NBDHE NBDHE Dental Radiography and Interpretation 3 — Questions and Answers
Question 1: Which of the following appears radiopaque on a dental radiograph?
- Pulp chamber
- Periapical cyst
- Amalgam restoration (Correct answer)
- Periodontal ligament space
Correct answer: Amalgam restoration
Amalgam is a high-density metal alloy that absorbs X-rays and appears as a bright white (radiopaque) area on radiographs.
Question 2: The maximum permissible dose (MPD) of radiation for occupationally exposed dental workers per year is:
- 0.05 Sv (5 rem) (Correct answer)
- 0.1 Sv (10 rem)
- 0.5 Sv (50 rem)
- 0.001 Sv (0.1 rem)
Correct answer: 0.05 Sv (5 rem)
NCRP guidelines set the annual MPD for occupationally exposed workers at 0.05 Sv (50 mSv or 5 rem) per year.
Question 3: Interproximal bone loss appearing parallel to the cementoenamel junction (CEJ) on a bitewing radiograph is classified as:
- Vertical bone loss
- Angular bone loss
- Horizontal bone loss (Correct answer)
- Furcation involvement
Correct answer: Horizontal bone loss
Horizontal bone loss occurs when bone resorption proceeds evenly, resulting in a pattern parallel to the CEJ.
Question 4: The ALARA principle in radiography stands for:
- As Low As Reasonably Achievable (Correct answer)
- Accurate Lateral Angular Radiographic Assessment
- As Large As Radiographically Apparent
- Adjusted Low Angle Radiographic Alignment
Correct answer: As Low As Reasonably Achievable
ALARA means 'As Low As Reasonably Achievable' and guides practitioners to minimize patient radiation exposure while obtaining diagnostic quality images.
Question 5: A ghost image on a panoramic radiograph is characterized by:
- Appearing on the same side as the object, higher and blurred
- Appearing on the opposite side of the object, higher and blurred (Correct answer)
- Appearing below the object at the same horizontal level
- Appearing on the same side, sharper than the real image
Correct answer: Appearing on the opposite side of the object, higher and blurred
Ghost images on panoramic radiographs appear on the opposite side of the object, positioned higher and more blurred than the real image.
Question 6: Which projection is best for detecting calculus on proximal tooth surfaces?
- Periapical
- Occlusal
- Bitewing (Correct answer)
- Panoramic
Correct answer: Bitewing
Bitewing radiographs provide the most accurate view of interproximal surfaces, making them ideal for detecting proximal calculus deposits.
Question 7: Foreshortening of a tooth image on a periapical radiograph results from:
- Too little vertical angulation
- Too much vertical angulation (Correct answer)
- Incorrect horizontal angulation
- Film bending or curvature
Correct answer: Too much vertical angulation
Excessive vertical angulation causes foreshortening because the X-ray beam is directed too steeply, compressing the apparent length of the tooth.
NBDHE NBDHE Dental Radiography and Interpretation 3
Which of the following appears radiopaque on a dental radiograph?