CHAPTER 18: BISECTING TECHNIQUE Flashcards
To divide into two equal parts
bisect
this technique is based on two triangles are equal if the triangles have two equal angles and share a common side
bisecting technique
In the bisecting technique the receptor must be placed along the _____ surface of the tooth
lingual
a plane that divides in half, or bisects, the angle formed by the receptor and the long axis of the tooth. This plane is termed the
imaginary bisector
the central ray is directed at an angle of _____ degrees to the imaginary bisector, two imaginary equal triangles are formed.
90
When the rule of isometry is followed strictly, the image of the tooth will be accurate. TRUE OR FALSE
true
In dental imaging, _____images occur when the beam angulation is too flat
longer
Shorter images occur when the beam angulation is too ______
steep
used to position an intraoral receptor in the mouth and maintain it in position during exposure
beam alignment devices
can be added to the plastic aiming rings to reduce the radiation received by the patient
snap-on-ring collimators
designed to aid in the determination of horizontal and vertical angulations, prevent cone-cuts, and minimize distortion from receptor bending
Rin BAI system
used to position the receptor in the mouth and maintain it in position during exposure.
Receptor holding devices
examples of receptor holders include
stabe bite block
rinn snap a ray holder
(reusable and must be sterilized after each use)
what size is used for all periapical projections with the bisecting technique.
size 2 intraoral receptor
a term used to describe the alignment of the central ray of the x-ray beam in horizontal and vertical planes.
angulation
refers to the positioning of the PID and the direction of the central ray in a horizontal, or side-to-side, plane
horizontal angulation
With correct horizontal angulation, the central ray is directed _______ to the curvature of the arch and through the contact areas of the teeth. As a result, the contact areas on the dental image appear “opened.”
perpendicular
Incorrect horizontal angulation results in _______ contact areas
overlapped (unopened)
refers to the positioning of the PID in a up-and-down, plane
Vertical angulation
With the bite-wing technique using tabs, the vertical angulation is predetermined; the central ray is directed at ___ degrees to the occlusal plane
+10
Correct vertical angulation results in a dental image that is _______________________
the same length as the tooth
results from excessive vertical angulation.
foreshortening
When the vertical angulation is too steep, the image of the tooth appears what ?
shorter than the actual tooth
________ refer to images of the teeth that appear too long. Results from insufficient vertical angulation
Elongation
When the vertical angulation is too flat, the image of the tooth appears what?
longer than the actual tooth
5 rules for bisecting technique
- RECEPTOR PLACEMENT
- RECEPTOR POSITION - Must be placed against the lingual surface of the tooth
- VERTICAL ANGULATION - central ray of xray beam must be perpendicular to the IMAGNINARY sector.
- HORIZONTAL ANGULATION- central ray must be directed through contact areas between teeth
- Receptor Exposure- xray beam centered on the receptor.
When using the bisecting technique, an __________ or definite order for periapical receptor placements and exposures, must be followed
exposure sequence
the specific area where the receptor must be positioned before exposure, is dictated by the teeth and surrounding structures that must be included on the resultant dental image.
receptor placement
advantages of bisecting technique
can be used without a beam alignment device
decreased exposure time
disadvantages of bisecting technique
image distortion
angulation problems
• The bisecting technique is an intraoral technique used to expose ________ images. This technique is based on the concept of bisecting the angle formed by the receptor and the ___ _____ of the tooth.
periapical
long axis
(1) the receptor is placed along the ____ surface of the tooth;
(2) at the point where the receptor contacts the tooth, the __________and the _________ of the tooth form an angle
(3) an imaginary bisector divides the angle in half, or _____ it; and
(4) the central ray of the x-ray beam is directed _______to the imaginary bisector.
lingual
plane of the receptor/ long axis
bisects
perpendicular
is a shorter or longer PID recommended for bisecting technique?
shorter PID
