A Brief description of the causes and clinical manifestations of the internal derangement of the temporomandibular joint , with particular emphasis on Disc Displacements .

1. Understanding TMJ
Internal Derangements
Dr. Marwan Mouakeh , DDS, Doc.Ortho.Sc
Consultant Orthodontist and Academic Adviser
Al-Hokail Polyclinic - Khobar , Saudi Arabia

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

3. Anatomic and Physiologic
Background

4. The Masticatory System:
 TMJs
 Muscles
 Teeth ( Occlusion)

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

9. • The Articular Disc ( Meniscus )
Retrodiscal
Tissue

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

14.  Masticatory Muscles
 The Primary Movers of the Mandible

15. Lateral Pterygoid Muscle
Inf. Belly : Depressor
Sup. Belly : Elevator

16. ClosureOpening
• The Function of the 2 heads of the lateral pterygoid muscle
during mouth opening and closing

17. T MJ Pain & Dysfunctions
TMJ Origin
Masticatory
Muscles
Origin
TMJ &
Muscles
Origin

18. TMJ Internal Derangement
Disc Displacements

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 .

21. Classifications of TMJ Disc Displacements

22.  Anatomical Classification :
 Anterior
 Antero-medial
 Antero-distal
 Lateral
 Medial
 Posterior ( very rare )
Rotational
Sideways
of TMJ Disc DisplacementsClassifications

23. DisplacementsDisc
Anterior Displacement

24. Early phase
Late phase
• Frequently , the displacement is antero-medial ( rotational )
DisplacementsDisc

25. lateral sections central sections open-mouth
 Partial Anterior Disc Displacement

26. Disc Displacements
Sideways Displacements
Medial

27.  Medial Disc Displacement
Oblique coronal MRIcoronal MRI

28. Disc Displacements
Sideways Displacements
Lateral

29. Lateral Disc Displacement

30. Disc Displacements
• Posterior Displacement
 Very Rare
 “ Open Lock “ condition

31.  Posterior Disc Displacement
“ Open Lock “ condition

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

34.  Disc Displacement With Reduction
Closed Partially Open Fully Open

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

36. •Complete Anterior Disc Displacement

37. Closed Open
 Disc Displacement Without Reduction

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

39. Etiopathology of TMJ Internal
Derangements

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

50.  Disc Perforations
 Evolution of TMJ Disc Displacements

51. Disc Perforations
 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

57. Parafunctional Activities : Bruxism
• Microtrauma
 Causes of TMJ Disc Displacements : Intinsic Factors

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

62. Signs & Symptoms of
TMJ Internal Derangement

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

65. • Disc Displacement With Reduction
• Reciprocal Click
1
2

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

74. Mandibular Midline Deflection : A common sign of
ADD Without Reduction
 Disc Displacement Without Reduction

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

76. Acute Phase
 Disc Displacement Without Reduction
Clinical Signs & Symptoms

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

80. Clicking Crepitation
 Joint Sounds

81. Aleppo – Citadel