Temporomandibular Syndrome

What Is TMJ Dysfunction?

Temporomandibular syndrome or dysfunction is a combined group of conditions that affect and involve the orofacial musculature attached to the temporomandibular joint. Though normal temporomandibular joint issues can be corrected by the surgeon or self-limiting with resolving medications over a span of time, TMJ dysfunction or syndrome can become a long-term and severe disorder causing chronic pain and fatigue or tension within the masticatory muscles.

Restricted movements of the lower jaw (mandible) and discomfort while swallowing, speaking, and chewing actions, can cause psychosocial limitations to the patient on palpation or touching the affected region. Pain increases in the patient that may be a result of various causes impacting the joint or the joint space like the derangement, displacement, disc dislocation (luxation or subluxation and dislocation with or without reduction), structural disorder impacting the particular joint surfaces, adherence, adhesion, and joint deviation.

Often this group of dysfunction can be caused due to trauma upon the temporomandibular joint or the facial bones, as in the case of facial bone fractures. Inflammation of the synovial joint (synovitis) and of the capsular ligament of the joint (capsulitis) can cause continuous pain and extreme tenderness of the joint even upon palpation.

What Are the Symptoms of TMJ Dysfunction?

The symptoms of this syndrome can possibly occur in any age group, but more incidents in adults between 20 to 40 years group. Patients with TMD may frequently suffer or report headaches and otological symptoms such as otalgia, tinnitus, or even vertigo.

Aural fullness and hearing impairment are long-term consequences found in chronic patients of TMJ dysfunction. These groups of TMJ disorders need to be differentiated from similar clinical symptoms that are more common in myofascial disorders. In myofascial disorders, the cause is believed to be due to the disturbance in the embryological origin of middle ear structures and masticatory muscles.

The physical examination by the dental or maxillofacial surgeon should warrant signs of enamel wear out, bruxism or grinding, abnormal mandibular or jaw movements, tenderness of muscles of mastication, neck, and shoulder, pain, and lastly, the assessment of postural asymmetry must be done by the dentist or physician. A neurologist should be referred to in case of suspicion of cranial nerve abnormalities by the dental surgeon. Careful palpation of muscles of mastication or the surrounding neck muscles helps identify trigger points.

What Can Be Affected in the TMJ?

The muscles involved in temporomandibular disorders are the masticatory muscles that help us in chewing food, i.e., temporalis, masseter, medial and lateral pterygoid muscles. Also, three major ligaments that stabilize the joint are: temporomandibular, stylomandibular, and sphenomandibular ligaments. The primary blood supply of the joint is through the superficial temporal and maxillary branches of the external carotid artery. Other accessory branches include the anterior tympanic, deep auricular, and ascending pharyngeal arteries. The TMJ has its sensory innervation from the auriculotemporal and masseteric branches of the mandibular nerve (V3), i.e., a branch of the trigeminal nerve or cranial nerve V.

When TMJ Dysfunction Requires Specialist Referral?

The red flag set of symptoms that require a specialist referral from the dentist to either a neurologist or ENT special would include the following abnormalities that would pose a challenge greater than just temporomandibular joint dysfunction, i.e., they can be linked to further systemic complications, these are

• Worsening pain, i.e., chronic or persistent with time.

• Trismus or limited mouth opening.

• Cranial nerve abnormalities.

• Neurologic dysfunctionalities.

• Systemic illness or immunosuppressive patients having TMJ dysfunction.

• Sudden or recent weight loss.

• Asymmetrical facial swellings.

• Unilateral hearing loss.

• Vestibular dysfunctions such as unilateral tinnitus or a ringing sensation in the ears.

Several factors lead to the pathogenesis of TMJ dysfunction:

• Stress.

• Parafunctional habits like bruxism.

• Abnormal posture.

• Psychological conditions like depression, anxiety.

• Autoimmune diseases.

Other intra-articular causes include trauma, capsular inflammation, osteoarthritis, hypermobility of the joint, and inflammatory diseases (e.g., commonly rheumatoid arthritis).

How Is TMJ Dysfunction Diagnosed?

Magnetic resonance imaging (MRI) is the gold standard or the preferred imaging study to assess the TMJ due to its capacity to accurately show effusion within the joint space, disc displacement, or soft tissue problems or disorders. Even though a simple panoramic X-ray can help in evaluating the mild to moderate TMJ disorders like dislocation or derangement, assessing the state of the dentition and joint tends to be important in identifying the causes of permanent TMJ dysfunction.

CT scans are beneficial in highlighting the key causatives like severe joint degeneration, fractures, and dislocations. Ultrasonography also shows the disc position, but it does not help or is ineffective in diagnosing osteoarthritis, which is the leading cause of joint dysfunction.

Computed tomography (CT) and magnetic resonance imaging (MRI) are hence preferred and more beneficial in severe, chronic, or suspected structural abnormalities of TMJ. Currently, dental and maxillofacial surgeons have adopted newer techniques of nerve blocks or botulinum toxin injections that have proved to be of significant diagnostic benefit apart from other recently developed techniques like arthrography and mandibular motion data assessment.

How Is the TMJ Dysfunction Managed?

Conservative treatment is adopted by the dentist to reduce clinical symptoms in almost 50 to 90% of patients reported with major or chronic joint dysfunctions. The patient's morale should be boosted through proper awareness that includes patient reassurance and education on the joint care and daily regimen. Lifestyle modification can be done with a soft diet, jaw rest, warm compresses applied to the painful area, and passive stretching of the muscles. Some dentists can give a referral to the orthodontist for occlusal and non-occlusal splints for TMD. However, the research remains elusive about the impact of these splints on permanent or long-term patient prognosis.

Anti-inflammatory drugs (NSAIDs) and Benzodiazepines are the first line drugs prescribed for cases of recurrent masticatory muscle spasms, especially in bruxists (individuals predisposed and have grinding habits). When relaxation techniques or stress-relieving techniques also fail, only then do tricyclic antidepressants may be prescribed by the surgeon since they improve symptoms of TMJ dysfunction just like other chronic pain disorders.

Conclusion:

TMJ dysfunction or syndrome can have a long-term impact, causing stress and psychosocial limitations to the affected individuals. These conditions develop primarily due to trauma or insult to the temporomandibular joint. In case the person have any traumatic habits like bruxism that should also be tackled with appropriate measures as it can create chronic stress in the joint area. Management by the maxillofacial surgeon and timely referral to the ENT specialist or the neurologist in case of systemic involvement like craniofacial abnormalities will result in a good prognosis.