Chapter 23: Extraoral Imaging
Iannucci: Dental Radiography, 5th Edition
MULTIPLE CHOICE
1. An extraoral image is placed __________ the mouth during x-ray exposure. Extraoral imaging
is used to image _________ areas of the skull or jaws.
a.
outside; small
b.
outside; large
c.
inside; small
d.
inside; large
2. (1) A thyroid collar is used for Waters, submentovertex, and reverse Towne projections. (2) A
thyroid collar is not used for the lateral jaw, lateral cephalometic, and the posteroanterior
projections.
a.
Both statements are true.
b.
Both statements are false.
c.
The first statement is true; the second statement is false.
d.
The first statement is false; the second statement is true.
3. (1) Temporomandibular joint tomography is used to evaluate the condyle, articular eminence,
and glenoid fossa. (2) Other landmarks are blurred in TMJ tomography.
a.
Both statements are true.
b.
Both statements are false.
c.
The first statement is true; the second statement is false.
d.
The first statement is false; the second statement is true.
4. Which of the following would you evaluate using an extraoral image?
a.
Gutta percha placement in the root canal
b.
Level of crestal bone
c.
Recurrent decay
d.
Growth and development
5. Extraoral images may be used in conjunction with intraoral images. Extraoral images are not
as defined or sharp as intraoral images.
a.
Both statements are true.
b.
Both statements are false.
c.
The first statement is true; the second statement is false.
d.
The first statement is false; the second statement is true.
6. Which of the following is the most commonly used extraoral film size?
a.
3 5
b.
4 6
c.
5 7
d.
8 10
7. An occlusal receptor (size ____) may be used for some extraoral images.
a.
0
b.
1
c.
2
d.
4
8. An occlusal receptor ________ be used for some extraoral images. When used extraorally, it
covers a ________ area than a screen film.
a.
may; smaller
b.
may not; smaller
c.
may; larger
d.
may not; larger
9. The front side of the cassette is typically constructed of ________ and permits the passage of
the x-ray beam, whereas the back side is made of _________ to reduce scatter radiation.
a.
metal; metal
b.
plastic; plastic
c.
plastic; metal
d.
metal; plastic
10. Which of the following is the fastest recommended screen and screen film combination?
a.
Calcium tungstate screen with blue light
b.
Calcium tungstate screen with green light
c.
Rare earth screen with blue light
d.
Rare earth screen with green light
11. For the transcranial projection, the central ray is directed toward a point _____ inches above
and 0.5 inches behind the opening of the ear canal.
a.
0.5
b.
1.0
c.
2.0
d.
4.0
12. Scatter radiation
a.
increases film fog.
b.
increases image contrast.
c.
decreases film fog.
d.
decreases density.
13. A grid can be used to decrease scatter radiation, decrease film fog, and increase contrast on
film and PSP receptors. A grid should only be used when it is necessary to improve image
quality and increase contrast because it requires increased x-ray exposure.
a.
Both statements are true.
b.
Both statements are false.
c.
The first statement is true; the second statement is false.
d.
The first statement is false; the second statement is true.
14. A grid is composed of a series of
a.
wire mesh that is similar to the screen in a window or door.
b.
copper wires around an armature.
c.
thin lead strips.
d.
thick lead strips.
15. The grid is placed between the ____________ and the ______________.
a.
aluminum filter; PID
b.
PID; patient’s head
c.
patient’s head; film or PSP receptors
d.
film or PSP receptors; cassette
16. To compensate for the strips found in the grid, _______________ must be used to expose a
film or PSP receptor.
a.
increased kilovoltage
b.
increased milliamperage
c.
increased exposure time
d.
decreased exposure time
17. The lateral jaw projection
a.
requires the use of a special x-ray unit.
b.
provides for more diagnostic information than a panoramic image.
c.
is used to examine the anterior portion of the mandible.
d.
is valuable for patients with limited jaw opening because of a fracture or swelling.
18. Which of the following choices is a type of lateral jaw projection?
a.
Lateral cephalometric projection
b.
Reverse Towne projection
c.
Waters projection
d.
Body of the mandible projection
19. For which of the following projections would be you place the receptor parallel to the
patient’s cheek and have the patient tip her head 15 degrees toward the receptor with her chin
slightly extended and elevated?
a.
Lateral cephalometric projection
b.
Ramus of the mandible projection
c.
Reverse Towne projection
d.
Waters projection
20. For the _____________ projection, the patient’s face is against the receptor with both the
forehead and chin touching the receptor.
a.
posteroanterior
b.
lateral cephalometric
c.
reverse Towne
d.
Waters
21. The beam should be directed _______________ degrees for the ramus of the mandible
projection.
a.
downward at 15 to 20
b.
upward at 15 to 20
c.
downward at 45
d.
upward at 45
22. The left side of the patient’s head is positioned adjacent to the cassette for the _____________
projection.
a.
lateral cephalometric
b.
posteroanterior
c.
Waters
d.
submentovertex
23. The patient’s head and neck are tipped back as far as possible for the _____________
projection.
a.
lateral cephalometric
b.
posteroanterior
c.
Waters
d.
submentovertex
24. Your patient thinks she has fractured her zygomatic arch. Which of the following projections
would you take?
a.
Lateral cephalometric
b.
Posteroanterior
c.
Waters
d.
Submentovertex
25. You have been asked to take a dental image to locate a fracture at the neck of the condyle.
Which projection would you take?
a.
Reverse Towne
b.
Posteroanterior
c.
Waters
d.
Submentovertex
26. In order to take this projection, you need to have your patient face the receptor, touch his
forehead to the receptor, tuck his chin down to his chest, and open his mouth as wide as he
can. Which projection is this?
a.
Waters
b.
Posteroanterior
c.
Reverse Towne
d.
Submentovertex
27. The purpose of the transcranial projection is to evaluate the articular eminence and _________
surface of the condyle.
a.
anterior
b.
posterior
c.
superior
d.
inferior