8. Intraoral Projection Geometry

Question 1

What is image sharpness in radiography?

Answer 1

Measures how well boundaries of differing radiodensity are revealed. Higher sharpness = clearer image.

Question 2

What is spatial resolution and how is it measured?

Answer 2

Ability to reveal small, close objects; measured in line pairs/mm.

Question 3

How does focal spot size affect image sharpness?

Answer 3

Smaller focal spot increases sharpness by focusing electrons on a smaller area.

Question 4

How does the distance between the focal spot and object influence sharpness?

Answer 4

Increasing the source-to-object distance reduces divergence, improving sharpness.

Question 5

What is foreshortening in image size distortion?

Answer 5

Occurs when the X-ray beam is perpendicular to the receptor but the object is not parallel.

Question 6

What is elongation in image size distortion?

Answer 6

Occurs when the beam is at a right angle to the object but not the receptor.

Question 7

How can shape distortions be minimized?

Answer 7

Position the receptor parallel to the tooth and the X-ray beam perpendicular to both.

Question 8

What is the SLOB rule in object localization?

Answer 8

Same Lingual Opposite Buccal: Determines object position using angle changes.

Question 9

What is the Egg Shell Effect in radiography?

Answer 9

Bone periphery appears more opaque due to attenuation differences in cortical bone.

Question 10

What are the types of intraoral radiographs?

Answer 10

Periapical, bitewing, and occlusal projections.

Question 11

What is the difference between the bisecting angle and paralleling techniques?

Answer 11

Bisecting: Beam is perpendicular to the bisected angle. Paralleling: Beam is perpendicular to the tooth and receptor.

Question 12

What is the preferred technique for periapical radiography and why?

Answer 12

Paralleling technique: Minimizes distortion and reduces radiation exposure.

Question 13

What is the purpose of bitewing radiography?

Answer 13

Detect interproximal caries and evaluate restorations; shows crowns and alveolar crests.

Question 14

What are the uses of occlusal radiography?

Answer 14

Localize objects, evaluate jaw disease, and for patients with limited mouth opening.

Question 15

How should radiographic techniques be adapted for pediatric patients?

Answer 15

Use child-sized receptors, minimize radiation, and follow Image Gently guidelines.

Question 16

What is the purpose of radiography for edentulous patients?

Answer 16

Assess bone condition before dentures or implants; adjust for less dense anatomy.

Question 17

What are key radiographic needs in endodontics?

Answer 17

Ensure root apex visibility and use specialized receptor holders for root canal access.

Question 18

How can the gag reflex be managed during radiography?

Answer 18

Minimize triggers, use distraction techniques, or apply topical anesthetic spray.

Question 19

What are the take-home messages for intraoral projection geometry?

Answer 19

Use paralleling for quality, ensure correct positioning, and minimize retakes to reduce radiation.