Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DS4102 > CBCT - Amar > Flashcards

CBCT - Amar Flashcards

1
Q

Can CBCT see soft tissues?

A

Nein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Estimated scanning time of CBCT

A

1-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Compare the radiation dose of OPG vs CBCT

A

1 small CBCT = 1 pan
1 large CBCT (ortho) = around 10 OPG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the issue with these cbct machines

A

Takes up a lot of space

$$$

High radiation dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

pros of this machine (3)

A

Cheaper Occupies

less space

Lower dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Required characteristics for ideal diagnostic cbct (5)

A

Good density and contrast

Sharpness

Good resolution

Accuracy in measurements

Free of artifacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some advantages of CBCT (5)

A
  • 3D
  • Good image accuracy and resolution
  • Rapid scan time
  • Allows for selective FoV
  • No magnification
  • Low radiation dose compared to Med CT
    *
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does CBCT radiation differ from med CT

A

CBCT - 0.052 – 1.025 mSv

Med CT - 1.4 - 2.1 mSv

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Disadvantages of CBCT

A
  • Artifacts
  • Motion artifacts due to increased scan time compared to med ct
  • Poor contrast resolution (no soft tissue observation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Limitations of Panoramic imaging (5)

A
  • 2D
  • Horizontal and vertical magnification
  • Distortion
  • Superimposition
    • Positioning errors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 4 components of CBCT image acquisition

A
  1. XRay generation
  2. Image formation / detection
  3. Image reconstruction
  4. Image display
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe how the xray generator works in CBCT (4)

A

During rotation, many exposures are made at fixed intervals, each offset from one another - called basis images

150-600 basis images produced

Complete series of basis images called projection data // (step called image acquisition)

Projection data then reconstructed in 3 planes (axial, sagittal and coronal) using complicated algorithm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
A

Sagittal, axial, coronal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is CBCT FoV and how can it change?

A

Visible Field of View

  • Can be adjustable
  • Full FoV = nearly full skull (used for ortho)
  • Medium / standard = both arches and TMJ
  • Small FoV = one arch or quadrant

Want to limit the field size to the smallest volume that can accomodate the region of interest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is CBCT frame rate? Pros (1) and cons (2) of high frame rate?

A

Speed at which images are acquired

Higher frame rates = more pics = increased primary reconstruction time

Higher frame rate = higher radiation dose

Higher frame rate reduces metallic artifacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

2 types of image detectors for CBCT

A

Image intensifier tube / CCD / CMOS

Flat panel detector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are these two cbct image detectors

A
  1. CCD / CMOS
  2. Flat panel detector
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Pixel vs Voxel

A

Pixel = digital equivalent of silver halide crystal in conventional. Smallest controllable element of a picture on screen

Voxel = volumetric pixels, cubic in nature (CBCT is 3D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

CBCT vs CT voxels

A

CBCT = isotropic voxel

  • Perfect cube 0.1 - 0.7 mm

CT = anisotropic voxel

  • Brick shaped
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a “tomographic plane”

A

Single slice of the area interest in a CBCT shown by a line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 3 image types that can be produced by Multiplanar Reformatting (MPR)

A

Axial images with computer generated superimposed curve of alveolar process

Cross sectional Images

Panoramic like images

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the two types of radiograph resolution?

A

Spatial resolution - differentiate btw two objects of different radio density

Contrast resolution - differentiate two objects of the same color type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q
A
24
Q
A

Lingual foramen

  • careful when placing implant
25
Q

What should you do medico-legally when you take a full-volume / full size CBCT

A

Refer to dento-maxillofacial radiologist for proper reporting of radiograph

  • May not need to refer for small section CBCT
26
Q
A

Arrows - eustachian tube

27
Q
A

mental foramen

28
Q

What is the dotted line and what happens if it gets blocked

A

Sinus ostium

If blocked - Mucocele

AES - anterior ethmoidal sinus

MNC - middle nasal concha

INC - inferior nasal concha

29
Q

Purposes of CBCT in endodontics (3)

A

Diagnosis of treatment failure (missed canals)

Identifying root fractures

Assessment of endo tx complications (ex. broken file, extrusion of material into IAC)

Evaluation of anatomy / complex morphology (dens invaginatus)

Root canal morphology

30
Q

When should CBCT NOT be used for Endo

A
  1. Assessing outcome when there were no difficulties
  2. To determine working length
31
Q

What type of CBCT should be taken for endo purposes

A

Small volume CBCT

32
Q

indications for CBCT in OMFS

A
  1. Investigate exact location of jaw pathologies
  2. Assess impacted and supernumary teeth and proximity to vital structures
  3. Consideration of resorption of adjacent tooth
  4. pre-post surgical assessment of bone graft sites
  5. paranasal sinus pathology
  6. planning orthognathic surgery
33
Q
A

nasopalatine cyst

34
Q
A

retention pseudocyst of maxillary sinus

Should NOT have taken CBCT - unnecessary

35
Q

What diseases of the maxillary sinus warrant a CBCT?

A

Mucocele - painful expanding lesion

A. Polyp

B. Retention pseudocyst

C. Mucocele

36
Q

What should be advised

A

CBCT to see effect on IAC

“Breach in continuity of lingual cortical plate”

37
Q

Uses of CBCT in implantology (6)

A

Determine presence of disease at site

Measure available jaw bone to see if its feasible

Determine quality and quantity of bone

Nerve mapping / determine proximity to critical structures

Determine implant orientation

Select the right size of implant for optimal stability

38
Q

What is the required distance between implant and any vital structure

A

at least 2mm

39
Q

What 2 important structures must you be aware of when placing an implant in the mx anterior region

A

Incisal foramen

Nasopalatine canal

40
Q
A

Accessory mental foramen

Very rare

41
Q

What must you do before placing mandibular posterior implant

A

CBCT nerve mapping - manually, not automatic

  • Choose best panoramic-like slice that shows good nerve anatomy
  • Start at mental foramen
  • Trace it all the way back
42
Q
A

Bifid mandibular canal

43
Q
A

Bifid mandibular canal

44
Q

Orthodontic applications of CBCT

A

Plus:

orthognathic surgery tx planning

Accurate estimation for space requirement for unerupted/impacted teeth

Assessment of ortho induced RR

Post treatment TMD

45
Q
A

Transposition of 12/13

46
Q

Why is CBCT effective for TMJ assessment

A

Ability to accurately define the true position of condyle in the fossa

47
Q
A

Degenerative joint disease

“birds beak condyle”

48
Q

What is the ALARA principle

A

As Low As Reasonable Achievable

  • take conserative xrays/CBCT, based on diagnostic yield expected
49
Q
A

Dentoalveolar trauma

50
Q

Is CBCT suitable for internal/external root resorption?

A

Yes - could potentially be hiding palatally/lingually

  • Use small volume CBCT
51
Q
A

External/internal RR

  • Couldnt see clinically bc subgingival
52
Q

Is CBCT indicated for caries?

A

No

53
Q

Is cbct indicated for perio?

A

Not for determining perio bone levels

However

can be used for infra-bony defects and furcations

54
Q
A

Perio furcation involvement

55
Q

Is cbct indicated for soft tissue assessment / oral malignancy?

A

No - should do medical CT or MRI instead

HOWEVER, if cancer involves bone - CBCT indicated

56
Q

Benefits of CBCT over med CT

A

Faster

Smaller

Safer (lower dose)

Less expensive

More convenient

Specific to dentistry

57
Q

Compare CT with CBCT

A

Update scan time: CBCT 5-10s

Med CT - <10s

DS4102 (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions