Temporomandibular Dysfunctions – Part 1(Etiology, Sign and Symptoms)

1. Temporomandibular
Dysfunctions – Part 1
(Etiology, Sign and Symptoms)
Presented by:
Bishow Prakash Thakur
PG Resident
Department of orthodontics and Dentofacial orthopaedics
Peoples Dental College and Teaching Hospital
Kathmandu, Nepal

2. Contents
Part I
• Etiology of Functional Disturbances in the Masticatory
System
• Signs and Symptoms of Temporomandibular Disorders
Part II
• History of and Examination for Temporomandibular
Disorders
• Diagnosis of Temporomandibular Disorders
2

3. Etiology of Functional
Disturbances in the
Masticatory System
Etiology
?
The clinician who only looks at occlusion is missing as much as the clinician
who never looks at occlusion
— Jeffrey P Okeson

4. Topics
• Terminology
• History of Temporomandibular Disorders
• Epidemiologic Studies of Temporomandibular Disorders
• Etiologic Considerations in Temporomandibular
Disorders
• Etiologic factors underlying TMDs
• Occlusal factors
• Trauma
• Emotional stress
• Deep pain input
• Parafunction
4

5. Terminology
• Over years functional disturbances of masticatory
system have been identified by a variety of terms
• In 1934, James Costen gave term Costen syndrome for
pain centering around ear and TMJ, which later became
popular as term TMJ disturbances
• In 1959, Shore introduced term TMJ dysfunction
syndrome
• Ramfjord and Ash termed Functional TMJ disturbances
5

6. Terminology
• Later, on the basis of etiology it was termed as:
• Occlusomandibular disturbance
• Myoarthropathy of TMJ
• Few stressed on Pain, so termed as
• Pain-dysfunction syndrome
• Myofascial pain-dysfunction syndrome
• TM pain-dysfunction syndrome
• Symptoms are not always related to TMJ, so broader
term Craniomandibular disorders was suggested
6

7. Terminology
• In 1982, Bell suggested term Temporomandibular
disorders which includes disturbances related to
function of masticatory system
• Later in 1983, American Dental Association adopted
the term Temporomandibular disorders to include all the
functional disturbances in masticatory system
7

8. History of Temporomandibular Disorders
• In 1934:
• Based on 11 cases, Coston suggested dental condition
were responsible for various ear symptoms and TMJ
pain, since then Dentists were drawn into area of TMDS
(Costen JB: Syndrome of ear and sinus symptoms dependentupon functions of the
temporomandibular joint, Ann Otol RhinolLaryngol 3:1–4, 1934 )
• In late 1930s- 1940s:
• Dentist managed these problems by using bite raising
appliances described by Coston
8

9. History of Temporomandibular Disorders
• In Late 1940s- 1950s:
• Dentist began to look closely at occlusal interferences as
major etiology factors in TMD complains
• In 1950s:
• First scientific investigations in TMDs using
Electromyography began which suggested occlusal
condition could influence masticatory muscle function
• First textbook describing masticatory dysfunction was
written
9

10. History of Temporomandibular Disorders
• In 1960-1970s:
• Occlusion and Emotional Stress were considered as
major etiologic factor for TMDs
• In 1990s- 2000s:
• Dentists embraced concept of evidence-based medicine,
and training programmes to manage TMD patients
• In 2010:
• Commission on Dental Accreditation (US), recognized and
standardize these programs hoping that these
advancements in research and education will greatly
improve diagnosis and management of TMD
10

11. Epidemiologic Studies of TMDs
11

12. Epidemiologic Studies of TMDs
12

13. Epidemiologic Studies of TMDs
• 57 epidemiologic studies of variety of populations that
attempted to look at relationship between occlusion and
signs and symptoms associated with TMD
• 22 studies found no relationship between occlusal
factors and TMD symptoms
• 35 studies found relationship between occlusal factors
and TMDS
• Confusion and controversy concerning relationship
between occlusion and TMDs
13

14. Etiologic Considerations in TMDs
• No single etiology that accounts for all signs and
symptoms
• To simplify how TMDs Symptom develop, Following
formula is suggested:
14
Normal Function
+
Event
Physiologic
Tolerance
TMD
Symptoms
Exceeds
• High restoration
• LA injection
• Trauma
• Bruxism
• Stress

15. Etiologic factors underlying TMDs
• Review of the scientifc literature reveals five major
factors associated with TMD
15
1.
2.
3.
4.
5.

