LP2 Chapter 17 Flashcards
Why is an increased target-receptor distance required in the paralleling technique?
To avoid image magnification.
Which of the following describes the relationship of the central ray to the film in the paralleling technique?
90 degrees to the film and long axis of the tooth.
Describe the relationship of the film and the long axis of the tooth in the paralleling technique.
The film and the tooth are parallel to each other.
Describe the distance between the film and the tooth in the paralleling technique.
The film is placed away from the tooth and toward the middle of the oral cavity.
What are two steps that are correct concerning film placement?
- Anterior films are placed vertically.
2. Posterior films are placed horizontally.
What is a possible result if there is a lack of parallelism between the film and the long access of the tooth?
If less than 20 degrees, the film is generally acceptable.
What are the advantages of the paralleling technique?
- Increased Accuracy; produces an image without dimensional distortion
- Simplicity of Use
- Ease of Duplication
What happens to the radiographic image when the object-film distance is increased?
Image magnification, loss of definition
What piece of equipment is required to hold the film parallel to the long axis of the tooth in the paralleling technique?
Film holder/Receptor Holder
What size film is used with the anterior XCP instrument?
Size 1
What size film is used with the posterior XCP instrument?
Size 2
Which film holders are recommended for use with the paralleling technique because they reduce patient exposure.
Precision film holders; Rinn XCP instruments with snap-on collimators
How is the patient’s head positioned before exposing films?
Upper arch parallel to the floor; midsagittal plane perpendicular to the floor
What happens as the tooth and receptor get closer together in the paralleling technique?
Less Magnification
What creates more magnification in the paralleling technique?
The farther away the receptor is from the tooth.
