocation.
•Inflammatory
Synovitis.
Capsulitis.
•Arthritides
Osteoarthrosis.
Osteoarthritis.
Polyarthritides.
•Ankylosis
Fibrous / bony
Non-Articular OR Masticatory muscle disorders.
•Myofascial pain.
•Myositis.
•Spasm.
•Protective splinting.
•Contracture.
•Neoplasia.
McNeill Charles : Management of temporomandibular disorders. J Prosthet Dent 1997; 77: 510-22.

21. CONTENTS
Definition
Functional anatomy
Epidemiology
Etiology
Treatment
Discussion
Diagnosis
Classification
Literature review
Conclusion

22. CONTENTS
Etiology

23. TMD
ETIOLOGIC FACTORS
TMD
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

24. OCCLUSAL FACTORS
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
The effects of occlusal factors on orthopedic stability
Orthopedic stability exists when the stable intercuspal position of the teeth is in
harmony with the musculoskeletally stable position of the condyles in the fossae.
Functional forces can be applied to the teeth and joints without tissue injury.

25. occlusal instability
but still joint stability
the mandible is shifted forward
and the intercuspal position is achieved
Occlusal loading - intracapsular disorder.
condyles in their musculoskeletally
stable position

26. The
THE EFFECTS OF ACCUTE CHANGES IN THE OCCLUSAL CONDITION AND TMJ
• Accute change produce protective co-contraction.
• Inhibitory effect on parafunctional activity

27. TRAUMA
Greater impact on intracapsular disorders than on muscular disorders.
Macrotrauma [ eg :-Direct blow to the face ]
Trauma
Microtrauma. [ eg :-Clenching, Bruxism ]
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

28. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Stress affects the body by activating the
hypothalamic-pituitary-adrenal (HPA) axis
The HPA axis
[ through complex neural pathways]
Increases the activity of the gamma efferents
Intrafusal fibers of the muscle spindles to contract
sensitized spindles
Any slight stretching of the muscle will cause a
reflex contraction
Increase in the muscle’s tonicity.
EMOTIONAL STRESS

29. DEEP PAIN INPUT

30. PARAFUNCTION
Diurnal activity - Parafunctional activity during the day
Clenching
Grinding
Other oral habits often performed without the individual’s awareness
Nocturnal activity
Form of single episodes - Clenching
Rhythmic contractions - Bruxing
Bruxing events
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

31. TMDs can be classified broadly as :
1. Masticatory muscle disorders
2. Structural intracapsular disorders.
Functional Occlusion: From TMJ to Smile Design- PETER E DAWSON

32. Occluso-Muscle Disorders
Functional Occlusion: From TMJ to Smile Design- PETER E DAWSON

33. Masticatory muscle Disorders
• Protective co-contraction
• Local muscle soreness
• Myofascial pain
• Myospasm
• Centrally mediated myalgia
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

34. Protective co-contraction [ protective muscle splinting ]
Deep pain input or an increase in emotional stress
Sudden change in sensory or proprioceptive input from associated
structures
CNS response to injury or threat of injury
First response of the masticatory muscles
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Key to identify Protective splinting immediately follows an event
If continues for several hours or days, the muscle tissue can
become compromised and a local muscle problem may develop

35. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Local muscle soreness (Noninflammatory Myalgia)
The first response of the muscle tissue to prolonged co-contraction
The most common type of acute muscle pain seen in dental practice
Inflammatory changes in the local environment of the muscle tissues.
release of certain algogenic substances (i.e., bradykinin,
substance P, histamine)
produce pain
Muscles - tender to palpation
- increased pain with function
- actual muscle weakness
Eg :- If elevator muscles are involved -- limited mouth opening

36. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Myospasm(Tonic Contraction Myalgia)
Etiology :-
Muscle fatigue & changes in local electrolyte balances.
Deep pain input
Results in –
• Structural dysfunction - major positional changes in the jaw -
acute malocclusions.
• Firm muscle on palpation
Myospasms are short-lived, lasting for only minutes
Uncontrolled muscle contractions repeated over time = Dystonia

37. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Myofascial pain ( Trigger point myalgia)
Deep pain input
+
Increased levels of emotional stress
[ upregulation of the autonomic nervous system ]
excite peripheral sensory neurons
(primary afferents)
antidromic release of algogenic substances into the peripheral tissues
(neurogenic inflammation)
muscle pain

38. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Centrally mediated myalgia
Chronic, continuous muscle pain disorder originating predominantly from CNS
effects that are felt peripherally in the muscle tissues.
Prolonged nociceptive input
Can result in an antidromic effect on afferent peripheral neurons.
Neurons that normally only carry information from the periphery into the CNS can
now be reversed to carry information from the CNS out to the peripheral tissues
The afferent neurons in the periphery can release nociceptive
neurotransmitters (e.g., substance P, bradykinin)
Peripheral tissue pain.
Neurogenic inflammation

39. Intracapsular Disorder of the TMJ.
Any disease, deformation, or disorder that involves the
tissues within the capsule of the TMJ.

40. Intracapsular Disorder of the TMJ.
 Derangement of the condyle-disc complex
• Displacement of the disc.
• Dislocation with reduction
• Dislocation without reduction
 Structural incompatibility of articular surfaces
• Deviation of form
• Adhesions
• Subluxations
• Spontaneous dislocation
 Inflammatory disorders
• Synovitis
• Capsulitis
• Retrodiscitis
• Arthitides.

41. Functioning of normal healthy joint.
• Inferior joint cavity
• Superior joint cavity
• Absence of intra articular pressure-----joint dislocate.
• Superior retrodiscal lamina
• During opening----superior retrodiscal lamina rotates disc
posteriorly & condyle moves anteriorly
• During closing---- superior lateral pterygoid rotates
condyle forward & condyle moves posteriorly.

43. Functioning of normal healthy joint.
• The disc maintains its position on the condyle during
movement because of its morphology and interarticular
pressure.
• If morphology is altered discal ligaments elongate,disc is
permitted to translate across articular surface of condyle.
BIOMECHANICS OF JOINT ALTERED

44. Progressive events in condyle – disc dysfunction

45. 1. Normal healthy joint
2. A loss of normal condyle-disc function due to either
a. Macrotrauma, resulting in elongation of the discal ligaments
b. Microtrauma, causing changes in the articular surface and reducing the
frictionless movement between the articular surfaces
3. Abnormal translatory movement between the disc and condyle begins.
4. The posterior border of the disc becomes thinned.
5. There is further elongation of the discal and inferior retrodiscal ligaments.
6. The disc becomes functionally displaced.
a. Single click
b. Reciprocal click
7. The disc becomes functionally dislocated.
a. Dislocation with reduction (catching)
b. Dislocation without reduction (closed lock)
8. Retrodiscitis
9. Osteoarthritis
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

46. 1. Normal healthy joint

47. 1. Normal healthy joint
2. A loss of normal condyle-disc function due to either
a. Macrotrauma, resulting in elongation of the discal ligaments
b. Microtrauma, causing changes in the articular surface and reducing the
frictionless movement between the articular surfaces
3. Abnormal translatory movement between the disc and condyle begins.
4. The posterior border of the disc becomes thinned.
5. There is further elongation of the discal and inferior retrodiscal ligaments.
6. The disc becomes functionally displaced.
a. Single click
b. Reciprocal click
7. The disc becomes functionally dislocated.
a. Dislocation with reduction (catching)
b. Dislocation without reduction (closed lock)
8. Retrodiscitis
9. Osteoarthritis
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

48. 2. A loss of normal condyle-disc function due to either
a. Macrotrauma, resulting in elongation of the discal ligaments
b. Microtrauma, causing changes in the articular surface and reducing the
frictionless movement between the articular surfaces
Macrotrauma
Any sudden force to the joint that can result in structural alterations.
Direct - blow to the chin,
Indirect trauma - injury that may occur to the TMJ secondary to a sudden force but
not one that occurs directly to the mandible. Eg :- cervical extension-flexion injury
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Microtrauma
Any small force that is repeatedly applied to the joint structures over a long period
of time. Eg :- bruxism or clenching

