This document discusses techniques for localizing foreign objects or impacted teeth in 3 dimensions using dental radiographs. The Clark technique uses two radiographs taken from different angles based on the principle of parallax to determine if an object is positioned lingually or buccally. The right angle technique uses a periapical view and occlusal view taken at right angles to locate an object in three planes. Radiopaque wire techniques can be used when teeth are missing to localize objects by placing wires of different shapes in wax molded over the edentulous area. These techniques help locate foreign materials, salivary gland stones, canal positions and more in 3 dimensions.

1. OBJECT
LOCALISATION

2. ~ It is used for the localization of foreign object or an
impacted tooth with in jaw.
~ Dental radiograph is a two dimentional image, that
gives orientation of image in either IOPA view
(superoinferior or anteroposterior direction) or
OCCLUSAL view (buccolingual direction).
~ Sometimes, it become necessary to determine the
three-dimentional position of object.

3. INDICATIONS
 Foreign objects
 Salivary gland stones
 Canal position
 Impacted/Unerupted teeth
 Root piece
 Filling material in alveolar process
 Broken needle
 Superimposition

4. Buccal Object Rule
• Discovered by Richard in 1952
• The relative position of radiographic
images of two separate objects changes
when the projection angle at which images
were made is changed

6. TECHNIQUES
 Clark technique
 Right angle technique
 Radiopaque wire technique

7. CLARK Technique
• By C.A. Clark in 1910
• Tube shift cone technique or SLOB (same
lingual opposite buccal).
• It is based on the principle of Parallax-
When an object is viewed from two different
positions,the object appears to move in
different directions.

8. • To determine the relative buccolingual
relationship between two structures that
appear radiographically superimposed , a
second radiograph is taken with a different
horizontal angulation(or a horizontal tube
shift).
All factors remain same for second
exposure, except that the tube is shifted
about 20 degree either mesially or distally.

11. Two periapical radiograph are taken of the
same area , with the horizontal angulation of
tube when the second film is taken.
If the object in question moves in Same
direction as the cone, it is Lingually
positioned.
If the object moves in the Opposite direction
, it is situated closer to the source of
radiation and is therefore Buccally positioned.
This relationship can be summed up with the
word SLOB ~ Same- lingual Opposite- buccal

14. Lingual body moves in
same direction

16. Buccal body moves in
opposite direction

17. • This technique is more useful in the
mandibular region because in mandibular
region cross sectional view is possible.
• While in maxillary region x-ray beam has
to pass through various parts of facial
bones this will results in superimposition of
images.

18. • This technique employs two projections of
the same object taken at right angles
(perpendicular) to each other.
• One of the standard intraoral radiograph is
taken along with an occlusal radiograph
• Periapical radiograph shows the object in
inferior/superior and anterior/posterior
direction
• Occlusal radiograph shows the
facial/lingual and anterior/posterior
position

19. Object seen in
periapical
radiograph
Periapical
radiograph showing
impacted canine

20. Occlusal radiograph
showing object on
lingual side
Occlusal view
taken at right
angle showing
impacted canine is
lingually positioned

21. Radiopaque Wires technique
• This technique is used in case of
edentulous region.
• When the teeth are not present,
radiopaque wires of different shape are
placed in sheet of wax that is molded over
the edentulous area as denture base.
• Other principles are same as that used in
SLOB technique.

23. LOCALIZES in 3 Dimensions
DISADVANTAGES
Can be used in maxilla but not that useful
like in mandible due to superimpositions

24. FISS
URE BUR

25. FOREIGN BODY

26. WATER VIEW LATERAL VIEW

27. INTRA OSSEOUSTUMOURS
Occlusal
view
Lateral view

28. Lateral
oblique
Occlusal view