Disorders of the temporal mandibular joint

Anatomy, physiology and pathologies of the temporal mandibular joint

1. TMJ DISORDERS LINAH KWANGU

2. OUTLINE Definition Classification Evaluation Reversible Treatment Occlusion Modification Surgical Management Distraction Osteogenesis References

3. DEFINITION TMJ disorders are a group of conditions that cause pain and dysfunction in the jaw joint and muscles that control jaw movement.

4. CLASSIFICATION Myofascial Pain Internal Derangement Degenerative Joint Disease Systemic Arthritic Conditions Dislocations Ankylosis Infections Neoplasia

5. SIGNS AND SYMPTOMS Pain of the joint on palpation Pain on movement of the joint Altered TMJ function, including trismus , reduced opening, and mandibular deviation on opening Joint popping, clicking or crepitus Fascial pain Pain on palpation of the muscles of mastication Pain on opening.

6. EVALUATION The most common causes of temporomandibular disorders (TMDs) are muscular disorders - myofascial pain. Temporomandibular pain or dysfunction originate primarily within the temporomandibular joint (TMJ). Internal derangement, osteoarthritis, rheumatoid arthritis, chronic recurrent dislocation, Ankylosis , neoplasia, and infection.

7. History Muscular pain is usually described as “dull” and “achy”. Acute joint pain may be “sharp” or “shooting.” Pain that occurs primarily in the morning may indicate a systemic arthritis such as rheumatoid arthritis or myofascial pain resulting from nocturnal bruxism. If pain only occurs toward the end of the day, osteoarthritis may be explored as a potential cause.

8. MYOFASCIAL PAIN Masticatory muscles developing tenderness and pain as a result of abnormal muscular function or hyperactivity. Usually associated with daytime clenching or nocturnal bruxism. Complaint of diffuse, poorly localized, pre-auricular pain that may involve muscles of mastication such as the temporalis and medial pterygoid muscles as well as Bi-temporal headaches Examination reveals diffuse tenderness of the masticatory muscles. Isolated MPD, joint noises are usually not present.

9. Symptoms Pain during function Limited oral opening Masticatory and cervical tenderness

10. Management Following steps in initial consultation/management phase should be considered and treatment plan is pre­ pared: Reassurance and education Pain control: Analgesics, anti­inflammatory drugs, muscle relaxants, antianxiety drugs, tranquilizers, anti­ depressants, corticosteroids, etc. Injecting into active trigger points/TMJ with local anesthesia (LA) solution. Stress management: Habit modification, life style modification, progressive relaxation. Self-care: Rest during acute phase, jaw exercises, physiotherapy. Soft resilient splint for short time.

11. Home care instructions: Soft diet, physiotherapy, rest, relaxation/stress reducing techniques. Educate the patient about biomechanics of the jaw, neck and head posture. Behavioral therapy: Hypnosis, acupressure, acupunc­ ture, biofeedback, relaxation exercises, yoga. Nonsteroidal anti-inflammatory drugs —to reduce inflammation and to provide pain relief, both in the muscles as well as in the joints (for 14–21 days). Muscle relaxants —are recommended only for short duration, as they produce sedation and addiction. Diazepam 2–5 mg or cyclobenzapine 10 mg at bedtime can be given for 10 days or meprobamate 400 mg TDS × 7 days. Ethyl chloride spray or intramuscular local anesthetic injections in the affected muscles can also give relief. The patient is asked to follow the stretch exercises subsequently. 2% lignocaine or 0.05% bupivacaine can be used.

12. C ryotherapy for acute pain: Ice packs application to the painful area 4 times a day for 20 minutes. Cold compres­ sions lower the thermal gradient in the skin, interrupting massive concentration of histamines, thus lowering pain threshold in the skin. Spread of pain is interrupted by sudden cold stimulus, it also raises cutaneous pain threshold by counter­irritation. Massage with counter-irritants and vibrators: Firm friction massage produces temporary ischemia followed by hyperemia. It inactivates trigger points. Use of vapocoolant spray: Fluoromethane or ethyl chloride spray is applied to painful area for 5 seconds. The muscle is gently stretched after that. The eyes, nose and ears are protected from the spray. Tetanizing and sinusoidal currents: Fatiguing the muscle helps to recover gradual rhythmic movement.

