MJDF Radiology & IRMER 2

Question 1

What is the classic radiographic appearance of a periapical granuloma?

Accepted Answer

Diffuse periapical radiolucency (1–2 mm) without corticated margin at the apex of a non-vital tooth

Answer

Periapical granulomas appear as small (usually <10 mm), diffuse radiolucencies without a distinct sclerotic (corticated) border at the root apex, associated with a non-vital tooth.

Question 2

What is a 'ghost image' on a panoramic radiograph and how is it formed?

Accepted Answer

An inverted, blurred image of a radiopaque object on the contralateral side, formed when the object passes through the X-ray beam twice (above and below the rotation centre)

Answer

Ghost images appear on the contralateral and superior side to a radiopaque object (e.g., earring, spine of the mandible); they form because the object passes through the beam twice during panoramic rotation.

Question 3

What are the FGDP(UK) radiographic selection criteria guidelines based on?

Accepted Answer

Evidence-based clinical indicators — radiographs should only be taken when the clinical information gained changes patient management

Answer

FGDP(UK) selection criteria are evidence-based, specifying clinical indications (caries risk, signs and symptoms, monitoring) that justify each type of radiograph to ensure benefit outweighs radiation risk.

Question 4

What is the cause of a 'radiopaque' appearance on a dental radiograph?

Accepted Answer

Dense structures (bone, enamel, metallic restorations) absorb more X-rays, allowing fewer photons to reach the detector, appearing white

Answer

Radiopaque structures (metals, enamel, bone) absorb X-ray photons strongly, reducing the beam reaching the image receptor; this results in white areas on the radiograph where fewer photons were recorded.

Question 5

What is the recommended kV range for dental bitewing radiographs to reduce patient dose?

Accepted Answer

60–70 kVp (increasing to 65–70 kVp with rectangular collimation to minimise dose)

Answer

Increasing kVp (to 65–70 kVp) with rectangular collimation reduces patient dose by improving beam penetration and reducing scatter, while maintaining diagnostic image quality for bitewing radiographs.

MJDF Part 1 Practice Test

MJDF Part 1 Practice Test

MJDF Radiology & IRMER 2