16. 1. Occlusal Factors
• In past, it was very convinced that occlusion was most
important contributing factor in TMD
• Recently, many researchers have argued that occlusal
factors play little to no role in TMD
• Even if there is little role, it should be properly identified
and managed properly
• Sound static and dynamic occlusal relationships and
stability are basic to successful masticatory function
16

17. Static relationship between Occlusal Factors
and TMDS
• Pullinger (1993) studied relationship between combination
of occlusal factors in TMDs patient ,using blinded
multifactorial analysis
• Interaction of 11 occlusal factors was considered in
randomly collected groups compared with asymptomatic
controls
• They concluded that no single occlusal factor could
differentiate TMDs patients from healthy subjects
17
Pullinger AG, Seligman DA, Gornbein JA: A multiple logistic regression analysis of
the risk and relative odds of temporomandibular disorders as a function of common
occlusal features, J Dent Res 72(6):968–979, 1993

18. Static relationship between Occlusal Factors
and TMDS
• 4 occlusal features that occurred mainly in TMD patients
and were rare in normal
1. Skeletal anterior open bite
2. Retruded contact position to intercuspal contact position
slides of greater than 2 mm
3. Overjet of greater than 4 mm, and
4. 5 or more missing and unreplaced posterior teeth
• They also concluded occlusion cannot be considered most
important etiologic factor associated with TMD
18
Pullinger AG, Seligman DA, Gornbein JA: A multiple logistic regression analysis of
the risk and relative odds of temporomandibular disorders as a function of common
occlusal features, J Dent Res 72(6):968–979, 1993

19. Dynamic functional relationships between
occlusion and TMDs
• Considering dynamic functional relationship, occlusal
condition can impact TMDs in 2 ways:
i. Effects of occlusal factors on orthopedic stability
ii. Effects of acute changes in occlusal condition and
temporomandibular disorders
19

20. Effects of occlusal factors on orthopedic stability
• Orthopedic stability exists when stable intercuspal
position of teeth is in harmony with musculoskeletally
stable position of condyles in fossae
• If there is disharmony, overloading and injury can occur
leading to TMDs
20

21. Effects of occlusal factors on orthopedic stability
21
Fig: A. With the teeth apart, the elevator muscles maintain the condyles in their
musculoskeletally stable positions (superior-anterior positions resting against the
posterior slopes of the articular eminences). In this situation there is joint stability

22. Effects of occlusal factors on orthopedic stability
22
Fig: B. As the mouth is closed, a single tooth contact does not allow the entire dental
arch to gain full intercuspation. At this point there is occlusal instability but still joint
stability. Since the condyles and teeth do not fit in a stable relationship at the same
time, this is orthopedic instability

23. Effects of occlusal factors on orthopedic stability
23
Fig: C. In order to gain the occlusal stability necessary for functional activities, mandible is
shifted forward and intercuspal position is achieved. At this point patient achieves occlusal
stability but condyles may no longer be orthopedically stable.
This orthopedic instability may not pose a problem unless unusual loading occurs. If loading
begins, condyles will seek out stability and unusual movement can lead to strains on
condyle/disc complex, resulting in an intracapsular disorder.

24. Effects of occlusal factors on orthopedic stability
• 2 factors determine whether intracapsular disorder will
develop:
i. Degree of orthopedic instability:
• Orthopedic instabilities with discrepancies greater than 3-
4 mm
ii. Amount of loading
• Bruxing patient
• Forceful unilateral chewing
24

25. Effects of occlusal factors on orthopedic stability
• Dental malocclusion does not necessarily reflect any risk
factors for development of functional disturbances in
masticatory system
• Only by observing occlusal relationship with respect to
stable joint position can one appreciate degree of
orthopedic instability that is present
• Term Stable malocclusion must be introduced in
dentistry where malocclusion is not creating TMDs
25

26. Effects of acute changes in occlusal condition and
TMDs
• It has been demonstrated that introducing a slightly high
contact between teeth can induce masticatory muscle
pain in some individual
Occlusal contacts and muscle hyperactivity :
• Increased muscle activity is associated with bruxism,
clenching, increased muscle tonicity (related to habits),
posture, or increased emotional stress
• High occlusal contact could increase muscle activity such
as bruxism
26

27. Effects of acute changes in occlusal condition and
TMDs
27
Fig: The nociceptive reflex is activated by unexpectedly biting on a high point. The noxious
stimulus is initiated when tooth and periodontal ligament is stressed. Afferent nerve fibers
carry the impulse to the trigeminal spinal tract nucleus which stimulate both excitatory and
inhibitory interneurons. Inhibitory interneurons synapse with efferent fibers leading to the
elevator muscles. The message carried is to discontinue contraction. Excitatory
interneurons synapse with the efferent neurons that innervate the jaw, depressing
muscles. The message sent is to contract, which brings teeth away fromnoxious stimulus

28. Etiologic factors underlying TMDs
• Review of the scientifc literature reveals five major
factors associated with TMD
28
2.

