What imaging study should be ordered first for jaw discomfort when chewing?

Imaging for Jaw Discomfort When Chewing

For jaw discomfort when chewing, panoramic radiography (orthopantomography) should be ordered first as the initial imaging study, followed by MRI or CBCT only if specific pathology is suspected based on clinical findings. 1, 2

Initial Imaging Approach

• Panoramic radiography serves as the appropriate first-line imaging for evaluating jaw discomfort during mastication, providing a broad overview of the temporomandibular joint (TMJ), mandible, and surrounding structures 1
• This 2D technique allows initial assessment of bony structures and helps determine if advanced imaging is necessary 1
• Panoramic films alone are insufficient for definitive TMJ diagnosis but serve as an effective screening tool 1, 2

When to Advance to Specialized Imaging

For Suspected Soft Tissue/Disc Problems:

• Contrast-enhanced MRI is the gold standard for detecting active TMJ inflammation and evaluating ligament-capsule structures, including the articular disc 1, 2
• MRI should be ordered when clinical examination suggests internal derangement (disc displacement), synovitis, or capsulitis 1
• The presence of small amounts of TMJ fluid or minor contrast enhancement may represent normal variation rather than pathology 1, 2

For Suspected Bone Pathology:

• CBCT or CT is indicated when condyle and glenoid cavity involvement is suspected based on history and clinical examination 1, 2
• These modalities are the gold standard for bone lesion assessment, including condylar hypoplasia/hyperplasia, ankylosis, arthritis, or fractures 1, 2
• CBCT should use small to medium fields of view (FOV) to minimize radiation exposure 1

Critical Clinical Decision Points

Look for these specific findings to guide imaging selection:

• Pain location and character: Joint pain versus muscle pain helps differentiate TMJ disorders from masticatory muscle disorders 1
• Joint sounds: Clicking or crepitus suggests disc displacement or degenerative changes requiring MRI evaluation 1
• Limited mouth opening: Suggests possible disc displacement without reduction or ankylosis 1
• History of trauma or systemic arthritis: Increases suspicion for bony pathology requiring CT/CBCT 1

Important Caveats

• Panoramic radiography does not provide adequate information about the articular disc or soft tissue components and may unreliably reproduce condyle-glenoid cavity relationships due to projection errors 1, 2
• Using CBCT solely to obtain panoramic projections is inappropriate—the same information can be obtained with lower radiation dose techniques 1, 2
• MRI interpretation has inherent subjectivity influenced by technique, equipment, and reader expertise, requiring JIA-specific TMJ protocols when available 1, 2
• Radiographic findings do not always correlate with clinical symptoms—imaging should only be performed when it will change management 3

Algorithmic Approach

1. Start with clinical examination assessing pain patterns, joint sounds, range of motion, and muscle tenderness 1
2. Order panoramic radiography as initial screening for all patients with jaw discomfort during chewing 1
3. If panoramic shows bony abnormalities or clinical suspicion of bone disease exists: Order CBCT or CT 1, 2
4. If clinical findings suggest soft tissue/disc pathology (clicking, locking, inflammatory symptoms): Order contrast-enhanced MRI 1, 2
5. If panoramic is normal and symptoms persist: Consider MRI to evaluate for early inflammatory changes or disc displacement not visible on plain films 1, 2