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
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.
9.
10.
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
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
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.
22.
23. LOCALIZES in 3 Dimensions
DISADVANTAGES
Can be used in maxilla but not that useful
like in mandible due to superimpositions