Re: Occlusal radiographs

TECHNIQUE

Occlusal radiographs are exposed using thebisected angle technique.

MAXILLARY OCCLUSAL RADIOGRAPHS
Maxillary occlusal radiographs are taken by usingthe following procedures:
1. Set the X-ray machine at 10 mA, 90 kVp, and 60impulses (1 second). (Reduce the kilovoltage 5 kVp ifthe arch is edentulous. Use 70 kVp if the patient is achild.)
2. Position the patient so that the ala-tragus line isparallel with the floor, and the mid-sagittal plane isperpendicular to the floor.
3. Place the film in the patient’s mouth. Occlusalfilms are normally very comfortable. Have the patientrelax the muscles of the mouth and cheek as much aspossible. The pebbled surface of the packet should betoward the occlusal surfaces of the maxillary teeth, andthe narrow side of the packet toward the patient’scheeks. To place the packet, retract one corner of thepatient’s mouth until the packet can be inserted. Positionthe packet far enough in the mouth so that it covers allthe teeth. Special care must be taken to avoid gaggingthe patient. Have the patient close gently but firmly onthe packet to hold it in place.
4. Position the tube head.a. For maxillary anterior occlusal radiographs,set the vertical angulation of the tube head at +65°.Center the tube head cylinder on the bridge of theFigure 1-38.—Projection of central ray (CR) for maxillaryanterior occlusal radiographs.patient’s nose so that the central X-ray beam will beprojected as shown in fig. 1-38.b. For maxillary posterior occlusalradiographs, set the vertical angulation of the tube headat +75°. Center the tube head at the top of the patient’snose so that the central X-ray beam will be projected asshown in fig. 1-39.
5. Make the exposure.

MANDIBULAR OCCLUSAL RADIOGRAPHS
Mandibular occlusal radiographs are taken byusing the following procedures:
1. Program the X-ray machine for 10 mA, 90 kVp,and 60 impulses (1 second). (Reduce the kVp setting foredentulous patients and children as discussed earlier).
2. Position the patient.a. For mandibular anterior occlusalradiographs, position the patient so that the ala-tragusline is at a 45° angle with the floor, and the midsagittalplane is perpendicular to the floor.b. For mandibular posterior occlusalradiographs, position the patient so that the ala-tragusline and mid-sagittal plane are perpendicular to the floor.
3. Place the film packet in the patient’s mouth withthe pebbled surface toward the occlusal surfaces of themandibular teeth, and the short sides of the packet aretoward the patient’s cheeks. Have the patient closegently on the packet to hold it in place.
4. Position the tube head.a. For mandibular anterior occlusal radio-graphs, set the vertical angulation of the tube head at -10°. Center the tube head cylinder on the tip of thepatient’s chin so that the central X-ray beam will beprojected as shown in figure 1-40.b. For mandibular posterior occlusalradiographs, set the vertical angulation of the tube headat 0°. Center the tube head cylinder beneath the patient’schin so that the central X-ray beam will be projected asshown in figure 1-41.
5. Make the exposure.