TMJ DISORDERS BY DR. VAJENDRA JOSHI

1. Dr VAJENDRA JOSHI
PROFESSOR
IV YEAR

2. TEMPOROMANDIBULAR
JOINT DISORDERS
DR. VAJENDRA JOSHI

3. Temporomandibular joint:
•In human beings, the masticatory
process demands that the mandible be
capable not only of opening and closing
movements but also of protrusive,
retrusive, and lateral movements and
combinations thereof.

4. • To achieve all these movements, the
condyle undertakes translatory and rotary
movements.
• Therefore, the human TMJ is described
as a sinovial sliding-ginglymoid joint.
Bones of the TMJ
• The bones of the temporomandibular
articulation are the glenoid fossa (on the
undersurface of the squamous part of the
temporal bone) and the condyle (supported
by the condylar process of the mandible).

7. • Unlike most synovial joints, the
temporomandibular articulation is covered by
a layer of fibrous tissue.
• The fibrous layer covering the condyle
consists of fibroblasts scattered through a
dense, largely avascular layer of type of type
I collagen (the lamina splendens).
• The glenoid fossa always is covered by a thin
fibrous layer that directly overlies the bone,
much as periosteum does, but this layer
becomes appreciably thicker where it covers
the slope of the articular eminence.

8. Cartilage associated with the TMJ
• Although fibrocartilage is associated
with the temporomandibular
articulation, it does not form part of
the articulation and has no formal
functional role to play in the everyday
movements occuring between the two
bones of TMJ.

9. Capsule, ligaments, and disk of the joint.
• Capsule consists of dense collagenous
membrane that seals the joint space and
provides passive stability enhanced by
increased local thickenings in its walls as well
as active stability from proprioceptive nerve
endings in the capsule.
• Recognizing the disk as an extension of the
capsule, the capsule of the TMJ can be
described as a fibrous, nonelastic membrane
surrounding the joint.

10. • The lateral part of the capsule is
thickened to form a fan shaped
ligament known as the
temporomandibular ligament.
• The ligament consists of two parts:
1. An outer oblique portion arising from
the outer surface of the articular
eminence and extending backward and
downward to insert into the outer
surface of the condylar neck and
2. An inner horizontal portion with the
same origin but inserting inti the
lateral pole of the condyle.

11. Temporomandibular ligament.

12. • There are two other ligaments which
does not have any functional role.
• First is the sphenomandibular ligament
representing residual perichondrium of
Meckel’s cartilage, and
• Second is the stylomandibular
ligament, representing the free border
of the deep cervical fascia.
• An inward circumferential extension of
the capsule forms a tough, fibrous disk
that divides the joint into upper and
lower compartments.

13. • The disk consists of dense fibrous
tissue.
• The lower surface of the disk is
concave and generally matches the
convex contour of the condyle.
• The upper surface of the disk also
presents a concave surface because its
posterior and anterior components are
considerably thickened.
• Type I collagen bundles constitute the
disk.

14. • The anterior portion of the disk fuses with the
anterior wall of the capsule. Posteriorly, the dis
also appears to divide into two lamellae, but
again these lamellae represent the posterior wal
of the capsule.
• The disk is well supplied with vascular and
neural elements at its periphery but is avscular
and not innervated in its central region.
• During function, the disk makes only short
movements in a passive manner to fit best with
the changing relationships of the condylar head
and the glenoid fossa and articular eminence.

15. Synovial membrane
• The capsule is lined on its inner
surface by a synovial membrane.
• Generally, the synovial membrane is
considered to line the entire capsule,
with folds or villi of the membrane
protruding into the joint cavity.
•

16. • The synovial membrane is responsible
for the production of synovial fluid,
which is characterized by well-defined
physical properties of viscosity,
elasticity, and plasticity.
• Synovial fluid contains a small
population of monocytes, lymphocytes,
free synovial cells and occasionly
neutrophils.

17. • Its function is to provide
1. A liquid environment for the joint
surfaces and
2. Lubrication to increase efficiency and
reduce erosion.
• Whether it also provides nutrition for
disk & articular surfaces of joint is
debatable.

18. Diagnostic studies
Plain radiography
• Routine TMJ series including
transorbital and transcranial views.
• 30%-60% addition or subtraction of
calcified elements for changes to
become apparent on routine x-ray
films(Dunn et al).
• Doesn’t accrately reflect the joint
components and their spatial
relations(Eckerdal and Lundberg).
• Transcranial films tend to depict only

19. Conventional Tomography
• Depict greater portion of the joint.
• Provides a series of sectional
radiographs.
• Reproduces changes in the central
position of the joint and therefore
decrease false-negative
interpretations.
• Limited ability to detect early lesions.
• More radiation and more expensive.