29. 2. Trauma
• Trauma seems to have a greater impact on intracapsular
disorders than on muscular disorders
• 2 types of Trauma:
1. Macro trauma: sudden force resulting in structural
alterations eg: direct blow to face
2. Micro trauma: Small force that is repeatedly applied to
over a long period of time eg: bruxism or clenching
29

30. 3. Emotional Stress
• “The nonspecific response of body to any demand made
upon it” – Hans Selye
• Emotional centers in brain have influence on muscle
function
• Different structures / system associated with individual’s
emotional state includes:
• Hypothalamus
• Reticular system and
• Limbic system
30

31. 3. Emotional Stress
• Stress activates hypothalamic pituitary-adrenal (HPA)
axis, which in turn prepares body to respond (through
autonomic nervous system)
31

32. 3. Emotional Stress
• The HPA axis, through complex neural pathways,
increases activity of gamma efferents, which causes
intrafusal fibers of the muscle spindles to contract
32

33. 3. Emotional Stress
33
• Thus Stress causes
• Increase in tonicity of head and neck muscles
• Influence individual’s sympathetic activity or tone to
prepare for Fight and Flight response
• Therefore Stress represents an etiologic factor that can
influence TMD symptoms

34. 4. Deep Pain Input
• Deep pain input can centrally excite CNS, producing a
muscle response called protective co-contraction, which
is normal response of body
• Eg: Patient suffering with toothache have limited mouth
opening but as soon as pain is resolved, mouth opening
restores
• Source of constant pain may be:
• Tooth pain
• Sinus pain
• Ear pain or
• Referred Pain from sources remote to face, such as
cervical pain
34

35. 4. Deep Pain Input
• Any source of constant deep pain input can represent an
etiologic factor that may lead to limited mouth opening
and therefore clinically present as TMD
• If clinician does not recognize this phenomenon,
however, he or she may conclude that limited mouth
opening is a primary TMD problem and treatment would
be misdirected
35

36. 5. Parafunctional activity
• Activities of masticatory muscles can be divided into 2
basic types:
1. Functional : includes chewing, speaking, and
swallowing
2. Parafunctional (nonfunctional): includes bruxism,
clenching, grinding teeth or other oral habits
• For purposes of discussion, parafunctional activity can
be subdivided into two type:
a) Diurnal activity
b) Nocturnal activity
36

37. Diurnal Parafunctional activity
• Occurs during day
• Includes:
• Clenching and Grinding of teeth
• Habits (Cheek and tongue biting, Finger
and thumb sucking)
• Occupation-related activities
eg: biting on pencils, pins, or nails or
holding objects under chin, or underwater
diver biting on mouthpiece
37

38. Diurnal Parafunctional activity
• It is common, during daily activities that individuals place
their teeth together and apply force who is concentrating
on task or performing a strenuous physical work
• In such condition, masseter muscle contracts periodically
• These all activities occur at a subconscious level, so
patient may not be aware of this
• Clinician should make patient aware about possibility of
these diurnal activities, so that patient will recognize them
and can then decrease them
38

39. Diurnal Parafunctional activity
39
Fig: A: Evidence of cheek biting

40. Diurnal Parafunctional activity
40
Fig: B: Lateral borders of
tongue are scalloped,
conforming to lingual surfaces
of mandibular teeth.
Combination of negative
intraoral pressure and forcing
of tongue against
teeth produces this altered
tongue shape

41. Nocturnal parafunctional activity
• Various studies suggest that parafunctional activity
during sleep is common and occurs in form of:
• Single episodes: Clenching
• Rhythmic contractions: Bruxing
• In many patients both activities occur and are difficult to
separate and commonly termed as “Bruxing events”
41

42. Nocturnal parafunctional activity
42
• Light stages:
• Stage 1 and Stage 2
• Deep stage:
• Stage 3 and stage 4
• Non REM sleep:
• Stage 1,2,3 and 4
• REM sleep:
• Stage 5
Fig: stages of sleep

