A Brief description of the causes and clinical manifestations of the internal derangement of the temporomandibular joint , with particular emphasis on Disc Displacements .
2. Internal Derangements
General orthopedic term implying a mechanical
fault that interferes with the smooth action of a
joint
The most common internal derangement is
Disc Displacement
5. Temporo-Mandibular Joint (TMJ)
A compound synovial joint ,
connecting the mandible to the
temporal bone
Diarthrodial Paired Joint
6. • a Biconcave oval structure dividing
the joint cavity into 2 distinct
compartments
• Nonvascular and Noninnervated
dense fibrous connective tissue
instead of the hyaline cartilage found
in other body joints
• The Articular Disc ( Meniscus )
Temporo-Mandibular Joint (TMJ)
7. Divides the joint cavity into
2 separate compartments
Insures stability of the TMJ
during function
Absorbs forces acting on the
joint during function
Temporo-Mandibular Joint (TMJ)
• The Articular Disc ( Meniscus )
8. Temporo-Mandibular Joint (TMJ)
• The Articular Disc ( Meniscus )
- 2 types of joint movements
occur in separate compartments of
this joint :
• sliding or translation in the
upper compartment
• hinge or rotation in the lower
compartment
10. •The lower condylar
lamina : Non-Elastic
•The upper temporal
lamina : Elastic
(Retrodiscal Tissue or Bilaminar Zone):
a highly vascularized and well-innervated
tissue
• Posterior Attachment
11. Physiologic Position of the Articular Disc
1
2
3
The absence of blood vessels & nerves in the Intermediate Zone
enables this part of the disc to act as a Pressure-bearing area .
12. •12 O’clock position
The posterior band ends, in healthy TMJ , at the apex of the
condyle when teeth are in occlusion
13. Collateral Discal Ligaments : short and non-elastic
• Frontal View
The Articular Disc
Medial
Distal
19. • a Disorder characterized by an abnormal relationship
between the articular disc , mandibular condyle, and
articular eminence .
• The disc is most often
displaced anteriorly or
antero-medially
Disc Displacement
20. Disc Displacements
• The most frequent abnormality found in patients
presenting with signs and symptoms of
temporomandibular disorders ( TMDs)
• The main cause of TMJ internal derangement
• Using the MRI techniques, the prevalence of disc
displacements in patients suffering from TMDs
symptoms was about %84 .
32. Functional Classification
• Disc Displacement With Reduction
• Disc Displacement Without Reduction -Acute Phase -
• Disc Displacement Without Reduction -Chronic Phase -
of TMJ Disc DisplacementsClassifications
33. Closed Partially Open Fully Open
• The displaced disc recaptures its normal relationship with
the mandibular condyle during mouth opening
• Disc Displacement With Reduction
35. Disc Displacement Without Reduction
• Displacement of the articular disc on closing , and failure to
reduce or recapture the normal relationship with the condyle
upon opening
38. Disc Displacement Without Reduction
Closed
Open
• Contact is lost between the condyle , disc, and articular
eminence
• Articular space collapsed trapping the disc in front of the
condyle
40. Normal TMJ Function is dependant on :
Disc morphology
Disc attachments ( post. / collat. )
Lateral Pterygoid ( functional) coordination
Etiopathology of TMJ Internal Derangements
41. Disc morphology : Loss of self-seating property
Disc attachments ( post. / collat. )
Lateral Pterygoid ( functional) coordination
Etiopathology of TMJ Internal Derangements
42. Disc morphology : Loss of self-seating property
Disc attachments ( post. / collat. ) : Loosening or tearing
Lateral Pterygoid : ( functional) Incoordination
Etiopathology of TMJ Internal Derangements
43. Etiopathology of TMJ Internal Derangements
Disc morphology : Loss of self-seating property
Disc attachments ( post. / collat. ) : Loosening or tearing
Lateral Pterygoid : ( functional) Incoordination
44. 1 – Thickening of the posterior
band of the disc
2 - Elongation or loosening of the
disc’s collateral or posterior
attachments
3 – Change in the shape of the disc
from biconcave to biconvex
4 – Incoordination of the two
heads of the lateral pterygoid
muscle .
Etiopathology of Disc Displacements
45. Etiopathology of Disc Displacements
Posterior positioning of the
mandibular condyle relative to the
articular disc
The codylar head loads against the
posterior part of the disc
Progressive alteration in the form
of the posterior band
The disc looses its “ self-seating”
property and aggravation of the
anterior displacement of the disc
46. • Alteration of the normal
disc / condyle relation
• The condyle will load on
the richly vascularized
and well innervated
posterior part of the disc
• Pain in the TMJ and
Dysfunction
Development of Disc Displacements
47. Evolution of TMJ Disc Displacements
Disc Displacement With Reduction
Disc Displacement Without Reduction
Disc Perforations
Degenerative Joint Disease
Complete
Partial
Acute
Chronic
48. •Anteriorly displaced and deformed, degenerated disc and irregular
cortical outline with osteophytosis and sclerosis of condyle .
