2 Radiographic techniques (1)

Question 1

what are the 3 main intra-oral techniques

Answer 1

• periapical
• bitewing - horizontal/vertical
• occlusal - maxilla/mandible

Question 2

what are the 5 main extra-oral radiographs?

Answer 2

• Dental panoramic tomograph (DPT)
• Lateral cephalogram
• Postero-anterior mandible
• Lateral oblique mandible
• Occipito-mental views of facial bones

Question 3

what are the main indications for a periapical radiograph?

Answer 3

• detect apical inflammation/infection to include cystic changes
• assess periodontal problems
• trauma - fractures to tooth and associated alveolar bone
• tooth morphology pre extraction
• presence/position of unerupted teeth
• endodontics
• evaluation of implants
• ore/post apical surgery

Question 4

what are the 2 intra-oral radiograph techniques? (describe briefly)

Answer 4

• paralleling technique
  (receptor places in a holder and positioned parallel to the long axis of the tooth - in the mouth
• bisected angle technique
  (can be done without a holder, operator dependant, receptor is placed as close to possible to tooth, angle formed is assessed and mentally bisected, x-ray beam aimed at a right angle to the bisected line)

Question 5

In what scenario would the bisected angle technique be used?

Answer 5

if a patient cannot tolerate the holder

Question 6

What is the advantage to the paralleling technique to the bisected angle technique?

Answer 6

The paralleling technique uses a holder to facilitate positioning - so it produces an accurate and reproducible image. This also reduces dose to patient as repeats are reduced
Whereas, the bisected angle technique is operator dependant, therefore not reproducible.

Question 7

What is a blue holder used for?

Answer 7

Blue = anterior teeth

Question 8

What is a yellow holder used for?

Answer 8

Yellow = posterior teeth

Question 9

What is a red holder used for?

Answer 9

Bitewings

Question 10

What is a green holder used for?

Answer 10

Endodontic procedures

Question 11

What do holders consist of?

Answer 11

A bite block - retains receptor
An indicator arm/rod - fits into bite block
An aiming ring - slides onto the arm to establish alignment of collimator with receptor

Question 12

What are the 2 main types of image receptors?

Answer 12

Radiographic film
Digital receptors

Question 13

What are the types of digital receptos?

Answer 13

• solid-state sensors
• phosphor plates

Question 14

what are the types of radiographic film?

Answer 14

• direct action or packet film
• indirect action film used in conjunction with intensifying screens in a cassette

Question 15

what does using a holder allow for?

Answer 15

allows accurate geometry of an image

Question 16

what is the ideal tooth to receptor relationship in the paralleling technique?

Answer 16

tooth and receptor should be parallel
should be as close as possible

Question 17

what position should the x-ray beam be in relation to the tooth/receptor

Answer 17

at a right angle/perpedicular

Question 18

how will the image appear if there is an upwards angulation of the x-ray beam?

Answer 18

elongated

Question 19

how will the image appear if there is a downwards angulation of the x-ray beam?

Answer 19

fore-shortened

Question 20

what is the end of the x-ray tube called

Answer 20

a collimator

Question 21

how should the collimator and the aiming tube of the holder touch

Answer 21

all 4 corners of the collimator touching the aiming ring

Question 22

what 2 factors affect the image size (magnification)?

Answer 22

• x-ray source to receptor distance
• receptor to object (tooth) distance

Question 23

why should the x-ray beam be further away from the object?

Answer 23

the beam diverges less - more accurate depiction of the image

Question 24

what is the solution for keeping the posterior teeth and receptor parallel if the dentition is arched?

Answer 24

taking 2 separate images (molars and pre-molars)

Question 25

what teeth should the receptor cover for a posterior bite-wing?

Answer 25

the anterior edge of the receptor should be positioned opposite the distal edge of the 3 (mesial edge of 4) the posterior edge of the receptor extends usually just beyond the mesial aspect of the 8s

Question 26

what are the main indications for bite-wing radiographs?

Answer 26

- detection of lesions of caries - monitoring progression of caries - assessment of existing restorations - assessment of the periodontal status

Question 27

what size receptor size should be used for a adult anterior periapical radiograph, using the bisecting angle technique?

Answer 27

size 2

Question 28

What size receptor may be used for an adult anterior periapical radiograph?

Answer 28

size 0 or 1

Question 29

What size receptor should be used for an adult posterior periapical radiograph?

Answer 29

size 2

Question 30

What size receptor should be used for a a deciduous/primary anterior periapical radiograph?

Answer 30

size 0

Question 31

What size receptor should be used for a a deciduous/primary posterior periapical radiograph?

Answer 31

0

Question 32

For both horizontal and vertical bitewings, what size should be used for permanent teeth?

Answer 32

size 2

Question 33

For both horizontal and vertical bitewings, what size should be used for deciduous teeth?

Answer 33

size 0

Question 34

what is the controlled area?

Answer 34

the immediate vecinity around the x-ray source (1.5-2m) only patient should be in the controlled area when image is taken - carer if necessary