chapter 16 occlusal

Question 2

Each of the following statements regarding occlusal radiographs is correct EXCEPT one. Which one is the EXCEPTION?

a. They do not require the use of an image receptor holder.
b. They image both of the arches on a single film.
c. They may be either topographical or cross-sectional.
d. They are placed in the mouth between the occlusal surfaces of the maxillary and mandibular teeth.

Answer 2

b. They images both of the arches on a single film.

The purpose of the occlusal exam is to view large areas of the maxilla or mandible on a single radiograph.

Question 3

Which of the following statements is correct?

a. Topographical occlusal radiographs yield a greater amount of information in the alveolar crest and apical areas than periapical radiographs.
b. Topographical occlusal radiographs may be exposed only on the maxillary arch.
c. Cross-sectional occlusal radiographs work best to image the maxilla.
d. Topographical occlusal radiographs cannot be used on children.

Answer 3

a. Topographical occlusal radiographs yield a greater amount of information in the alveolar crest and apical areas than periapical radiographs.

Topographical occlusal radiographs are best used to image conditions of the teeth and supporting structures when an area larger than that imaged by periapical radiographs is required.

Question 4

Each of the following is a use of an occlusal radiograph EXCEPT one. Which one is the EXCEPTION?

a. Detecting incipient, interproximal caries
b. Locating soft tissue calcifications
c. Assisting in the evaluation of fractures
d. Revealing retained roots of extracted teeth

Answer 4

a. Detecting incipient, interproximal caries

The size and direction of placement of occlusal radiographs allows for viewing information not adequately seen on smaller periapical radiographs. Bitewing radiographs are ideally suited for detecting incipient interproximal decay.

Question 5

Each of the following statements regarding orientation of the occlusal radiographic image receptor is correct EXCEPT one. Which one is the EXCEPTION?

a. If using film, the white side must face the arch of interest.
b. The image receptor must be placed in the mouth with the long dimension horizontal.
c. The image receptor should protrude from the mouth about ¼ inch.
d. If using film, the embossed dot should be positioned toward the anterior.

Answer 5

b. The image receptor must be placed in the mouth with the long dimension horizontal.

The image receptor may be placed into the mouth with the long dimension positioned horizontally or vertically, centered over one small region of interest or over the entire right or left sides of the dental arches. The position used will depend on the type of occlusal radiograph needed and the area to be imaged.

Question 6

Which of these statements is FALSE?

a. Cross-sectional occlusal radiographs of the mandible are taken with the occlusal plane perpendicular to the floor.
b. Topographical occlusal radiographs of the mandible may be taken with the head positioned the same as for maxillary topographical occlusal radiographs.
c. An image receptor holder is not required for stabilization of the image receptor.
d. Mandibular topographical radiographs are taken with the midsaggital plane parallel to the floor.

Answer 6

d. Mandibular topographical radiographs are taken with the midsaggital plane parallel to the floor.

Topographical occlusal radiographs of the mandible may be taken with the head positioned the same as for maxillary exposures, with the occlusal plane parallel to the floor and the midsagittal plane perpendicular to the floor.

Question 7

Which of the following statements is correct?

a. Occlusal radiographs have some amount of dimensional distortion.
b. The occlusal technique is similar to the paralleling technique.
c. Occlusal films should be inserted completely into the oral cavity.
d. An image receptor holder will allow for correct positioning of occlusal radiographs.

Answer 7

a. Occlusal radiographs have some amount of dimensional distortion.

The occlusal technique is similar to the bisecting technique for periapical radiographs. For this reason, occlusal radiographs will have some dimensional distortion.

Question 8

Assuming that the patient’s head is in the correct position, which of the following is the correct vertical angulation setting for a maxillary anterior topographical occlusal radiograph?

a. +65 degrees
b. +45 degrees
c. -55 degrees
d. -45 degrees

Answer 8

a. +65 degrees

+65 degrees is the correct vertical angulation setting for a maxillary anterior topographical occlusal radiograph.

