Localisation

Question 1

When is localisation required?

Answer 1

Identify the position of unerupted teeth
Location of roots/ canals
Relationship of pathological lesions
Trauma
Soft tissue swellings - identifying the source

Question 2

What is the parallax mnemonic?

Answer 2

PAL
My pal goes with me (moves in the same direction if palatal)

Question 3

What are the options for parallax localisation?

Answer 3

Horizontal tube shift:
- 2 periapicals
- 2 bitewings
- 2 oblique occlusal

Vertical tube shift:
- panoramic and oblique occlusal
- panoramic and lower (bisecting angle) periapical

Question 4

How to carry out parallax?

Answer 4

Ensure radiographs are arranged correctly (identify direction of tube shift)
Pick reference point
Observe movement (my pal goes with me)

Question 5

If tooth stays in the same position in both radiographs, what does this suggest?

Answer 5

Tooth is in line of arch