20. Computed tomography
• Provides images without
superimposition,
• Permits the section of optimal views
through multiple plane reconstructions.
• Also may yield information concerning
the position of the soft tissue disc in
addition to depecting the osseous
structures.
• More expensive and more radiation
compared to conventional tomography.
• Conventional tomography is superior to
CT in diagnosis of single structural bone
changes (Tanimoto et al, Dentomaxillofac

21. Arthrography
• Defects in the position or structure
of the joint disk and its attachments
can be determined.
• Derangements that are detectabale
include displacement or perforation of
the disk, irregularities in the posterior
attachment of the disk, adhesions, and
synovial proliferations.
• Water soluble, iodine-containing
contrast material is injected into the
lower joint space.

22. • Lateral or anteroposterior radiographs
or tomograms are subsequently taken.
• Cinefluoroscopy (a movie produced
with relatively low levels of radiation
and providing a dynamic depiction of
soft tissue components of the joint
while in function) also has been used.
• Safe technique (except iodine
hypersensitivity cases).
• Disadvantages: Invasiveness, technical
difficulty and poor visualization of the
disc in medial-lateral plane.

23. Magnetic Resonance Imaging
• Depicts soft-tissue anatomy with
detail through its effect on tissues with
high water content.
• Non-radiation and noninvasive.
• Superior to arthrography in
demonstrating medial and lateral
displacements of the disc but doesn’t
detect perforation as consistently.
• Use of coronal MRI, in addition to
sagittal view provides more information
regarding bony lesions.

24. Arthroscopy
• Arthroscopy of upper compartment
permits direct visual inspection of the
articular surfaces of the temporal bone
and superior aspect of the disc.
• Helps to confirm the impression
derived from preceding clinical,
radiographic and imaging findings.
• High specificity but low sensitivity.
• Reliable in diagnosing arthrosis,
remodeling, adhesions, or perforation

25. Classification of TMJ disorders
Intracapsular disorders of the TMJ (Burket)
Sourse Disorder
 Degenerative
 Inflammatory
 Infections
 Developmental
 Degenerative joint disease
 Rheumatoid arthritis (&
other collagen diseases)
Psoriatic arthritis
 Spread from contiguous site
Gonorrhea
Tuberculosis
Syphilis
 Condylar hyperplasia,
hypoplasia, and agenesis

26.  Traumatic  Condylar fracture
Ankylosis
Dislocation
Disc displacement
Metabolic
 Neoplasia
 Gout
 Malignant
Benign
 Drug-induced  Steroid

27. Derangement of the Condyle-Disc
complex
Anterior disc displacement is
classified into (Burket’s Oral Medicine,
10th edn).
1. Anterior disc displacement with
reduction (clicking joint)
2. Anterior disc displacement with
intermittent locking, and
3. Anterior disc displacement without
reduction (closed lock)

28. Classification system used for
diagnosing temporomandibular
disorders (Okeson)
I. Masticatory muscle disordres
1. Protective co-contraction (11.8.4)
2. Local muscle soreness (11.8.4)
3. Myofascial pain (11.8.1)
4. Myospasm (11.8.3)
5. Centrally mediated myalgia (11.8.2)

29. II. Temporomandibular joint disorders
1.Derangement of the condyle-disk
complex
a. Disk displacements (11.7.2.1)
b. Disk dislocation with reduction (11.7.2.1)
c. Disk dislocation without reduction
(11.7.2.2)
2. Structural incompatibility of the
articular surfaces
a. Deviation in form (11.7.1)
i. Disc ii. Condyle iii. Fossa

30. b. Adhesions (11.7.7.1)
i. Disc to condyle
ii. Disc to fossa
c. Subluxation (hypermobility) (11.7.3)
d. Spontaneous dislocation (11.7.3)
3. Inflammatory disorders of the TMJ
a. Synovitis/Capsulitis (11.7.4.1)
b. Retrodiscitis (11.7.4.1)
c. Arthritides (11.7.6)
i. Osteoarthritis (11.7.5)
ii. Osteoarthrosis (11.7.5)
iii. Polyarthritides (11.7.4.2)

31. d. Inflammatory disorders of associated
structures
i. Temporal tendinitis
ii. Stylomandibular ligament inflammation
III. Chronic mandibular hypomobility
1. Ankylosis (11.7.6)
a. Fibrous (11.7.6.1)
b. Bony (11.7.6.2)
2. Muscle contracture (11.8.5)
a. Myostatic
b. Myofibrotic
3. Coronoid impedance

32. IV. Growth disorders
1. Congenital and developmental bone
disorders
a. Agenesis (11.7.1.1)
b. Hypoplasia (11.7.1.2)
c. Hyperplasia (11.7.1.3)
d. Neoplasia (11.7.1.4)
2. Congenital and developmental muscle
disorders
a. Hypotrophy

33. b. Hypertrophy (11.8.6)
c. Neoplasia (11.8.7)
Code number after each disorders
has been established by American
Academy of orofacial pain in
cooperation with the International
Headache Society(Okeson JP 1996).

34. Disc displacement and Disc
dislocation with reduction
• Represent early stages of disc
derangement disorders.
•Etiology
• Disc derangement disorders result from
elongation of the capsular and discal
ligaments coupled with thinning of the
articular disc.
• Either due to
microtrauma or
macrotrauma. Anteriorly dislocated disc

35. • Common sourses of microtrauma are
bruxism and orthopedic instability.
• Some studies suggest that class II,
division 2, malocclusion is commonly
associated with orthopedic instability and
therefore is an etiologic factor (Wright 1986).

