TMJ Disorders: Symptoms, Causes and Physiotherapy

Temporomandibular joint disorders

Temporomandibular joint disorders (TMDs) comprise a heterogeneous group of conditions affecting the jaw joint, masticatory muscles, and associated structures. They are extremely common: it is estimated that 25-30% of the population experiences at least one TMD symptom, with a peak between 20 and 40 years of age and a clear prevalence in females (F:M ratio of 3-5:1).

TMDs manifest with jaw pain, difficulty opening the mouth, joint noises (clicks, crepitus), and can be associated with tension headache, neck pain, and tinnitus. Despite the significant impact on quality of life, most TMDs respond very well to conservative treatment based on physiotherapy, manual therapy, and exercises, with success rates of 85-90%.

Anatomy of the Temporomandibular Joint

The TMJ is a double synovial joint (one on each side) that connects the mandible to the skull. It is a unique joint in the human body for several reasons:

Bony Components

• Mandibular condyle: the lower articular surface, elliptical in shape
• Mandibular fossa (glenoid) of the temporal bone: the upper articular surface
• Articular eminence: a bony prominence anterior to the fossa, over which the condyle slides during mouth opening

Articular Disc

The articular disc is a biconcave fibrocartilaginous meniscus that divides the joint into two compartments:

• Upper compartment (discotemporal): translation (gliding) movement
• Lower compartment (condyle-disc): rotation (hinge) movement

The disc is fundamental for TMJ function: it absorbs loads, distributes pressures, and guides movement. Disc displacements are the most common cause of intra-articular TMD.

Masticatory Muscles

• Masseter: the most powerful muscle of mastication, generating a force of 70-100 kg
• Temporalis: a large fan-shaped muscle, important for closing and retrusion
• Lateral pterygoid: two heads — the superior head inserts on the disc (controls disc movements), the inferior head on the condyle (protrudes the mandible and opens the mouth)
• Medial pterygoid: elevator of the mandible, works in synergy with the masseter

Ligaments

• Temporomandibular ligament (lateral): the main stabilizer, limits excessive opening
• Sphenomandibular ligament and stylomandibular ligament: accessory ligaments

Innervation

The TMJ is innervated by the auriculotemporal nerve (a branch of the trigeminal nerve V3), which explains the referral of pain to the temple, ear, and jaw.

Classification of TMDs

1. Muscular Disorders (the most frequent, 50-60%)

• Myofascial pain: pain and tension in the masticatory muscles with active trigger points. It is the most common form of TMD
• Myositis: acute muscle inflammation
• Muscle spasm: involuntary and painful contraction
• Myofibrotic contracture: chronic shortening of the muscle

2. Articular Disorders (Intra-articular)

• Disc displacement with reduction (click): the disc is displaced but repositions during opening (opening click) and displaces again during closing (closing click). Present in 25-35% of the population
• Disc displacement without reduction (locking): the disc remains permanently displaced, limiting mouth opening (“locked jaw”)
• TMJ osteoarthritis: degeneration of articular surfaces with crepitus, pain, and limitation
• Inflammatory arthritis: rheumatoid arthritis, psoriatic arthritis

3. Hypermobility Disorders

• Subluxation: the condyle overrides the articular eminence but spontaneously returns to its position
• Dislocation: the condyle remains locked in an anterior position to the eminence (mouth locked open)

Causes and Risk Factors

Main Causes

• Bruxism (teeth grinding/clenching): the most frequent cause of muscular TMD. Nocturnal bruxism is present in 8-16% of the population
• Malocclusion: bite alterations that modify the distribution of forces on the TMJ
• Trauma: blow to the jaw, cervical whiplash, prolonged orotracheal intubation, excessive mouth opening (yawning, dental procedures)
• Stress and psychosocial factors: chronic stress is strongly associated with bruxism and masticatory muscle tension. Anxiety and depression are frequent comorbidities
• Postural factors: cervical posture directly influences mandibular position — forward head posture is associated with increased activity of masticatory muscles
• Hormonal factors: female prevalence and worsening in the premenstrual phase suggest a role for estrogens

Risk Factors

• Female gender (20-40 years)
• Stress, anxiety, depression
• Bruxism (nocturnal and/or diurnal)
• Parafunctional habits: chewing gum, biting nails, chewing pens
• Incorrect cervical posture: cervical osteoarthritis and forward head posture
• Fibromyalgia: TMDs are present in 75% of fibromyalgia patients
• Generalized joint hypermobility (Ehlers-Danlos syndrome)
• Prolonged dental treatments: forced mouth opening

