Figure 1-16.Film and cylinder placement: maxillary bicuspid area.
6. Make the exposure.
VARIATION TO THE EXPOSURE
FACTORS AND FILM ALIGNMENT
Some variations to the exposure factors and film
alignment may be necessary for a specific area of the
The dentist may request a radiograph of an
impacted third molar. If so, you would prepare the
paralleling device in the usual manner, placing the film
packet off center in the backing support so the film
extends posteriorly to cover the entire third molar area.
When you place the paralleling device in the patient's
mouth, position it so the anterior edge of the film
includes the distal half of the first molar.
Use special film placement procedures when a
patient has a low palatal vault or edentulous arches.
Place one cotton roll on each side of the bite-block as
shown in figure 1-22. This ensures that the X-ray film
will be parallel with the long axis of the teeth being
Use the bisecting-angle technique when
paralleling devices are not available; or when a
patient finds it painful or impossible to close on the
bite-block; or when an X-ray is needed when a rubber
dam is in place. This technique incorporates the use of
a tube head with an X-ray source to cylinder end
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