7 - Dental Radiography Techniques

Question 1

why take bitewings?

Answer 1

• detect caries
• monitor lesion progress
• assess periodontal status
• assess existing restorations

Question 2

horizontal & vertical bitewings: which factors do they differ in?

Answer 2

• long axis of film
• how many on each side?
• demonstrates which teeth?
• demonstrates which part of the teeth?

Question 3

horizontal & vertical bitewings - describe the differences:
1 long axis of film
2 how many on each side?
3 demonstrates which teeth?
4 demonstrates which part of the teeth?

Answer 3

1) horizontal: long axis of film horizontal
vertical: long axis of film vertical

2) horizontal: one on each side
vertical: 2 on each side

3) horizontal: demonstrates distal 4 to mesial 8
vertical: demosntrates premolars and molars

4) horizontal: demonstrates crowns and 1/3 roots
vertical: demonstrates more of the roots

Question 4

holder types: rigid plastic v.s. paper tab?

Answer 4

rigid plastic: holds film accurately, assists x-ray tube positioning, but is uncomfortable

paper tab: comfortable, but x-ray tube is positioned by eye and can be inaccurate

Question 5

horizontal overlap:

• occurs due to?
• how much is acceptable?
• what will be missed?
• what must be shown on the radiograph?

Answer 5

• occurs due to crowding or tilted teeth
• acceptable if less than hald of enamel superimposed
• will miss early carious lesions
• must show enamel-dentinal junction & dentinal half of enamel

Question 6

bitewings: where does the dot go?

Answer 6

always towards the palate

Question 7

collimation: what benefit does the use of rectangular collimation bring?

Answer 7

it reduces the dose to the patient by up to 50%

Question 8

describe grade 1/2/3 radiographs

Answer 8

1: good diagnostic image, no faults
2: diagnostic image, some minor faults e.g. small overlap/collimation. still gives some info.
3: undiagnostic image. may need to be repeated -> increased dose for patient.

Question 9

positioning requirements?

Answer 9

1. film and object parallel
2. film close to object
3. x-ray beam perpendicular to object and film