Radiographic Localisation Flashcards
Why is radiographic localisation needed?
To determine location of a structure or pathological lesion in relation to other structures
Only needed where clinical examination is insufficient to provide answer
In which clinical situations is radiographic localisation most used?
Find position of unerupted teeth
Locate roots/root canals
Relationship of pathological lesions
Trauma eg - bone fractures
Soft tissue swellings
What are the steps of radiographic localisation?
Observation - look and see
Interpretation - listen and think
Management - patient’s needs
How should radiographs be observed?
Look carefully and consider:
Technical acceptability
Abnormalities
Need for further radiography
What is radiographic localisation?
Using two radiographically views at right angles in their projection geometry
What is parallax?
An apparent change in the position of an object, caused by a real change in the position of the observer
Which radiographic views can be used at right angles to each other for radiographic localisation?
Panoramic and lower true occlusal
Paralleling periapical and lower true occlusal
Cone beam CT - each of the views are at right angles to the others
What mnemonics can be used for parallax?
Same
Lingual
Opposite
Buccal
or
PAL - my pal (palatal) goes with me
What is the sequence of events in parallax?
Identify the direction of tube movement
What do we need to know the location of
Choose a reference point
Observe movement of the point in comparison to the movement of the tube
Which horizontal tube shift views can be used for parallax?
2 periapicals
2 bitewings
2 oblique occlusals
Which vertical tube shift views can be used for parallax?
Panoramic and oblique occlusal
Panoramic and lower (bisecting angle) periapical