36. Heavy and prolonged loading
Exceeding functional capacity
Fragmentation of collagen fibrils
Decreased stiffness of collagen network
Swelling of proteoglycon-water gel
Flow out of proteoglycon-water gel into joint space
Softening of articular space (Chondromalacia)
Continued loading
Focal roughening of articular surfaces
Alterations of frictional characteristics of surface
Sticking of articular surfaces
Strains on the discal ligaments during movements
Disc displacement

37. Clinical features:
• A reducing disc displacement is common in general population.
• Clicking or popping joint is of little clinical significance unless the
clicking is accompanied by pain or unless the patient experiences
dysfunction due to intermittent locking.
• Symptoms of pain and dysfunction associated with anterior disc
displacement with reduction resolve over time with minimal
noninvasive therapy.
•With significant anterior disc displacement with reduction, patient will
complain of pain during mandibular movement;
• The pain is most noticeable at the time of click.
• Palpation and auscaltation reveals a clicking or popping sound
during both opening and closing mandibular movements ( so-called
reciprocal click).
• Click occurs at a different point during opening and closing.

38. • This is due to movement of the disc as the condyle
moves it forward during mandibular opening.
• Deflection of the mandible early in the opening cycle,
with correction towards the midline after click.
• Tenderness will be present when ADD is accompanied
with capsulitis or synovitis.
• TMJ effusion may be noted on a T2-weighted MRI
scan.

39. Management
• No pain--No therapy.
• Flat-plain stabilization splints that do not change mandibular position
and anterior repositioning splints are used to treat painful clicking.
• Anterior repositioning splints maintain the mandible in an anterior
position, preventing the condyle from closing posterior to the disc.
• Previous studies have shown that repositioning splints are more
effective than stabilization splints in eliminating both clicking and pain in
patients with ADD (Santacatterina et al. J Oral Rehabil 1998).
• Side effects of repositioning splints: Tooth movement and open bite.
• Splint therapy, arthrocentesis, or arthroscopy rarely replaces the disc
in a normal position.
• Painful symptoms resolve although disc remains displaced.

40. Anterior disc displacement without reduction (Closed lock)
• A clinical condition in which the disc is dislocated,most commonly
anteromedially, from the condyle and does not return to normal
position with condylar movement.
Etiology: Macrotrauma and microtrauma.
•Clinical features: Seen more frequently in
patients with clicking joints that progress to intermittent brief locking
and then permanent locking. A patient with an acute closed lock will
have an history of long standing TMJ click that suddenly disappears
with a sudden restriction in mandibular opening.
• Limited mandibular opening occurs when the disc interferes with the
normal translation of the condyle along the glenoid fossa.
• Pain directly over the joint during mandibular opening.

41. • Limited lateral movement to the side away from the ADD
since discs are most frequently displaced medially as well as
anteriorly.
• During maximum mandibular opening, mandible will deviate
towards the side of the displacement.
• Palpation will reveal decreased translation of the condyle on
the side of the disc displacement.
Management:
• Treatment depends on degree of pain associated with ADD.
• Nonsurgical or surgical.
• Goals:Eliminate pain and restore function
• Replacing the disc in a normal position is not necessary to
achieve these goals.
• Patients with restricted movement and minimal pain: Manual
manipulation of mandible and exercise program (manual
methods and commercial mandibular range-of-motion

42. Technique for manual manipulation
• Success of reduction of a dislocated disc is
dependent on 3 factors:
1. Level of activity in the superior lateral pterygoid
muscle. This muscle must be relaxed to permit
successful reduction. If it is active, give LA before
attempting to reduce.
2. The disc space must be increased so that the disc
can be repositioned on the condyle. Patient must be
encoraged to relax and avoid foarceful closing of
mouth.

43. 3. Condyle must be in the maximum
forward translatory position. The only
structure that can actively reduce an
anterior dislocation of the disc is the
superior retrodiscal lamina, and if this
tissue is to be effective the condyle must
be in the most forward position.
• First attempt to reduce the disc should
begin by patient attempt to reduce the
dislocation without assistance.
A. Patient should be asked to move the
mandible to the contralateral side as for as
possible.

44. B. From this eccentric position the mouth is opened maximally.
C. Even after several attempts this fails, assistance with manual
manipulation is needed.
Manual Manipulation:
• Clinician’s thumb is placed intraorally over the mandibular second
molar on the affected side.
• Clinician’s fingers are placed on the inferior border of the mandible
anterior to the thumb position.

45. • Firm and controlled
downward force on
the molar by the
thumb and at the
same time upward
force is placed by the
clinician’s fingers.
• Clinician’s opposite hand should
stabilize the patient’s cranium above
the joint that is being distracted.
• The condyle is brought downward and
forward, which translates it out of the
fossa.