49. Mechanism : 1
1. Functional limitation of load exceeded
2. Collagen fibrils become fragmented( ARTICULAR SURFACE)
3. Decrease in the stiffness of the collagen network
4. Allows proteoglycan-water gel to swell and flow out into the joint space
5. Softening of the articular surface
6. Chondromalacia .
7. Loading continues to exceed the capacity of the articular tissues
8. Irreversible changes
9. Regions of fibrillation begin to develop
10. Focal roughening of the articular surfaces
11. This alters the frictional characteristics
12. Lead to sticking of the articular surfaces
13. changes in the mechanics of condyle-disc movement
14. Continued sticking and/ or roughening
15. Leads to strains on the discal ligaments during movements
16. Disc displacements.
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

50. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Mechanism : 2
Hypoxic/reperfusion theory
1. The forces applied to the articular surfaces can exceed the capillary
pressure of the supplying vessels
2. Hypoxia
3. When the interarticular pressure returns to normal, the blood is
reperfused into the capillaries supplying the joint structures.
4. Free radicals are released.
5. It cause breakdown of hyaluronic acid that protects phospholipids
that line the joint surfaces and joint moves with friction.
6. Friction between articular surfaces leading to breakdown.
7. The resulting sticking can lead to disc displacement.

51. 1. Normal healthy joint
2. A loss of normal condyle-disc function due to either
a. Macrotrauma, resulting in elongation of the discal ligaments
b. Microtrauma, causing changes in the articular surface and reducing the
frictionless movement between the articular surfaces
3. Abnormal translatory movement between the disc and condyle begins.
4. The posterior border of the disc becomes thinned.
5. There is further elongation of the discal and inferior retrodiscal ligaments.
6. The disc becomes functionally displaced.
a. Single click
b. Reciprocal click
7. The disc becomes functionally dislocated.
a. Dislocation with reduction (catching)
b. Dislocation without reduction (closed lock)
8. Retrodiscitis
9. Osteoarthritis
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

52. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
3.Abnormal translatory movement between the disc and
condyle begins.
4. The posterior border of the disc becomes thinned.
5. There is further elongation of the discal and inferior
retrodiscal ligaments

53. 1. Superior lateral pterygoid muscle hyperactivity
2. Influence on the disc position
3. The condyle translates across the disc to intermediate zone
4. Increased interarticular pressure prevent the smooth sliding of articular surfaces
5. The disc can stick or be bunched slightly
6. Abrupt movement of the condyle over it into the normal condyle-disc relationship
7. Clicking sound – Single click
8. The normal relationship of the disc and condyle is reestablished
9. This relationship is maintained during the rest of the opening movement.
10. Early stages of disc derangement disorder
11. internal derangement.

54. 12. If this continues ---second stage derangement
13.Disc is more anteriorly and medially placed.
14. On closing the jaw ------Less superior retrodiscal pull,combination of disc
morphology and pull of superior lateral pterygoid muscle
15.Disc slip back into more anterior displaced position.
16. Thus final movement of condyle across the posterior border of the disc creates a
second clicking called Reciprocal click.

55. 1. Normal healthy joint
2. A loss of normal condyle-disc function due to either
a. Macrotrauma, resulting in elongation of the discal ligaments
b. Microtrauma, causing changes in the articular surface and reducing the
frictionless movement between the articular surfaces
3. Abnormal translatory movement between the disc and condyle begins.
4. The posterior border of the disc becomes thinned.
5. There is further elongation of the discal and inferior retrodiscal ligaments.
6. The disc becomes functionally displaced.
a. Single click
b. Reciprocal click
7. The disc becomes functionally dislocated.
a. Dislocation with reduction (catching)
b. Dislocation without reduction (closed lock)
8. Retrodiscitis
9. Osteoarthritis
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

56. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Disk dislocation with reduction:
The disk is displaced from its position between the condyle
and the eminence to an anterior and medial or lateral position, but
reduces on full opening, usually resulting in a noise.
Etiology:
• macro/microtrauma (elongation of the capsular and discal
ligaments +thinning of the articular disc)
• orthopedic instability plus joint loading.
History:
When macrotrauma is the etiology the patient will often
relate an event that precipitated the disorder. The patient will also
report the presence of joint sounds and catching sensation during
mouth opening

57. Clinical characteristics:
• Normal range of movement is present after the disc is recaptured
during opening of mouth.
• Discal movement can be felt by palpation of the joints during opening
and closing.
• Deviations in the opening pathway are common.
• Presence of catching sensation present.

