Temporomandibular Joint Disorder

Temporomandibular disorder (TMD) is a group of conditions affecting the masticatory muscles, the temporomandibular joint (TMJ) and associated structures, causing pain, joint noise and restricted jaw movement. It affects 5 to 12 percent of adults, with peak age 20 to 40 years and a female to male ratio of about 2 to 1. It is the commonest cause of non-dental orofacial pain.

Classification: myofascial pain with or without limited opening; disc displacement with reduction (clicking), disc displacement without reduction with limited opening (closed lock), disc displacement without reduction without limited opening; arthralgia; degenerative joint disease (osteoarthritis); and subluxation.

The aetiology is multifactorial: parafunctional habits (bruxism, clenching, gum chewing), trauma (macrotrauma, whiplash), psychological factors (stress, anxiety, depression), joint hypermobility, rheumatoid arthritis, and central sensitisation. Most cases are self-limiting or manageable with conservative care, and only 5 to 10 percent need advanced treatment.

• Pain in the preauricular area, masseter, and temporalis, worse with chewing and yawning.
• Joint noises: clicking (reciprocal click), crepitus (osteoarthritis).
• Limited mouth opening (under 35 to 40 mm), deviation on opening, locking (open or closed).
• Headache (temporal), earache without ear disease, tinnitus, dizziness, neck pain.
• Tender masticatory muscles on palpation (masseter, temporalis, lateral pterygoid), tender TMJ capsule.
• Comorbid: fibromyalgia, irritable bowel syndrome, sleep disorders, chronic fatigue, and migraine.
• Red flags: trauma with malocclusion (fracture), fever with swollen joint (septic arthritis), progressive trismus, unilateral facial weakness or numbness, weight loss, and age over 50 with jaw claudication (giant cell arteritis).

• Clinical examination: palpation of muscles and joint; mouth opening (maximum unassisted opening 40 to 55 mm; limited if under 35 mm); lateral excursion (7 to 10 mm); deviation; joint sounds with stethoscope or palpation.
• Diagnostic criteria use a structured history and examination to identify subtypes (myalgia, arthralgia, disc displacement, degenerative joint disease).
• Imaging if diagnosis is unclear, trauma, or failed therapy: panoramic radiograph (condylar changes), cone beam CT (bony osteoarthritic change, erosions), MRI (disc position, effusion, marrow oedema, the gold standard for disc displacement).
• Blood tests (ESR, C-reactive protein, rheumatoid factor, anti-CCP) when inflammatory arthritis is suspected; temporal artery ultrasound for giant cell arteritis.
• Screen for depression, anxiety and sleep disorder (questionnaire).
• Exclude dental pain, sinusitis, otitis, trigeminal neuralgia, giant cell arteritis, parotid disease, migraine, cervical spine disease, tumour, and Eagle syndrome.

• First line (all patients): education and reassurance, self-care (soft diet for 1 to 2 weeks, avoid gum, wide yawning and nail biting), jaw exercises (passive stretching 5 times daily for 10 repetitions, opening exercises with tongue-to-palate technique), heat packs (20 minutes 3 times daily) for muscle pain or cold packs for acute joint pain, sleep hygiene, and stress management.
• Analgesia: ibuprofen 400 mg orally every 8 hours with food or naproxen 500 mg every 12 hours for 2 weeks (with omeprazole 20 mg daily when needed); paracetamol 1 g every 6 hours; topical diclofenac gel 1 percent four times daily for TMJ pain.
• Muscle relaxant: diazepam 2 mg orally at night for 7 to 14 days only (avoid prolonged use); tizanidine 2 mg at night increasing to 4 mg is an alternative.
• Chronic myofascial pain: amitriptyline 10 mg orally at night, increased by 10 mg weekly to 25 to 50 mg for 3 months; or gabapentin 300 mg at night increasing to 300 mg three times daily; cognitive behavioural therapy.
• Occlusal stabilisation splint (hard acrylic splint for the upper or lower teeth) worn at night for 3 to 6 months; physiotherapy, trigger point injection of lidocaine 1 percent 0.5 to 1 mL, botulinum toxin A 25 to 50 units into each masseter (and 10 to 20 units into the temporalis) every 3 to 4 months for refractory myofascial pain.
• Arthralgia or closed lock: arthrocentesis (lavage with 100 to 300 mL lactated Ringer or saline under local anaesthesia), with hyaluronic acid 1 mL (10 mg/mL) or corticosteroid injection (triamcinolone 20 mg, not more than 2 injections yearly); repeated corticosteroid injection risks cartilage damage.
• Arthroscopy, open surgery (discectomy, disc repositioning), or joint replacement for failed conservative care with imaging confirmed structural disease (under 5 percent of patients).
• Rheumatoid or juvenile idiopathic arthritis: rheumatology care with methotrexate 7.5 to 25 mg orally once weekly and folic acid 5 mg weekly.
• Follow up: review at 4 to 6 weeks; chronic cases at 3 months.
• Counselling: most cases improve; avoid irreversible dental treatments such as extensive occlusal adjustment.