Rheumatoid arthritis (RA) of the temporomandibular joint (TMJ) is a chronic autoimmune inflammatory disorder in which the body's immune system attacks the synovial membrane of the temporomandibular joint, resulting in persistent synovitis, progressive cartilage destruction, bone erosion, and joint deformity. Although rheumatoid arthritis typically affects the small joints of the hands and feet, the TMJ may become involved during the course of the disease, particularly in patients with longstanding or severe disease.

TMJ involvement may occur unilaterally or bilaterally and can lead to chronic facial pain, reduced mouth opening, impaired mastication, malocclusion, and significant deterioration in quality of life. Early recognition and treatment are essential to prevent irreversible joint destruction and functional disability.

Etiology

The exact cause of rheumatoid arthritis remains unknown. The disease develops through an abnormal autoimmune response in genetically susceptible individuals.

Factors associated with disease development include:

• Genetic susceptibility (HLA-DRB1 alleles)

• Autoimmune dysregulation

• Environmental triggers

• Cigarette smoking

• Periodontal disease

• Female sex

• Family history of rheumatoid arthritis

TMJ disease usually develops as part of generalized rheumatoid arthritis rather than occurring in isolation.

Risk factors

Risk factors for TMJ involvement include:

• Established rheumatoid arthritis

• Female sex

• Long disease duration

• High disease activity

• Positive rheumatoid factor (RF)

• Positive anti-cyclic citrullinated peptide (anti-CCP/ACPA) antibodies

• Smoking

• Delayed initiation of disease-modifying therapy

Pathophysiology

The disease begins with autoimmune inflammation of the synovial membrane.

The pathological process includes:

1. Autoimmune activation against synovial tissue.

2. Synovial inflammation and proliferation (pannus formation).

3. Progressive destruction of articular cartilage.

4. Bone erosion of the mandibular condyle and glenoid fossa.

5. Fibrosis and joint deformity.

6. Reduced mandibular movement and chronic pain.

Long-standing disease may result in condylar resorption, malocclusion, ankylosis, or severe limitation of jaw function.

Differential diagnosis

Conditions that should be considered include:

1. Osteoarthritis of the temporomandibular joint

2. Temporomandibular myofascial pain disorder

3. Septic arthritis of the TMJ

4. Internal derangement of the TMJ

5. Crystal-induced arthritis (gout or pseudogout)

Signs and symptoms

Patients may present with:

General features of rheumatoid arthritis

• Morning stiffness lasting more than 1 hour

• Symmetrical inflammation of multiple joints

• Swelling of small joints of the hands and feet

• Rheumatoid nodules

• Fatigue

• Low-grade fever

Temporomandibular joint involvement

• Pain over the TMJ

• Pain during chewing

• Morning jaw stiffness

• Reduced mouth opening

• Difficulty chewing

• Joint tenderness

• Swelling over the TMJ

• Crepitus or clicking

• Deviation of the mandible during opening

• Progressive malocclusion

• Facial pain

Advanced disease may result in:

• Condylar destruction

• Mandibular retrusion

• Open bite deformity

• Ankylosis (rare)

Diagnostic criteria

Diagnosis of rheumatoid arthritis should follow the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Classification Criteria.

Patients should have:

• At least one joint with definite clinical synovitis (swelling).

AND

• Synovitis not better explained by another disease.

A total score of 6 or more out of 10 supports the classification of definite rheumatoid arthritis.

ACR/EULAR classification criteria

Investigations

No single laboratory test is diagnostic of rheumatoid arthritis. Investigations assist in diagnosis, assessment of disease activity, and monitoring treatment response.

Laboratory investigations

Recommended investigations include:

• Full blood picture with differential

• Erythrocyte sedimentation rate (ESR)

• C-reactive protein (CRP)

• Rheumatoid factor (RF)

• Anti-cyclic citrullinated peptide antibody (anti-CCP/ACPA)

• Antinuclear antibody (ANA)

• Liver function tests

• Renal function tests

• Synovial fluid analysis where appropriate

Imaging

Assessment of TMJ involvement may include:

• Orthopantomogram (OPG)

• Computed tomography (CT)

• Magnetic resonance imaging (MRI) where available

Radiographic findings may demonstrate:

• Condylar erosion

• Joint space narrowing

• Flattening of the condyle

• Subchondral bone destruction

• Condylar resorption

• Ankylosis in advanced disease

Management

Management aims to:

• Suppress inflammation

• Prevent joint destruction

• Relieve pain

• Preserve jaw function

• Improve quality of life

Treatment should ideally involve collaboration between rheumatologists, dentists, oral and maxillofacial surgeons, physiotherapists, and occupational therapists.

