It is especially helpful in investigating jaw pain, clicking, locking, and planning for facial or jaw surgery.
Common Indications for CT TMJ
Your doctor may request a CT TMJ scan for:
- Evaluating jaw fractures (such as condylar fractures) after facial trauma.
- Investigating severe pain, clicking, or difficulty opening your mouth.
- Checking for arthritis or degenerative changes in the jaw joint.
- Assessing benign bone tumors (like osteochondromas) or cysts in the jaw.
- Planning for corrective jaw surgery.
What does the CT scanner look like?
The CT scanner looks like a large, wide, circular ring. You lie on a narrow table that gently moves your head into the center while images are captured.
What happens during a CT TMJ scan?
You will lie flat on your back with your head supported to keep it perfectly still. The table moves through the scanner while multiple images are taken. You may be asked to hold your breath briefly. The Radiographer may also take two sets of images: one with your mouth closed, and one with your mouth open, to see how the joint moves.
Do I need to prepare for a CT TMJ scan?
Usually, no special preparation is needed.
Can I eat or drink before my CT TMJ scan?
Yes, you can usually eat and drink normally before this scan, as contrast dye is rarely required for looking at the jawbones.
How long does a CT TMJ scan take?
The scan itself usually takes 5 to 10 minutes.
Are there different types of CT TMJ scans?
No, it is a straightforward scan, though your doctor might also order an MRI if they suspect the pain is coming from the soft tissue disc rather than the bone.
Why might contrast be needed?
Contrast is rarely used for a standard TMJ scan. However, if your doctor is looking for an infection, an abscess, or a specific type of tumor, they may use an IV contrast dye to highlight the soft tissues.
Is a CT TMJ scan safe?
CT uses ionising radiation. Dose depends on the field, scanner, and protocol, and the examination should be justified for a bone or surgical-planning question that CT can answer better than a lower-dose test.
Pregnancy Precaution
Tell the clinician and CT team if you are pregnant or could be pregnant. Fetal exposure from a correctly performed focused jaw CT is expected to be very low because the pelvis is outside the beam. The scan still requires justification and optimisation; MRI may be preferable for joint-disc soft tissue.
What are the risks of contrast dye?
If contrast is used, most people tolerate it well. Allergic-like reactions can occur and severe reactions are rare. Kidney-function testing is based on risk factors and local policy; report a previous iodinated-contrast reaction, acute kidney injury, or severe kidney disease.
Will the scan hurt?
The scan itself does not usually hurt. If you have a jaw injury, holding your mouth open for some images may be uncomfortable; tell the radiographer if pain is worsening.
Will I need to remove anything before the scan?
You must remove necklaces, earrings, hearing aids, hairpins, and removable dental work (like dentures or retainers) so they do not interfere with the images.
What happens after the scan?
You can resume your normal activities immediately.
Questions to ask your team
- Is CT needed for bone detail, fracture, arthritis, or surgical planning?
- Would MRI be more appropriate for the joint disc and other soft tissues?
- Should the scan include open- and closed-mouth positions, and what will that change?
Sources and further reading
Conclusion
A CT TMJ scan is a quick, painless, and effective way to assess the bony structures of your jaw. It gives your doctor the exact details needed to treat your jaw pain and restore comfortable movement.