Object localization, extra oral radiography and advanced imaging in Dentistry

Question 1

Why is object localization challenging in 2D images?

Answer 1

Hard to determine spatial relationships.

Question 2

What are two methods to compare 2D images?

Answer 2

Examine projections at right angles or use the tube-shift technique (SLOB).

Question 3

What advanced method aids in object localization?

Answer 3

3D imaging modalities.

Question 4

What is the reference direction in the tube-shift technique?

Answer 4

Central ray directed perpendicular.

Question 5

SLOB Rule(mnemonic)

Answer 5

Same side – Lingual
Opposite side - Buccal

Answer 6

Tube shift technique

Answer 7

Tube shift – Vertical angulation

Question 8

Where is the receptor placed in extraoral imaging?

Answer 8

Outside the patient’s mouth.

Question 8

What areas does extraoral imaging cover?

Answer 8

Large areas of the skull and jaws.

Question 9

What are examples of extraoral imaging?

Answer 9

◈PA skull
◈Lateral cephalometric
◈Orthodontics
◈Oral Surgery

Question 10

What do extraoral imaging detect?

Answer 10

Diseases, lesions, and conditions of Jaws

Question 11

What do extraoral images evaluate?

Answer 11

◈Growth & Development
◈ Impacted teeth
◈ Trauma
◈Temporomandibular joint
◈Extent of large lesions

Question 12

Why might intraoral imaging be challenging?

Answer 12

Due to swelling or discomfort.

Question 13

How is the receptor positioned in a lateral cephalogram?

Answer 13

Parallel to the midsagittal plane.

Question 14

What relationships does a lateral cephalogram evaluate?

Answer 14

Anteroposterior (AP) relationships between the maxilla, mandible, and cranial base.

Question 15

What does a lateral cephalogram assess?

Answer 15

◈Skeletal structures
◈Soft-tissue relationships

Question 16

What does a lateral cephalogram examine

Answer 16

◈Orthodontic evaluation
◈ Orthognathic evaluation

Question 17

For a posteroanterior cephalometric projection, how is the canthomeatal line positioned?

Answer 17

At 10 degrees with the receptor.

Question 18

How is the central beam directed in a posteroanterior cephalometric projection?

Answer 18

Perpendicular to the receptor.

Question 19

Posteroanterior cephalometric projection indications:

Answer 19

◈Assess jaw skeletal relationships
◈Orthognathic surgical treatment planning
◈Evaluate craniofacial asymmetry

Question 19

What anatomical landmarks define the canthomeatal line?

Answer 19

The outer canthus and external auditory meatus.

Question 19

What do lateral and PA cephalometric views help examine?

Answer 19

Skeletal relationships in all three planes.

Question 20

What is the relationship between lateral and posteroanterior cephalometric views?

Answer 20

They are at right angles to each other.

Question 21

How are lateral and PA cephalometric views useful in treatment?

Answer 21

They monitor progress and treatment outcomes.

Question 22

How is the canthomeatal line positioned in Water’s projection?

Answer 22

At a 37-degree upward angle to the receptor.

Question 23

How is the central beam directed in Water’s projection?

Answer 23

Perpendicular to the receptor.

Question 24

What other sinuses are shown in a Water’s projection?

Answer 24

The frontal sinus and ethmoid air cells.

Question 25

What is another name for the Water's projection?

Answer 25

Occipitomental projection.

Question 26

What does the Water’s projection primarily display?

Answer 26

The maxillary sinus.

Question 27

What other structures does the Water’s projection demonstrate?

Answer 27

Midfacial bones and orbits.

Question 28

What type of X-ray beam does CBCT use?

Answer 28

A cone-shaped X-ray beam.

Question 29

What does CBCT capture in the maxillofacial region?

Answer 29

A 3D volume.

Question 30

What type of X-ray source is used in CBCT?

Answer 30

A collimated X-ray source.

Question 31

What does the detector in CBCT do?

Answer 31

Records the number of photons exiting the patient.

Question 32

How do the X-ray source and detector move in CBCT?

Answer 32

They synchronously rotate around the patient.

Question 32

How many rotations are typically used in CBCT imaging?

Answer 32

180° to 360° rotation.

Question 33

How many images does the detector capture during each rotation?

Answer 33

100 to 600+ images at several hundred rotational angles.

Question 34

What type of images are captured during each rotation?

Answer 34

Raw or basis images.

Question 35

What type of projection are the captured images in CBCT?

Answer 35

2D projections.

Question 36

How do the images in CBCT relate to cephalometric images?

Answer 36

Each image is slightly offset from the next.

Question 37

What is the complete series of images in CBCT called?

Answer 37

Raw data or projection data.

Question 38

What is used to create 3D anatomical planes in MPR?

Answer 38

A stack of images, projection data, or raw data.

Question 39

What does MPR stand for in imaging?

Answer 39

Multiplanar Reformation.

Question 40

Where is the data imported for MPR?

Answer 40

Into viewing software.

Question 41

What does MPR allow for in terms of visualization?

Answer 41

Creation of 3D anatomical planes of the body.

Question 42

3 Anatomic Planes

Question 43

Curved planar reformat – Panoramic reformat

Question 44

Patient preparation & stabilization for CBCT

Answer 44

◈ Lead Apron for all patients ◈ No jewelry or dentures ◈ Stabilized patient to prevent motion artifact ◈ Chin up ◈ Lateral head support ◈ Head restraints

Question 45

Field of View

Question 46

In what format are CBCT images stored?

Answer 46

DICOM format.

Question 47

Can CBCT images be imported into third-party treatment planning software?

Answer 47

Yes

Question 48

Advantages of CBCT

Answer 48

◈ Better Visualization of structures ◈ Better Spatial orientation ◈ Finer detail ◈ Less radiation dose

Question 49

Disadvantages of CBCT

Answer 49

◈ Patient motion during the scan – motion artifacts ◈ Cost of equipment

Question 50

Uses of CBCT

Answer 50

◈Implants ◈Endo( Missed MB-2 canal, Root fracture, Internal root resorption) ◈Ortho ◈Evaluation of impacted tooth ◈TMJ ◈Airway analysis ◈Pathology ◈Virtual planning of surgeries