13. Electrogalvanic stimulation: Positive and negative current is delivered to the targeted area . Delivers a wide range of intensity (voltage) to activate the injured muscle. It stimulates local circulation, achieves excitability and conductivity without painful heating. Pulse at 80 cycles/ second for 10 minutes followed by exercise for 5 minutes is used. Rhythmtic contractions increase circulation and reduce edema. Transcutaneous electronic nerve stimulator (TENS): It interferes with the sensation of pain in the brain and increases blood flow to the site. Active stretch exercises: It includes opening and closing of mouth 10 times as a warm up against resistance. It can help to restore the normal ROM, by flexibility and strengthening the muscles. Each of these physiotherapy modalities can be very helpful to reduce the pain and increase the ROM along with the medication.

14. INTERNAL DERANGEMENTS In normal circumstances, the condyle functions in a hinge and a sliding fashion. During full opening, the condyle also translates forward to a position near the most inferior portion of the articular eminence. During function, the biconcave disk remains inter-positioned between the condyle and the fossa.

15. ANTERIOR DISC DISPLACEMENT WITH REDUCTION The disk is positioned anterior and medial to the condyle in the closed position. During opening, the condyle moves over the posterior band of the disk and eventually returns to the normal condyle-and-disk relationship. During closing, the condyle then slips posteriorly and rests on the retro- diskal tissue. Maximal opening can be normal or slightly limited. The click occurring during the opening movement.

16. ANTERIOR DISK DISPLACEMENT WITHOUT REDUCTION The disk displacement cannot be reduced, and thus the condyle is unable to translate to its full anterior extent. Prevents maximal opening and causes deviation of the mandible to the affected side. No clicking happens. The restricted mouth opening may be due to the adherence of the disk to the fossa. Plain radiography or CT will produce similar findings as in anterior disk displacement with reduction. MRI generally demonstrates anteromedial disk displacement in the closed mouth position

17. DEGENERATIVE JOINT DISEASE Irregular, perforated, or severely damaged disks. Current concepts of DJD incorporate three possible mechanisms of injury: (1) Direct mechanical trauma; Significant and obvious to Micro-trauma (2) Hypoxia reperfusion injury (3) Neurogenic inflammation. The diagnosis of DJD includes Wilkes stage IV and V internal derangements. Pain associated with clicking or crepitus located directly over the TMJ. Radiographic findings are variable but generally exhibit decreased joint space, surface erosions, osteophytes, and flattening of the condylar head.

18. SYSTEMIC ARTHRITIC CONDITIONS The most common is Rheumatoid Arthritis - Inflammatory process results in abnormal proliferation of synovial tissue in a so-called pannus formation. Symptoms are rarely isolated to the TMJs and usually bilateral. May be earlier in age than DJD Radiographic findings initially show erosive changes in the anterior and posterior aspects of the condylar heads. Small, pointed condyle in a large fossa. Anterior Open Bite and Premature Bite on Posterior teeth.

19. DISLOCATION Mandibular hypermobility. Subluxation; displacement of the condyle, self-reducing. May occur spontaneously after opening the mouth widely such as when yawning, eating, or during a dental procedure. Dislocations should be reduced as soon as possible. Downward pressure on posterior teeth and upward pressure on the chin, accompanied by posterior displacement of the mandible. If Muscular spasm is present, Anesthesia of the auricular temporal nerve or sedation. After reduction the patient should be instructed to restrict mandibular opening for 2 to 4 weeks. Moist heat and NSAIDs are also helpful in controlling pain and inflammation.

20. Condyle displaced anteriorly beyond eminence. Subluxation—soft reducing displacement. Acute versus chronic (>1 month). Stability of TMJ Governed By Shape of glenoid fossa/condylar head. Ligament of joint—lateral capsule/ligament, sphenomandibular and stylo- mandibular muscles. Occlusion or lack of it (loss of dentition). Hyperfunction of protractor muscles.

21. Recurrent Dislocations Laxity of ligaments following dislocation due to trauma with tearing of liga- ments/capsule. Hyperactivity of the mandibular depressor muscles—suprahyoid/lateral ptery- goid by conditions such as epilepsy, cerebral palsy, medications (anti-psychotics), Parkinson’s disease. Psychiatric disease. Systemic disease—arthritis, Ehler’s Danlos syndrome. Loss of dentition—overclosure and joint laxity. Degeneration of ligaments secondary to disease (e.g., rheumatoid arthritis).

