March 3- Object Localization Final Flashcards
Why is object localization important?
- Situations in which 3 dimensional information is required from a 2
dimensional radiograph
- Foreign objects or impacted teeth, retained roots, filling materials can be localiZed.
- CBCT often now used.
What are the 3 techniques used for object localization?
1) Right-angle technique
2) Tube shift method
3) Buccal object rule
How does the Right Angle Technique work?
2 images are taken at right angles from each other in order to localize an object on the radiographs.
What is the tube shift technique used for?
How is it done?
Determines buccal-lingual relationships of:
- Foreign radiopaque objects n Impacted teeth
- Unerupted teeth
2 images must be taken; the X-ray tube shifts horizontally (mesially or distally) between the 2 exposures
How is the tube method interpreted to localize an image?
If the foreign body moves in the same direction as the x-ray tube head when compared to a reference point, the object is located on the lingual aspect of the jaw
If the foreign body moves in the opposite direction as the x-ray tube head when compared to a reference point, it is located on the buccal aspect of the jaw
Where is this restoration located? Buccal or Lingual?
Because the restoration moves OPPOSITE from the shift in the BID the restoration is BUCCAL
Where is the abscess of 3.4 located? Buccal or Lingual?
this one appears to be lingual? because when the tube head is shifted the image moves in the SAME direction
What is the Buccal Object rule?
When two different radiographs are made of a pair of objects, the image of the most buccal object moves, relative to the lingual object, in the same direction that the x-ray beam (BID) is directed.
How is the buccal-object rule used to locate an object?
When locating vertically aligned images such as root canals, change the horizontal (ie. left to right) angulation of the x-ray beam/BID.
When locating horizontally aligned images such as the mandibular canal change the vertical (ie. up and down) angulation of the BID.
Using the buccal-object rule, if the triangle and the circle are superimposed and both are located above the palatal root of the second molar what will happen to the circle if the beam is moved distally?
Here, the tubehead is moved distally and the beam is directed mesially. On the radiograph, the distal buccal object (yellow circle) moves mesially (opposite to tubehead movement) in relation to the second molar and the lingual object (red triangle) moves distally (same direction as tubehead) in relation to the second molar.
Which root is the arrow pointing at? the buccal or lingual?
lingual.