43. Nocturnal parafunctional activity
• Stages of Sleep and Bruxing events:
• Controversy
• Few studies says it takes place mainly during REM stage,
while others says bruxism never occurs during REM sleep
• Some says, It occur during both REM and non-REM sleep
but that mostly is seen in lighter stages (1 and 2) of non-
REM sleep
• Experimentally, by directing a flashing light toward a
sleeping person’s face during change from deeper to
lighter sleep, it induced tooth grinding
43

44. Bruxing events and masticatory symptoms
• Ware and Rugh studied a group of bruxism patients
without pain and another group with pain
• Found that “Pain group” had a signifcantly higher
number of bruxing events during REM sleep than “non
pain group”
44
(Ware JC, Rugh JD: Destructive bruxism: sleep stage relationship, Sleep 11(2):172–
181, 1988.)

45. Muscle activities and masticatory symptoms
• Different factors which determines parafunctional
muscle activities as risk factors for TMDs includes:
i. Force of tooth contacts
ii. Direction of force applied
iii. Mandibular position
iv. Type of muscle contraction
v. Influnces of protective reflex
vi. Pathologic effects
45

46. Muscle activities and masticatory symptoms
46
Factor Functional Activity Parafunctional
Activity
Forces of tooth contacts 17,200 lb/s per day 57,600 lb/s per day,
possibly more
Direction of applied
forces to teeth
Vertical
(well tolerated)
Horizontal
(not well tolerated)
Mandibular position Centric occlusion
(relatively stable)
Eccentric movements
(relatively unstable)
Type of muscle
contraction
Isotonic
(physiologic)
Isometric
(nonphysiologic)
Influence of protective
reflexes
Present Obtunded
Pathologic effects Unlikely Very likely

47. Etiology of Bruxing events
• Occlusal interference: Controversy
• Emotional stress is other factor that cause bruxism
• Rugh et al monitored levels of nocturnal bruxing activity
which demonstrated strong temporal pattern associated
with stressful events
47
Rugh JD, Solberg WK: Electromyographic studies of bruxist behavior before
and during treatment, J Calif Dent Assoc 3(9): 56–59, 1975

48. 48
Fig: Rugh demonstrated that daily stress is reflected in nocturnal masseter muscle activity.
(Adapted from Rugh JD, Solberg WK. In Zarb GA, Carlsson, GE, editors. Temporomandibular
Joint: Function and Dysfunction. St. Louis: Mosby–Year Book; 1979:255

49. 49
Fig: Long-term relationship of stress, muscle activity, and pain. These three
measurements have been obtained from a single subject for a 140-day period.
Shortly after a stressful experience the nocturnal muscle activity increases. Not
long thereafter the subject reports pain. (Adapted from Rugh JD, Lemke RL. In
Matarazzo JD, et al, editors. Behavioral Health: A Handbook of Health
Enhancement and Disease Prevention. New York: Wiley; 1984.)

50. Bruxism in children
• Very common finding in children
• 20% - 38% of children brux
• Unfortunately data on children are very scarce and it is
accepted that although bruxing in children is common, it
is rarely associated with symptoms
50

51. Bruxism in children
• Study by Kieser, out of 126 bruxing children (ages 6-9)
only 17 were still bruxing 5 years later and no associated
symptoms were reported for any
• The study concluded that bruxing in children is a self-
limiting phenomenon, not associated with significant
symptoms and not related to an increased risk of
bruxing as they grow to adulthood
51
Kieser JA, Groeneveld HT: Relationship between juvenile bruxing and
craniomandibular dysfunction, J Oral Rehabil 25(9):662–665, 1998

52. Signs and
Symptoms of
TMDs
YOU CAN NEVER DIAGNOSE SOMETHING YOU HAVE NEVER HEARD ABOUT
—Jeffrey P Okeson

53. Topics
 Functional Disorders of the Muscles
 Clinical Model of Masticatory Muscle Pain
 Functional Disorders of TMJ
 Derangements of condyle-disc complex
 Structural incompatibility of articular surfaces
 Inflammatory joint disorders
53

54. Sign and Symptoms
 Clinical signs and symptoms of masticatory dysfunction
can be grouped into
 Muscles
 Temporomandibular joints and
 Dentition
 Sign: Objective clinical finding that clinician uncovers
during a clinical examination
 Symptom: Description or complaint reported by patient
54

55. Functional Disorders of Muscles
 Most common TMD complains of patient
 Grouped in large category called masticatory muscle
disorder
 2 major symptoms observed by patient:
 Pain
 Dysfunction
55