Question 9

Each of the following should be done prior to placing the image receptor intraorally EXCEPT one. Which one is the EXCEPTION?

a. Turning on the dental x-ray machine
b. Placing the tube head in the approximate position for the exposure
c. Selecting the appropriate exposure setting
d. Assembling a sterile image receptor holder

Answer 9

d. Assembling a sterile image receptor holder

An image receptor holder is not required to stabilize the image receptor for occlusal radiographs.

Question 10

The topographical occlusal radiographic technique is similar to what technique?

a. Paralleling
b. Bisecting
c. Bitewing
d. Panoramic

Answer 10

b. Bisecting

The topographical occlusal technique is similar to the bisecting technique used to produce periapical radiographs.

Question 11

Which of the following statements regarding managing occlusal radiograph exposures is FALSE?

a. Exposure factors are the same as those used for periapical and bitewing radiographs in the same region.
b. The open end of the PID should be positioned as close to the patient’s skin as possible, without touching.
c. A modification of the paralleling technique is used to determine the vertical angulation.
d. A shorter PID minimizes distortion.

Answer 11

c. A modification of the paralleling technique is used to determine the vertical angulation.

The vertical angulation for topographical occlusal radiographs follows the rules of the bisecting technique used for periapical radiographs, where the central rays of the x-ray beam are directed through the apices of the teeth perpendicularly toward the bisector.

Question 12

What size image receptor is used for occlusal radiographs on most adult patients?

a. 1
b. 2
c. 3
d. 4

Answer 12

d. 4

The large size #4 occlusal image receptor is useful for recording information that cannot be adequately recorded on the smaller periapical image receptors.

Question 13

The embossed identification dot on occlusal film should be positioned toward the:

a. anterior.
b. posterior.
c. mesial.
d. distal.

Answer 13

a. anterior.

Because the embossed identification dot (on the film packet) should be positioned away from the area of interest, positioning it toward the anterior should leave it outside the mouth and therefore prevent it from interfering with the image.

Question 14

The patient’s head should be reclined and the chin tipped upward for which occlusal projection?

a. Maxillary anterior topographical
b. Maxillary posterior topographical
c. Mandibular posterior topographical
d. Mandibular cross-sectional

Answer 14

d. Mandibular cross-sectional

Mandibular cross-sectional occlusal radiographs are taken with the patient reclined in the chair so that the head is tipped back, positioning the occlusal plane perpendicular to the plane of the floor.

Question 15

A vertical, zero-degree angulation is used for exposure of which occlusal radiograph?

a. Maxillary posterior topographical
b. Mandibular anterior topographical
c. Mandibular posterior topographical
d. Mandibular cross-sectional

Answer 15

d. Mandibular cross-sectional

The patient’s head position is such that the occlusal plane is perpendicular to the plane of the floor when exposing a mandibular cross-sectional radiograph. In other words, the patient should be reclined and the chin tipped upward. In this position, the vertical angulation will most likely be set at 0 degrees, allowing the x-rays to strike the image receptor perpendicularly.

Question 16

The thyroid collar may be in the path of the primary beam during which occlusal technique?

a. Maxillary posterior topographical
b. Mandibular anterior topographical
c. Mandibular posterior topographical
d. Mandibular cross-sectional

Answer 16

d. Mandibular cross-sectional

When exposing an occlusal radiograph on the mandible, it may be necessary to modify placement of the lead/lead-equivalent thyroid collar.

Question 17

Through a point on the middle of the chin toward the center of the image receptor describes the recommended point of entry of the central ray of the x-ray beam for which of the following occlusal radiographs?

a. Maxillary anterior topographical
b. Maxillary posterior topographical
c. Mandibular anterior topographical
d. Mandibular posterior topographical

Answer 17

c. Mandibular anterior topographical

The point of entry for directing the central ray of the x-ray beam when exposing a mandibular anterior topographical occlusal radiograph is through a point on the middle of the chin toward the center of the image receptor.

