L1. Introduction to Dental Radiology

Question 1

What are the three principles of radiation protection?

Answer 1

• Justification;
• Optimisation (ALARA or ALARP);
• Dose limitation.

Question 2

Explain the basic process of creating an X-ray:

Answer 2

• Creation of X-rays;
• X-rays directed at patient;
• Interaction between tissues;
• Capture of interaction.

Question 3

What is the latent image?

Answer 3

An X-ray image not yet visible, must be processed (chemically or digitally)

Question 4

Why is it so important that warning signals are relayed when X-rays are produced?

Answer 4

• X-rays dangerous to the body;

- They are not perceptible to the body (i.e. we cannot see/ hear/ smell/ taste them).

Question 5

What are the three main interaction classes of X-rays with matter? Provide examples.

Answer 5

• No effect (e.g. air);
• Complete absorption (e.g. metals);
• Absorption and scatter [partial absorption] (e.g. soft tissues).

Question 6

What is a radiographic image?

Answer 6

• A pictorial representation of a part of the body;

- A record of the pattern of attenuation of the X-ray beam after it has passed through matter.

Question 7

What are the three main types of intra-oral radiographic views?

Answer 7

• Bitewings;
• Periapicals;
• Occlusals.

Question 8

What are the two main types of extra-oral radiographic images?

Answer 8

• Panoramic (DPT/DPR/OPT);

- Cephalometric.

Question 9

What (where) do bitewing radiographs show?

Answer 9

Side teeth (premolars and molars)

Question 10

What are bitewing radiographs used to demonstrate?

Answer 10

• Upper and lower crowns of one side;
• Mesial first premolar contact to most distal contact point or surface;
• Enamel-dentine junction;
• Coronal pulp morphology;
• Interdental bone.

Question 11

What pathologies are bitewing radiographs typically used to see?

Answer 11

• (Inter)proximal caries;
• Cervical caries;
• Occlusal, buccal and lingual caries;
• Restorations: ledges and defects;
• Interdental bone changes.

Question 12

What (where) do periapical radiographs show?

Answer 12

Full length of at least one tooth

Question 13

What pathologies are periapical radiographs typically used to see?

Answer 13

• Crown: caries, trauma, other non-carious tooth surface loss;
• Changes related to restorations;
• Pulpal pathology;
• Root;
• Supporting bone.

Question 14

What are the two kinds of occlusal radiographs and what (where) do they show?

Answer 14

• Oblique: similar to periapical but larger area;

- Cross-sectional: to show section of jaw or floor of mouth.

Question 15

What (where) do panoramic radiographs show?

Answer 15

Full view of dentition

Question 16

What are panoramic radiographs typically used for?

Answer 16

• Orthodontic planning;

- Viewing impacted wisdom teeth.

Question 17

What (where) do cephalometric radiographs show?

Answer 17

View of facial bones to enable dental and skeletal relationships

(primarily the hard tissues but show some soft too)