Non-pharmacological management

Patient education

Patients should be counseled regarding:

• The chronic nature of rheumatoid arthritis

• Importance of medication adherence

• Smoking cessation

• Regular follow-up

Joint protection

Advise patients to:

• Eat a soft diet during painful episodes

• Avoid excessive chewing

• Avoid gum chewing

• Limit prolonged mouth opening

Occlusal splints

Occlusal stabilization splints may reduce joint loading and improve symptoms in selected patients.

Physiotherapy

Recommended interventions include:

• Jaw range-of-motion exercises

• Stretching exercises

• Manual therapy

• Heat therapy

• Muscle strengthening exercises

Occupational therapy

Occupational therapy helps patients adapt activities of daily living while minimizing stress on affected joints.

Pharmacological management

Symptomatic treatment

Non-steroidal anti-inflammatory drugs (NSAIDs) may be used for symptom control while waiting for disease-modifying therapy to become effective.

Options include:

• Ibuprofen 400–800 mg orally every 8 hours for 5 days.

OR

• Meloxicam 7.5–15 mg orally once or twice daily for 5–14 days.

OR

• Piroxicam 20 mg once daily or 10 mg twice daily for 5–14 days.

OR

• Ketoprofen 50–75 mg orally every 8 hours for 7–14 days.

OR

• Dexketoprofen trometamol 12.5 mg every 6 hours or 25 mg every 8 hours for 7–14 days.

Corticosteroids

Short-term corticosteroids may be used to rapidly control inflammation.

Options include:

• Prednisolone 40 mg orally daily for 3 days, followed by gradual tapering over 2–4 weeks.

OR

• Triamcinolone 40 mg intramuscularly every 6 weeks when clinically indicated.

Disease-modifying antirheumatic drugs (DMARDs)

DMARDs are the cornerstone of treatment and should be initiated early.

Recommended options include:

• Methotrexate starting at 7.5 mg orally once weekly, increasing gradually according to response (maximum 20 mg/week).

OR

• Hydroxychloroquine 400–600 mg orally daily for 4–12 weeks, followed by 200–400 mg daily.

OR

• Sulfasalazine starting at 500 mg to 1 g daily, increasing gradually to a maintenance dose of 2 g/day.

NSAIDs or corticosteroids may be used temporarily until DMARDs become effective.

Monitoring

Patients should undergo:

• ESR and CRP every two weeks during treatment adjustment.

• Liver and renal function monitoring while receiving DMARDs.

• Regular blood glucose monitoring in patients receiving corticosteroids.

• Ophthalmological examination for patients receiving long-term hydroxychloroquine.

Patients taking NSAIDs for more than two weeks should receive proton pump inhibitor therapy when indicated.

Surgical management

Surgery is reserved for severe TMJ destruction or persistent functional impairment.

Options include:

• Synovectomy

• Arthroscopy

• Arthrocentesis

• Reconstructive arthroplasty

• Total temporomandibular joint replacement

• Arthrodesis in selected cases

Complications

Untreated rheumatoid arthritis involving the TMJ may result in:

• Chronic pain

• Progressive condylar destruction

• Malocclusion

• Reduced mouth opening

• Ankylosis

• Facial deformity

• Difficulty chewing

• Nutritional compromise

• Reduced quality of life

Prevention

Although rheumatoid arthritis cannot be prevented, early diagnosis and prompt initiation of DMARD therapy reduce joint destruction.

Patients should also be encouraged to:

• Stop smoking

• Maintain good oral hygiene

• Control periodontal disease

• Attend regular rheumatology and dental follow-up

Patient education

Patients should be advised that:

• Rheumatoid arthritis is a lifelong autoimmune disease.

• Early treatment prevents irreversible joint damage.

• TMJ symptoms should be reported promptly.

• DMARDs require regular monitoring.

• Medication should not be stopped without medical advice.

• Regular jaw exercises may help maintain joint function.

Prognosis

The prognosis has improved substantially with early diagnosis and modern DMARD therapy. Patients receiving timely treatment often achieve good disease control and preservation of temporomandibular joint function. Delayed diagnosis or uncontrolled disease increases the risk of irreversible condylar destruction, deformity, and chronic disability.