Causes and risk factors
The development of TMJ dysfunction is driven by multiple factors, which are divided into predisposing and triggering.
- Biomechanical and dental factors: occlusive disturbances due to dental wear or prosthetic defects, orthodontic intervention, bruxism (teeth grinding), and trauma.
- Psychogenic factors: anxiety states, depression, hypochondriasis, and sleep disorders play a crucial role in the development of pain syndrome.
- Pharmacological factors: use of estrogen-containing drugs.
Chronification of the process is promoted by prolonged static loads (uncomfortable posture during reading or work), bruxism, emotional instability, and the patient's pessimistic attitude towards their condition.
Clinical presentation
The symptoms of TMJ dysfunction are varied and include both subjective complaints and objective signs.
Pain syndrome:
- Localization: unilateral or bilateral pain in the temporal, auricular, buccal, or mandibular region.
- Character: between exacerbations — constant, dull, moderate; during an attack — severe, accompanied by muscle spasm and jaw "locking".
- Triggering factors: chewing, yawning, jaw movements.
Objective signs:
- Limited mouth opening: less than 40 mm (three-finger width) due to muscle spasm or intra-articular disc displacement.
- Joint sounds: clicks or pops upon mouth opening, indicating disc displacement.
- Local symptoms: pain upon palpation of the masticatory muscles, their rapid fatiguability, and jaw deviation during movement.
Diagnostic criteria
To establish a diagnosis of TMJ dysfunction, at least two of the following criteria must be present:
- Pain increases with chewing movements and/or clenching of the teeth.
- The range of mandibular motion is limited.
- Sound phenomena (clicks) are present during joint movements.
- The articular capsule is painful (tender) upon palpation.
Important: In chronic courses, comorbid pain (neck, back, headaches) and a reduced quality of life due to the patient's pessimistic outlook are frequently observed.
Treatment approaches
Treatment of TMJ dysfunction is often successfully based on non-pharmacological methods targeting the masticatory muscles.
- Therapeutic exercises to restore normal muscle tone.
- Manual techniques and massage:
- Massage of the masticatory muscles (circular movements with three fingers).
- Massage of the temporal region (using the palm and fingers).
- Ischemic compression (kneading) of trigger points with the tip of the index finger.
- Stretching of the masticatory muscles using the fingers.
Briefly: answers to topical questions
Which specific muscles form the group of masticatory muscles involved in myofascial syndrome in TMJ pathology?
Myofascial pain syndrome in TMJ pathology involves the masticatory muscle group. The main muscles involved in the pathogenesis are:
- Lateral pterygoid muscle — particularly frequently the site of chronic muscular pain syndrome.
- Medial pterygoid muscle — may be affected in isolation on the affected side.
- Masseter muscle — is also involved in the pathological process.
- Temporalis muscle — belongs to the masticatory musculature and requires massage in the treatment of dysfunction.
Which branches of the trigeminal nerve provide sensory innervation to the capsule of the temporomandibular joint?
Sensory innervation of the temporomandibular joint capsule is provided by the third branch of the trigeminal nerve, the mandibular nerve (n. mandibularis). Its following branches approach the capsule directly:
- Auriculotemporal nerve (n. auriculotemporalis) — is the primary source, giving off 4–7 independent permanent branches innervating the internal, external, and posterior surfaces of the joint capsule.
- Posterior deep temporal nerve — acts as an additional source of sensory innervation of the joint.
With which neurological and dental diseases must differential diagnosis of TMJ dysfunction be performed?
Differential diagnosis of temporomandibular joint dysfunction must be carried out with the following neurological conditions:
- Trigeminal neuropathy — differs by a constant character of pain, absence of trigger zones, and presence of sensory disturbances (paresthesia, hypesthesia).
- Trigeminal neuralgia — characterized by short-term paroxysms of acute pain and the presence of trigger zones.
Intrasyndromic differential diagnosis between muscular and articular pain in TMJ dysfunction is also performed using therapeutic and diagnostic nerve blocks (according to Bershe–Dubov or Egorov).
Which instrumental imaging methods are used to confirm TMJ articular disc displacement?
Magnetic resonance imaging is used to confirm displacement and visualize the articular disc of the temporomandibular joint.
- MRI — the main imaging method for soft tissue elements of the joint, allowing confirmation of the diagnosis in the presence of adhesions and altered disc shape.
- Dynamic MRI — used simultaneously with the recording of mandibular movements, it allows the creation of second-by-second slices and analysis of the dentognathic system's function at all stages of chewing to assess disc position.
Which pharmacotherapeutic groups are used to relieve pain and muscle spasm in TMJ dysfunction?
The following groups of pharmacological agents are used to relieve pain and muscle spasm in temporomandibular joint dysfunction:
- Analgesics — used to eliminate pain sensations.
- Muscle relaxants (e.g., tolperisone) — prescribed to relieve masticatory muscle spasm.
- Tranquilizers (diazepam, chlordiazepoxide, oxazepam) — used to correct the neuro-psychological background.
- NSAIDs (diclofenac sodium, nimesulide) — indicated when synovitis develops.
- Homeopathic remedies (Traumeel S, Zeel T) — prescribed according to indications as part of complex therapy.
Which branches of the mandibular nerve provide motor innervation to the masticatory muscles?
Motor innervation of the masticatory muscles is provided by the following branches of the mandibular nerve (n. mandibularis):
- Masseteric nerve (n. massetericus) — innervates the masseter muscle.
- Deep temporal nerves (nn. temporales profundi) — pass deep to the temporal muscle (m. temporalis) and supply it.
- Medial and lateral pterygoid nerves — provide motor innervation to the corresponding pterygoid muscles.
Class and exam questions
Why is TMJ dysfunction often referred to as myofascial syndrome?
Because the pathogenetic basis of the disease in many cases is chronic muscle spasm, particularly in the lateral pterygoid and other masticatory muscles.
How many symptoms are needed to make a diagnosis?
The diagnosis is established in the presence of at least two of the four key criteria: pain with movement/clenching, restricted mobility, joint sounds, and capsule tenderness.
How does bruxism affect the TMJ?
Bruxism (teeth grinding during sleep) is both a major biomechanical factor in the development of dysfunction and a cause of its chronic course due to continuous muscle and joint overload.
What else to study on this topic
- Anatomical structure of the temporomandibular joint and function of the intra-articular disc
- The role of the lateral pterygoid muscle in TMJ biomechanics
- Differential diagnosis of facial neuralgias and TMJ dysfunction
- Methods of occlusion correction in dentistry
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Other topics in "Chapter 29. Facial Pain"
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