analysis of errors

Question 1

artifact

Answer 1

something weird on plate

Question 2

exposed backwards

Answer 2

improper plate placement in RINN instrument

Question 3

cone cut

Answer 3

failure to center beam to completely cover the image receptor in a partial image
-improper assembly–biteblock should be centered within the ring

Question 4

displayed incorrectly

Answer 4

caused by mismounting images–common in maxillary and mandibular canine shots

Question 5

foreign object

Answer 5

like glasses, earrings, etc

Question 6

horizontal angulation error

Answer 6

caused by improper horizontal angulation of cone and/or image receptor placement

• horizontal angulation of beam should be directed through the contacts of the teeth and perpendicular to the image receptor
• should be parallel to lingual surfaces of teeth

Question 7

how would you eval the distal of canine?

Answer 7

• premolar BW

- premolar PA

Question 8

PSP bending during image acquistion

Answer 8

causes image lengthening and distortion

Question 9

movement

Answer 9

movement of image receptor, patient or tubehead during exposure causes a blurred image

Question 10

noisy image

Answer 10

uneven density in a uniformly exposed radiograph

caused by: inadequate exposure, PSP exposure to visible light, post processing errors, artifacts on PSP plate

Question 11

patient open

Answer 11

-incisal edges or occlusal surfaces MUST be touching biteblock

Question 12

where do you place the biteblock?

Answer 12

cotton roll must be placed between the biteblock and the arch you are NOT imaging or else your apices will be cut off

Question 13

image receptor should be where to get an image of the posterior maxilla in the paralleling technique?

Answer 13

at or across midline

Question 14

vertical angulation error

Answer 14

• leads to foreshortening and elongation

- improper vertical alignment of cone or improper image receptor placement

Question 15

how is the paralleling technique used to minimize distortion?

Answer 15

1. position the image receptor parallel to long axis of teeth
2. orient central ray of beam perpendicular to teeth and image receptor

Question 16

to achieve parallel orientation between the image receptor and the teeth in the maxilla, often the image receptor must be positioned ___?

Answer 16

toward the middle of the oral cavity

Question 17

foreshortening

Answer 17

incorrect image receptor placement (image receptor not positioned parallel to the long axis of teeth)

Question 18

how can you tell if there is foreshortening present on posterior periapical radiographs?

Answer 18

compare PA to BW

Question 19

insufficient vertical angulation leads to—

Answer 19

elongation

when beam is aligned perpendicular to the long axis of the tooth but not to image receptor