Symptoms

Pain

• Preauricular pain: in front of the ear, in the TMJ region — the most characteristic symptom
• Masticatory muscle pain: masseter (cheek), temporalis (temple), pterygoids (behind the last molar)
• Tension headache: often unilateral, in the temporal region
• Ear pain (otalgia): without otological pathology — a frequent cause of negative ENT visits
• Neck pain: TMJ dysfunction and cervical dysfunction are closely related
• Pain worsens with: chewing (especially hard foods), wide mouth opening, yawning, prolonged talking, stress

Joint Noises

• Click: a dry, brief sound during opening and/or closing — indicates disc displacement with reduction. It is the most common symptom and is often not painful
• Crepitus: fine, continuous grinding sounds during movement — suggest degenerative changes in the articular surfaces (osteoarthritis)
• Pop: a louder sound, may accompany condylar subluxation

Movement Limitation

• Limited opening: normal opening is 40-50 mm (3 transverse fingers). Opening < 35 mm is considered limited
• Deviation: the mandible deviates towards the affected side during opening (in disc displacement without reduction)
• Deflection: the mandible deviates but returns to midline (in displacement with reduction)
• Locking: sudden inability to open or close the mouth

Associated Symptoms

• Tinnitus (ringing or buzzing in the ear): present in 30-60% of patients with TMD
• Feeling of ear fullness
• Dizziness: less common, may be related to associated cervical dysfunction
• Atypical dental pain: in the absence of dental pathology

Diagnosis

Clinical Examination

Clinical examination is the diagnostic cornerstone:

• TMJ palpation: tenderness of the joint during opening/closing
• Muscle palpation: search for trigger points in the masseter, temporalis, pterygoids, digastric, sternocleidomastoid muscles
• Measurement of opening: with a ruler, in mm — active and passive
• Assessment of noises: clicks (timing, reproducibility), crepitus
• Assessment of opening pattern: straight, deviated, deflected
• Cervical assessment: mobility, posture, pain — cervical dysfunction coexists in 70% of TMDs
• Occlusal assessment: bite, dental contacts, dental wear (signs of bruxism)

Diagnostic Criteria (DC/TMD)

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) are the international standard for diagnosis:

• Axis I: physical diagnosis (myofascial pain, arthralgia, disc displacement, osteoarthritis)
• Axis II: psychosocial evaluation (chronic pain, disability, depression, anxiety)

Imaging

• Orthopantomography (OPT): dental panoramic X-ray — useful for ruling out dental pathology and roughly evaluating the condyles
• TMJ MRI: gold standard for evaluating the articular disc (position, morphology, mobility). Performed with the mouth closed and open
• TMJ CT scan: for evaluating bony structures (osteoarthritis, ankylosis)
• Ultrasound: increasingly used for dynamic TMJ evaluation and as a guide for infiltrations

Conservative Treatment

The temporomandibular joint is a bilateral synovial articulation connecting the mandible to the temporal bone, composed of bony surfaces, an articular disc, and supporting muscles and ligaments that enable complex jaw movements. Conservative treatment is effective in 85-90% of cases and is always the first approach.

Patient Education

• Mandibular rest: avoid hard foods, chewing gum, excessive mouth opening
• Postural awareness: avoid diurnal clenching (lips should be closed but teeth separated — “lips together, teeth apart”)
• Stress management: relaxation techniques, mindfulness
• Heat application: warm compresses on masticatory muscles for 15-20 minutes, 2-3 times a day
• Soft diet: during acute flare-ups

Splint (Occlusal Splint)

Made by the gnathologist dentist, the splint is a resin plate worn at night (and sometimes during the day) to:

• Protect teeth from bruxism wear
• Reduce load on the TMJ
• Relax masticatory muscles
• Reposition the condyle (repositioning splint)

Physiotherapy and Manual Therapy

Manual therapy is one of the most effective treatments for TMDs:

Manual Techniques

• TMJ mobilization: distraction, translation, and glide techniques of the condyle to restore joint mobility
• Myofascial release: treatment of trigger points in the masticatory muscles (masseter, temporalis, pterygoids) with ischemic pressure, intraoral techniques (with a glove) for the pterygoid muscles
• Cervical mobilization: treatment of associated cervical dysfunctions (C0-C3 in particular)
• Dry needling: acupuncture of muscular trigger points — growing evidence of efficacy in muscular TMDs

TMJ Exercises

Exercises should be performed 3-4 times a day, for 5-minute sessions:

Mobilization exercises:

• Assisted active opening: open the mouth to the painful limit, assist with slight finger pressure to gain a few more mm. 10 repetitions
• Lateral movements: move the mandible right and left (5-10 mm). 10 repetitions per side
• Protrusion/retrusion: move the mandible forward and backward. 10 repetitions
• “6-by-6” exercise: 6 times opening, 6 times right lateral movement, 6 times left lateral movement, 6 times protrusion, 6 times closing against resistance, 6 times opening against resistance

