PANORAMIC

Question 1

Panoramic: 2 advantages

Answer 1

• A large area is imaged and all the tissues within the focal trough are displayed on one film, including the anterior teeth, even when the patient is unable to open the mouth.
• The image is easy for patients to understand, and is therefore a useful teaching aid.
• Patient movement in the vertical plane distorts only that part of the image being produced at that instant.
• Positioning is relatively simple and minimal expertise is required.
• The overall view of the jaws allows rapid assessment of any underlying, possibly unsuspected, disease.
• The view of both sides of the mandible on one film is useful when assessing fractures and is comfortable for the injured patient.
• The overall view is useful for evaluation of periodontal status and in orthodontic assessments.
• The antral floor, medial and posterior walls are well shown.
• Both condylar heads are shown on one film, allowing easy comparison.
• The radiation dose (effective dose) is about one- third of the dose from a full-mouth survey of intraoral films.
• Development of field limitation techniques with resultant dose reduction.

Question 2

Panoramic: 2 disadvantages

Answer 2

• The tomographic image represents only a section of the patient. Structures or abnormalities not in the focal trough may not be evident.
• Soft tissue and air shadows can overlie the required hard tissue structures.
• Ghost or artefactual shadows can overlie the structures in the focal trough.
• The tomographic movement together with the distance between the focal trough and film produce distortion and magnification of the final image (approx. x 1.3).
• The use of indirect-action film and intensifying screens results in some loss of image quality.
• The technique is not suitable for children under 5 years or on some disabled patients because of the length of the exposure cycle.
• Some patients do not conform to the shape of the focal trough and some structures will be out of focus

Question 3

Describe the head alignment when taking panoramic radiograph (4) (Summative, 2017)

Answer 3

 Spine is straight and instructed to hold any stabilizing supports or handles provided
 The patient should be instructed to bite their upper and lower incisors edge-to-edge on the bite-peg with
their chin in good contact with the chin support.
 The head should be immobilized using the temple supports
 The light beam markers should be used so that the mid-sagittal plane is vertical, the Frankfort plane is
horizontal and the canine light lies between the upper lateral incisor and canine.
 The patient should be instructed to close their lips and press their tongue on the roof of their mouth so
that it is in contact with their hard palate and not to move throughout the exposure cycle (approximately 15-18 seconds)