22. Management Acute . Radiographs to exclude fractures. Stimulation of gag reflex (not predictable). Manipulation—sustained pressure on posterior teeth to overcome muscle spasm (LA/GA/I.V. sedation). Consider limiting opening for 2 weeks—barrel bandage/MMF.

23. Chronic Non-invasive – Reconstruction with/without (sedation/muscle relaxation/GA)—barrel bandage to limit mouth opening/MMF. –  Physiotherapy to improve muscle function/awareness. –  Patient education—avoiding wide opening, self-reduction. Dentures to prevent overclosure. Invasive Allteration of ligaments – Lateral capsule tarsorrhaphy. 386 15 TMJ Surgery – Injection of sclerosing agent into joint space (blood/sodium tetradecyl sulphate). – Reinforcement procedure—Mitek anchor suture from condyle to zygomatic arch/or temporal fossa.

24. Relaxation of Muscles Botulinum toxin injection to lateral pterygoid. Temporalis—scarification. Detachment of lateral pterygoid muscle.

25. ANKYLOSIS Fusion of joint with reduced/absent movement. Trismus (muscle spasm)

26. Trauma, infection, neoplasia, TMJD, drugs (phenothiazines). Pseudoankylosis –  Extracapsular mechanical intervention → trauma (depressed malar fracture), coronoid hyperplasia/neoplasms. –  Scarring of masticatory muscles (previous radiotherapy, submucous fibrosis). False Ankylosis—Extracapsular –  Trauma (periauricular fibrosis), infection (chronic peri-auricular suppuration). –  Radiation (periauricular fibrosis/osteoradionecrosis). True Ankylosis –  Trauma: Birth, intracapsular fracture. –  Infection: Osteomyelitis, mastoiditis, iatrogenic (post-TMJ surgery). –  Neoplasia: Primary/secondary. Autoimmune: Juvenile idiopathic arthritis, ankylosing spondylitis, rheumatoid arthritis. Etiology

27. Trauma y Congenital y At birth, forceps delivery y Hemarthrosis (direct/indirect trauma) y Condylar fractures ƒ Intracapsular ƒ Extracapsular y Glenoid fossa fracture (rare) Infections y Otitis media y Parotitis y Tonsilitis y Furuncle y Abscess around the joint y Osteomyelitis of the jaw y Actinomycosis Inflammation y Rheumatoid arthritis y Osteoarthritis y Septic arthritis—hematogenous spread Rare causes Polyarthritis Measles Systemic diseases y Smallpox y Scarlet fever y Typhoid y Gonococcal arthritis y Scleroderma y Beriberi y Marie-Strümpell disease y Ankylosing spondylitis Other causes y Bifid condyle y Prolonged trismus y Prolonged immobilization y Unknown y Burns

28. Classification Location: Extra-/intracapsular. Type of tissue: Bony/fibrous/mixed. Extent of ankylosis: Complete/incomplete.

29. Intracapsular Ankylosis Leads to reduced mandibular opening Fusion of the condyle, disk, and fossa complex. Macrotrauma , Previous surgeries or infections. Severe restriction of maximal opening, deviation to the affected side, and decreased lateral excursions to the contralateral side. Fibrous Tissue vs. Bony Tissue Radiographs; irregular articular surfaces of the condyle and fossa.

30. EXTRACAPSULAR ANKYLOSIS Coronoid process and the temporalis muscle. Coronoid process enlargement, or hyperplasia, and trauma to the zygomatic arch area. Initially have limitation of opening and deviation to the affected side. Complete restriction of opening is rare, lateral and protrusive movements can usually be performed, Panoramic radiography generally demonstrates the elongation of a coronoid process. A submental vertex radiograph or CBCT may be useful in demonstrating impingement caused by a fractured zygomatic arch or zygomaticomaxillary complex.

31. Topazian’s Staging true ankylosis I. Ankylotic bone limited to condylar process. II. Extending to sigmoid notch. III. Extending to coronoid process –  Type I: fibrous adhesions in or around joint. –  Type II: Formation bony bridge between condyle and glenoid. Condylar neck is ankylosed.

32. Sawhney (1986) Type 1: Extensive fibrous adhesions around the joint. Type II: More bony fusion at the outer edge of the articular surface, but no fusion within the medial area of the joint. Type III: Bony bridge between the mandible and the temporal bone. Type IV: The joint is replaced by a mass of bone.

