radiographs

Question 1

What are radiographs?

Answer 1

Images created using x-ray photons

Question 2

How are radiographs produced?

Answer 2

x-ray photons pass through an object and interact with a receptor

Question 3

3 ways x-rays can interact with matter

Answer 3

transmit, absorb, scatter

Question 4

Which interactions cause attenuation (reduce in amplitude) of x-ray photons?

Answer 4

absorption and scattering

Question 5

term referring to darker areas

Answer 5

radiolucent

Question 6

term referring to lighter areas

Answer 6

radiopaque

Question 7

What happens to the x-rays to causes more radiolucent areas?

Answer 7

less attenuation of x-rays (more transmission, less absorption and scattering)

Question 8

What happens to the x-rays to causes more radiopaque areas?

Answer 8

more attenuation of x-rays (less transmission but more absorption and scattering)

Question 9

Materials that are more radiopaque

Answer 9

enamel, dentine, bone, some fillings

Question 10

Why are radiographs useful?

Answer 10

Assess anatomy and pathology of hard tissues not visible to naked eye. Assess caries, bone loss

Question 11

How will caries appear in a radiograph?

Answer 11

more radiolucent compared to rest of tooth (caries decreases radiodensity)

Question 12

Types of intra-oral radiographs

Answer 12

bitewing, periapical, occlusal radiographs

Question 13

Types of extra-oral radiographs

Answer 13

panoramic radiograph, lateral cephalogram

Question 14

Type of cross-sectional radiograph

Answer 14

cone beam computed tomography (CBCT)

Question 15

What does a bitewing show?

Answer 15

View of multiple upper and lower side teeth (premolars and molars). shows crowns, part of roots (not apex), some interdental bone

Question 16

Use of bitewing

Answer 16

shows interdental caries

Question 17

How can you reduce overlap between adjacent teeth in a bitewing?

Answer 17

Take more than one bitewing

Question 18

What does a periapical radiograph show?

Answer 18

Full-length view of a particular tooth/teeth in one dental arch. Shows height of bone support around tooth.

Question 19

Why may the receptor be a different size for anterior and posterior teeth?

Answer 19

Anterior teeth may require a smaller receptor to fit the curvature of the arch

Question 20

What does a panoramic radiograph show?

Answer 20

entire dentition, jaws, mid-face. Can be full or sectional

Question 21

Disadvantage of a panoramic radiograph

Answer 21

worse resolution than intra-oral radiographs

Question 22

What does an occlusal radiograph show?

Answer 22

one dental arch (mandibular or maxillary) that can be seen from different viewpoints

Question 23

Different angles of occlusal radiograph

Answer 23

anterior / lateral and true / oblique

Question 24

What does cone beam computed tomography show?

Answer 24

cross-sectional imaging of the teeth/jaws (3D scan)

Question 25

When is cone beam computed tomography used?

Answer 25

when routine dental imaging cannot provide the required information e.g. implant planning, fractures

Question 26

Disadvantages of cone beam computed tomography

Answer 26

high radiation dose, low resolution, high cost

Question 27

Advantages of a radiographic assessment

Answer 27

visualise caries, reveal RCT, depth of restoration

Question 28

Limitations of a radiographic assessment

Answer 28

superimposition (2 distinct restorations may appear joined, buccal-lingual position of structures unknown.

Question 29

how should you arrange multiple radiographs for viewing?

Answer 29

position radiographs as if you are facing the patient

Question 30

Examples of anatomical features that can indicate which teeth are shown

Answer 30

crown morphology, root morphology, curve of Spee, surrounding non-dental anatomy

Question 31

Aspects of tooth morphology that can identify teeth in radiographs

Answer 31

crown shape, number of cusps, number of roots

Question 32

Which teeth have 1 root?

Answer 32

incisors, canines, some premolars

Question 33

Which teeth have 2 roots?

Answer 33

some premolars, lower molars

Question 34

Which teeth have 3 roots?

Answer 34

upper molars

Question 35

What is the curve of Spee?

Answer 35

Normal anatomical upwards curvature of the occlusal plane posteriorly

Question 36

Examples of non-dental anatomy used to identify maxillary teeth

Answer 36

maxillary sinus, nasal cavity, maxillary tuberosity

Question 37

Examples of non-dental anatomy used to identify mandibular teeth

Answer 37

inferior alveolar canal, mental foramen, inferior border of mandible, external oblique ridge.

Question 38

Location of mental foramen

Answer 38

below mandibular premolars