Question 18

A vertical +65-degree angulation is used for which occlusal radiograph?

a. Maxillary anterior topographical
b. Maxillary posterior topographical
c. Mandibular posterior topographical
d. Mandibular cross-sectional

Answer 18

a. Maxillary anterior topographical

Vertical angulation for exposing a maxillary anterior topographical radiograph is perpendicular to the imaginary bisector between the long axes of the teeth and image receptor in the vertical dimension. When the patient is in the correct seated position, that vertical angulation is +65 degrees.

Question 19

Through a point on the ala-tragus line below the outer cantus of the eye toward the center of the image receptor describes the recommended point of entry of the central ray of the x-ray beam for which of the following occlusal radiographs?

a. Maxillary anterior topographical
b. Maxillary posterior topographical
c. Mandibular anterior topographical
d. Mandibular posterior topographical

Answer 19

b. Maxillary posterior topographical

The point of entry for directing the central ray of the x-ray beam when exposing a maxillary posterior topographical occlusal radiograph is through a point on the ala-tragus line below the outer cantus of the eye toward the center of the image receptor.

Question 20

Which of the following occlusal radiographs yields more information about the location of tori and impacted or malpositioned teeth and calcifications of soft tissues?

a. Maxillary anterior topographical
b. Maxillary posterior topographical
c. Mandibular posterior topographical
d. Mandibular cross-sectional

Answer 20

d. Mandibular cross-sectional

The mandibular cross-sectional occlusal radiograph yields more information about the location of tori and impacted or malpositioned teeth and calcifications of soft tissues.

Question 21

Assuming that the patient’s head is in the correct position, which of the following is the correct vertical angulation setting for a maxillary posterior topographical occlusal radiograph?

a. +65 degrees
b. +45 degrees
c. -55 degrees
d. -45 degrees

Answer 21

b. +45 degrees

+45 degrees is the correct vertical angulation setting for a maxillary anterior topographical occlusal radiograph.

Question 22

The cross-sectional technique produces an occlusal radiograph that resembles a large periapical radiograph.

True

False

Answer 22

False

The topographical technique produces an occlusal radiograph that resembles a large periapical radiograph.

Question 23

When imaging the mandibular arch, the printed side of the occlusal film packet will face the mandible.

True

False

Answer 23

False

When imaging the mandibular arch, the white, unprinted side of the film packet will face the mandible.

Question 24

When imaging the maxillary arch, the white, unprinted side of the occlusal film packet will face the maxilla.

True

False

Answer 24

True

The film packet is positioned with the white, unprinted side (front side) of the film packet against the arch of interest.

Question 25

The identification dot on an occlusal film should be placed toward the posterior to the oral cavity.

True

False

Answer 25

False

The embossed identification dot should be placed away from the area of interest to prevent it from interfering with the image. When placing an occlusal radiograph, the embossed identification dot should be positioned toward the anterior region of the oral cavity.

Question 26

The vertical angulation used for topographical occlusal radiographs follows the rules of the bisecting technique used for periapical radiographs.

True

False

Answer 26

True

In the topographical occlusal technique, the central ray is directed through the apices of the teeth perpendicularly toward the imaginary bisector.

Question 27

Topographical occlusal radiographs of the mandible may be taken with the head positioned the same as for maxillary topographical occlusal radiographs.

True

False

Answer 27

True

For both maxillary and mandibular topographical occlusal radiographs, the occlusal plane should be parallel to the floor and the midsagittal plane perpendicular to the floor.

Question 28

Specialized image receptor holders should be used for occlusal radiographs.

True

False

Answer 28

False

An image receptor is not used for the placement of occlusal radiographs. Instead, the patient lightly occludes on the image receptor, which is placed flat in between the arches.

Question 29

A 16-inch (41-cm) PID should be used for the occlusal radiographic exam.