Stabilization exercises:

• Controlled opening with the tongue: place the tip of the tongue on the palate (behind the upper incisors) and open the mouth keeping the tongue in position. This guides the condyle into the correct position and prevents deviation. 15 repetitions
• Closing isometrics: place two fingers under the chin, try to open the mouth against finger resistance. Hold for 5 seconds, 10 repetitions
• Opening isometrics: place the thumb under the chin, try to close the mouth against resistance. 5 seconds, 10 repetitions

Relaxation exercises:

• Diaphragmatic breathing: to reduce global muscle tension
• Progressive jaw relaxation: contract masticatory muscles for 5 seconds, then completely relax for 10 seconds. 10 repetitions
• Masseter self-massage: with two fingers, massage the masseter muscle with circular movements for 2 minutes per side

Cervical Stretching

Stretching of the cervical musculature is an integral part of the treatment:

• Upper trapezius stretch: lateral head tilt. 30 seconds per side
• Scalene stretch: rotation + head tilt. 30 seconds per side
• Sternocleidomastoid stretch: extension + contralateral rotation. 30 seconds per side
• Cervical retraction (chin tuck): pull the chin backward creating a “double chin”. 10 repetitions of 5 seconds

Pharmacotherapy

By the doctor:

• NSAIDs: ibuprofen, naproxen in the acute phase (2-4 weeks)
• Muscle relaxants: cyclobenzaprine, tizanidine — especially useful in the evening for nocturnal bruxism
• Tricyclic antidepressants (low-dose amitriptyline): in chronic cases with a centralized pain component
• Botulinum toxin: injection into hypertonic masseter muscles — effective in severe bruxism

When Invasive Procedures Are Needed

Arthrocentesis

Joint lavage with saline solution through two thin needles, under local anesthesia. Indicated in disc displacement without reduction (locking). Success in 70-80% of cases.

Arthroscopy

Minimally invasive surgical procedure with a small camera. Allows visualization of the joint, release of adhesions, repositioning of the disc. Indicated in refractory cases.

Open Surgery

Reserved for very selected cases: condylar fractures, ankylosis, neoplasms, severe unresponsive osteoarthritis.

Prognosis

The prognosis for TMDs is generally very favorable:

• 85-90% of patients significantly improve with conservative treatment
• Isolated joint clicking (without pain) does not require treatment and does not necessarily worsen over time
• Muscular TMDs have the best prognosis
• Disc displacement without reduction tends to improve spontaneously in 6-12 months (adaptation of the retrodiscal band)
• TMJ osteoarthritis is generally less symptomatic than imaging would suggest

Frequently Asked Questions (FAQ)

Frequently Asked Questions

How common are temporomandibular joint disorders?

Temporomandibular joint disorders are highly prevalent, affecting an estimated 25-30% of the population. They are more common in individuals between 20 and 40 years of age, with a higher incidence observed in females.

What role does a physical therapist play in managing TMDs?

A physical therapist plays a crucial role in the conservative management of temporomandibular joint disorders. Treatment often involves patient education, manual therapy techniques, therapeutic exercises, and strategies to reduce pain and improve jaw function.

What are the common causes of temporomandibular joint disorders?

Temporomandibular joint disorders can arise from various factors, including muscular issues such as myofascial pain, internal derangements like disc displacement, and joint inflammation. Risk factors may include bruxism, trauma, and certain systemic conditions.

What is the typical outcome for individuals with TMDs?

Most temporomandibular joint disorders respond very well to conservative treatment approaches, often achieving high success rates. Early intervention and adherence to treatment protocols generally lead to significant improvement in symptoms and jaw function.

Sources and Scientific References

1. Urbański P et al. (2021). The Application of Manual Techniques in Masticatory Muscles Relaxation as Adjunctive Therapy in the Treatment of Temporomandibular Joint Disorders. Int J Environ Res Public Health. 18. DOI | PubMed
2. Chellappa D et al. (2020). Comparative efficacy of low-Level laser and TENS in the symptomatic relief of temporomandibular joint disorders: A randomized clinical trial. Indian J Dent Res. 31:42-47. DOI | PubMed
3. Byra J et al. (2020). Physiotherapy in hypomobility of temporomandibular joints. Folia Med Cracov. 60:123-134. PubMed
4. Liu F et al. (2013). Epidemiology, diagnosis, and treatment of temporomandibular disorders. Dent Clin North Am. 57:465-79. DOI | PubMed
5. Buescher JJ (2007). Temporomandibular joint disorders. Am Fam Physician. 76:1477-82. PubMed