33. Clinical assessment CT ± modelling—important to measure the medial extent, relation of coronoid process to zygomatic arch and distance of maxillary artery. Relationship of ankylotic mass is important anatomic structure especially skull base, pterygoid plates, carotid canal, jugular foramen, and foramen spinosum.

34. Clinically Affects growth, reduces posterior facial height—influences maxillary growth. Affects joint tissues—pterygomasseteric sling. During growth –  Deviation of the chin/mandible to affected side. –  Reduced vertical height—ipsilateral, retrognathic mandible (short ramus/body). –  Retruded mandible—facial profile = convex. –  Occlusal cant/class II/posterior cross bites. A irway problems.

35. Management Restore mouth opening, joint function. Allow condylar growth. Relieve upper airway problems.

36. Examination The muscles should be palpated for the presence of tenderness, fasciculation, spasm, or trigger points. The most common forms of joint noises are clicking (a distinct sound) and crepitus (i.e., scraping or grating sounds). Maximum Opening = 45 mm Vertical and 10 mm Horizontal Wear Facets

37. RADIOGRAPHIC EVALUATION Panoramic radiography . Both TMJs on the same film. Bony anatomy of the articulating surfaces of the mandibular condyle and glenoid fossa.

38. Tomograms . Radiographic sectioning of the joint at different levels providing individual views. Elimination of bony superimposition and overlap, relatively a clear picture of the bony anatomy of the joint.

39. Temporomandibular Joint Arthrography . Indirect Visualization of the intra-articular disk. Injection of contrast material into the inferior or superior spaces of a joint, after which the joint is radiographed. Position and morphology of the articular disk, presence of perforations and adhesions of the disk or its attachments.

40. DISC DISPLACEMENT WITHOUT REDUCTION

41. Computed tomography. Variety of hard and soft tissue pathologic conditions in the joint. Most accurate radiographic assessment of the bony components of the joint.

42. Cone Beam Computed Tomography. Three-Dimensional reconstructions of the mandibular condyle and articular eminence. Much less Radiation dose No Diagnostics of soft tissue

43. Magnetic resonance imaging . Excellent images of intra-articular soft tissue. Does not use ionizing radiation is a significant advantage.

44. Nuclear imaging. Intravenous injection of technetium-99 - γ-emitting isotope concentrated in areas of active bone metabolism. Approximately 3 hours after injection of the isotope, images are obtained using a gamma camera.

45. PHYSIOLOGICAL EVALUATION The comorbidity of psychiatric illness and temporomandibular dysfunction can be as high as 10% to 20% of patients seeking treatment. A third of these patients is suffering from depression on initial presentation. More than two thirds have had a severe depressive episode in their history

46. REVERSIBLE TREATMENT Patient Education Physical Therapy Medications: NSAIDs Stronger Analgesics Muscle Relaxants Antidepressants Botox

47. SPLINT THERAPY Reversible or Conservative Most splints can be classified into two distinct groups: (1) Auto- repositioning splints and (2) anterior repositioning splints.

48. SURGICAL JOINT TREATMENT Indications Absolute Indications; Ankylosis Gap arthroplasty Interpositional arthroplasty Costochondral graft Prosthetic joint

49. HYPERMOBILITY Sclerosing agent Plication Daughtry procedure Eminectomy

50. ARTHROSCOPY Small cannula into the superior joint space, followed by insertion of an arthroscope to allow direct visualization of all aspects of the glenoid fossa, superior joint space, and superior aspect of the disk. One cannula is used for visualization of the procedure with the arthroscope , whereas instruments are placed through the other cannula Internal derangements, hypomobility as a result of fibrosis or adhesions, DJD, and hypermobility. Advantage of less surgical morbidity and fewer and less severe complications.

51. ARTHROCENTESIS Minimally invasive technique that involves placing ports (needles or small cannulas) into the TMJ to lavage the joint and to break up fine adhesions. IV Sedation and Auricotemporal Nerve Blocks Lactated Ringer solution is injected to distend the joint space and release fine adhesions that may be limiting disk mobility. Post-Operative Complaints are usually Mild pain

52. REFERENCES Oral maxillofacial surgery by James R. Hupp, Edward Ellis and Myron R. Tucker. Temporomandibular and Other Facial Pain Disorders

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