Figure 1-17.Film and cylinder placement: maxillary molar area.
distance of 8 inches (short cone). The bisecting-angle
technique is not recommended for routine use.
Since paralleling devices are not used with the
bisecting-angle technique, you must pay special
attention to positioning the patient, the film packet, and
the tube head.
Positioning the Patient
For all maxillary periapical radiographs, position
the patient's head as shown in figure 1-23 from the ala
of the nose (the outer portion of the nostril) to the
tragus of the ear (a projection of the cartilage on the
front center of the ear). This ala-tragus line should be
parallel with the floor. The patient's head should also
be positioned so that the midsagittal plane is
perpendicular to the floor.
For mandibular periapical radiographs, lower the
headrest so the patient's head is positioned as shown in
figure 1-24. The figure shows a line running from the
corner of the patient's mouth to the tragus of the ear.
This line should be parallel with the floor. Again, the
mid-sagittal plane is perpendicular to the floor.
Positioning the Film
Once the patient is positioned, insert the film
packet in the patient's mouth with a pair of hemostats
or other holding device. Never slide the packet in; this
might irritate the oral mucosa or cause the patient to
gag. Gently direct the holding device to the desired