Evolution of TMJ Disc Displacements
49. Advanced osteoarthritis and anterior disc
displacement, with joint effusion
Evolution of TMJ Disc Displacements
52. What causes TMJ disorders?
The Exact Causes Are Not Clear Yet …
- Trauma to the jaw or TMJ :
> Macrotrauma
> Microtrauma
- Malocclusion (Bad Bite)
- A possible link between Female Hormones and
TMJ disorders ?
- Stress
53. Causes of TMJ Disc Displacements
Extrinsic FactorsIntrinsic Factors
54. Causes of TMJ Disc Displacements
Extrinsic Factors ( Macrotrauma) :
Direct : sudden blow following traffic
accidents or violent sports
Indirect : Whiplash
55. Acute Trauma to the Neck : Whiplash
Macrotrauma: Blow, Traumatic extraction , Intubation…
Causes of TMJ Disc Displacements : Extrinsic Factors
56. Causes of TMJ Disc Displacements
Intrinsic Factors (Microtrauma) :
Bruxism
Excessive mouth opening : prolonged
dental treatment – 3rd molars extraction
( traumatic) - intaoral intubation during
general anesthesia
Hard foods
58. Stress: Emotional & Physical
Stress frequently leads to unreleased nervous energy. It is very
common for people under stress to release this nervous energy by
grinding and clenching their teeth.
Causes of TMJ Disc Displacements
59. Specific Forms of Malocclusion
Causes of TMJ Disc Displacements
Anterior Open Bite Occlusal Interferences
with mandibular shift
60. Causes of TMJ Disc Displacements
Posterior Crossbite
with mandibular shift
Class II-division2 Malocclusion
Specific Forms of Malocclusion
61. Causes of TMJ Disc Displacements
Other Possible Causes
• Loss of posterior occlusal support
( missing > 5 posterior teeth ) and TMJ
overloading
• Generalized Hyperlaxity of
body joints
63. • Disc Displacement With Reduction
Clinical Signs & Symptoms
• Clicking or popping sounds during mandibular
opening and closing – Reciprocal Clicking –
• Deviation of the mandibular midline to the
affected side early on opening
• Pain resulting from the strained discal ligaments
or condylar pressure against posterior
attachment
• Limited mouth opening ( only in case of secondary
muscle splinting )
64. • Disc Displacement With Reduction
• The main sign of DD With Reduction
• The first click occurs early during mouth opening ,indicating
recapture of the displaced disc
• The second click occurs during mouth closure, indicating
displacement of the disc anteriorly .
• Reciprocal Click
66. • Disc Displacement With Reduction
to the side of the displaced disc
indicative of interference during
movement
midline returns to the centered
position after reduction of disc
displacement
Deviation of the mandibular midline
67. • Disc Displacement With Reduction
Articular Pain ( Arthralgia)
Resulting from strained discal
ligaments or,
Codylar pressure against posterior
attachments
68. Arthralgia (Articular Pain)
Localized in the TMJ Region
Increased with mandibular
movement.
Origin of pain :
posterior attachment - collateral
ligaments -articular capsule.
69. Myalgia ( Muscular Pain)
Dull , Deep , and Diffuse pain
Depressing
Felt in the morning when
related to Nocturnal Bruxism
Influenced by functional
demands ( chewing…)
70. Acute Disc Displacement Without Reduction
Clinical Signs and Symptoms
1- Severely restricted opening ( < 25-30 mm)
2- Mandibular midline Deflection
3- Limitation of protrusive excursion (accompanied by
deflection to the ipsilateral side )
4- Restriction of the lateral movement to the
contralateral side
71. Disc Displacement Without Reduction
• Clinical Signs & Symptoms
Sudden absence of joint clicking associated with
severe restricted opening ( closed lock )
Mandibular midline deflection towards the
affected side
Limitation in protrusive and lateral ( to the affected
side ) mandibular movements
Severe articular pain
Acute Phase
72. Disc Displacement Without Reduction
Sudden absence of joint
clicking associated with
severe restricted opening
( mechanical interference)
Closed Lock
73. Disc Displacement Without Reduction
Closed Lock :
Severe limited mandibular
movement (20 -25 mm) due to
abnormal positioning of the
articular disc in front of the
condyle
75. - Continuous displacement
of mandibular midline along
the whole opening movement
- A common sign of ADD
Without Reduction
Midline Deviation ,vs , Midline Deflection
- The mandible returns to the
centered position on opening
- Indicative of interference
during condyle movement
- A prominent sign of ADD
With Reduction
DeflectionDeviation
77. Chronic ADD without Reduction
and SymptomsClinical Signs
- Slight limitation in mandibular opening
- Slight deflection to the affected side
- Joint Sounds “ Crepitus “
78. Disc Displacement Without Reduction
• Progressive improvement of opening due to elongation
of posterior attachment and discal ligaments
• Moderate articular pain
• Joint Crepitation indicative of degenerative changes in
the articular surfaces
Chronic Phase
79. Pseudo-disc
Disc Displacement Without Reduction
Chronic Phase
Formation of “ pseudo-disc” as an
extension of the posterior band
this structure can withstand the
condylar pressure because it is
deprived of innervation and
vascularization