Radiographic Localisation

Question 1

What is radiographic localisation?

Answer 1

Determination of the location of a structure or pathological lesion in relation to other structures, when clinical examination does not suffice

Question 2

What situations may radiographic localisation need be done?

Answer 2

Determine position of unerupted teeth

Determine position and location of root canals for endodontic treatment

View trauma to soft or hard tissues that cannot be seen clinically

To view relationship of pathological lesions

Question 3

What considerations should be made with regards to this radiograph? What else should be done?

Answer 3

Is it technically acceptable

Any abnormalities ? (Position of 8)

What can be done is take a radiograph at a right angle to this view so we know which direction the 8 is facing

Question 4

What are two examples of radiographs and their right angled partners?

Answer 4

Periapical and lower/upper true occlusal

OPT and lower true occlusal

Question 5

When can one not use a right angled image?

Answer 5

When the projection angles are KNOWN

Both radiographs must include a localised and stable reference point

Question 6

What is parallax?

Answer 6

Apparent change in position of object due to change in position of observer

Question 7

How does horizontal tube shift work in radiographic localisation?

Answer 7

S ame
L ingual
O pposite
B uccal

If object is lingual to the tooth, it will move in the same position as the tubehead

If object is buccal to tooth, it will move in the opposite side to the tubehead

Use a reference point for this