46. • Also bring the mandible to the
contralateral side, since the disc is likely
to be dislocated anteriorly and medially
and a contralateral movement will move
the condyle into it better.
• Once the full range of laterotrusive
excursion has been reached, the patient
is asked to relax while 20-30 secs of
constant distractive force is applied to
joint.
• This force is then discontinued, and
clinician’s fingers are removed.

47. • If, the tissue has lost its elasticity and
ability to retract the disc, the dislocation
becomes permanent.
• Studies (Lund et al, Oral Surg 1992)
have revealed that over time many
patients can achieve relatively normal joint
function even with the disc permanently
dislocated.
• Patients with permanent disc dislocation
should be given a stabilization appliance
that reduces forces to the retrodiscal
tissues (i.e., bruxism).

48. • Flat-plane occlusal stabilization
appliance to decrease the adverse effect
of bruxism.
• NSAIDs to reduce pain.
• Patients with severe pain may benefit
from either arthrocentesis or arthroscopy.
• Intra-articular corticosteroids to reduce
inflammation.
• Intra-articular sodium hyaluronate to
increase joint lubrication and decrease
adhesions.
•Arthrotmy and discectomy are last option.

49. Posterior disc displacement
• Condyle slipping over the anterior rim of the disc during
opening, with the disc being caught and brought backward in
an abnormal relationship to the condyle when the mouth is
closed.
Disc is folded in the dorsal part of the joint space, preventing
full mouth closure.
Clinical features:
1. Sudden inability to bring the upper and lower teeth
together in maximal occlusion, 2. Pain in the affected joint
when trying to bring the teeth firmly together,
3. Forward displacement of the mandible on the affected
side,
4. Restricted lateral movement to the affected side, and
5. No restriction of mouth opening.

50. INFLAMMATORY DISORDERS OF TMJ
Synovitis and Capsulitis
Etiology:
• Trauma
• Spreading infection from adjacent structure
Clinical features:
• Any movement that tends to elongate the capsular ligament accentuates the
pain.
• Preauricular pain.
• Lateral aspect of the condyle is tender on palpation.

51. Treatment:
• When cause is macrotrauma, the condition is
self limiting.
Due to microtrauma:
• Restrict all the mandibular movements
within the painless limits.
• Soft diet, slow movements, small bites.
• Mild analgesics for constant pain.
•Thermotherapy: moist heat:10-15min, 4-5
times/day.
• Ultrasound therapy: 2-4 times/week.
• Single injection of corticosteroid to the
capsular tissues.

52. Retrodiscitis
• An inflammatory condition of the retrodiscal tissues.
•Etiology:-
• Trauma- Extrinsic, Intrinsic.
• Extrinsic trauma is created by a sudden movement of the condyle into the
retrodiscal tissues.
• These tissues often respond to this type of trauma with inflammation,
which leads to swelling.
•Swelling of retrodiscal tissues can force the condyle forward, resulting in
an acute malocclusion.
• In such a condition, patient complains of inability to bite on the posterior
teeth on the ipsilateral side.
• On occasion, trauma to the retrodiscal tissues causes intercapsular
hemarthrosis which is a serious complication and may lead to adhesions or
ankylosis of the joint.

53. Osteoarthritis(Degenerative joint disease)
Definition:
Degenerative joint disease (DJD) is a non-inflammatory disorder of joints
characterized by joint deterioration and proliferation.
- Joint deterioration is characterized by loss of articular cartilage and bone erosion.
- The proliferative component is characterized by new bone formation at the
articular surface and in the subchondral region.
- Deterioration is more common in acute disease, and proliferation predominates in
chronic disease.

54. Clinical features
-Occur at any age, incidence increases with age
- Female prepondarance
- Signs and symptoms are very similar to those
of other TM disorders with subtle yet very
significant exceptions:
1.They almost invariably occur unilaterally;
2.Symptoms appear to worsen as the day goes on;
3.Pain is over the joint per se, especially the distal
aspect when the mouth is open;
4.Crepitation (crepitus) as distinct from clicking is
often present;
5.Radiographic evidence is frequent.

55. Rasmussen described the development of
the symptomatolgy of OA in 3 stages and
6 phases.
Phase 1-6 Stage 1-3
1. Clicking
2. Periodic locking
Initial
3. TMJ pain at rest
4. TMJ pain on function Intermediary
5. Residual symptoms
other than pain
6. Absence of symptoms
Terminal

56. Examination:
• Tenderness and crepitus on intra-auricular and pretragus palpation
with deviation of the mandible to the painful side.
Radiographic findings:
• Narrowing of joint space,
• Irregular joint space,
• Flattening of articular spaces,
• osteophytic formation,
• Anterior lipping of the condyle,
• Presence of Ely’s cysts.

57. • In maximal intercuspation, the joint space may be
narrow or absent, often correlated with an internal
derangement and frequently with a perforation of the
disc or posterior attachment, resulting in bone-to-
bone contact of the joint components.
- Loss of cortex or erosions of the articulating
surfaces of the condyle or temporal component (or
both) are characteristic of this disease.

58. •Ely’s cyst.

