Dental Radiology & Imaging Flashcards
7 cards from real ADAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Dental Radiology & Imaging flashcards as text
Which radiographic appearance is most characteristic of a periapical (radicular) cyst compared to a periapical granuloma or abscess?
Answer: Well-defined radiolucency with a thin corticated (sclerotic) border at the apex
Periapical cysts characteristically form a well-defined, corticated (smooth white border) radiolucency because the cyst expands slowly and stimulates reactive bone formation at its periphery.
What is the primary function of the lead apron during dental radiographic procedures?
Answer: Shield the patient's gonads and abdominal region from scatter radiation
The lead apron reduces scatter radiation reaching the patient's radiosensitive reproductive organs and abdomen, lowering the risk of genetic or somatic damage.
Which imaging modality is most appropriate for initially evaluating the position and angulation of an impacted mandibular third molar?
Answer: Panoramic radiograph
A panoramic radiograph provides an overview of the entire dentition and jaws in one image, allowing assessment of an impacted tooth's angulation, depth, and relationship to the inferior alveolar canal.
On a panoramic radiograph, a 'ghost artifact' appears as a faint, blurred image on the opposite side of the film from the actual structure. What is the most common cause?
Answer: Radiopaque objects (e.g., earrings, removable prostheses) outside the focal trough
Radiopaque objects outside the focal trough (such as earrings or a retained lead apron corner) are captured by the rotating beam and projected as a ghost image on the contralateral side.
What is the primary purpose of collimation in dental radiography?
Answer: Restrict the beam to the area of diagnostic interest and reduce patient dose
Collimation limits the cross-sectional area of the X-ray beam, reducing the volume of irradiated tissue and thus lowering patient exposure while maintaining diagnostic quality.
On a panoramic radiograph, a broad horizontal radiolucent band overlying the ramus region is most likely caused by which structure?
Answer: The air shadow of the oropharynx and pharyngeal airway
The air-filled pharyngeal airway space behind the tongue creates a dark radiolucent band that is superimposed over the ramus on panoramic radiographs when the tongue is not positioned against the palate.
According to the National Council on Radiation Protection (NCRP), what is the maximum permissible dose (MPD) of effective radiation dose for occupationally exposed dental personnel per year?
Answer: 50 mSv (5 rem)
The NCRP recommends a maximum permissible effective dose of 50 mSv (5 rem) per year for occupationally exposed radiation workers, with a lifetime cumulative limit of 10 mSv × age.