Identify 3 possible aetiologies associated with restricted mouth opening

  • Disc displacement without reduction with limited opening (closed lock)
  • Masticatory myalgia with protective co-contraction
  • Arthralgia
  • Degenerative joint disease (osteoarthroses/arthritis)
    • structural breakdown of the articular surfaces. Typically with crepitus and opening usually < 35

Based solely on the information provided above, what are the possible diagnoses for this patient

  • Anterior disc displacement without reduction With limited opening (closed lock) of the left TMJ
  • Left masticatory myalgia
  • Left arthralgia

Describe your diagnostic approach and the investigatinos required to determine the cause of his restricted mouth opening

  • Palpation of TMJs for joint sounds, characterizing timing (opening click, closing click, crepitus)
  • Palpation of the TMJs (lateral pole and posterior attachment) and masticatory muscles (masster, termporalis, medial and latery ptrygoid) for tenderness
  • MRI of TMJs

Name 3 distinct subtypes of internal derangement of the TMJ

  • Disc displacement with reduction
  • Disc displacement with reduction wiht intermittent locking
  • Disc displacement without reduction with limited opneing (closed lock

Key diagnostic features of above subtypes

  • Disc displacement with reduction
    • Reproducible clicking/popping on opening . Normal opening wiht ipsilateral deviation that corrects
  • Disc displacement with reduction with intermittent locking
    • episodes of intermittened locking on a background of clicking, the jaw can be freed by a small movement restoring normal opening
  • Closed lock
    • loss of prior click and a limited opneing (<35-40 mm ) with uncorrected ipsilateral deflection and restricted contralateral excursion

Management options

  • First line
    • Patient education and reassurance
    • soft diet and parafunctional habit control
      • avoid clenching, jaw bracing, gum and wind instruments
    • Thermotherapy and physiotherapy
      • heat/ice, jaw exercises, tongue to roof controlled opening to correct deviation

What factors may affect this patient’s overall prognosis

  • Severity and chronicity of the disorder at presentation
  • Patient compliance/adherence to self-management
  • Psychosocial comorbidities (anxiety, depression, pain catastrophising) and genetic predisposotoin