56. Functional Disorders of Muscles
PAIN:
 Most common complain
 Myalgia: pain felt in muscle
 Symptoms associated is muscle fatigue and tightness
 Pain is due to accumulation of metabolic waste products
in muscle tissue (bradykinins, prostaglandins)
 Another very common symptom associated with
masticatory muscle pain is headache
56

57. Functional Disorders of Muscles
DYSFUNCTION:
 Decrease in range of mandibular movement
 Can be seen as
 Inability to open mouth widely
 Acute malcocclusion due sudden change in resting length
of muscle that controls jaw position
Eg: functional shortening of ILP Muscle result in discocclusion
of posterior teeth in ipsilateral side and premature contact of
canine in contralateral side
57

58. Types of Masticatory muscles disorder
 Many clinicians consider all masticatory muscle disorders
to be same : not true
 There are at least 5 different types of masticatory muscle
disorder
1. Protective co-contraction (muscle splinting)
2. Local muscle soreness
3. Myofascial (trigger point) pain
4. Myospasm and
5. Chronic centrally mediated myalgia
o 6th condition Fibromyalgia must also be considered
58

59. Clinical Model of Masticatory Muscle Pain
Fig: A masticatory muscle model. This model depicts the relationship between various clinically
identifiable muscle pain disorders along with some etiologic considerations
(Modified from the original model developed by Okeson JP, Falace DA, Carlson CR, Nitz A, and
Anderson DT at the Orofacial Pain Center, University of Kentucky, 1991.)
59

60. EVENT:
 Local Factors:
 Tooth fracture
 High restorations ,crowns
 Trauma due to LA injections
 Too wide opening of mouth
60
 Systemic factors:
 Emotional stress
 Acute illness
 viral infections
 Immunologic resistance
 Anatomic balance

61. Protective co-contraction
 Protective Muscle splinting
 Normal CNS response to injury
Eg: increased muscle activity of elevator muscles during
mouth opening. This coactivation of antagonistic muscles is
considered a normal protective or guarding mechanism
 Not a pathologic condition, but if continues for several
hours or days, muscle tissue can become compromised
and a local muscle problem may develop
61

62. Local muscle soreness
 Noninflammatory myalgia
 1st response of muscle tissue to prolonged co-contraction
 Characterized by change in local environment eg: release
of algogenic substances producing pain (bradykinin,
substance P, histamine)
 Clinically, presents as tender to palpation, increased pain,
structural dysfunction, limited mouth opening
62

63. CNS effect on Muscle pain
 May occur
 Secondary to ongoing deep pain input
 Altered sensory input or
 Upregulation of ANS (i.e., emotional stress)
 Centrally influenced muscle pain disorders are divided
into
 Acute myalgic disorders (eg: myospasm)
 Chronic myalgic disorders
Regional myalgic disorders and
Systemic myalgic disorders
63

64. Myospasm
 Tonic contraction myalgia
 Caused by:
 Muscle fatigue, Changes in local electrolyte, Deep pain
input
 May create acute malocclusion
 Short lived, last for few minutes but if repeatedly seen
then condition called dystonia
64

65. Myofascial pain
 Trigger point myalgia
 Trigger point: Firm, hypersensitive, localized area in
muscle and/or their tendinous attachments which elicits
pain
 Certain nerve endings in muscle may become sensitized
by algogenic substances that create localized zone of
hypersensitivity, local temperature rise
65

66. Trigger points
 In many instances, patient are aware only of referred
pain and not even acknowledge trigger points
 May present in
 Active state: produces CNS excitatory effect, Sensitive to
palpation resulting in pain
 Latent state: Not sensitive to palpation
 Pain is most commonly associated with CNS excitatory
effects created by trigger points
66

67. Trigger points and referred pain
67
A trigger point in occipital
belly produce referred
headache pain behind
eye
Trigger points in
sternocleidomastoid
produce refered pain to
temple area
Trigger points in
trapezius produce
refer pain behind
ear, temple, and
angle of jaw

68. Centrally mediated myalgia
 Chronic Myositis
 Characterised by extended duration of symptoms:
 constant, aching myogenous pain
 pain present during rest and increases with function
 Muscles tender on palpation and
 Structural dysfunction is common
 Management must be directed to central mechanisms ,
not muscle tissue
68

69. Chronic systemic myalgia
 Fibromyalgia
 Global musculoskeletal pain disorder that can be
confused with acute masticatory muscle disorder
 It is not a masticatory pain disorder yet many patients
(42 %) often report complaints similar to those
associated with TMD
69

