Radiography and Emerging Technology
Radiography and Emerging Technology tests image selection, interpretation, and appropriate use of CBCT, apex locators, magnification, and digital tools.
Core rules
- Paralleling periapical radiographs remain the baseline; they show anatomy, fill length, and periapical bone but not all canals.
- CBCT is indicated when 2D imaging is insufficient: suspected missed canals, perforation, root fracture, complex anatomy, or surgical planning. Use the smallest field of view and justify exposure.
- Apex locators improve working-length accuracy, especially in curved canals; combine with radiographs.
- Magnification and illumination improve access and canal location; ultrasonic tips help troughing and retreatment.
- Emerging tools such as AI-assisted radiograph interpretation support, but do not replace, clinical judgement.
Worked example
A maxillary molar has a negative cold test and a periapical radiolucency, but the radiograph cannot show whether MB2 is present. A limited-field CBCT demonstrates an untreated MB2. The finding changes the plan to retreatment. A CBCT would not be justified for every routine root canal.
Traps that cost marks
Ordering CBCT routinely; accepting a cone-cut radiograph; relying on a single apex-locator reading; and treating an AI suggestion as a diagnosis.