object localization

what is object localization

approaches for deriving 3D information from 2D images

what are the two different techniques of object localization

• right angle technique

• tube shift technique

what is the right angle technique

ID position of object relative to surrounding anatomic landmarks on both projections

in the right angle technique, the periapical localizes in the

MD and SI dimensions

in the right angle technique, the occlusal localizes in the

MD and BL dimensions

what is the tube shift technique

uses the change in relative positions of two seperate objects that occurs when the image projection angle is changed- beam angulation changes opposite to the direction of the tube movement

what is the SLOB rule

SL: same lingual- lingual objects shift is the same direction as the tubehead

OB: opposite buccal- buccal objects shift opposite direction from the tubehead

if the object does not move w respect to reference object, it lies at the same depth (same vertical plane) as the reference object

where do we expect this object to shift when the tube is moved mesially

mesial

where do we expect this object to shift when the tube is moved mesially

distally

what should you use as a reference to determine the direction of the tube head shift

anatomy

how does distance play a role in the tube shift technique

the farther the object from the reference, the more the object moves

what are steps to take to identify where an object of interest is relative to a reference point

• identify reference structure

• identify tube shift

• identify how object shifted

where is the opaque foreign object relative to #3

object is B to #3

where is the supernumerary tooth A relative to #28

lingual

which RCT of #12 is indicated by the green arrow

buccal

which root of #12 is indicated by the blue arrow

palatal/lingual (L root of #14 is projected closer to the DB root so this means the tube head is also coming from distal→ #13 distal root is the palatal root)

where is the mandibular canal relative to the apices of #17

lingual

is the crown of the supernumerary tooth facial or palatal to the apex

facial