Temporomandibular Joint Disorders

Diagnostic Imaging

• The American College of Radiology recommends using imaging modalities that provide superior visualization of the articular disc location and morphology, such as MRI, with approximately 95% accuracy in assessing disc position and form, and can detect inflammation and other soft tissue abnormalities 1, 2
• MRI is the gold standard for TMJ soft tissue assessment, and CBCT or CT is recommended for TMJ bone structure evaluation, according to the American College of Radiology, the Radiological Society of North America, and the American Dental Association 2
• Contrast-enhanced MRI is recommended for TMJ arthritis or inflammation diagnosis, as stated by the European Society of Radiology and the European League Against Rheumatism 3
• CBCT provides high-resolution multiplanar reconstruction of the TMJ with lower radiation dose than conventional CT and is superior for detecting structural abnormalities and damage, as recommended by the American Association of Orthodontists and the International Association of Dentomaxillofacial Radiology 2, 3
• High-resolution ultrasonography can be useful for diagnosing disc displacements, but its diagnostic value is highly dependent on the examiner's skills and equipment used, according to the World Federation for Ultrasound in Medicine and Biology 3
• When selecting imaging, prioritize the modality that will directly impact treatment decisions and improve patient outcomes, and limit radiation exposure by choosing appropriate field of view (FOV) for CBCT, as recommended by the American Medical Association and the National Council on Radiation Protection and Measurements 2

Physical Examination

• A standardized approach to TMJ physical examination should include visual inspection, palpation of muscles of mastication, TMJ movement evaluation, and assessment of associated structures, according to the American College of Physicians 4
• The examination should include palpation of the TMJ laterally during opening and closing movements, and palpation of muscles of mastication, including masseter, temporalis, medial, and lateral pterygoid muscles, to note tenderness, hypertrophy, or trigger points 4
• Measurement of maximum unassisted jaw opening, maximum assisted jaw opening, lateral excursions, and protrusive movements, as well as evaluation of midline deviation during opening, should be performed to assess TMJ function 4
• Listening and feeling for clicking, popping, or crepitus during opening and closing, and noting at which point in the range of motion sounds occur, can help assess joint sounds and mobility 4

Diagnostic Considerations

• Relying solely on conventional radiography for TMJ assessment is not recommended, as stated by the American Dental Association
• Ordering unnecessary imaging when clinical examination is sufficient should be avoided, according to the Choosing Wisely campaign
• Using large FOV CBCT for simple clinical cases is not recommended, as suggested by the American Association of Oral and Maxillofacial Surgeons
• Failing to correlate imaging findings with clinical presentation can lead to misdiagnosis, according to the American College of Radiology
• Overlooking the need for contrast enhancement in MRI when evaluating for active inflammation can result in inaccurate diagnosis, as stated by the European Society of Radiology 3
• Physical examination has limitations in detecting TMJ inflammation, and clinicians should be aware of these limitations when interpreting examination findings, with clinical examination correctly identifying only 58% of patients with active TMJ arthritis compared to MRI findings 3, 5
• Clinicians should not rely solely on joint sounds for diagnosis, and should assess both TMJs, as the condition can be unilateral or bilateral, and consider the contribution of head and neck muscles to TMJ symptoms 4