Occlusion and TMJ by Dr. Hadi Fouladgar

1. In the name of God

2. DIAGNOSTIC IMAGING OF THE TEMPOROMANDIBULAR JOINT

3. Disorders of the temporomandibular joint include:
• dysfunction of the articular disk
• associated ligaments
• Muscles
• joint arthritides
• Inflammatory lesions
• neoplasms
• growth or developmental abnormalities

4. • Temporomandibular joint (TMJ) dysfunction is
a common jaw disorder, with 28% to 86% of
adults
• higher incidence in females

5. Signs and symptoms
• pain in the TMJ or ear or both
• headache
• muscle tenderness
• joint stiffness
• clicking or other joint noises,
• reduced range of motion, locking

6. • In most cases the clinical signs are transitory,
and treatment is not indicated.
• A small group of patients (5%) has severe
dysfunction (e.g., severe pain, marked
functional impairment), which requires a
thorough diagnostic workup, including
diagnostic imaging, before treatment is begun.

7. Application of Diagnostic Imaging
• TMJ imaging is not indicated for joint sounds if
other signs or symptoms are absent for
asymptomatic children and adolescents before
orthodontic treatment

8. Radiographic Anatomy of the
Temporomandibular Joint
• A thorough understanding of the anatomy and
morphology of the TMJ is essential so that a
normal variant is not mistaken for disease.

9. • The TMJs are unique in that, although they
constitute two separate joints anatomically,
they function together as a single unit.

10. Radiographic Anatomy of the
Temporomandibular Joint
• Each condyle articulates with the mandibular
fossa of the temporal bone.
• A disk composed of fibrocartilage is
interposed between the condyle and
mandibular fossa.
• A fibrous capsule lined with synovial
membrane surrounds and encloses the joint.
• Ligaments and muscles restrict or allow
movement of the condyle.

13. Normal Anatomy

14. Lateral pterygoid muscle raphe
Lower head of lateral pterygoid muscle
Anterior band of articular disc
Mandibular condyle (head)
Posterior band of articular disc
Posterior disc attachment

15. Mandibular condyle (head)
Articular disc

16. INTERARTICULAR DISK
• composed of fibrous connective tissue, is
located between the condylar head and
mandibular fossa.
• The disk divides the joint cavity into two
compartments, called the inferior (lower) and
superior (upper) joint spaces
• A normal disk has a biconcave shape with a
thick anterior band, thicker posterior band,
and a thin middle part

17. INTERARTICULAR DISK
• The anterior band is attached to the superior
head of the lateral pterygoid Muscle
• the posterior band attaches to the posterior
retrodiskal tissues (also called the posterior
attachment)

18. INTERARTICULAR DISK
• During mandibular opening, as the condyle
rotates and translates downward and forward,
• the disk also moves forward and rotates so
that its thin central portion remains between
the condylar head and articular eminence

19. POSTERIOR ATTACHMENT (RETRODISKAL TISSUES)
• consists of a zone of vascularized and
innervated loose fibroelastic tissue.
• As the condyle moves forward, tissues of the
posterior attachment expand in volume

20. TEMPOROMANDIBULAR JOINT BONY RELATIONSHIPS
• Radiographic joint space is a general term used to
describe the radiolucent area between the condyle
and temporal component

21. Condylar displacement
• inferior condylar positioning (widened joint
space) is seen in cases involving fluid or blood
within the joint
• superior condylar positioning (decreased joint
space or no joint space, with osseous contact of
joint components) indicate loss or perforation of
intracapsular soft tissue components(disk).
• posterior condylar positioning is seen in ant. disk
displacement,
• anterior condylar positioning may be seen in
juvenile rheumatoid arthritis.

22. Diagnostic Imaging of the Temporomandibular Joint
• The type of imaging technique selected
depends on the specific clinical problem
• whether imaging of hard or soft tissues is
desired
• the cost of the examination
• and the radiation dose
• Both joints should be imaged during the
examination, for comparison.