59. - Later in the course of the disease, bony
proliferation occurs at the periphery of the
articulating surface, increasing the
articulating surface area.
- This new bone is called
an osteophyte, which
typically appears on the
anterosuperior surface
of the condyle, lateral
aspect of the temporal
component, or both.
Joint
mouse
Osteophyte

60. - Osteophytes also may form on the lateral,
medial, and posterosuperior surface aspect of
the condyle.
- Osteophyte may
break off and lie
free within the
joint space (these
fragments are
known as
joint mice).
joint mice

61. Treatment:
Conservative treatment:
• NSAIDs; heat; soft diet; rest; occlusal splints to allow free
movement of mandible.
• Intra-articular steroids during acute episodes.
• Concomitantly treat MPDS or meniscal defects.
Surgical management:
• When significant loss of function persists and when distinct
radiographic evidence of degenerative joint changes exists.
• Arthroplasty (removal of osteophytes and erosive areas) is
commonly performed.
• Artificial TMJ (in advanced degenerative changes).

62. Polyarthritides
Rheumatoid arthritis
• A systemic connective tissue disease that involves, among other
tissues, the joints of the human body.
• The disease may involve any joint of the body, but often starts in
peripheral joints like finger and toe joints, eventually spreading
proximally to involve the big joints like knee and shoulder joints.
• TMJ involvement may be 40%-80% in patients with
rheumatoid arthritis (Avrahami et al, J Rheumatol 1989). The
general diagnosis of RA might be determined by the diagnostic
criteria presented by the American Rheumatism Association
(ARA;1987). The criteria are as follows.
1. Morning stiffness for more than 1 hour (more than 6 weeks).
2. Swelling of three or more joints (more than 6 weeks).
3. Swelling of wrist joint, metacarpophalan- geal joint or proximal
interphalangeal joint (more than 3 weeks).
4. Systemic swelling.

63. 5. Radiographic changes in the hand
joints.
6. Subcutaneous noduli.
7. Positive rheumatoid factor.
• Presence of 4 of these 7 criteria
determines the diagnosis.
• Significant diagnostic criteria for local
involvement of the TMJ are as follows.
1. Bilateral joint involvement.
2. Tenderness to palpation of lateral or
posterior aspects of the joint.

64. 3. Joint crepitus.
4. Radiographic signs of erosion of the
articular cortical bone of the TMJ.
5. Swelling over the TMJ (acute phase).
6. Temperature change in or over the TMJ.
Increase in the acute phase and decrease
in the chronic phase.
7. Anterior bite opening.
8. Abundance of polymorphonuclear
leukocytes in the joint fluid (acute phase) or
mononuclear leukocytes (chronic phase).

65. • The presence of four of these eight criteria should be able to
determine the local diagnosis.
• CT is superior to detect TMJ changes in rheumatoid arthritic
patients compared to conventional radiography or tomography
(Avrahami et al, J Rheumatol 1989).
•.The disease process starts as a vasculitis of the synovial
membrane.
• It progresses to chronic inflammation marked by an intense
round cell infiltrate and subsequent formation of granulation
tissue.
• The cellular infiltrate spreads from the articular surfaces
eventually to cause an erosion of the underlying bone.
Clinical features:
• TMJs are usually bilaterally involved.
• Most common symptoms include limitation of mouth opening
and joint pain.

66. • Pain is usually associated with early acute phases and may not be
seen in later stages.
• Other symtoms include morning stiffness, joint sounds, and
tenderness and swelling over the joint area.
• Usually symptoms are transient.
• Most consistent clinical findings include pain on palpation of the
joints and limitation of opening.
• Crepitus also may be evident.

67. - Juvenile RA patients may present with
micrognathia and an anterior open bite.
- Ankylosis of TMJ is rare in patients
with RA.
Radiographic changes:
- Initial changes may be generalized
osteopenia (decreased density) of the
condyle and temporal component.
- The pannus may destroy the disc,
resulting in diminished width of the joint
space.

68. - Bone erosions by the pannus most often
involve the articular eminence and the anterior
aspect of the condylar head, which permits
anterosuperior positioning of the condyle
when the teeth are in maximal intercuspation
and results in an anterior open bite.

69. - Erosion of the anterior and posterior condylar
surfaces at the attachment of the synovial
lining may result in a “sharpened pencil”
appearance of the condyle.
- Joint destruction eventually leads to
secondary DJD.
- Subchondral sclerosis and flattening of
articular surfaces may occur, as well as
subchondral cyst and osteophyte formation.
- Fibrous ankylosis or, in rare cases, osseous
ankylosis, may occur.

70. Treatment
• Anti-inflammatory drugs.
• Soft diet during acute exacerbation.
• Intermaxillary fixations should be
avoided because of risk fibrous ankylosis.
• Flat plane occlusal plane to control
parafunctional habits.
• Exercise programme to increase
mandibular movements (After acute
symptoms subside).

71. • Intra-articular steroids if severe
symptoms persists.
• Prosthesis in edentulous patients.
• Surgical treatment of the joints
(including placement of prosthetic
joints) is indicated in patients who
have severe functional impairment or
intractable pain not successfully
managed by other means.

