Temporomandibular Dysfunction (TMD)

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Temporomandibular dysfunction (TMD) refers to a range of disorders causing pain in the pre-auricular area and muscles of mastication. It is the most common non-dental cause of orofacial pain and often goes hand in hand with other chronic pain disorders such as headaches and fibromyalgia. This article will discuss the aetiology and clinical signs of TMD and then outline its management.


Anatomy of the TMJ

The temporomandibular joint (TMJ) connects the skull to the lower jaw. The TMJ comprises the following structures:

  • Mandibular fossa of the temporal bone
  • Articular disc
  • Mandibular condyle
  • Supporting ligaments

The superior compartment of the TMJ is responsible for the translational movement of the joint.

The inferior compartment of the TMJ is responsible for the rotational movements of the joint.

 

Tempomandibular Joint
Figure 1. An illustration of the TMJ. The meniscus of the TMJ is located between the head of the mandibular condyle and the glenoid fossa of the temporal bone and can contribute to clicking and locking of the joint.

Aetiology

TMD involves multifactorial pathophysiology and there is no conclusive theory on the exact cause of the condition. Possible underlying causes include:

  • Stress
  • Low mood
  • Bruxism (tooth grinding)
  • Co-morbidities such as chronic pain (e.g. fibromyalgia, chronic fatigue syndrome, back pain, headache)
  • Trauma to the teeth/face causing malocclusion (an abnormal bite)

Clinical features

History

Typical symptoms of TMD include:

  • Pain in the pre-auricular area which can radiate to the jaw and temporal region.
  • Clicking sounds: due crepitus of the TMJ joint.
  • Locking: as a result of the articular disc becoming trapped preventing the jaw from closing.
  • Trismus: difficulties opening the mouth fully.

Clinical examination

Typical clinical signs of TMD include

  • Tenderness on palpation of the TMJ
  • Tenderness at the insertion point of masseter and temporalis
  • Crepitus of the TMJ during jaw movement
  • Trismus
  • Locking of the jaw
Examining the TMJ

Begin by inspecting the mouth to look for dental pathology and to assess the patient’s occlusion (bite).

Palpate the TMJs bilaterally and then the muscles of mastication to identify any tenderness.

Ask the patient to open and close their mouth whilst palpating the joint to detect clicking as a result of joint crepitus. Deviation or locking of the jaw may also be observed at this point.


Investigations

In most cases, the diagnosis of TMD is clinical, with no further investigations required.

Further investigations which may be performed in a minority of cases include:

  • ESR and CRP: to assess for evidence of inflammation (e.g. if considering rheumatological disease)
  • X-ray: to identify gross bony pathology
  • MRI: provides detailed views of the soft tissues of the TMJ (e.g. intra-articular disc)

Management

The primary goals of treatment are to eliminate pain and restore normal jaw function.

The vast majority of cases can be managed conservatively with only a small minority requiring surgical management.

Conservative management

Conservative management of TMD includes:

  • Education and reassurance: advise that most cases of TMD are benign and will improve with conservative measures.
  • Identification of problem habits such as nail-biting and chewing gum.
  • Jaw exercises to strengthen muscles of mastication (advice sheets are available online and in OMFS units).
  • Analgesia: typically paracetamol and NSAIDs are adequate to control pain. 
  • Antidepressants: such as TCAs, SSNRIs and SSRIs 
  • Occlusal splint: a bite guard worn over the teeth to help with malocclusion or bruxism.
  • Physiotherapy: improves joint function through jaw stretch and muscle relaxation.
  • Acupuncture: may be helpful, although evidence is inconclusive.

Surgical management

Surgical management is only considered in a small number of cases when conservative measures have failed to control the patient’s symptoms.

Some examples of surgical intervention include:

  • Arthrocentesis
  • Arthroplasty
  • TMJ replacement surgery (very rare)

  • Temporomandibular dysfunction (TMD) refers to a range of disorders causing pain in the pre-auricular area and muscles of mastication.
  • Typical symptoms of TMD include pain in the pre-auricular area, clicking sounds, locking of the jaw and trismus.
  • Typical clinical signs of TMD include tenderness of palpation of the TMJ and muscles of mastication.
  • In most cases, the diagnosis of TMD is clinical, with no further investigations required.
  • The primary goals of treatment are to eliminate pain and restore normal jaw function.
  • The vast majority of cases can be managed conservatively with only a small minority requiring surgical management.
  • Conservative management involves patient education, identification of problem habits, jaw exercises, analgesia, antidepressants, occlusal splints and physiotherapy.
  • Examples of surgical management include arthrocentesis, arthroplasty and replacement of the TMJ.

References

  1. Dwonkin SF. The OPPERA study: Act One. J pain 2011; 12: T1-T3
  2. Durham J, Newton-John TR, Zakrzewska JM. Temporomandibular Disorders. BMJ2015;350:h4154
  3. Ghurye S, McMillan R. Pain-Related Temporomandibular Disorder – Current Perspectives and Evidence-Based Management. Dental Update 2015; 42 (6): 533-546
  4. TMJ image: Anatomy & Physiology, Connexions Web site. Available from: [LINK]

 

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