CIT CIT Radiography & Imaging 5 — Questions and Answers
Question 1: Which radiographic landmark on a panoramic image indicates the floor of the maxillary sinus?
- A curved radiopaque line superior to the maxillary posterior teeth
- The J-shaped radiolucency below the maxillary tuberosity
- A triangular radiopaque area at the pterygomaxillary fissure
- The Y-line formed by the nasal floor and sinus wall intersection (Correct answer)
Correct answer: The Y-line formed by the nasal floor and sinus wall intersection
The inverted Y-shape (Ennis' Y) on panoramic images marks where the nasal floor meets the anterior wall of the maxillary sinus.
Question 2: An implant placed in the maxillary anterior region shows a periapical radiolucency 6 months post-loading. The FIRST imaging step should be:
- Standardized periapical radiograph using a paralleling technique (Correct answer)
- Full-mouth series with bisecting angle technique
- CBCT of the entire maxilla
- Panoramic radiograph only
Correct answer: Standardized periapical radiograph using a paralleling technique
A standardized periapical film allows precise comparison to baseline images to assess changes in bone level around the implant.
Question 3: What does a 'halo' radiolucency around the entire implant body on a periapical radiograph indicate?
- Complete osseointegration failure (Correct answer)
- Normal osseointegration in progress
- Periapical cement overhang
- Partial implant fracture
Correct answer: Complete osseointegration failure
A circumferential radiolucency encompassing the entire implant indicates failed osseointegration with fibrous encapsulation.
Question 4: In implant planning software, 'interactive implant placement' relies on which imaging dataset?
- CBCT DICOM data merged with optical surface scan (Correct answer)
- Panoramic JPEG images only
- 2D periapical radiographs stacked into a series
- Intraoral photographs aligned to patient record
Correct answer: CBCT DICOM data merged with optical surface scan
Virtual implant planning requires 3D CBCT DICOM data, often merged with an optical scan for prosthetically driven placement.
Question 5: Which principle explains why CBCT provides lower radiation dose than medical CT for implant planning?
- CBCT uses a cone-shaped beam with a flat-panel detector, reducing scan time and dose compared to fan-beam medical CT (Correct answer)
- CBCT operates at higher kVp, which reduces scatter radiation
- CBCT images are acquired without rotating the gantry
- CBCT eliminates the need for collimation, lowering exposure
Correct answer: CBCT uses a cone-shaped beam with a flat-panel detector, reducing scan time and dose compared to fan-beam medical CT
CBCT's cone beam geometry and flat-panel detector allow a single rotation to capture the entire volume, greatly reducing dose versus multi-slice medical CT.
Question 6: When reviewing a CBCT for sinus proximity, which anatomic variation increases risk of sinus perforation during implant placement?
- Inferior pneumatization of the sinus with <2 mm of crestal bone above the sinus floor (Correct answer)
- Superior positioning of the sinus floor with >10 mm of bone
- Presence of a Haller cell lateral to the sinus
- Thickened Schneiderian membrane of >2 mm
Correct answer: Inferior pneumatization of the sinus with <2 mm of crestal bone above the sinus floor
Extensive inferior pneumatization reduces available bone height, increasing the likelihood of sinus membrane perforation without a sinus lift.
Question 7: A radiograph taken immediately after implant placement shows a gap between the implant threads and the surrounding bone. This finding is MOST likely:
- Expected, as primary stability gaps fill with new bone during healing (Correct answer)
- Indicative of immediate failure requiring implant removal
- A sign of osteonecrosis at the surgical site
- Evidence of a fractured implant body
Correct answer: Expected, as primary stability gaps fill with new bone during healing
Small peri-implant radiolucent gaps immediately post-placement are normal and typically resolve as bone regenerates into the space.
CIT CIT Radiography & Imaging 5
Which radiographic landmark on a panoramic image indicates the floor of the maxillary sinus?