72. Structural incompatibility of the
articular surfaces
- Can cause several types of disc derangement
disorders.
- The most common etiologic factor is macro-
trauma.
- The four types of structural incompatibilities
of the articular surfaces are
1. Deviation in form,
2. Adherences and adhesions,
3. Subluxation (hypermobility), and
4. Spontaneous dislocation (open lock).

73. Adherences and adhesions
Etiology:
- An adherence represents a temporary sticking of
the articular surfaces and may occur between the
condyle and the disc (inferior joint space) or
between the disc and the fossa (superior joint space).
- Adherences commonly result from prolonged static
loading of the joint structures.
- If the adherence is maintained, the more permanent
condition of adhesion may develop.
- Adhesions may also develop secondary to
hemarthrosis caused by macrotrauma or surgery.

74. Subluxation (hypermobility):
- Subluxation of the TMJ represents a sudden
forward movement of the condyle during the
latter phase of mouth opening.
- As the condyle moves beyond the crest of the
articular eminence, it appears to jump forward
to the wideopen position.
Etiology:
- Subluxation occurs in the absence of any
pathologic condition.
- It represents normal joint movement as a
result of certain anatomic features.

75. - Since the disc cannot rotate any further
posteriorly, the remaining condylar translation
occurs in the form of an anterior movement of
the condyle and disc as a unit.
- This represents a sudden forward jump of the
condyle and disc to the maximum translated
position.
Clinical characteristics:
- Subluxation can be observed clinically
merely by requesting the patient to open wide.
- At the latter stage of opening the condyle
jumps forward, leaving a small void or
depression behind it.

76. - The midline pathway of mandibular opening
is seen to deviate and return as the condyle
moves over the articular eminence.
- The deviation is much greater and much
closer to the maximally open position than that
seen with a disc derangement disorder.
- Usually no pain is associated with the
movement unless it is repeated often (abuse).
Treatment:
-Educate the patient regarding the cause of
subluxation and which movements create the
interference.

77. -On occasion, when the interference cannot be
voluntarily resolved, an intraoral device to
restrict movement is employed.
- Wearing the device develops a myostatic
contracture of the elevator muscles, thus
limiting mouth opening to the point of
subluxation.
An intraoral device to restrict to restrict mouth opening

78. - The only definitive treatment for
subluxation is surgical alteration of the
joint itself.
- This can be accomplished by an
eminectomy, which reduces the steepness
of the articular eminence and thus
decreases the amount of posterior rotation
of the disc on the condyle during full
translation.

79. SPONTANEOUS DISLOCATION
- Spontaneous dislocation is commonly
referred to as an open lock.
- It can occur following wide-open mouth
procedures.
- This condition refers to a spontaneous
dislocation of both the condyle and the disc.
Etiology
- When the mouth opens to its fullest extent,
the condyle is translated to its anterior limit.
- In this position the disc is rotated to its most
posterior extent on the condyle.

80. - If the condyle moves beyond this limit, the disc can
be forced through the disc space and trapped in this
anterior position as the disc space collapses as a result
of the condyle moving superiorly against the articular
eminence.
A through C, Spontaneous dislocation of the TMJ results in an
open lock" with the disc dislocated anterior to the condyle. D
through F, Representation of a spontaneous dislocation with the
disc dislocated posterior to the condyle.

81. - Spontaneous dislocation of the TMJ can
occur in any individual if the condyle is
brought anterior to the crest of the articular
eminence.
- Although the disc has been described as
being forced anterior to the condyle, Kai et al
have demonstrated that the disc may be
trapped posterior to the condyle.
- In either condition the condyle becomes
trapped in front of the articular eminence,
resulting in the patient's inability to close the
mouth.

82. Clinical characteristics
- The patient remains in a wide-open mouth
condition.
- Pain is commonly present secondary to the
patient's attempts to close the mouth.
- Clinically the anterior teeth are usually
separated, with the posterior teeth closed.
- The patient cannot
verbalize the problem
because the jaw is
locked open, but the
patient needs to make
known the distress and pain he or she feels.

83. -This disorder contrasts with subluxation, in which
the condyle moves anterior to the
eminence during wide opening but is able to return
to the resting position without manipulation.
- Dislocations of the mandible usually result from
muscular incoordination in wide opening during
eating or yawning and less commonly
from trauma;
- They may be unilateral or bilateral.
- On clinical examination, a deep depression may
be observed in the pretragus region - corresponding
to the condyle being positioned anterior to the
eminence.

84. Treatment:
- The most effective method of treating spontaneous
dislocation is prevention.
- When a spontaneous dislocation is recurrent, the
patient is taught the reduction technique.
- Definitive treatment is directed toward increasing
the disc space, which allows the superior retrodiscal
lamina to retract the disc.
- When attempts are being made to reduce the
dislocation, the patient must open wide as if
yawning.
- This activates the mandibular depressor muscles
and inhibits the elevator muscles.

85. -At the same time slight posterior pressure applied to
the chin sometimes reduces a spontaneous dislocation.
- If this is not successful, the clinician's thumbs are
wrapped in gauze and placed on the mandibular
molars and downward pressure is exerted as the
patient yawns.
- This usually provides enough space to recapture
normal disc position.