70. Functional Disorders of TMJ
 High prevalence of Signs but not symptoms
 2 major symptoms of functional TMJ problems are:
 Pain: Arthralgia (nociceptors present in discal ligaments,
capsular ligaments, retrodiscal tissues)
 Dysfunction: presents as disruption in condyle-disc
movements with production of joint sounds like click,
popping or crepitations
70

71. Functional Disorders of TMJ
 Classified into 3 broad categories:
1. Derangements of condyle-disc complex
2. Structural incompatibility of articular surfaces,
3. Inflammatory joint disorders
71
Fig: Lateral view of TMJ

72. Normal movement of TMJ
72
Fig: Rotational movement
of condyle until Terminal
Hinge position
Fig: Translatory movement of
condyle and disc together
during maximum opening

73. Normal movement of TMJ
73
Fig: Lateral View of TMJ
Fig: Anterior View of TMJ

74. Normal movement of TMJ
74

75. Derangements of condyle-disc complex
 If morphology of the disc is altered—such as a thinning
of the posterior border accompanied by elongation of
the discal ligaments—changes in normal function of disc
occur
 If disc is free to move due to above etiology, tonicity of
superior lateral pterygoid muscle will encourage disc to
assume a more forward position on condyle
 Disc can be displaced further into discal space so that the
condyle becomes positioned on the posterior border of
the disc
 This condition is known as functional disc displacement
75

76. 76
Fig: A, Normal position of disc on
condyle in closed-joint position
Fig: B: Functional displacement
of disc
Fig C: Condyle is articulating on
posterior band of disc (PB) and not on
intermediate zone (IZ). Posterior border
of disc has been thinned and discal
and inferior retrodiscal ligaments are
elongated, allowing activity of superior
lateral pterygoid to displace disc
anteriorly (and medially)

77. Derangements of condyle-disc complex
77
Fig: A . In the closed-joint
position, the pull of superior
lateral pterygoid muscle is in an
anteromedial direction (arrows).
Fig: B. When the mandible
translates forward into a protrusive
position, the pull of the superior
head is even more medially
directed (arrows). Note that in this
protruded position the major
directional pull of the muscle is
medial and not anterior
Fig A, B courtesy of Dr. Samuel J.
Higdon, Portland OR.)

78. Derangements of condyle-disc complex
78
Fig C: From a superior view, the entire
disc may be displaced anteriorly
medially.
Fig D: In some instances, the
lateral portion of the disc may be more
displaced than the medial portion.

79. Derangements of condyle-disc complex
79
Fig: E, In still another instance, the medial portion of the disc
may be more displaced than the lateral portion

80. Internal derangement of disc
 During functional disc displacement, increased
interarticular pressure prevents articular surfaces from
sliding across each other smoothly, there is abrupt
movement of condyle over disc into normal condyle-disc
relationship, accompanied by Single clicking sound
 This single click observed during opening movement
represents very early stages of disc derangement
disorder or what is also called internal derangement of
disc
80

81. Internal derangement of disc
81
Fig: Single click
Between positions 2&3
click is felt as condyle
moves across posterior
border into intermediate
zone of disc
Normal condyle-disc
function occurs during
remaining opening and
closing movement.
In closed-joint position (1)
disc is again displaced
forward and medially by
activity of superior lateral
pterygoid

82. Reciprocal Click
 If early stage of disc derangement (i.e internal
derangement) persists, elongation of inferior retrodiscal
lamina and continued thinning of posterior border
occurs, permiting disc to be repositioned more
anteriorly, so condyle is positioned more posteriorly on
posterior border
 This morphologic changes of disc at area where condyle
rests can create a second click just prior to the closing
joint position
 This stage of derangement is called the reciprocal click
82

83. Reciprocal Click
83
Fig: Reciprocal click
Between positions 2&3
click is felt as condyle
moves across posterior
border
Normal condyle-disc
function occurs during
remaining opening and
closing movement until
closed-joint position is
approached
Second click is heard as
condyle once again
moves from intermediate
zone to posterior border
of disc

84. Reciprocal Click
Characterized as follows
1. During mandibular opening, sound is heard that represents
condyle moving across posterior border of disc to its normal
position on intermediate zone. Normal disc-condyle
relationship is maintained through remaining opening
movement
2. During closing, normal disc position is maintained until
condyle returns to very near closed joint position
3. As closed joint position is approached, posterior pull of
superior retrodiscal lamina is decreased
4. Combination of disc morphology and pull of superior lateral
pterygoid muscle allows disc to slip back into more anterior
displaced position, where movement began. This final
movement of condyle across posterior border of disc
creates a second clicking sound, and thus reciprocal click
84

