Radiology & Radiation Protection Flashcards

What radiographic feature is characteristic of a dentigerous cyst?

Answer: Well-defined unilocular radiolucency with corticated borders enclosing the crown of an unerupted tooth from the CEJ

The dentigerous cyst appears on radiograph as a well-defined (corticated), unilocular radiolucency enclosing the crown of an unerupted (usually impacted) tooth, attached at the cemento-enamel junction.

What is the radiographic appearance of 'ground glass' opacity in bone?

Answer: A fine granular, homogeneous, ill-defined 'frosted glass' appearance of bone, characteristic of fibrous dysplasia

Ground glass opacity describes the 'frosted glass' appearance in fibrous dysplasia, where normal bone trabeculae are replaced by fibrous tissue containing irregular woven bone, creating a granular, featureless bone density on radiograph.

What radiographic changes are seen in chronic periodontitis on horizontal bitewing radiographs?

Answer: Horizontal or vertical alveolar bone loss with the bone crest more than 2 mm apical to the CEJ, loss of lamina dura and calculus deposits

Bitewing radiographs in periodontitis show: horizontal bone loss (bone crest >2 mm below CEJ), angular/vertical defects in severe cases, loss of lamina dura continuity, calculus deposits, and furcation radiolucencies in severe posterior cases.

What is the 'inverted Y' radiopaque shadow on a dental panoramic tomograph?

Answer: The intersection of the nasal septum and lateral border of the nose creating an inverted Y shape over the upper incisor region on DPT — a normal anatomical landmark

On a DPT, the nasal septum and the floor/lateral wall of the nasal cavity form an inverted Y-shaped radiopaque shadow projected over the upper incisor region — a normal radiographic anatomical feature.

What is the radiographic appearance of a radicular (periapical) cyst?

Answer: Well-defined radiolucency at the root apex with a corticated (white) margin, continuous with the lamina dura, associated with a non-vital tooth

The periapical (radicular) cyst typically appears as a well-defined, round/oval radiolucency at the root apex with a corticated border (continuous with the lamina dura), associated with a non-vital tooth. It is indistinguishable radiographically from a periapical granuloma.

What is 'cervical burnout' on a dental radiograph and how can it be avoided?

Answer: A radiolucent artefact at the cervical region of the tooth (CEJ) caused by the shape of the tooth and underexposure in this region — it can mimic cervical caries; avoided by correct exposure and clinical correlation

Cervical burnout is an artefact at the cervical constriction of the tooth where the reduced tooth thickness causes apparent radiolucency, mimicking caries. Clinical examination and correct exposure technique help distinguish it from true caries.