CIT CIT Radiography & Imaging 4 — Questions and Answers
Question 1: Which radiographic finding most strongly suggests peri-implant bone loss rather than normal crestal remodeling?
- Vertical defect pattern extending apically along the implant body (Correct answer)
- Horizontal bone loss of 1–2 mm in the first year of loading
- Crestal bone resorption limited to the first thread
- Slight radiolucency at the implant shoulder immediately post-placement
Correct answer: Vertical defect pattern extending apically along the implant body
Vertical or saucer-shaped defects extending apically along the implant indicate peri-implantitis rather than normal initial remodeling.
Question 2: In cone beam computed tomography (CBCT), what does the term 'voxel size' refer to?
- The three-dimensional resolution unit of the reconstructed volume (Correct answer)
- The field of view diameter selected by the operator
- The exposure time per rotation of the X-ray source
- The gray-scale bit depth of the final image
Correct answer: The three-dimensional resolution unit of the reconstructed volume
Voxel size is the three-dimensional pixel unit that defines spatial resolution in CBCT volumes.
Question 3: A patient presents with a CBCT showing a dense, well-corticated radiopaque mass above the maxillary sinus floor. This is MOST consistent with:
- Antrolith or rhinolith (Correct answer)
- Osteosarcoma
- Periapical cemento-osseous dysplasia
- Implant fixture fracture
Correct answer: Antrolith or rhinolith
A well-corticated radiopaque mass within or adjacent to a sinus is classic for an antrolith (sinus stone).
Question 4: When assessing the mandibular canal on a panoramic radiograph prior to implant placement, which limitation is MOST clinically significant?
- Magnification and distortion can misrepresent canal position relative to proposed implant site (Correct answer)
- Panoramic images cannot detect cortical bone quality
- The X-ray beam cannot penetrate the mandibular symphysis
- Panoramic imaging always overestimates available bone height
Correct answer: Magnification and distortion can misrepresent canal position relative to proposed implant site
Panoramic magnification and geometric distortion make precise canal localization unreliable without cross-sectional imaging.
Question 5: Which CBCT artifact appears as bright streaks radiating from metallic restorations or implants?
- Beam hardening artifact (Correct answer)
- Ring artifact
- Motion artifact
- Partial volume artifact
Correct answer: Beam hardening artifact
Beam hardening causes bright streaks around dense metallic objects because low-energy photons are preferentially absorbed.
Question 6: For digital periapical radiographs used in implant follow-up, the RECOMMENDED technique to ensure reproducible angulation is:
- Paralleling technique with a film-holding device and aiming ring (Correct answer)
- Bisecting angle technique with freehand positioning
- Occlusal projection with a horizontal beam
- Lateral skull projection for posterior implants
Correct answer: Paralleling technique with a film-holding device and aiming ring
The paralleling technique with a positioning device standardizes geometry, making sequential images comparable.
Question 7: On a CBCT cross-section, which measurement is used to plan the safe distance between the proposed implant apex and the mandibular canal?
- At least 2 mm of bone between the apex and the superior wall of the canal (Correct answer)
- At least 5 mm between the implant collar and the canal
- The canal diameter must be less than 2 mm before placement
- The implant length must equal the bone height without any safety margin
Correct answer: At least 2 mm of bone between the apex and the superior wall of the canal
A 2 mm safety zone between the implant apex and the mandibular canal is the widely accepted minimum to prevent nerve injury.
CIT CIT Radiography & Imaging 4
Which radiographic finding most strongly suggests peri-implant bone loss rather than normal crestal remodeling?