85. Derangements of condyle-disc complex
 Disc is displaced most commonly anteromedial direction,
or sometimes can be displaced only anteriorly or, in a
few cases, even laterally
 Sometimes only medial or lateral aspect of disc is
displaced with the remaining portion maintained in its
normal position
85

86. Derangements of condyle-disc complex
 With all these variations, it is sometimes diffcult to
determine exact position of the disc clinically, soft tissue
imaging is needed using MRI
86
Fig: Variations in disc displacement
A, Medially displaced disc, B, MRI of a medially displaced disc
C,MRI of a laterally displaced disc.

87. Functional dislocation of disc
 If previous condition (single click and reciprocal click)
persists, and posterior border becomes more thin,
superior lateral pterygoid will cause more anterior
migration of disc completely through discal space,
trapping disc in forward position
 This inhibits full translation of condyle and individual
feels joint being locked in a limited closed position
 Since articular surfaces have actually been separated,
this condition is referred to as functional dislocation of
the disc
87

88. Functional dislocation of disc
88
Fig C: Condyle is articulating on posterior band of disc (PB)
and not on intermediate zone (IZ). Posterior border of disc
has been thinned and discal and inferior retrodiscal
ligaments are elongated, allowing activity of superior lateral
pterygoid to displace disc anteriorly (and medially)

89. Functional dislocation with reduction
 Some people with functional dislocation of disc are able
to move mandible in various lateral or protrusive
directions to accommodate movement of condyle over
posterior border of disc, thus locked condition is resolved
 If lock occurs only occasionally and individual can resolve
it with no assistance, it is referred to as a functional
dislocation with reduction
 The patient will often report that the jaw “catches” when
mouth is opening wide, Pain may or may not be present
89

90. Functional dislocation with reduction
90
Fig: Functional
dislocation of disc
with reduction.
During opening
condyle passes over
posterior border of
disc onto
intermediate area of
disc, thus reducing
dislocated disc

91. Anterior dislocation with reduction
91

92. Anteromedial and Medial Disc Dislocation
with reduction
92

93. Functional dislocation without reduction
 The next stage of disc derangement is known as
functional disc dislocation without reduction where
person is unable to return dislocated disc to its normal
position on condyle
 Mouth cannot be opened maximally due to position of
disc anteriorly
 Initial opening will be only 25 to 30 mm intrincisally,
which represents maximal rotation of joint
93

94. Functional dislocation without reduction
 Usually only one joint becomes locked
 Affected joint doesn’t allow complete translatory
movement of condyle, so when patient opens mouth
widely, midline of mandible is deviated to affected side
 Able to perform normal lateral movements to affected
side only
 Since patient feels that he or she is locked near closed
mouth position, it is termed as closed lock
94

95. Functional dislocation without reduction
95
Fig: Functional
dislocation of disc
without reduction.
(Closed lock)
Condyle never
assumes a normal
relationship on disc
but instead causes
disc to move forward
ahead of it. This
condition limits
distance it can
translate forward

96. Anterior dislocation without reduction
96

97.  If the closed lock continues, condyle will be chronically
positioned on retrodiscal tissues (not anatomically
structured to accept force)
97
Fig: functionally anterior dislocated disc and the condyle is
totally articulating in the retrodiscal tissues (RT)
 Breakdown of tissue occurs
resulting in inflammation of
tissue resulting in Inflammatory
joint disorders

98. Functional Displacement Vs
Functional Dislocation of disc
 Functionally displaced disc: Create joint sounds as
condyle skids across the disc during normal translation of
mandible
 Functionally dislocated disc: Joint sounds are eliminated,
since no skidding can occur
 Helpful information in distinguishing a functional
displacement from a functional dislocation of disc
98

99. Orthodontics and disc derangement disorders
 Recently, concern has arisen regarding effect of
orthodontic treatment on disc derangement disorders
 Some authors previously suggested that certain
orthodontic treatments can lead to such disorders
 But long term studies reported, that incidence of TMD
symptoms in orthodontically treated patients is no
greater than that in untreated general population
99

100. Orthodontics and disc derangement disorders
 Extraction of teeth for orthodontic purposes did not
reveal a greater incident of TMD symptom after
treatment
 Incidence of TMD symptoms in orthodontically treated
populations were found to be generally no lower than
that in untreated population which suggest that
orthodontic treatment is not effective in preventing
TMDs
100

