CDS: special tests (radiographs)

Question 1

What are radiographs?

Answer 1

Images created using X-ray photons

Question 2

What are the 3 things the X-ray (radiograph) can do when being passed through an object?

Answer 2

Transmitted
Absorbed
Scattered

Question 3

What does ‘transmitted’ mean in terms of an X-ray beam?

Answer 3

It passes through unaltered

Question 4

What does ‘absorbed’ mean in terms of an X-ray beam?

Answer 4

it is stopped by the tissue

Question 5

What does ‘scattered’ mean in terms of an X-ray beam?

Answer 5

it changes direction

Question 6

What pathways of an X-ray beam contribute to the attenuation of X-ray photons?

Answer 6

Absorbed and Scattered

Question 7

What does attenuation mean?

Answer 7

It is the reduction of the intensity of an x-ray beam as it passes through matter.

Question 8

What is the radiographic image?

Answer 8

It represents the pattern of attenuation of the X-ray photons after they have passed through matter

Question 9

What area of the teeth are good at attenuating X-ray beams?

Answer 9

Enamel (occlusal surface)

Question 10

why is enamel good at attenuating X-ray beams?

Answer 10

the beam hits enamel and gets ABSORBED - therefore, doesn’t reach the receptor on the other side

Question 11

What does radiolucent mean?

Answer 11

darker areas on image - LESS ATTENUATION of x-rays
(x-ray beams pass through)

Question 12

Example of radiolucent area on mouth x-ray

Answer 12

spaces between teeth, maxillary sinus

Question 13

What does radiopaque mean?

Answer 13

lighter areas on image - MORE ATTENUATION of x-rays
(X-ray beam doesn’t pass through therefore get white area)

Question 14

Example of radiopaque area on mouth X-ray

Answer 14

dentine, enamel, bone, filling

Question 15

Why are radiographs used?

Answer 15

to show anatomy and pathology not visible to the naked eye
e.g., caries and bone loss, tooth morphology (shape) of teeth (see shape of roots)

Question 16

What is the most common reason to use radiographs in dentistry?

Answer 16

to assess caries

Question 17

How would caries look in a radiograph?

Answer 17

appears radiolucent compared to rest of tooth
caries = darker area in tooth

Question 18

What are the different types of radiographs in dentistry? (broad types)

Answer 18

intra-oral, extra-oral, cross-sectional

Question 19

What are the different types of intra-oral radiographs?

Answer 19

bitewing radiograph
periapical radiograph
occlusal radiograph

Question 20

What are the different types of extra-oral radiographs?

Answer 20

panoramic radiograph
lateral cephalogram

Question 21

What is the type of cross-sectional radiograph?

Answer 21

cone beam computed tomograph

Question 22

What does a bitewing radiograph show and what is it mainly used for? (intra-oral)

Answer 22

provides a view of multiple side teeth (i.e., premolars and molars)
- shows crowns, parts of the roots, shows some interdental bone
mainly looking for caries

Question 23

What does a periapical radiograph show and what is it used for? (intra-oral)

Answer 23

provides a full-length view of a particular tooth/teeth
good for looking at pulp and potential bone loss

Question 24

What does occlusal radiograph show? (intra-oral)

Answer 24

provides a view of one dental arch
allows teeth to be seen from different view points

Question 25

what does a panoramic radiograph show? (extra-oral)

Answer 25

provides a zoomed-out view of the jaws can show entire dentition as well as jaw and mid-face

Question 26

is the resolution of extra-oral radiographs better or worse than intra-oral?

Answer 26

resolution is worse in extra-oral radiographs

Question 27

what does a cone-beam computed tomography show? (cross-sectional)

Answer 27

provides a cross-sectional imaging of the teeth/jaws "3D-scan" good at spotting fractures or unusual tumours

Question 28

When is cone beam computed tomography used?

Answer 28

only used when routine dental imaging cannot provide the required information

Question 29

What are the cons of using cone beam computed tomography?

Answer 29

increased radiation dose decreased resolution increased cost

Question 30

What is a limitation of radiographs?

Answer 30

don't know what side of tooth caries is on

Question 31

how do you position radiograph scans to view?

Answer 31

put in correct order and position as if facing the patient

Question 32

what anatomical features can indicate which teeth are shown?

Answer 32

- crown morphology - root morphology - curve of spee (smile line - goes up towards molars) - surrounding non-dental anatomy (e.g., maxillary sinus)

Question 33

examples of non-dental anatomy associated with maxillary teeth

Answer 33

maxillary sinus nasal cavity maxillary tuberosity (rounded bony protrusion on the lower part of the upper jaw that houses the wisdom teeth sockets)

Question 34

examples of non-dental anatomy associated with mandibular teeth

Answer 34

inferior alveolar canal (contains inferior alveolar nerve, artery and vein) mental foramen (opening in the mandible - allows the mental nerve to exit; located between the premolars) inferior border of mandible external oblique ridge (Bony prominence on the outside of the mandible that appears as a radiopaque band on radiographs )