radiographic techniques

Question 1

name 3 types of intra-oral radiographs

Answer 1

-periapical
-bitewing
-occlusal (mandibular and maxillary)

Question 2

where is the receptor placed for intra oral radiographs?

Answer 2

placed within the mouth of the patient

Question 3

name 5 examples of extra oral radiographs

Answer 3

-dpt
-lateral celphalogram
-postero-anterior mandible
-lateral oblique mandible
-occipito-mental views of facial bones

Question 4

where is the receptor found in extra-oral radiographs?

Answer 4

external to the patients body

Question 5

what can be seen in peri-apical radiographs?

Answer 5

from crown to apex of root and in between teeth

Question 6

what can be seen in horizontal bitewing radiographs?

Answer 6

4d-8m
bone levels

Question 7

what can be seen in vertical bitewing radiographs?

Answer 7

more of bone but still NOT entire root

Question 8

what can be seen in occlusal radiographs?

Answer 8

mandibular- FOM and teeth
maxillary- anterior teeth and anterior part of maxillary

Question 9

how is a dpt taken?

Answer 9

the X-ray tube moves round the patients head

Question 10

how long is the exposure of dpt’s?

Answer 10

14 seconds

Question 11

what can be seen on a dpt?

Answer 11

teeth and supporting structures

Question 12

what does a lateral cephalogram radiograph show?

Answer 12

skull

Question 13

what is a lateral cephalogram commonly used for?

Answer 13

orthodontics

Question 14

what can lateral cephalograms show?

Answer 14

relation of teeth to mandible
relation of mandible to rest of facial skeleton

Question 15

what are postero-anterior mandible radiographs used for?

Answer 15

to view mandibular fractures

Question 16

how are posters-anterior mandible radiographs taken?

Answer 16

two images taken at right angles to each other
- as mandibular fractures often occur in more than 1 place

Question 17

when are lateral oblique mandible radiographs taken?

Answer 17

-for children who cannot tolerate bitewing radiographs
-mandibular fractures

Question 18

when would occipito-mental views of facial bones be used?

Answer 18

facial trauma fractures

Question 19

what sort of fractures can be seen on occipito-mental radiographs?

Answer 19

-orbital
-maxillary
-zygomatic arches

Question 20

why are peri-apical radiographs used?

Answer 20

-apical pathology (inflammation, infection, cysts)
-periodontal status
-endodontics
-pre extraction to view roots
-trauma to teeth/bone
-unerupted teeth position
-implants
-apical surgery

Question 21

what are the 2 radiographic intra-oral techniques called?

Answer 21

-paralleling technique
-bisected angle technique

Question 22

describe the paralleling technique?

Answer 22

-accurate geometry of image
-receptor is held in holder
-holder keeps receptor parallel to tooth and beam
-produced accurate and reproducible image
-x-ray beam positioned perpendicular to tooth/receptor

Question 23

what are the negatives to the paralleling technique?

Answer 23

-holders are bulky and may not be tolerated by the patient
-but paralleling prevents repeats and exposure of radiation to finger

Question 24

what is the bisected angle technique?

Answer 24

-no holder used
-operator dependent so image is not reproducible
-receptor held in place by patients finger or lollipop holder (finger exposed to radiation)

Question 25

what is the most commonly used technique for intra-oral radiographs?

Answer 25

the paralleling technique

Question 26

what are the following coloured holders used for? blue yellow red green

Answer 26

blue- anterior PA yellow- posterior PA red- H and V bitewings green-endodontics

Question 27

what type of image receptor is used at DDH?

Answer 27

phosphor plates

Question 28

what does computed radiology receptors mean?

Answer 28

receptor film is processed, erased and reused

Question 29

finish the sentence holders reduce variables in ...

Answer 29

geometry

Question 30

what does the geometry of an image mean?

Answer 30

it means that the image does not change has much when looking at it from a different angle

Question 31

what are 3 variables that affect the geometry of a radiographic image?

Answer 31

-receptor to tooth relationship -perpendicular direction of X-ray to receptor -magnification

Question 32

how should the receptor be in relation to the tooth?

Answer 32

-vertical axis of receptor must be parallel to long axis of the tooth -horizontal axis of receptor must be parallel to dental arch

Question 33

how would wrong position of vertical and horizontal planes of receptor to tooth affect image?

Answer 33

vertical- distort image- elongate or shorten horizontal-overlapping

Question 34

what is magnification of an image affected by?

Answer 34

xray beam to receptor distance tooth to receptor distance

Question 35

what shape is an xray beam?

Answer 35

divergent cone shaped

Question 36

what is the ideal positioning for correct magnification?

Answer 36

long xray beam to receptor distance short receptor to tooth distance

Question 37

when taking an image of posterior teeth what orientation should the film be?

Answer 37

horizontal

Question 37

when taking an image of posterior teeth what orientation should the film be?

Answer 37

horizontal

Question 38

when taking an image of anterior teeth what orientation should the film be?

Answer 38

vertical

Question 39

what is cone cutting?

Answer 39

seen when corners of collimator are not touched the ring slides and they absorb the radiation

Question 40

what are the film sizes used in DDH?

Answer 40

0,1,2 and 4

Question 41

what film size should be used for an adult anterior PA?

Answer 41

0,1

Question 42

what film size should be used for an adult posterior PA?

Answer 42

2

Question 43

what film size should be used adult and children over 10 bitewings?

Answer 43

2

Question 44

what film size should be used for children posterior PA of deciduous teeth and permanent teeth ?

Answer 44

d- 0 p-2

Question 45

what film size should be used for child anterior PA?

Answer 45

0

Question 46

what film size should be used for bitewings for children under 10?

Answer 46

0/1

Question 47

where should the dot on receptor be during PA?

Answer 47

to the crown (bite block)

Question 48

where should the dot on receptor be during bitewings?

Answer 48

to the palate

Question 49

what is the controlled area?

Answer 49

the immediate vicinity around the x ray- must be outside this area to keep personal radiation dose to a minimum