Where is the receptor placed for the bisecting technique?
Close to the tooth on the lingual surface; forming an angle.
How is the imaginary bisector created for the radiographer?
By dividing the angle formed by the receptor and long axis of the tooth in half to give a plane to direct the central rays perpendicular to.
What does the imaginary bisector bisect?
The angle formed by the receptor and the long axis of the tooth.
How is the central ray directed to the imaginary bisector?
Perpendicular
What does the imaginary bisector create?
Two right, congruent triangles.
What are two advantages to using the bisecting technique?
- More comfortable for the patient.
2. No anatomical restrictions
What are 4 anatomical situations that may require the use of the bisecting angle technique.
- A shallow palate
- A large palatal torus
- Shallow or tender floor of the mouth
- A short lingual frenum (tongue-tied)
What are two disadvantages to the bisecting angle technique?
- More distortion; not parallel (apecies mesh with other structures)
- X-Ray beam position; difficult to visualize
What are the five steps to the bisecting technique?
- Receptor placement (make sure you have the teeth you need)
- Receptor placement (close to tooth/teeth)
- Vertical angulation (perpendicular to the imaginary bisector)
- Horizontal angulation
- PID (make sure it covers the receptor)
What occurs if the vertical angulation is off?
Foreshortened images = too steep
Elongation images = too shallow
What happens if horizontal angulation is off?
overlapping in contact areas or cone cuts.
What happens to the dental image hen a short(8-in) PID is used?
Magnification results
Which size receptor is used with the bisecting technique?
Size 2
Which beam alignment deice is recommended for use with the bisecting technique because it aids in the alignment of the PID and reduces patient exposure?
Rinn BAI instruments (we use snap a ray)
How is the patient’s head positioned before exposing mandibular periapicals with the bisecting technique?
Mandibular arch parallel to the floor; midsagittal plane perpendicular to the floor.