86. -If the spontaneous dislocation is still not
reduced, it is likely that the inferior lateral
pterygoid muscle is in myospasm, preventing
posterior positioning of the condyle.
- When this occurs, it is appropriate to inject
the lateral pterygoid muscle with local
anesthetic without a vasoconstrictor in an
attempt to eliminate the myospasms and
promote relaxation.
- If the elevator muscles appear to be in
myospasm, local anesthetic is also helpful.
- When spontaneous dislocation becomes
chronic or recurrent, definitive treatment
consisting surgical procedure may be required.

87. -Various surgical procedures have been
advocated for treating recurrent dislocations of
the mandible;
These include
- bone grafting to the eminence,
- lateral pterygoid myotomy,
- eminence reduction,
- eminence augmentation with implants,
- shortening the temporalis tendon by intraoral
scarification,
- plication of the joint capsule, and
- positioning of the zygomatic arch.

88. Chronic mandibular hypomobility
 Longterm painless restriction of the
mandible.
 Pain is elicited only when force is used
to attempt opening beyond the
limitations.
The condition can be classified
according to the cause as
 Ankylosis,
 Muscle contracture, and
 Coronoid process impedance.

89. Ankylosis
 Ankylosis is a condition in which condylar
movement is limited by a mechanical
problem in the joint ("true" ankylosis) or
by a mechanical cause not related to
joint components ("false" ankylosis).
 True ankylosis may be bony or fibrous.
 In bony ankylosis the condyle or ramus
is attached to the temporal bone by an
osseous bridge.

90.  In fibrous ankylosis a soft tissue
(fibrous) union of joint components
occurs; the bone components appear
normal.
 False ankylosis may result from
conditions that inhibit condylar
movement such as muscle spasm,
myositis ossificans, or coronoid process
hyperplasia.

91. Clinical features
 Most unilateral cases are caused by
mandibular trauma or infection.
 The most common cause of bilateral
TMJ ankylosis is rheumatoid arthritis,
although in rare cases bilateral
fractures may be the cause.
 Most if not all cases of TMJ ankylosis
in infancy occur secondary to birth
injury.
 Patients have a history of progressively
restricted jaw opening, or they may
have a long-standing history of limited
opening.

92.  Some degree of mandibular opening
usually is possible through flexing of the
mandible, although opening may be
restricted to only a few millimeters,
particularly in the case of bony
ankylosis.
 Lateral movements
are restricted.
 During mouth
opening the
opening pathway
deflects to the ipsilateral side.

93. Radiographic Features
 In fibrous ankylosis the articulating
surfaces are usually irregular because of
erosions.
 The joint space is usually very narrow and
the two irregular surfaces may appear to
fit one another like a jigsaw puzzle.
 Little or no condylar movement is seen.
 Radiographic signs of remodeling
occasionally are visible as the joint
components adapt to repeated attempts
at mandibular opening.

94.  In bony ankylosis the joint space may
be partly or completely obliterated by
the osseous bridge, which can vary
from a slender segment of bone,
which may be difficult to locate, to a
large bony mass.
 This extensive new bone may fuse the
condyle to the cranial base.
 Secondary degenerative changes of
the joint components are common.

95.  Often morphologic changes occur, such
as compensatory progressive
elongation of the coronoid processes
and deepening of the antegonial notch
in the mandibular ramus on the
affected side as a result of muscle
function during attempted mandibular
opening.
 If ankylosis occurs before mandibular
growth is complete, growth of the
affected side of the mandible is
inhibited.

96.  Coronal CT images are the best
diagnostic imaging method to evaluate
ankylosis.
Treatment
 Laskin advocated the interposition of
polymeric silicone to prevent possible
fusion of the traumatic cases.
 Ankylosis has been treated with several
surgical procedures.
 Gap arthroplasty using interpositional
materials between the cut segments is
the technique most commonly performed.

97. CORONOID PROCESS IMPEDANCE
 During mandibular opening the coronoid
process passes anteroinferiorly
between the zygomatic arch and the
lateral surface of the maxilla.
 If its pathway is impeded, the coronoid
process does not slide
smoothly and the
mouth does not
open fully.

98. Clinical features
 Limitation is evident in all movements
but especially during mandibular
protrusion.
 If the problem is unilateral, opening
deflects the mandible to the same side
as the restriction.

99. Treatment
 Asymptomatic: no supportive therapy is
indicated.
 Definitive treatment for coronoid
process impedance is alteration of the
tissue responsible.
 Sometimes ultrasound followed by
gentle passive stretching helps mobilize
the structures.

100.  A true definitive treatment is
surgery that either shortens the
coronoid process or eliminates the
tissue obstruction (whichever is the
cause).
 Since the condition is generally
painless, surgical intervention is
usually contraindicated because of
its aggressiveness.

101. Tumors
 Tumors may be intrinsic or extrinsic
(adjacent) to the TMJ.
 Intrinsic tumors may develop in the
condyle, temporal bone, or coronoid
process.
 Extrinsic tumors may affect the
morphology, structure, or function of the
joint without invading the joint itself.
 They may cause indirect effects on
growth, such as those vascular lesions or
they may influence mandibular
positioning.

