Temporomandibular Disorders: Assessment and Classification

Temporomandibular disorders (TMD) is a broad term used to describe pain and dysfunction in the temporomandibular joint, face, head and neck. It also has been associated with tinnitus, dizziness, fatigue and emotional stress, with an estimated prevalence of 75 percent of the general population being affected at one time or another. The exciting news is that the current research supports a multimodal, conservative approach in the treatment of TMD, including CMT of the cervical spine.

History and Examination

As with all conditions, assessment begins with a history and examination. If you are the first clinician to evaluate the sudden onset of sharp, excruciating facial pain in the trigeminal region, immediate referral is needed. (See my previous article, "Headache Pain: Treat or Refer?" in the October 2021 issue). Once emergent situations are ruled out, the subjective and objective findings will indicate the primary driver of the pain / dysfunction as joint- (arthrogenic), soft-tissue- (myogenic) or nerve (neurogenic) related. Often more than one variable is involved.

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Clinical Tip: In the rehab continuum, mobility trumps stability. First, restore motion; second, develop strength and stability. However, in the treatment of TMD, the recovery continuum is not as clear since movement dysfunction is often secondary to soft-tissue and nerve involvement. Once the myogenic and neurogenic factors are alleviated, the arthrogenic involvement resolves.

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Active and passive motion is assessed for pain, quality and quantity of motion; always on the lookout for noises. Active opening is expected to be at a ratio of 4:1 to lateral deviation, and lateral deviation restricted by more than 5 mm to one side indicates intra-articular TMJ dysfunction. Palpation of the TMJ for localized tenderness is an additional arthrogenic indicator.

Patients with bruxing, clenching and grinding often need dental appliances; as does the patient who does not "hold" their treatments. Having a dentist on your referral team is necessary to treat TMD patients.

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Clinical Tip: Consider mandible motion as a bilateral hinge joint. Both sides need to be assessed individually so the pair can function symmetrically as a unit. For example, one side may have muscle spasm creating a hypermobile, inflamed joint syndrome on the other. Each would need to be addressed appropriately.

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Soft-tissue palpation for the region involves the muscles of mastication, as well as related head and neck muscles. Brush up on the attachments for the primary mastication muscles: temporalis, lateral pterygoid, medial pterygoid and masseter; and the secondary mastication muscles: buccinator and strap muscles. Don't forget about the suboccipital and cervical spine musculature as well.

Palpate for taut and tender fibers, myospasm, fibrosis and trigger points. Remember, SCM and upper-trapezius trigger points can also refer pain into the jaw and face!

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Clinical Tip: The muscles of mastication can be easily challenged with manual testing to determine their involvement. With the jaw slightly open, test protrusion, retraction, lateral deviation (both sides) opening and closing. Pain with resisted testing indicates involvement of the respective muscles. See Table 1.

The mandibular branch of the trigeminal nerve innervates the primary muscles of mastication and has sensory innervation to the lower third of the face. It can become entrapped by the mastication muscles and also may be involved in trigeminal neuralgia. While palpating the region, be attentive for provocation of nerve pain throughout its distribution.

In addition, patients with chronic trigeminal neuralgia need to be screened for central sensitization syndromes and may require pain neuroscience education.

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Clinical Tip: Pain management for neurogenic sub-classification patients can include photobiomodulation and topicals without counterirritants. Wearable low-level light patches are safe around the eyes, as are topicals that are menthol and counterirritant free. Use homeopathic and transdermal topicals that are menthol and capsaicin free to prevent irritation to the eyes, ears and mouth.

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The Clinical Examination in a Nutshell: 7 Component Points

Clinical examination of temporomandibular joint disorders can be summarized into seven component points:

1. Active and passive joint motion
2. Soft-tissue exam for trigger points
3. Joint palpation
4. Noise detection during movement
5. Resisted muscle testing
6. Nerve entrapment palpation
7. Cervical spine assessment

Once performed, the dominant tissues can be identified and treated. Remember, the subclassification dysfunction pattern on one side may be different than the other side, each requiring different treatment. TMD treatment must address function bilaterally, as both sides work synergistically.

Headache, face and neck pain are common symptoms that present to our offices. Many conditions can be treated in your office and some will require co-management with other specialties. This classification system is an excellent tool to determine if co-management is needed; as well as the pain drivers for TMD so your ancillary treatment to CMT can be targeted for maximum results.

Editor's Note: Dr. DeFabio joins DC as a regular columnist beginning in 2022, starting with the February issue.

Resources

• Fernández-de-las-Peñas C, Von Piekartz H. Clinical reasoning for the examination and physical therapy treatment of temporomandibular disorders (TMD): a narrative literature review. J Clin Med, 2020 Nov 17;9(11):3686.
• Jayaseelan DJ, Tow NS. Cervicothoracic junction thrust manipulation in the multimodal management of a patient with temporomandibular disorder. J Man Manip Ther, 2016;24:90-97.
• Wieckiewicz M, et al, Reported concepts for the treatment modalities and pain management of temporomandibular disorders. J Headache & Pain, 2015;16:106.