True

False

Answer 29

False

The shorter, 8-inch (20.5-cm)-length PID may be easier to position into the steeper vertical angulations required for this technique. Because of the increased object–image receptor distance, a longer PID would also add to the dimensional distortion.

Question 30

If the patient is seated in the correct position, the vertical angulation for a mandibular cross-sectional occlusal radiograph will most likely be set at 0 degrees.

True

False

Answer 30

True

When the patient’s head is reclined and the chin is tipped upward, the central ray is directed to strike the image receptor perpendicularly at 0 degrees.

Question 31

The occlusal examination may be made alone or to supplement periapical or bitewing radiographs.

True

False

Answer 31

True

The occlusal examination may be made alone or to supplement periapical or bitewing radiographs. The large size #4 occlusal image receptor is useful for recording information that cannot be adequately recorded on the smaller periapical image receptors.

Question 32

A cross-sectional occlusal radiograph will significantly distort the image of the teeth, producing an image of the teeth that appear circular or elliptical.

True

False

Answer 32

True

The circular or elliptical appearance of the teeth results from the relationship of the central ray of the x-ray beam with the image receptor. As its name implies, the cross-sectional technique produces a circular or elliptical appearance of the teeth on the radiograph and an increased coverage of the sublingual area (under the tongue).

Question 33

Topographical radiographs of the mandible are ideal at detecting the presence of salivary stones (sialoliths) in the ducts of the sublingual and submandibular glands.

True

False

Answer 33

False

Cross-sectional radiographs of the mandible are ideal at detecting the presence of salivary stones (sialoliths) in the ducts of the sublingual and submandibular glands.

Question 34

Occlusal radiographs can be placed and exposed in five regions of the oral cavity.

True

False

Answer 34

False

Occlusal radiographs may be taken in any number and in any region of the oral cavity.

Question 35

An occlusal radiograph must be taken with the size #4 image receptor.

True

False

Answer 35

False

Smaller size #2 intraoral image receptors may also be used, depending on the area to be examined. The standard #2 periapical film or sensor is frequently used with children, either to image labiolingual or buccolingual unerupted tooth positions or in place of periapical radiographs when needed.

Question 36

If the image receptor is not placed in the mouth with at least 1/4 inch (1/2 cm) protruding outside, the result will be cone cutting.

True

False

Answer 36

False

In the correct position, the image receptor should be placed well back into the mouth but with at least 1/4 inch (1/2 cm) protruding outside the mouth to record the maximum amount of information.

Question 37

The horizontal angulation for topographical occlusal radiographs is determined by directing the central rays at the image receptor perpendicularly through the teeth embrasures (spaces).

True

False

Answer 37

True

The correct horizontal angulation for topographical occlusal radiographs is determined in the same manner as for periapical and bitewing radiographs; by directing the central rays at the image receptor perpendicularly through the teeth embrasures (spaces).

Question 38

If the patient is seated in the correct position, the recommended vertical angulation setting for a posterior mandibular topographical is 0 degrees.

True

False

Answer 38

False

The recommended vertical angulation setting for a posterior mandibular topographical is –45 degrees.

Question 39

Correct points of entry position are determined by directing the central rays of the x-ray beam at the center of the image receptor.

True

False

Answer 39

True

Correct points of entry position are determined by directing the central rays of the x-ray beam at the center of the image receptor.

Question 40

If the patient’s head is in correct position, predetermined vertical angulations and points of entry may be used.

True

False

Answer 40

True

If the patient’s head is in correct position, predetermined vertical angulations and points of the entry may be used.

Question 41

Determining the vertical angulation for exposure of a cross-sectional occlusal radiograph is assisted by positioning the open end of the PID parallel to the external aiming device of the image receptor holder.

True

False

Answer 41

False

An image receptor holder is not used for exposing occlusal radiographs. Determining the vertical angulation for exposure of a cross-sectional occlusal radiograph is assisted by positioning the open end of the PID parallel to the plane of the image receptor.