Clinical

CBCT in endodontics — when small-FOV 3D earns its dose

High-resolution small-FOV CBCT (75–100 μm) reveals canal anatomy, vertical fractures, periapical lesion extent and resorption that 2D imaging misses. The trick is restricting it to cases where the 3D really changes the plan.

Indications worth the dose

Failed RCT with persistent symptoms — CBCT often reveals missed canals (commonly MB2 in upper molars) or vertical root fracture. Complex anatomy like C-shaped mandibular molars and dilacerated roots is hard to characterize on PA radiographs.

Vertical root fracture is hard to see directly but the surrounding bone loss pattern (J-shaped or halo) is suggestive on CBCT. Internal vs external resorption distinction is much clearer in 3D than on a single PA.

Protocol notes

Small FOV (4×4 to 5×5 cm) centered on the tooth of interest is the standard endo protocol. High-resolution voxel (75–100 μm) is necessary to resolve canal anatomy. Beam-hardening from a metallic crown or post on the tooth itself may obscure findings — sometimes a sister tooth scan adds context.

CBCT is supplementary to clinical exam and PA. Endodontic societies (AAE, ESE) emphasize case-by-case justification, not routine pre-RCT CBCT.

FAQ

Should I take a CBCT before every root canal?

No. AAE and ESE position papers recommend it for complex cases, retreatment and surgical planning — not as a routine pre-treatment image.

Can metal posts hide a vertical fracture?

Yes. Beam-hardening artifacts can obscure the fracture line itself; the surrounding bone loss pattern is often more reliable.

What's the smallest FOV worth getting?

4×4 cm at 80 μm voxel. Smaller FOV with higher resolution preserves diagnostic value at a lower dose.

Open small-FOV CBCT at native resolution

CBCTHub renders 75 μm voxel volumes from Morita, Carestream, Planmeca and others without downsampling — find that MB2 in the browser.

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