23. OSSEOUS STRUCTURES?

24. OSSEOUS STRUCTURES
• Panoramic Projection
• Plain Film Imaging Modalities
• Conventional Tomography
• Computed Tomography

25. Panoramic Projection
• provides an overall view of the teeth and jaws,
provides a means of comparing left and right
sides of the mandible
• serves as a screening projection to identify
odontogenic diseases and TMJ disorders

26. Panoramic Projection
• Some panoramic machines have specific TMJ
programs, but these are of limited usefulness
because of superimposition and distorted
view
• Gross osseous changes in the condyles may be
identified, such as asymmetries, extensive
erosions, large osteophytes, tumors or
fractures

27. Panoramic Projection
• no information about condylar position or
function is provided because the mandible is
partly opened and protruded when this
radiograph is exposed

28. Plain Film Imaging Modalities
• transcranial
• Transpharyngeal(Parma)
• Transorbital
• submentovertex (base)

29. Plain Film Imaging Modalities
• Transcranial and transpharyngeal projections
provide lateral views.
• The transcranial view is taken in the closed
and open mouth positions and depicts the
lateral aspect of the TMJ
• the transpharyngeal projection is taken in the
mouth open position only

30. • The transorbital projection is taken in the
open / protruded position
• and depicts the entire medial-lateral aspect of
the condyle in the frontal plane and is very
useful in detecting condylar neck fractures.

31. • A submentovertex projection provides a view
of the skull base and condyles in the
horizontal plane
• These imaging techniques are gradually being
replaced with more advanced imaging such as
cone-beam computed tomography (CT).

32. Transcranial view

33. Transpharungeal -Transorbital

34. SMV

35. Conventional Tomography
• produces multiple image slices(sectional) ,
permitting visualization of the osseous
structures

36. Conventional Tomography

37. Computed Tomography
• Sectional images
• provides 3D image of components of the joint.
• There are two CT devices available,
conventional CT (medical CT) and CBCT.
• Both modalities can give excellent images of
the osseous structures, but only conventional
CT provides images of the surrounding soft
tissues;

38. Computed Tomography
• CBCT has the advantage of reduced patient dose
compared with medical CT
• In CBCT the patient is usually scanned in the closed
position
• low-resolution scans can be done in the open or other
positions
• axial slices, lateral and frontal images of the TMJs
• Panoramic and three-dimensional reformatted images
also can be produced
• Conventional CT and CBCT cannot produce accurate
images of the articular disk.

39. Applications
• CT is also useful for determining :
• ankylosis and neoplasms
• arthritides
• complex fractures

43. SOFT TISSUE STRUCTURES
• Soft tissue imaging is indicated when TMJ pain
and dysfunction are present and symptoms
that are unresponsive to conservative therapy.

44. Arthrography
• Arthrography was the first imaging modality
for soft tissues of the joint.
• Arthrography is a technique in which an
indirect image of the disk is obtained by
injecting a radiopaque contrast agent into the
joint spaces under fluoroscopic guidance.

46. • Magnetic resonance imaging (MRI) has replaced
arthrography and is now the imaging technique
of choice for the soft tissues of the TMJ
• MRI can not only display the articular disk but
also the surrounding soft tissue structures and
also can reveal the presence of joint effusion.
• MRI displays the osseous structures of the TMJ
but not in the comparable detail seen in CT
imaging.
• The technique is noninvasive and does not use
ionizing radiation.

47. MRI closed position

48. MRI
• These images usually are acquired in open and
closed mandibular positions
• T1-weighted and proton-density images best
demonstrate osseous and diskal tissues
• T2-weighted images demonstrate
inflammation and joint effusion.

49. MRI
• MRI is contraindicated in patients who are
pregnant or who have pacemakers,
intracranial vascular clips, or metal particles in
vital structures.
• Some patients may not be able to tolerate the
procedure because of claustrophobia or an
inability to remain motionless.

