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Assembling The Anterior Device | Up
Dental Technican, Volume 2 - Dentist training manual for military dentists | Next
Midsagittal and occlusal planes |
film are centered in the locator ring, the device is
properly assembled and ready for positioning in the
patient’s mouth.
Assembling The Posterior Device
Figure 1-12 shows a fully assembled posterior
paralleling device. Refer to this figure during the
following discussion.
Insert the film into the posterior bite-block as
previously discussed.
NOTE: The posterior device shown in figure 1-11
is used for film placement in the right maxillary and
left mandibular quadrants. You must reassemble the
device, rotating the locator ring and the bite-block,
before using it in the left maxillary or right mandibular
quadrants. Only the posterior device must be
reassembled in this manner, the anterior device does
not require reassembly.
Placing The Device
remedies discussed earlier.
Once you have assembled the posterior paralleling
device, place it in the patient's mouth. Be very careful
not to injure the oral tissue. If the patient gags, use the
Guide the bite-block and the film packet into
position, centering the packet behind the area being X-
rayed. The film packet should be positioned far enough
behind the tooth so it will be parallel to the long axis of
the tooth.
After positioning the film packet, slide the locator
ring down the indicator rod until the ring almost
touches the surface of the patient's face. Then, position
the tube head cylinder. The end of the cylinder should
be parallel with the locator-ring, and its side should be
parallel with the indicator rod.
Once these procedures have been accomplished,
the film packet and the tube head are in proper
alignment. You are now ready to expose the film.
Figure 1-12 .—Assembled posterior parallelling device.
EXPOSURE ROUTINE FOR FULL MOUTH
PERIAPICAL EXAMINATION
The full mouth periapical examination consists of
14 periapical radiographs (7 maxillary and 7
mandibular). The series includes the following films
and sequence starting with the maxillary arch and
proceeding to the mandibular arch:
1. Incisor area
2. Left cuspid area
3. Left bicuspid area
4. Left molar area
5. Right cuspid area
6. Right bicuspid area
7. Right molar area
GUIDELINES FOR TAKING PERIAPICAL
RADIOGRAPHS, PARALLELING
TECHNIQUE
The following guidelines apply if you are taking
either a full mouth series, or an individual periapical
radiograph. For training purposes, infection control
barriers are not used in the photographs in this section.
In most cases, the X-ray machine is set at 10 mA
for dental radiographs. The kVp may vary, depending
upon the thickness or the region being radiographed. If
the area being radiographed is edentulous (no teeth
present), reduce the recommended kVp by 5. When
you are taking radiographs on a child, reduce the
recommended kVp to 70. Always consult the dentist
before taking radiographs on a child. Because of the
different types of X-ray equipment in use, the exposure
time selector you use may not have the settings
suggested. Consult the film manufacturer's
instructions regarding the desired time setting to use.
Before you perform an individual radiograph or a
full mouth periapical examination, prepare the patient,
using the procedures explained earlier. When you are
using the parallel film placement technique, the
position of the patient's head is not critical. But, it is
best to adjust the head rest on the dental chair so that
the patient's "plane of occlusion" is parallel with the
floor and the "midsagittal plane" is perpendicular to
the floor (fig. 1-13.)
It is important to properly position the paralleling
devices and the tube head cylinder when using the
paralleling placement technique.
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