102. Benign tumors
 Most common benign tumors affecting
the TMJ are osteomas,
osteochondromas, Langerhans
histiocytosis and osteoblastomas.
 Benign tumors and cysts of the mandible
(e.g., ameloblastomas, odontogenic
keratocysts, simple bone cysts) may
involve the entire ramus and in rare
cases the condyle.

103. Clinical features
 Condylar tumors grow slowly,
 TMJ swelling, accompanied by pain and
decreased range of motion,
 Examination reveals facial asymmetry,
malocclusion, and deviation of mandible
to the unaffected side.
 Tumors of coronoid process are painless
with progressive limitation of motion.

104. Radiographic features
 Condylar tumors cause condylar
enlargement that often is irregular in
outline.
 The trabecular pattern may be altered,
resulting in regions of destruction seen
as radiolucencies or new abnormal bone
formation, which may increase the
radiopacity of the condyle with
abnormal trabeculae.

105.  An osteoma or osteochondroma
appears as an abnormal, pedunculated
mass attached to the condyle.
 Osteochondromas often extend from
the anterior or superior surface of
the condyle.
Treatment
 Surgical excision of tumor and
occasionally excision of condylar head
or coronoid process.

106. Malignant tumors
 May be primary or more commonly,
metastatic.
 Primary intrinsic tumors of condyle
are extremely rare and include
chondrosarcoma, osteogenic sarcoma,
synovial sarcoma, and fibrosarcoma of
the joint capsule.

107.  Extrinsic malignant tumors may
represent direct extension of adjacent
parotid salivary gland malignancies,
rhabdomyosarcoma (particularly in
children), or other regional carcinomas
from skin, ear, and nasopharynx.
 The most common metastatic lesions
include neoplasms originating in the
breast, kidney, lung, colon, prostate,
and thyroid gland.

108. Clinical features
 May be asymptomatic, or patients may
have symptoms of TMJ dysfunction
such as pain, limited mandibular
opening, mandibular deviation, and
swelling.

109. Radiographic features
 Appear as a variable degree of bone
destruction with ill-defined, irregular
margins.
 Most lack tumor bone formation, with
the exception of osteogenic sarcoma.

110. Treatment:
 In case of primary malignant tumors,
wide surgical removal of the tumor.
 Metastatic tumors are rarely treated
surgically; treatment mainly is palliative
and may include radiotherapy and
chemotherapy.

111. Bifid Condyle
 A bifid condyle has a vertical
depression, notch, or deep cleft in the
center of the condylar head, resulting
in the appearance of a “double” or
“bifid” condylar head.
 May be unilateral or bilateral.
 It may result from an obstructed blood
supply or other embryopathy.
 Traumatic cause has been postulated as
a result of a longitudinal linear fracture
of the condyle.

112. Clinical features
 Usually is an incidental finding in
panoramic views or anteroposterior
projections.
 Some patients have signs and
symptoms of temporomandibular
dysfunction, including joint noises and
pain.

113. Radiographic features
 A depression or notch is present on the
superior condylar surface, giving the
anteroposterior silhouette a heart
shape;
 In more severe cases a duplicate
condylar head is present in the
mediolateral plane.
 The mandibular fossa may remodel to
accommodate the altered condylar
morphology.
 Treatment is not indicated unless pain
or functional impairment is present.

114. Fracture
 Fractures of the TMJ usually occur at
the condylar neck and often are
accompanied by dislocation of the head.
 Fractures may be divided into those
involving the condylar head and those
involving condylar neck, although
occasionally both may be involved.
 On rare occasions the fracture may
involve the temporal component.

115. Clinical features
 Unilateral fractures, which are more
common than bilateral fractures, may
be accompanied by a parasymphyseal
or mandibular body fracture on the
contralateral side.
 Patient may have swelling over the
TMJ, pain, limited range of motion,
and an anterior open bite.

116. Radiographic features
 In relatively recent condylar neck
fractures, a radiolucent line limited to
the outline of the neck is visible.
 This line may vary in width, depending
on whether the bone fragments are still
aligned (narrow line) or displacent has
occurred (wider line).
 If the bone fragments overlap, an area
of apparent increase in radiopacity may
be seen instead of a radiolucent line.

117.  Also, the outer cortical boundary may
have an irregular outline or step defect.
 Fractures of the condylar head are
less common and may be of vertical
(responsible for the traumatic type of
bifid condyle) or compressive type.
 The amount of remodeling seen in the
TMJ after a condylar fracture with
medial displacement varies considerably.

118.  In some cases the condyle remodels to
a form that is essentially normal,
whereas in other cases the condyle and
mandibular fossa become flattened,
with loss of vertical height on the
affected side.
 The condyle eventually may show
degenerative changes, including
flattening, erosion, and osteophytes,
and ankylosis.
 Treatment may not be indicated if
mandibular mobility is adequate;
otherwise, the fracture is reduced
surgically.