15.2 Orofacial Pain and Temporomandibular Disorders
Key Takeaways
- Around 70% to 80% of patients with temporomandibular disorder improve with conservative management, so reversible measures precede any irreversible occlusal intervention.
- Disc displacement without reduction presents as sudden limited opening, typically under about 30 mm, with deviation to the affected side and loss of a previously present click.
- Trigeminal neuralgia causes paroxysmal electric-shock pain lasting seconds to two minutes with trigger zones and is treated first line with carbamazepine.
- Jaw claudication with scalp tenderness in a patient over 50 requires same-day corticosteroid and urgent referral because giant cell arteritis causes irreversible blindness.
- Burning mouth syndrome is diagnosed only after excluding candidiasis, haematinic deficiency, diabetes, xerostomia, parafunction and allergy.
Structuring a Facial Pain Diagnosis
Preparing for Practice outcome 1.14.2 requires registrants to "recognise and manage temporomandibular joint disorders", and outcome 1.7.5 requires them to prevent, diagnose and manage pain safely. Orofacial pain items in Paper B almost always present a stem that could be odontogenic and ask you to identify the non-odontogenic cause.
The first question is always: is this pain of dental origin? A tooth that is not carious, not restored, responds normally to sensibility testing, is not tender to percussion and has a normal periapex is very unlikely to be the source. Irreversible pulpitis and apical periodontitis account for most facial pain, and the first duty is to exclude them properly rather than to reach for an exotic diagnosis.
Temporomandibular Disorders
TMD is an umbrella term covering myofascial pain, disc displacement and degenerative joint disease. The three cardinal features are pain in the muscles of mastication or the joint, restricted or deviated movement, and joint noise.
| Subtype | Key features | Management |
|---|---|---|
| Myofascial pain | Dull ache in masseter and temporalis, worse on waking, tender muscle palpation, often bruxism and stress | Reassurance and explanation, soft diet, jaw rest, heat, analgesia, stabilisation splint, jaw exercises, address parafunction |
| Disc displacement with reduction | Reciprocal click on opening and closing, normal or near-normal opening range | Usually conservative; explain the mechanism and reassure |
| Disc displacement without reduction (closed lock) | Sudden limited opening, typically under about 30 mm, deviation to the affected side, loss of a previously present click | Conservative first; refer if persistent |
| Degenerative joint disease | Crepitus, older patient, radiographic flattening and osteophytes | Analgesia, splint therapy, referral if progressive |
Around 70% to 80% of patients with TMD improve with conservative management. That is why UK practice begins with explanation, reassurance and reversible measures, not with occlusal adjustment, which is irreversible and is not supported by evidence as a primary treatment.
Neuropathic and Neurovascular Facial Pain
| Condition | Character | Distinguishing features | First-line management |
|---|---|---|---|
| Trigeminal neuralgia | Severe, paroxysmal, electric-shock pain lasting seconds to 2 minutes | Trigger zones, refractory period, strictly unilateral, usually V2 or V3 | Carbamazepine; refer to neurology; MRI to exclude secondary cause |
| Persistent idiopathic facial pain | Continuous, dull, poorly localised, does not respect nerve boundaries | Often follows dental treatment; normal investigations; frequently comorbid anxiety or depression | Explanation, avoid further irreversible dentistry, tricyclic antidepressant, specialist referral |
| Burning mouth syndrome | Bilateral burning of the tongue tip and anterior palate, often relieved by eating | Mucosa looks normal; exclude candidiasis, haematinic deficiency, diabetes, xerostomia, parafunction, allergy | Treat any identified cause; otherwise reassurance, cognitive behavioural approaches, clonazepam or tricyclic on specialist advice |
| Giant cell arteritis | Severe temporal headache with jaw claudication | Age over 50, scalp tenderness, raised ESR and CRP, visual symptoms | Same-day high-dose corticosteroid and urgent referral to prevent blindness |
| Migraine and cluster headache | Unilateral headache, sometimes referred to the maxilla | Autonomic features, photophobia, periodicity | Medical referral; do not extract teeth for referred headache |
Jaw claudication in a patient over 50 is an emergency. Pain in the masseters on chewing, with scalp tenderness and any visual symptom, requires urgent same-day referral because untreated giant cell arteritis causes irreversible blindness within days.
