extraoral imaging Flashcards
Panoramic X-ray
the tubehead rotates behind the patient’s head
machine that captures the entire mouth in a single image
- evaluating large areas of the skull
- detecting impacted teeth, eruption patterns, and TMJ problems
what are the downsides of a panoramic x-ray?
usually not clear and detailed enough to assess caries and periodontal diseases
Focal trough
horseshoe-shaped narrow curved space where the structure is captured
objects inside the focal trough are?
clear
objects outside the focal trough are?
blurred
Collimator
a lead plate with a narrow vertical opening
panoramic x-ray
what can the clinician control?
the milliamperage and kilovoltage from the exposure setting
Can the exposure time be changed?
No
T/F: for x-rays, all objects should be removed from the mouth
including eyewear, earrings, nose rings, and other jewelry
dentures, retainers, tongue ring, etc
True
what should be worn to protect the patient’s back and shoulder?
a lead apron (without a thyroid collar)
to be worn like a poncho
wearing a thyroid collar would result in a shark’s fin artifact
which position of the machine is used to achieve the ideal position?
head position (consists of chin rest, notched bite-block, forehead rest, and lateral head support)
Frankfort plane
line from the bottom of the orbit to the top of the auditory meatus
Frankfort plane should be — to the floor
parallel
the patient should look forward and tip their chin?
slightly down (towards the floor)
this elevates the posterior palate so that it doesn’t overlap with the apices of the maxillary teeth
The midsaggital plane should be — to the floor
perpendicular
right before the exposure, the patient should swallow and — ?
lift the tip of the tongue up to the roof of the mouth
failure in lifting the tip of the tongue up to the roof of the mouth results in?
shadows over the maxillary teeth
shark’s fin error
lead collar above line
fix by lowering collar position
an exaggerated smile means?
patient’s chin is tipped too far down
fix by repositioning the chin
a flat or reversed smile means?
patient’s chin is tipped too far up
fix by repositioning the chin
if the Maxillary incisors’ roots are blurred?
the chin is tipped too far up
if one side of the x-ray shows larger teeth/condyle?
the patient’s head is twisted
reposition the head, midsagittal plane perpendicular to the floor (the larger side is the distant side)
Washington monument error
a white straight opacity in the middle of the image due to slumping caused ghost image of the spine
move patient’s feet forward, straighten the spine and lean backward
Air space error
Airway shadow in an arch shapeover maxillary teeth due to tongue not touching the roof of the mouth
have the patient swallow and reposition the tongue