RDA Radiographic Techniques and Errors 2

Question 1

Which radiographic technique uses a film/sensor holder with an aiming ring to align the central ray perpendicular to the film?

Accepted Answer

Paralleling technique

Answer

The paralleling technique uses XCP (Extension Cone Paralleling) instruments or similar film holders with indicator rings to ensure the film/sensor is parallel to the long axis of the tooth and the central ray is perpendicular.

Question 2

What radiographic error appears as a cone-shaped radiopaque shadow on the periapical image?

Accepted Answer

Cone cutting

Answer

Cone cutting occurs when the PID (cone) is not aligned correctly and the primary beam misses part of the film/sensor, resulting in a clear (unexposed) area with a cone/circular shape.

Question 3

What is the purpose of the lead apron and thyroid collar during dental radiography?

Accepted Answer

To prevent scatter radiation from exposing the patient's gonads and thyroid gland

Answer

The lead apron protects the patient's gonads and torso from scatter radiation, while the thyroid collar specifically protects the thyroid gland, which is particularly sensitive to radiation.

Question 4

Which error causes radiographic images to appear lighter (less dense) than normal?

Accepted Answer

Underexposure

Answer

Underexposure (too little radiation reaching the film/sensor) produces a light, low-density image that appears washed out and lacks proper contrast for diagnostic use.

Question 5

What technique error causes the teeth to appear shorter than their actual length on a periapical radiograph?

Accepted Answer

Foreshortening

Answer

Foreshortening occurs when the vertical angulation of the X-ray beam is excessive (too steep), causing the teeth to appear shorter than their actual length.

(RDA) Registered Dental Assistant Practice Test

(RDA) Registered Dental Assistant Practice Test

RDA Radiographic Techniques and Errors 2