The Dental Trap
The most damaging error in orofacial pain is irreversible dental treatment applied to non-dental pain. Root canal treatment or extraction performed on a normal tooth in a patient with persistent idiopathic facial pain does not relieve the pain and frequently escalates it, and the patient may then request treatment on the next tooth.
Rule. Do not perform irreversible treatment on a tooth unless there is objective evidence that the tooth is the source: caries, a defective restoration, an abnormal sensibility response, percussion tenderness or a periapical radiolucency. A patient pointing at a tooth is a symptom, not a diagnosis.
A Systematic Approach to the Facial Pain History
Facial pain is diagnosed by history far more than by examination, and the examinable framework is the standard pain history applied rigorously: site, onset, character, radiation, associated features, timing, exacerbating and relieving factors, and severity. Two additional questions do most of the diagnostic work in the head and neck. First, is the pain episodic or continuous? Trigeminal neuralgia, cluster headache and migraine are episodic with pain-free intervals; persistent idiopathic facial pain and myofascial pain are continuous. Second, is there an identifiable trigger? Light touch triggering a severe electric shock is almost diagnostic of trigeminal neuralgia; pain on chewing that builds through the day suggests a masticatory muscle disorder.
Distinguishing the Major Diagnoses
Trigeminal neuralgia gives unilateral, paroxysmal, severe, stabbing pain lasting seconds, in one or more trigeminal divisions, triggered by light touch, washing, shaving, eating or cold air, with complete remission between attacks. First-line treatment is carbamazepine, and the red flags requiring urgent neurological referral are onset before about 40 years of age, bilateral pain, sensory loss or other neurological signs, which raise the possibility of multiple sclerosis or a posterior fossa lesion.
Cluster headache gives strictly unilateral, excruciating retro-orbital pain lasting 15 minutes to three hours, occurring in bouts at predictable times, often waking the patient at night, with ipsilateral autonomic features — lacrimation, conjunctival injection, nasal congestion, ptosis. Migraine gives a throbbing, often unilateral headache lasting hours to days with nausea, photophobia and phonophobia, sometimes with aura; midfacial migraine can mimic sinus or dental pain. Giant cell arteritis in a patient over 50 with temporal headache, scalp tenderness and, characteristically, jaw claudication is a same-day emergency because of the risk of irreversible blindness.
Temporomandibular Disorders: Diagnosis and First-Line Care
Temporomandibular disorders are the commonest cause of non-dental orofacial pain and are examined through conservative management. The diagnostic subgroups are myofascial pain, disc displacement with or without reduction, and degenerative joint disease, and more than one may coexist. Key examination findings are tenderness of the masseter and temporalis, limited or deviating opening, and joint noises. Initial management is reversible and conservative in every UK guideline: explanation and reassurance that the condition is benign and usually self-limiting, a soft diet, avoidance of wide opening and parafunctional habits, jaw exercises and physiotherapy, simple analgesia with a non-steroidal anti-inflammatory drug, and a stabilisation splint where parafunction is prominent. Irreversible occlusal adjustment, orthodontics or surgery are not first-line, and recommending them is a reliable wrong answer.
The Trap: Pain of Dental Origin Mimicking Everything Else
Before any of these diagnoses is made, dental causes must be excluded rigorously — cracked tooth syndrome, a necrotic pulp, pericoronitis, maxillary sinusitis and an unerupted or infected tooth can all reproduce the pattern. Equally, non-dental pain must not be treated with irreversible dentistry. A patient whose "toothache" persists unchanged after a technically satisfactory root canal treatment, with no radiographic pathology and no response to local anaesthetic blockade of the suspect tooth, should be re-evaluated for a non-odontogenic cause rather than given a second procedure.
A 38-year-old woman describes a constant dull ache in the right maxilla that has persisted for two years, does not follow a nerve distribution and is unaffected by hot or cold. Teeth 14, 15 and 16 are unrestored, respond normally to cold testing, are not tender to percussion and have normal periapical appearances. She has previously had root canal treatment on tooth 17 for the same pain, without benefit, and now asks for tooth 16 to be extracted. What is the most appropriate management?