EFDA Radiography & Infection Control 4 — Questions and Answers
Question 1: A foreshortened radiographic image is most likely the result of:
- Too little vertical angulation
- Too much vertical angulation (Correct answer)
- Incorrect horizontal angulation
- Film/sensor placement too far from teeth
Correct answer: Too much vertical angulation
Foreshortening occurs when too much vertical angulation is used, causing the beam to project a compressed, shorter-than-actual image of the tooth.
Question 2: What is the purpose of using a position-indicating device (PID) during radiographic exposure?
- To hold the patient's mouth open
- To direct the X-ray beam and reduce scatter (Correct answer)
- To protect the patient's thyroid gland
- To develop the radiographic image
Correct answer: To direct the X-ray beam and reduce scatter
The PID (position-indicating device) directs the central ray of the X-ray beam toward the film/sensor and helps collimate radiation to reduce patient exposure to scatter.
Question 3: Which precaution is MOST important when handling sharps contaminated with blood in the dental office?
- Recap needles using both hands after use
- Place used sharps immediately in a puncture-resistant sharps container (Correct answer)
- Wipe sharps with an alcohol swab before disposal
- Soak sharps in disinfectant solution for 10 minutes
Correct answer: Place used sharps immediately in a puncture-resistant sharps container
Used sharps must be immediately disposed of in an approved puncture-resistant sharps container to prevent needlestick injuries and bloodborne pathogen transmission.
Question 4: What is the primary advantage of digital radiography over conventional film radiography?
- Higher resolution images
- Reduced radiation exposure of up to 80% (Correct answer)
- No need for infection control protocols
- Images cannot be overexposed
Correct answer: Reduced radiation exposure of up to 80%
Digital radiography can reduce radiation exposure by up to 80% compared to conventional film because digital sensors are much more sensitive to X-rays.
Question 5: Which standard precaution requires treating all patient blood and body fluids as potentially infectious?
- Universal precautions (Correct answer)
- Contact precautions
- Airborne precautions
- Reverse isolation
Correct answer: Universal precautions
Universal precautions, expanded into Standard Precautions by the CDC, require treating all blood and body fluids from every patient as potentially infectious regardless of known disease status.
Question 6: The herringbone pattern on a processed dental radiograph indicates:
- Double exposure
- Film placed backward in the mouth (Correct answer)
- Inadequate developer time
- Excessive fixation time
Correct answer: Film placed backward in the mouth
The herringbone (tire track) pattern appears when the film is placed with the tube side facing away from the X-ray source, causing the lead foil backing to partially block the beam.
Question 7: How should the dental professional handle a patient who refuses to wear a lead apron for radiographs?
- Proceed without the apron and document the refusal
- Cancel the appointment until the patient agrees
- Explain the safety rationale and document informed refusal (Correct answer)
- Drape the apron loosely without securing it
Correct answer: Explain the safety rationale and document informed refusal
The dental professional should educate the patient about radiation safety benefits, and if the patient still refuses, document the informed refusal and proceed per office protocol.
EFDA Radiography & Infection Control 4
A foreshortened radiographic image is most likely the result of: