Extraoral Radiographic Techniques

Extraoral Radiographic Techniques

Write short note on lateral oblique view for body of mandible.
Answer. It is an extraoral radiographic technique for mandible.

Type of lateral oblique view are:

• Anterior body of the mandible view.
• Posterior body of the mandible view.
• Ramus view.

Anterior Body of the Mandible View

Structure shown

Anterior body of the mandible and teeth in same area.

Read And Learn More: Oral Radiology Question And Answers

Film Placement

The cassette is placed flat against the patient’s cheek and is centered over the body of mandible, overlying the canine teeth. Cassette should be positioned parallel to the body of mandible. Patient should hold the cassette position with the thumb placed under edge of palm against outer surface of cassette.

Position of Patient

Patient’s head is so adjusted that:

• The ala tragus line is parallel to the flor.
• Inferior border of the cassette should be parallel to the lower border of the mandible and below it.
• The sagittal plane is tilted so that it is 5° to the vertical and rotate 30° from the true lateral position.

Central Ray

• Central ray is directed under the mandible opposite side, from 2 cm behind the angle of the mandible.
• Beam is directed upward (–10° to –15°) and centered on the anterior body to mandible.
• Beam must be directed perpendicular to horizontal plane of fim.

Exposure Parameter

Using intraoral X-ray machine

kVp – 65–70

mA – 7–10

Seconds – 0.8

Using extraoral X-ray machine

kVp–40

mA–40

Second—1

Posterior Body of the Mandible View

Structure shown: Body of mandible, ramus oft he mandible, angle of the mandible, position of teeth in same area.

Film Placement

The cassette is placed flat against the patient’s cheek and is centered over the body of the mandible. The cassette should be positioned parallel to the body of mandible. Patient should hold the cassette position with the thumb placed under edge of palm against outer surface of cassette.

Position of Patient

• Ala tragus line is parallel to the flor.
• Inferior border of the cassette should be parallel to the lower border of the mandible and below it.
• The sagittal plane is tilted so that it is 5° to the vertical and the head is rotated 10° to 15° from the true lateral position.

Central Ray

• Directed from under the mandible opposite side, from 2 cm behind the angle of the mandible.
• Beam is directed upward (–10° to –15°) and centered on the anterior body to mandible.

Exposure Parameters

Using intraoral X-ray machine

kVp: 65–70.

mA: 7–10.

Seconds: 0.8.

Using extraoral X-ray machine

kVp: 40

mA: 40

Second:1

Ramus of Mandible

Structure shown: To evaluate third molars, large lesions, fracture into the ramus of mandible.

Film Placement

• Cassette is placed against the cheek of patient and is centered over the ramus of the mandible.
• The cassette should be positioned parallel to the ramus of the mandible.

Position of Patient

• Patient’s head is so adjusted that the ala tragus line is parallel to the flor.
• Inferior border of the cassette should be parallel to the lower border of mandible and below it.
• Sagittal plane is tilted so that it is 10° to the vertical and head is rotated 5° from true lateral position.

Central Ray

• It is directed from under the mandible of opposite side from behind the angle of the mandible to a point posterior to the third molar region on the side opposite to the cassette.
• The beam is directed upward (–10 to –15°) and centered on the ramus of the mandible.
• Beam must be directed perpendicular to horizontal plane of fim.

Exposure

Using intraoral, X-ray machine

kVp: 65–70.

mA: 7–10.

Seconds: 0.8.

Using extraoral, X-ray machine

kVp: 40

mA: 40

Seconds: 1

Ramus View

Structure shown

Impacted third molar, retromolar area, angle of the mandible, condyle and fractures that extend into the ramus oft he mandible.

Film Placement

The film placement should be such that the central beam is directed towards the center of the imaged ramus, from 2 cm below the inferior border of the opposite side of the mandible at the area of the fist molar.

Position of Patient

• Patient’s head is so adjusted that the ala tragus line is parallel to the flor.
• Mandible is protruded slightly. The cassette is placed over the patient’s cheek and centered over the area of interest usually over the ramus and far enough posteriorly to include the condyle.
• Lower border of the cassette is parallel and at least 2 cm below the inferior border of the mandible.

Position of Patient

The head is tilted toward the side being examined so that the condyle of the area of interest and the contralateral angle of the mandible form a horizontal line.

Exposure Parameters

KVp: 65–70

mA: 7–l0

Seconds: 0.8