Veterinary dental radiology Flashcards
dental findings
missing dentition, fractured teeth, abnormal periodontal pocket, evaluation of tooth viability, resorptive lesions, oral masses, draining tracts, nasal discharge
radiation safety
gown, gloves, thyroid shield, eye protection, x-ray badge, 6 ft distance from beam
radiology equipment
x-ray machine, tube, tubehead, machine setting, dial, angle adjustment, digital sensor, plate, film, positioning device, gauze, towels
parallel technique
sensor, tooth root and tube are parallel
used for mandibular premolars and molars
bisecting angle technique
used when you can’t lay film parallel to the tooth root
tooth root angle= root plane
plate parallel to the hard palette
bisecting angle is midway between the root plane and the plate plane
tube head at 90 degrees to bisecting angle
proper film placement
place the film as near as possible to the teeth and oral mucosa to minimize distortion
large teeth: expose in 2 images (crown and root)
foreshortening
troubleshooting
tube head too perpendicular to film/sensor which creates shorter roots
decrease angle to correct
elongation
troubleshooting
tube head too parallel to film/sensor which creates longer roots
increase angle to correct
can be used in feline mandibular premolars and molars to throw zygomatic arch out of the way
horizontal elongation: tube head is rotated > 30 degrees horizontally
under exposure
troubleshooting
if image is too light increase kVp to increase exposure
over exposure
troubleshooting
if image is too dark decrease kVp to decrease exposure
what is the best way to remember how radiograph over and under exposures look like?
it’s like toast
if the toast is too light you put it in longer
if the toast is too dark (burnt) you wouldn’t put it in the toaster as long
missing intended structure
troubleshooting
if tooth/area of interest is not on the image, the sensor/film is not in the right position
film/sensor should be moved in the direction of the missing area
common when imaging large breeds with size 2 sensor
not all teeth of large breeds can be imaged on 1 view
cone cut
troubleshooting
occurs when the tube head is not placed in the correct position to expose entire film/sensor resulting in a white area on the image
brachycephalic
troubleshooting
none of the teeth are where they should be
often need to turn plates at different angles
using bisecting angles helps
often have less teeth
zygomatic arch is in the way
dolichocephalic
troubleshooting
longer skull
large roots
multiple images needed for 1 tooth
zygomatic arch usually not an issue
landmarks are different
canine maxillary: incisors
use bisecting angle
position tube: 60-65 degrees
canine maxillary: canines
use bisecting angle
position tube: 45 degrees
considered a lateral oblique image
canine maxillary: premolars
use bisecting angle
position tube: 45 degrees
canine maxillary: premolars/molars
use bisecting angle to image the 4th premolar and molars
position tube: 45 degrees
canine mandibular: incisors
use bisecting angle
position tube: 60-65 degrees
canine mandibular: canines
use bisecting angle
position tube: 60-65 degrees
incisors can also be demonstrated
canine mandibular: premolars
use bisecting angle
position tube: 45 degrees
canine mandibular: molars
use parallel technique
position tube: 90 degrees
feline maxillary: incisors
use bisecting angle
position tube: 60-65 degrees
feline maxillary: canines
use bisecting angle
position tube: 45-60 degrees
considered lateral oblique technique
feline maxillary: premolars/molars
use bisecting angle
position tube: 45 degrees
take zygomatic arch into consideration
extra maxillary (extraoral) image in cats
position tube: 35-60 degrees to sensor
use shoot through technique to take image of the opposite side
reduces zygomatic arch blocking image
how to take an extra maxillary image
- place film/sensor on table and patient’s head on sensor with dental arch to be imaged down
- place a radiolucent mouth gag (optional) to gently hold jaws apart
- beam is angled through the mouth to create a bisecting angle which is approximately 30 degrees
near parallel technique
lateral recumbency with target teeth up
sensor/film is placed across the mouth
beam is positioned almost parallel to the sensor
feline mandibular: incisors
use bisecting angle
position tube: 60-65 degrees
feline mandibular: canines
use bisecting angle
position tube: 60-65 degrees
typically included in incisor view
feline mandibular: premolar
use bisecting angle to obtain 3rd premolar
position tube: 45 degrees
great technique to use to isolate 304 and 404
feline mandibular: molars
use parallel technique to obtain 4th premolar and molars
easiest shot
