Chapter 31

Question 2

Which of the following describes radiolucent lines observed across an image?

Answer 2

D) Streaking

Question 3

Which of the following describes radiolucent distortion surrounding the dense radiopaque appearance of the metal object on an image?

Answer 3

B) Cupping

Question 4

Which stabilizing aid is NOT utilized during a CBCT scan to avoid movement artifacts?

Answer 4

C) Lead apron

Question 5

A smaller voxel size does all of the following except one. Which one is the exception?

Answer 5

D) Increases movement artifacts

Question 6

A CBCT examination produces as many as ________ image slices available for interpretation (including all three anatomical planes).

Answer 6

C) 1,500

Question 7

CBCT requires a higher dose of radiation compared to a medical CT scan.

Answer 7

FALSE

Question 8

CBCT produces three-dimensional radiographic images.

Answer 8

TRUE

Question 9

It is necessary to use a CBCT to determine the location of impacted third molars.

Answer 9

FALSE

Question 10

CBCT machines today are only marketed and used in specialty oral health care practices such as endodontic and orthodontic offices.

Answer 10

FALSE

Question 11

Most CBCT machines allow an operator to switch between 2-D and 3-D imaging options.

Answer 11

TRUE

Question 12

The FOV setting can be reduced or enlarged as needed in CBCT.

Answer 12

TRUE

Question 13

Voxel is short for ‘volume and element.’

Answer 13

TRUE

Question 14

A pixel captures a third dimension.

Answer 14

FALSE

Question 15

The coronal plane divides anatomy vertically into a right and left side.

Answer 15

FALSE

Question 16

A medium FOV classification for CBCT is indicated for capturing both maxillary and mandibular arches.

Answer 16

TRUE

Question 17

A CBCT examination requires multiple types of 2-D radiographs for orthodontic diagnoses and treatment planning.

Answer 17

FALSE

Question 18

CBCT can help with diagnosing pathology for endodontic therapy that are not present on intraoral or 2-D extraoral radiographs.

Answer 18

TRUE

Question 19

CBCT examinations are not meant to replace conventional 2-D oral and maxillofacial radiographic examinations for many conditions.

Answer 19

TRUE

Question 20

CBCT examinations are used as a screening tool for occult disease.

Answer 20

FALSE

Question 21

A lead/lead-equivalent barrier with a thyroid collar is not necessary if it will interfere with acquisition of the image.

Answer 21

TRUE

Question 22

The presence of a large metallic restoration can cause streaking and cupping artifacts to appear on radiographic images.

Answer 22

TRUE

Question 23

When an x-ray beam passes through two objects of equal high density that are close to one another, streaking may occur.

Answer 23

TRUE

Question 24

A larger voxel size utilized during CBCT will increase image detail and may increase radiation exposure.

Answer 24

FALSE

Question 25

A definitive interpretation of a CBCT image most commonly requires assistance from a trained oral and maxillofacial radiology specialist.

Answer 25

TRUE

Question 26

An oral health care professional is only legally responsible for the detection and subsequent recommendation for treatment or referral of the specific dental need requiring the prescription of a CBCT examination.

Answer 26

FALSE

Question 27

Please describe conditions classified under the Preferred category for the prescription of CBCT.

Answer 27

Conditions classified under the Preferred category require more careful consideration as a practitioner must assess whether the risk versus benefit warrants a CBCT examination; or could 2-D radiographs provide enough information. Examples include location of inferior alveolar nerve, endodontic therapy, evaluation of sinus cavities, evaluation of bony defects, evaluation of oral pathologic lesions, and TMJ evaluations.

Question 28

How many times does the beam from a CBCT rotate around a patient's head?

Answer 28

CBCT utilized a cone-shaped x-ray beam that rotates in one full or partial rotation around the head (194 to 360 degrees).

Question 29

What do scatter correction algorithms do?

Answer 29

Scatter correction algorithms are built into CBCT computer software to reconstruct the digital signal into enhanced 2-D and 3-D images that are displayed on a monitor.

Question 30

Why is a 3-D radiograph (CBCT) more useful than a 2-D radiograph in determining and monitoring orthodontic interventions?

Answer 30

CBCT is more reliable in determining location and position of unerupted, impacted, and supernumerary teeth, and other growth and developmental anomalies with a comparable radiation dose to a radiographic series of 2-D images.

Question 31

What does ALARA stand for and what is it in regard to?

Answer 31

Keep radiation exposure 'as low as reasonably achievable.'

Question 32

Why should CBCT be considered prior to exposing a series of extra- and/or intraoral radiographs?

Answer 32

CBCT should be considered prior to exposing a series of extra- and/or intraoral radiographs to prevent duplication and overlap of exposures, negative the need for one or the other.

Question 33

What are artifacts and how do they affect radiographic imaging?

Answer 33

Artifacts are images other than anatomy or pathology that do not contribute to a diagnosis and can be a significant problem affecting image quality.

Question 34

Why do artifacts and electronic noise occur more often with CBCT technology than medical CT scans?

Answer 34

The cone-shape beam and use of lower radiation energy by CBCT scans can lead to production of scatter radiation that negatively affects an image and can also decrease the contrast of soft tissues making it harder to compare hard and soft tissue structures.

Question 35

What causes the presence of artifacts that appear as a double or duplicate appearance of anatomical structures?

Answer 35

Patient movement during the scanning process causes duplication or movement artifacts.

Question 36

Provide three examples of anatomy beyond the oral cavity that a comprehensive CBCT interpretation must include regarding potential diseases and abnormalities.

Answer 36

A comprehensive interpretation must include detection of conditions affecting anatomy beyond the oral cavity such as diseases and abnormalities noted in the nasal airways, paranasal sinuses, craniofacial structures, cervical vertebrae, and other tissues outside the dentition and supporting structures.