101. 2. Structural incompatibility of articular surfaces
 Healthy joint: Articular surfaces are firm and smooth;
lubricated with synovial fluid, move almost frictionlessly
 Movement of joint can be impaired, if joint surfaces
become altered by:
 Microtrauma,
 Due to insuffcient lubrication , or
 Development of adherences between surfaces
101

102. 2. Structural incompatibility of articular surfaces
 If static loading continues for prolonged time, lubrication
can become exhausted and sticking of articular surfaces
can result
 Breaking apart of an adherence can be felt as a click,
which denotes the instant return to the normal range of
mandibular movement
 Eg: Clenching patient may wake up in morning after a
night of clenching and have sensation of restricted jaw
movement. As patient tries to open mouth, resistance is
felt until suddenly there is click and normal function
returns. This sound represents the breaking apart of
sticking surfaces
102

103. Adherences between disc and condyle
103
Fig: In position 1
there is adhesion
between condyle
and disc.
During opening no
discal rotation occurs
In position 3
adhesion is broken,
resulting in a click
and normal function
from that point on
There is no reciprocal
or additional clicking
unless it is followed
by a period of static
loading of joint

104. Adherences between disc and Fossa
104
Fig: Adherence/adhesion.
A, This is a fresh cadaver specimen with the condyle seated in the fossa.
Tissues appear normal.
B, However, as condyle moves out of the fossa, the posterior border of disc
does not move. There is an adherence (Ah) in the superior joint space.
(Courtesy of Dr. Terry Tanaka, San Diego, CA.)

105. Degenerative Joint Disease
105

106. Subluxation
 Also termed as Hypermobility
 Clinically, when mouth opens to its fullest extent,
momentary pause occurs, followed by sudden jump or
leap to maximally open position
 During maximal mouth opening, lateral poles of condyles
will jump forward, causing a noticeable auricular
depression
 This condition is called subluxation or hypermobility
106

107. Subluxation
107

108. Dislocation
 On occasion mouth is opened beyond its normal limit
and mandible locks
 Condition called spontaneous dislocation or open lock
 Patient cant close mouth
 It is almost always produced by wide opening—for
example, extended yawn or a long dental procedure
108

109. Dislocation
109

110. 3. Inflammatory Joint Disorders
 Condition where various tissues of joint becomes
inflamed
 Difficult to clinically differentiate inflammatory disorders
from each other because the clinical presentations are
very similar
 Includes:
 Synovitis
 Capsulitis
 Retrodiscitis
 Arthritides
110

111. Path of progression of TMDs
1. Normal healthy joint
2. Loss of normal condyle-disc function due to either
i. Macrotrauma, resulting in elongation of the discal
ligaments
ii. Microtrauma, causing changes in articular surface and
reducing frictionless movement between articular
surfaces
3. Abnormal translatory movement between the disc and
condyle begin
4. Posterior border of disc becomes thinned
5. Further elongation of discal & inferior retrodiscal tissue
111

112. Path of progression of TMDs
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
112

113. Conclusion
 Signs and symptoms of TMD are common in general
population and are not always severe or debilitating,
Only small percentage of population will look for
treatment
 In order to manage them effectively, clinician must be
able to recognize and understand its etiology and its
clinical manifestation, which is not always easy
 It is important to remember that clinician who evaluates
only occlusion is likely missing as much as the clinician
who never evaluates occlusion
113

114. References
 Jeffrey P. Okeson, Management of Temporomandibular
disorders and occlusion, 2013, 7th edition
 Costen JB: Syndrome of ear and sinus symptoms
dependentupon functions of the temporomandibular
joint, Ann Otol RhinolLaryngol 3:1–4, 1934
 Pullinger AG, Seligman DA, Gornbein JA: A multiple
logistic regression analysis of the risk and relative odds of
temporomandibular disorders as a function of common
occlusal features, J Dent Res 72(6):968–979, 1993
 Ware JC, Rugh JD: Destructive bruxism: sleep stage
relationship, Sleep 11(2):172–181, 1988
114

115. References
 Rugh JD, Solberg WK: Electromyographic studies of
bruxist behavior before and during treatment, J Calif
Dent Assoc 3(9): 56–59, 1975
 Kieser JA, Groeneveld HT: Relationship between
juvenile bruxing and craniomandibular dysfunction,
J Oral Rehabil 25(9):662–665, 1998
115

116.  History of and Examination for Temporomandibular
Disorders
 Diagnosis of Temporomandibular Disorders
To be continue………
THANK YOU 116