principle which states that two triangles are equal if they have two equal
angles and they share a common side is called: rule of isometry
geometry the side of a right triangle opposite the right angle is called: hypotenuse
- Where is
the film placed in relation to the tooth when performing bisecting angle
Along the lingual
surface of the tooth
- List two
ways to stabilize the film during bisecting angle radiography?
- Film holder
- Finger holding method
reasons why the digital method of film stabilization is least desirable?
1. Unnecessary radiation of patient’s/client’s hand
2. Patient/client may use excessive force to stabilize the film, causing
it to bend and distort the image
3. Patient/client may allow film to slip from its original position,
resulting in inadequate exposure of the area
4. Dental radiographer may align PID incorrectly, due to a lack of a film
holder, causing partial image or cone-cut
- How is
the vertical angulation different when using the bisecting angle technique
compared with paralleling technique?
technique, vertical angulation is directed perpendicular to the film,
whereas with bisecting technique, vertical angulation is directed
perpendicular to the imaginary bisector.
the proper direction of the central ray in the bisecting technique?
angulation of the central beam is directed perpendicular to the imaginary
- Horizontal angulation is directed through the contact areas between the
- X-ray beam has to be centered directly towards the film, to avoid
the distance between the film and tooth in the bisecting technique?
- Film must be
placed against the lingual surfaces of the tooth
- Occlusal end of the film must extend 1/8 of an inch beyond incisal edge
or occlusal surfaces
- The apical end must rest against the palatal or alveolar tissues
- What is
the result when using excessive vertical angulation with bisecting angle
the image results from excessive vertical angulation.
- What is
the result when using insufficient vertical angulation with bisecting
Elongation of the
image results from insufficient vertical angulation
the film placement for bisecting angle radiography with anterior teeth?
images are required for anterior section of the teeth, 4 for maxillary and
3 for mandibular teeth. Film with size No.1 is used. Procedure has to
begin from maxillary left side to maxillary right side, then down to
mandibular right side and finish with mandibular left side. Sequence for
1. Maxillary left canine
2. Maxillary left central and lateral incisor
3. Maxillary right central and lateral incisor
4. Maxillary right canine
5. Mandibular right canine
6. Mandibular incisors
7. Mandibular left canine
- List five
guidelines for film placement when using bisecting angle technique?
1. White side of
the film always faces the teeth
2. Anterior films are always placed vertically
3. Posterior films are always placed horizontally
4. Incisal or occlusal edge of the film has to be 1/8 of an inch extended
beyond incisal edge or occlusal surfaces of the teeth.
- What is
the major advantage of using bisecting angle radiography?
It can be used
without film holder when the anatomy of the patient precludes the use of a
- What are
some disadvantages of using bisecting angle radiography?
1. Image distortion
2. Angulation problems
3. Unnecessary exposure
- What is
the position of the identification dot when bisecting angle radiography?
incisal edge or occlusal surfaces of the tooth.
size film is used most often when performing bisecting angle radiography
on an adult?
film No.1, for posteriors film No.2
- What is
the direction of the central ray when using bisecting angle technique?
Central ray has
to be positioned centrally to the examined area so the film is positioned
in the middle of the central ray. Central ray has to be parallel to the imaginary
technique is preferred for exposure of periapical films?
technique is preferred to the bisecting technique for exposure of
periapical films and should be used whenever possible.