Paralleling technique l Oral radiology MCQs

Parallel line angle x-ray technique l Oral radiology MCQs for dental students 

IMPORTANT POINTS TO REMEMBER

1. • Parallel line angle technique is also called Fitzgerald technique, long cone technique and extended cone technique.
2. • The central ray of the X-ray beam should be perpendicular to the film and the long axis of the tooth. The film should be placed in the mouth parallel to the long axis of tooth being exposed.
3. • Film can be held with Rinn XCP (X, extension; C, cone; P, paralleling), precision film holders, stable bite-blocks and haemostat with bite-block.
4. • Film should be placed towards the midline, to achieve parallelism between film and tooth.
5. • In anterior region, film should be placed vertical in film-holding device.
6. • In posterior teeth film should be placed horizontal in holding device.
7. • Problems that may occur in placement of film in mandibular region are pain, active tongue movements, difficulty in placing film on lingual side, bending of film and cut-off.
8. • Vertical angulation: The central rays of the X-ray beam should be directed perpendicular to the film and the long axis of the tooth.
9. • Horizontal angulation: Central rays should be directed through the contact areas of the teeth.
10. • Point of entry: Point of entry should be directed through the centre of region being radiographed; otherwise it can result in cone cut.

MCQ on intraoral radiographic technique (Paralleling technique) for dental x-ray

1. In paralleling technique. increased target film distance is required to:

A. Magnify the image

B. Avoid image magnification

C. Avoid image elongation

D. Avoid distortion

2. Projection geometry of parallel line angle technique should be

a. Film should be placed to cover whole tooth to be examined

b. Vertical plane should be parallel to long axis of tooth

c. Horizontal angulation should be from contact area

d. All of the above

3. To compensate for the image magnification which occurs as film is placed away from the object the target to film distance is

a. Increased

b. Decreased

c. Equal to

d. None of the above

4. Film size used for children in parallel line angle technique is

a. 2

b. 0

c. 3

d. 1

5. Distal oblique parallel line angle technique is used to visualize

a. Retromolar area of mandible

b. Molar area

c. Premolar area

d. Submandibular area

6. Following are the advantages of parallel line angle technique except

a. Accuracy

b. No overlapping

c. No cone cut

d. Operator friendly

7. Positioning the holders within the mouth for parallel line angle technique is difficult in

a. Mandibular first molar

b. Mandibular second molar

c. Mandibular second premolar

d. Mandibular third molar

8. The axial inclination of the maxillary incisor is

a. 15–30°

b. 15–50°

c. 15–20°

d. None of the above

9. The use of long target film distance in the paralleling technique results in:

A. Less image magnification and increased definition

B. Less image magnification and decreased definition

C. Increased image magnification and increased definition

D . Increased image magnification and decreased definition

10. The use of a long target film distance in the paralleling technique results in:

A. Increased definition

B. Image magnification

C. Decreased definition

D. Reduced scatter radiation

11. In paralleling technique which of the following describes the relationship of the central ray to the film

A. .Plus 30 degrees to the long axis of the tooth

B. Plus 80 degrees to the long axis of the tooth

C. Minus 15 degrees to the long axis of the tooth

D. 90 degrees to the film and long axis of the tooth

12. Which of the following is appropriate regarding the film placement in paralleling technique: (MORE ANSWER)

1 . Anterior films are placed vertically

2. Anterior films are placed horizontally

3. Posterior films are placed horizontally

4. Posterior films are placed vertically

13. Which of the following is correct concerning the lack of parallelism between the film and the long axis of the teeth? If:

A. Greater than 40 degrees, the film is generally acceptable

B. Greater than 60 degrees the film is generally acceptable

C. Less than 20 degrees the film is generally acceptable

D. Less than 40 degrees the film is generally acceptable

14. Which of the following is a disadvantage in paralleling technique:

A. Film placement

B. Positioning of the cone

C. Positioning of the patient

D. Accurate angulation of the cone

15. Which of the following is an advantage of paralleling technique:

A. Easy film placement

B. Comfortable for patient

C. Dimensional accuracy

D. Can be easily done in adult and child patient