The temporomandibular joint (TMJ) connects the mandible to the skull. The image below shows the anatomy. The joints are essential for jaw movements.
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TMJ Disorders
TMJ disorders are common and cover musculoskeletal conditions impacting the muscles of mastication and the TMJ. Causes are multifactorial and related to anatomy, trauma, grinding or clenching of the teeth and psychosocial factors (stress, anxiety and depression).
History
- Presenting complaint of the patient – this is often pain, clicking of the joint, locking, reduced mouth opening and difficulty eating
- Take a thorough pain history and look into impact of quality of life
- Ask about any history of tooth grinding or clenching
- Ask about previous episodes of jaw locking or dislocation
- Has there been any preceding trauma?
- Take a thorough medical history, particularly asking about any systemic joint disorders
Examination
- Assess for facial symmetry and swelling
- Assess for any obvious dental pathology
- Palpate the TMJ, assessing for tenderness, range of movement, any sounds when moving/opening the jaw
- Record mouth opening (normal ranges from 35 – 55mm)
- Palpate the masseter and temporalis – assess for hypertrophy (bulky muscle) and tenderness
Diagnosis
Diagnosis is mainly through history and examination. Most patients will have pain around the TMJ/muscles of mastication that may radiate to the head and neck. Pain is worse on palpation and provoked by jaw movements. They may have clicking or crepitus on jaw movements, with or without jaw locking.
Management
A biopsychosocial approach should be taken to pain. This includes reassurance, education, soft diet and stress management strategies. If there are concerns over stress, anxiety or depression appropriate treatment and help should be given through psychology services. They should avoid opening their mouth wide, nail-biting, chewing gum and wide yawning. You can consider providing analgesia and a short course of benzodiazepines. Consider referral to a dentist if the patient may benefit from a mouthguard due to tooth grinding/clenching.
If there is no improvement in 6-8 weeks in primary care, an unclear diagnosis, severe dysfunction, a history of trauma, markedly reduced mouth opening, locking of the jaw or recurrent dislocations the patient should be referred to OMFS.
TMJ dislocation
TMJ dislocation is a common presentation to Emergency Departments. Some people suffer from recurrent dislocations. As seen in the figure below, when the TMJ dislocates, it is positioned in front of, anterior to, the articular eminence.
The joint should be reduced as soon as possible as with a time delay it becomes harder due to muscle spasm. When relocating the TMJ, the patient should be sitting up in a chair with the clinician placed in front of them. Some analgesia should be given, and another colleague should help support the head from behind. Each thumb should be placed intraorally, wrapped in gauze, on the retromolar region, behind the lower teeth. A ‘down and back’ motion is then used until the TMJ goes back into place. Ensure the patient keeps their mouth closed for a few hours and has a soft diet for 24-48 hours. The figure below shows how best to do this. If it is not possible, the patient may need sedation or a GA.
References
Payne, K.F., Goodson, A.M., Tahim, A.S., Ahmed, N. and Fan, K.F., 2015. On-call in Oral and Maxillofacial Surgery. Libri Publishing.
Isaac, R., Goodson, A.M., Payne, K.F., Tahim, A.S. and Brennan, P.A., 2022. Oral and Maxillofacial Surgery: An Illustrated Guide for Medical Students and Allied Healthcare Professionals. Libri Publishing.
Excellence NIfHaC. Temporomandibular disorders (TMDs) 2024 [Available from: https://cks.nice.org.uk/topics/temporomandibular-disorders-tmds/.
Written by Dr Janhvi Shah BDS (Hons) MBBS MFDS (RCSEd) PgCert MedEd