58. Disk displacement without reduction (closed lock)
A condition in which the disk is displaced from normal position
between the condyle and the fossa to an anterior and medial or lateral
position, associated with limited mandibular opening
Etiology:
Macrotrauma and microtrauma are the most common cause.
History:
• Patients most often report the exact onset of this disorder.
• The history may reveal a gradual increase in intracapsular symptoms
(clicking and catching) prior to the dislocation.

59. Clinical characteristics:
• Examination reveals limited mandibular opening (25-30mm).
• Normal eccentric movement to the ipsilateral side and restricted
eccentric movement to the contralateral side.
• Deviation on opening present.

60. Factors that predispose to disc derangement disorders
1. Steepness of the articular eminence
2. Morphology of the condyle and fossa
3. Joint laxity.
4. Hormonal factors.
5. Attachment of the superior lateral pterygoid muscle
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

61. Structural in compatibility of articular surfaces.
• Deviation in form.
• Adhesion.
• Subluxation (Hypermobility).
• Spontaneous dislocation (open lock).

62. Deviation in form:
Change in the shape of the articular surfaces
• Flattening of condyle/fossa.
• Bony protuberance on the condyle.
• Thinning of the borders of the disc.
• Perforations of the disc.

63. Adherence/Adhesion:
Adherence: Temporary sticking of articular surfaces.
Adhesion: Permanent sticking of articular surfaces.
.
Adherence :
• Due to static loading( as clenching during sleep)
• Single click then back to normal
• Boundary and Weeping lubrication

64. Subluxation / Hypermobility
Sudden forward movement of the condyle during latter
phase of mouth opening.
During maximal opening ---Lateral poles will jump forward
causing a noticeable preauricular depression.
Deviation on opening present
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
• Due to steep posterior slope of articular eminence.
• Rotational movement of disc is fully utilized before
complete translation of condyle
• So bodily shift occurs ------THUD SOUND.

65. Spontaneous dislocation or open lock
• If mouth is opened beyond its limit and the mandible
locks.
• Fixing the joint in open postion without any translation.
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

66. Inflammatory joint disorders
• Synovitis
• Capsulitis
• Retrodiscitis
• Arthritides.
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

67. Synovitis
The synovial tissues that line the recess areas of the joint become inflamed
Caused by any irritating condition within the joint( microtrauma)
Constant intracapsular pain that is enhanced by joint movement
Tenderness on lateral aspect of condyle is palpated.
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

68. The capsular ligament becomes inflamed
Capsulitis
• Etiology - macrotrauma (especially an open-mouth injury ).
• SAME clinical features of synovitis.
• Differential diagnosis by arthroscopy.
Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.

69. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Retrodiscitis
Etiology –
• Macrotrauma (especially an open-mouth injury ),
• Microtrauma.(As the disc is thinned and the ligaments become
elongated, the condyle begins to encroach on the retrodiscal tissues).
Clinical feature:-
 Constant dull, aching pain that is often increased by clenching.
 Severe inflammation leads to swelling and force the condyle slightly
forward down the posterior slope of the articular eminence. This shift
can cause an acute malocclusion. Ie, DISOCCLUSION
Inflammation of retrodiscal tissues are highly vascularized and innervated

70. Management of temporomandibular disorders and occlusion / Jeffrey P. Okeson. -- 7th ed.
Inflammation of articular surfaces of the joint.
Group of disorders in which destructive bony changes are seen
Arthritidis
Most common - TMJ osteoarthritis (degenerative joint disease)
1. Loading forces continue
2. Articular surface becomes softened (chondromalacia)
3. Subarticular bone begins to resorb
4. Progressive degeneration results in loss of the subchondral cortical layer
5. bone erosion & osteoarthritis.
once loading is decreased, the arthritic condition can become adaptive. The
adaptive stage is known as osteoarthrosis
Pain
Crepitus

71. REMAINING TOPICS WILL BE COVERED IN THE NEXT SECTION.
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