THE CLINICAL SYNDROME

• Temporomandibular joint dysfunction, also known as myofascial pain dysfunction of the muscles of mastication, is characterized by pain in the joint itself that radiates into the mandible, ear, neck, and tonsillar pillars.

  • This condition is referred to as temporomandibular joint dysfunction, or TMJ dysfunction.

• The temporomandibular joint (TMJ) is a genuine joint that is composed of an upper synovial cavity and a lower synovial cavity that are separated by a fibrous articular disk.

• Pain and dysfunction of the TMJ may be the result of internal disturbance of this disk; however, extracapsular causes of TMJ pain are significantly more common.

• Branches of the mandibular nerve provide sensation to the temporomandibular joint (TMJ).

• The temporalis, masseter, external and internal pterygoids, and sternocleidomastoid muscles are frequently involved in TMJ dysfunction. There is also a possibility that the trapezius and sternocleidomastoid muscles are involved.

SIGNS AND SYMPTOMS

• The pain associated with TMJ dysfunction is frequently accompanied by a headache, which, from a therapeutic perspective, is indistinguishable from tension-type headaches.

  • The development of TMJ dysfunction is frequently triggered or made worse by stress, which can be either a precipitating or aggravating cause.

  • There is frequently a history of bruxism, also known as grinding the teeth or clenching the jaw.

• Dental malocclusion may also have contributed to its development over time.

• When someone opens and closes their mouth, they may hear a clicking or grating sound that is caused by an internal disorder or arthritis in their TMJ.

• If the problem is not addressed, the patient may feel growing pain in the locations described above, in addition to having limited movement in their jaw and an impaired ability to open their mouth.

  • When palpating the muscles that are implicated in TMJ dysfunction, it is possible to locate trigger points.

  • The presence of crepitus across the joint's range of motion is more consistent with arthritis than dysfunction originating in the myofascia.

  • When the condition is severe, a deviation of the mandible may take place.

TESTING

• Radiographs of the TMJ are typically within normal limits in individuals who are diagnosed with TMJ dysfunction; nevertheless, radiographs of the TMJ may be helpful in assisting in the diagnosis of inflammatory or degenerative arthritis of the joint as well as disorders associated with crystal deposition.

• Arthroscopy and imaging of the joint can assist the doctor in determining whether or not the disk is misaligned, in addition to identifying any other abnormalities that may exist inside the joint. In more difficult instances, magnetic resonance imaging (MRI) should be examined since it has the potential to provide more in-depth information regarding the status of the disk and the articular surface.

• In the event that inflammatory arthritis or temporal arteritis is suspected, it is important to conduct a complete blood count, an erythrocyte sedimentation rate test, and an antinuclear antibody test. It is possible to do a diagnostic test on the joint by injecting it with a local anesthetic in very small amounts. This helps to identify whether or not the TMJ is the actual cause of the patient's suffering.

DIFFERENTIAL DIAGNOSIS

• The clinical symptoms of TMJ dysfunction can be mistaken for pain originating in the teeth, sinuses, or other areas of the face, or they can be categorized as atypical facial pain.

  • However, if the clinician asks the right questions and performs a thorough physical exam, they should be able to differentiate between these overlapping pain syndromes.

• It is possible for tumors of the zygoma and mandible, as well as tumors of the retropharyngeal tissue, to create ill-defined pain that is attributed to the TMJ.

  • These potentially life-threatening disorders need to be ruled out in any patient who is experiencing face discomfort.

• Any patient who presents with facial discomfort that is difficult to characterize as a result of trauma, infection, or injury to the central nervous system should also have reflex sympathetic dystrophy of the face evaluated.

• The pain associated with TMJ dysfunction is described as dull and aching, whereas the pain associated with reflex sympathetic dystrophy of the face is described as scorching and is often accompanied by substantial allodynia.

• Stellate ganglion block may be able to help differentiate between the two pain syndromes because the pain associated with reflex sympathetic dystrophy of the face responds rapidly to this sympathetic nerve block, whereas the pain associated with TMJ dysfunction does not respond in the same way.

• In addition, it is necessary to differentiate the pain caused by TMJ dysfunction from the discomfort caused by jaw claudication, which is associated with temporal arteritis.

TREATMENT

• A combination of medication treatment with tricyclic antidepressants, physical modalities such as oral orthotic devices and physical therapy, and intraarticular injection of the joint with modest doses of local anesthetic and steroid are the primary components of the therapy.

• Antidepressant medications, such as nortriptyline, taken as a single dose of 25 milligrams before going to bed will help reduce sleep disturbances and treat any underlying myofascial pain syndrome that may be present.

• Patients who use orthotic devices are better able to prevent behaviors like clenching their jaws and grinding their teeth, both of which can make the clinical syndrome worse.

• A joint arthritis that may be contributing to the patient's discomfort and joint dysfunction can be treated with an intraarticular injection of local anesthetic mixed with steroid medication.

  • This injection is also beneficial for palliating acute pain so that physical therapy can be performed. In the therapy of TMJ dysfunction, the intraarticular injection of platelet-rich plasma may also be useful.

• According to research conducted in clinical settings, the injection of type A botulinum toxin into the masseter and temporalis muscles may also give symptomatic alleviation.

  • On occasion, surgical treatment of the displaced intraarticular disk is necessary in order to return the joint to its normal function and alleviate the associated pain.

COMPLICATIONS AND PITFALLS

• Because of the high vascularity of the area and its close proximity to major blood vessels, there is a higher risk of postblock ecchymosis and hematoma formation.

  • The patient needs to be made aware of this potential consequence before the procedure is performed.

• In spite of the vascularity of the area, intraarticular injections can be performed safely (albeit with an increased risk of hematoma formation) in the presence of anticoagulation by making use of a needle with a gauge size of either 25 or 27.

  • This is only the case if the clinical scenario indicates that there is a favorable risk-to-benefit ratio.

• When manual pressure is administered to the area of the block shortly after the injection, the risk of these problems can be significantly reduced.

• A reduction in the amount of postprocedural pain and bleeding can also be achieved by applying cold packs immediately following the block for a period of twenty minutes.

• Inadvertent occlusion of the facial nerve, together with the facial paralysis that it brings about, is another another issue that occurs with some regularity.

  • When anything like this takes place, it is imperative that the cornea be protected with a sterile ophthalmic lubricant and a patch.