50. Abnormalities of
the Temporomandibular Joint

51. DEVELOPMENTAL
ABNORMALITIES

52. Condylar Hyperplasia
• Enlargement and occasionally deformity of the
condylar head
• Etiologic factors include hormonal influences,
trauma, infection, heredity
• usually is unilateral and may be accompanied
by varying degrees of hyperplasia of the
ipsilateral mandible

53. Clinical Features
• more common in males
• usually is discovered before the age of 20 years
• The condition is self-limiting
• and tends to arrest with termination of skeletal
growth
• may progress slowly or rapidly
• Patients have a mandibular asymmetry
• The chin may be deviated to the unaffected side

54. Clinical Features
• As a result of this growth pattern, patients
may have a posterior open bite on the
affected side.
• Patients may also have symptoms related to
TMJ dysfunction and may complain of limited
or deviated mandibular opening

55. Radiographic features
• Cortical thickness and trabecular pattern of
the enlarged condyle usually are normal
which helps to distinguish this condition from
a condylar neoplasm.
• The glenoid fossa may be enlarged
• The ramus and mandibular body on the
affected side also may be enlarged,

58. Differential Diagnosis
• A condylar tumor, an osteochondroma
• An osteochondroma is irregular in shape
• Continued growth after cessation of skeletal
growth should increase suspicion of this
tumor.
• condylar osteoma or large osteophyte may
simulate condylar hyperplasia

59. Treatment
• orthodontics combined with orthognathic
surgery
• treatment before condylar growth is
completed may result in relapse of occlusal
and esthetic problems.
• Cessation of growth of the condyle may be
determined with technetium bone scans.

60. Condylar Hypoplasia
• The condyle is small, but condylar morphology
usually is normal
• Some cases have been attributed to injury to
the articular cartilage by birth trauma or intra-
articular inflammatory lesion
• may be unilateral or bilateral (micrognathia,
Treacher Collins syndrome)
• may be associated with defects of the ear and
zygomatic arch.

61. Clinical Features
• Patients with condylar hypoplasia have
mandibular asymmetry and may have
symptoms of TMJ dysfunction.
• The chin commonly is deviated to the affected
side, and the mandible deviates to the
affected side during mandibular opening.
• Degenerative joint disease is a common long-
term sequela

62. Radiographic Features
• The condyle may be normal in shape and
structure but is diminished in size
• Mandibular fossa also is proportionally small

65. Differential Diagnosis
• Condylar destruction from juvenile
rheumatoid arthritis may appear similar to
that of hypoplasia

66. Treatment
• Orthognathic surgery, bone grafts, and
orthodontic therapy may be required

67. SOFT TISSUE ABNORMALITIES

68. internal derangement
• an abnormality in the position and
morphology of the articular disk that may
interfere with normal function
• The disk most often is displaced in an anterior
direction
• The cause: parafunction, jaw injuries
• Diagnosed by MRI.

69. Disk Reduction and Nonreduction

70. internal derangement
• A longstanding displaced disk become
deformed, losing its normal biconcave shape,
and become thickened and fibrotic.
• Complications are degenerative joint disease
and perforation through the disk or (more
commonly) the posterior attachment.

71. Signs
• decreased range of mandibular motion.
• Joint noises
• Click as the disk reduces to a normal position during
mandibular opening
• and a softer click as the disk becomes displaced again
during mandibular closing.
• Noises may be absent in long-term displaced,
nonreducing disks, or crepitus may be heard.
• pain in the preauricular region
• Headaches
• Episodes of closed or open locking of the joint

72. Radiographic Features
• The disk cannot be visualized with
conventional radiography
• MRI is the technique of choice
• In MRI the normal disk has a low signal
intensity (is dark between bone and muscle)

75. Perforation
• Perforations commonly occur in the
retrodiskal tissue, just behind the posterior
band of the disk (and can be detected in
arthrographic investigations but are not
reliably detected with MRI.

