MJDF Radiology & IRMER 3

Question 1

What are the three components of the radiation protection triangle (justification, optimisation, dose limitation)?

Accepted Answer

Justification: benefit must outweigh risk; Optimisation (ALARP): minimize dose; Dose limitation: restrict doses to defined limits

Answer

The three pillars of radiation protection are: justification (net benefit over risk), optimisation (ALARP — lowest reasonable dose for adequate image), and dose limitation (adherence to defined dose constraints and limits).

Question 2

What is the appearance of an odontogenic keratocyst on a panoramic radiograph?

Accepted Answer

Well-defined uni- or multilocular radiolucency with corticated border, often with scalloped margins, in the posterior mandible

Answer

OKCs appear as well-defined, often elongated radiolucencies with smooth corticated margins, sometimes multilocular ('soap bubble'), most commonly in the posterior mandible/ramus, with or without associated impacted teeth.

Question 3

What radiographic sign is associated with external root resorption?

Accepted Answer

Blunting or irregular shortening of the root apex on periapical radiograph

Answer

External root resorption appears as progressive shortening, blunting, or irregular excavation of the root apex; in orthodontic resorption, blunting of apices is the classic finding.

Question 4

What is the significance of a widened PDL space on a periapical radiograph?

Accepted Answer

Indicates occlusal trauma, early periapical inflammation, neoplastic infiltration, or systemic disease — requires clinical correlation

Answer

A widened PDL space has multiple causes: occlusal overload/trauma, early periapical inflammatory disease, Langerhans cell histiocytosis, scleroderma, or rare neoplastic infiltration; clinical and systemic assessment is needed.

Question 5

What is a dental panoramic tomograph (OPG) most commonly used for in routine dental practice?

Accepted Answer

Overview of the dentition, jaws, and TMJs — assessment of third molars, bone levels, pathology, and developing teeth

Answer

The OPG provides a broad survey image of both dental arches, sinuses, and TMJs, useful for third molar assessment, pathology screening, orthodontic planning, and bone level surveys, but lacks detail for caries or periapical diagnosis.

MJDF Part 1 Practice Test

MJDF Part 1 Practice Test

MJDF Radiology & IRMER 3