76. Effusion
• fluid in the joint
• an early change that may precede
degenerative joint disease.
• MRI can detect Joint effusion
• as an area of high-signal intensity in the Joint
spaces in T2-weighted images

78. Remodeling
• adaptive response of cartilage and osseous
tissue to excessive forces resulting in
alteration of the shape of the condyle and
articular eminence.
• result in flattening of curved joint surfaces,
which effectively distributes forces over a
greater surface area.
• The number of trabeculae also increases, and
density of cancellous bone

79. TMJ remodeling
• No destruction or degeneration of articular
soft tissues occurs.
• Occurs throughout adult life and is considered
abnormal only if it is accompanied by clinical
signs and symptoms of pain or dysfunction

81. Degenerative Joint Disease
• (DJD) is a noninflammatory disorder of joints
• destruction of articular cartilage and bone
erosion.
• new bone formation at the articular surface and
in the subchondral region.
• Usually a variable combination of deterioration
and proliferation
• deterioration is more common in acute disease,
and proliferation predominates in chronic
disease.

82. • DJD is thought to occur when the ability of the
joint to adapt to excessive forces (remodel) is
exceeded.
• The etiology: acute trauma, and parafunction.
• Internal disk derangements may be
contributing etiologic factors

83. Clinical Features
• incidence increases with age.
• DJD has a female preponderance.
• signs and symptoms :
• pain on palpation and movement,
• joint noises (crepitus),
• limited range of motion,
• and muscle spasm.

84. Radiographic Features
• Osseous changes in DJD : CT
• joint space may be narrow correlates with an
internal derangement or a perforation of the
disk or posterior attachment, resulting in
bone-to-bone contact
• flattening and subchondral sclerosis
• Loss of cortex , erosions of the articulating
surfaces of the condyle or temporal
component are characteristic

85. • small, round, radiolucent areas deep to the
articulating surfaces.
• These lesions are called “ Ely ” or
subchondral bone cysts
• Are not true cysts; they are areas of
degeneration that contain fibrous tissue,
granulation tissue, and osteoid

87. • bony proliferation at the periphery of
articulating surface
• increasing articulating surface area.
• osteophyte, on the anterosuperior surface of
the condyle, the lateral aspect of the temporal
component

90. Rheumatoid Arthritis
• Synovitis (synovial membrane inflammation)
in several joints.
• The TMJ involved in half of patients.
• formation of synovial granulomatous tissue
(pannus)
• Releasing enzymes that destroy articular
surfaces and underlying bone.

91. Clinical Features
• more common in females
• increases in incidence with increasing age.
• joints of the hands, wrists, knees, and feet are
affected in a bilateral, symmetric fashion
• TMJ involvement usually is bilateral and
symmetric.
• swelling, pain, tenderness, stiffness on opening,
limited range of motion, and crepitus.
• anterior open bite because of joint destruction

92. Radiographic Features
• The initial changes : osteopenia (decreased
density) of the condyle and temporal
component
• diminished width of the joint space.
• Bone erosions in joint surfaces by the pannus
• Erosion of condylar surfaces at the result in a
“ sharpened pencil ” appearance of the
condyle.

93. • Joint destruction eventually leads to
secondary DJD.
• Subchondral sclerosis and flattening of
articulating surfaces occur, as well as
subchondral “cyst”
• and osteophyte formation.
• Fibrous ankylosis or, osseous ankylosis, may
occur

95. Treatment
• pain relief (analgesics), reduction of
inflammation (nonsteroidal anti-inflammatory
drugs, gold salts, corticosteroids)
• physiotherapy

96. Thank you

97. Bifid Condyle
• a vertical cleft in condylar head, seen in the
frontal or sagittal plane
• rare
• often unilateral
• Bifid condyle usually is an incidental finding in
radiography
• Some patients have signs and symptoms of
temporomandibular dysfunction, including
joint noises and pain

99. Differential Diagnosis
• Vertical fracture through the condylar head.

100. Fibrous Adhesions
• masses of fibrous tissue or scar tissue in joint
space
• particularly after TMJ surgery.
• best identified with arthrography
• in MRI low signal intensity.
• The pressure of injected contrast agent may
tear some of these adhesions, resulting in
increased joint mobility after the procedure.