The document discusses Cone Beam Computed Tomography (CBCT) in orthodontics, highlighting its advantages over conventional X-ray imaging, including rapid and painless 3D imaging capabilities. CBCT offers detailed views of facial structures and assists in various applications such as implant site assessment, diagnosing temporomandibular joint issues, and surgical planning. The conclusion emphasizes that CBCT has transformed dental imaging by providing accurate, high-resolution images at lower radiation doses and costs.

1. O
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D
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5. WHY 3D?

6. conventional X-
ray image is
basically a
shadow.
Shadows give you an
incomplete picture of an
object's shape.

7. CBCT in Orthodontics
Dr Roni R kuttickal

8. CBCT, also known as cone
beam volumetric
tomography (CBVT) or
cone beam volumetric
imaging (CBVI), generates
3-D images of the teeth
and head using x-rays
and computer software

9. CONTENTS
• HISTORY
• INTRODUCTION
• CBCT VS CT
• PRINCIPLE
• IMAGE ACQUISITION
• IMAGE DETECTION
• IMAGE RECONSTRUCTION
• IMAGE DISPLAY
• CLINICAL
CONSIDERATIONS
• IMAGE ARTIFACTS
• SPECIFIC APPLICATIONS IN
DENTISTRY
• CONCLUSION
• REFERENCES

10. CBCT
HISTORY

11. Sir Godfrey Hounsfield

15. Introduction

16. What is cone beam ?
Cone Beam Imaging is fast, simple and
completely painless 3D xray – patients just sit
in a chair for a single 10-second scan. And,
from that scan, the specialist can quickly see
computer-generated views of the bones of the
face, the teeth, and other details from any
angle, in 3D and in color

18. HOW DOES CT WORK?
1. X-ray source and detector
mounted on a rotating gantry.
2. During rotation, platform will slowly
move & the receptor detects x rays
attenuated by the patient.
3. multiple images will be captured
during rotation.
4. “ raw data ” reconstructed by a
computer algorithm to generate
cross-sectional images.

19. HOW DOES CBCT WORK?
1)A 3D cone beam is directed through a
central object onto a detector.
2) a single two-dimensional projection is
acquired by the detector,
the x-ray source and detector rotate a
small distance around a trajectory arc.
3) At this second angular position another
basis projection image is captured.
4) This sequence continues around the object
for the entire 360 degrees.

22. PRINCIPLE
 All CBCT Scanners consist of an x-ray source and
a detector mounted on a rotating gantry.
 During rotation of the gantry, the receptor
detects the x-rays attenuated by the patient.
 These recordings constitute the, “raw data,”
which is then ready for reconstruction.
reconstructed by a computer algorithm

23. Scanner rotates 360º around
head
Multiple images (150 to
599views)
Software collects raw
data
Image
reconstruction

24. Cone-beam CT image production
The four components of CBCT image production are

25. 1) Acquisition configuration
• The patient is positioned into the machine with
the head stabilized to avoid movement
• a scout view will be acquired to verify that the
area of interest is within the FOV
• A full scan is done
• 150 to 600 2D images are collected in the
detector.
• Basis images

26. • detector panels comprise an array of individual
PIXELS with two components,
• 1) Photo diodes - IMAGES
2) Transistors- SIGNALS
• The Data from bad PIXELs are eliminated using an
average
• Details of CBCT imaging is determined by the
individual volume elements or VOXELS produced
from the volumetric dataset.

28. 3) Image reconstruction
• Once the basis projection frames
have been acquired, data must be
processed to create the volumetric
data set called primary
reconstruction.
• The number of individual projection
frames may be from 100 to more
than 600, each with more than one
million pixels, with 12 to 16 bits of
data assigned to each pixel.

29. A set of 150-600 basis images will be sent to dedicated software
That will then create a 3D volume reconstruction of the data volume
The multiplanar (MPR) reformatted images in axial, coronal, and sagittal orientation

30. • Acquisition stage
• Reconstruction stage
Image Reconstruction process

31. Acquisition stage
• The acquisition stage involves image collection
and detector preprocessing ie sequence of the
required calibration steps

32. Reconstruction stage
• Once images are corrected, they must be related to each other and assembled.
• One method involves constructing a sinogram: a composite image relating each
row of each projection image.
• A reconstruction filter algorithm is applied to the sinogram and converts it into a
complete 2D CT slice.

34. 4) Image display
• unique images demonstrating features in 3D
• Data can be reoriented so that the patient’s anatomic features are
realigned
• Isotropic nature lets images to be sectioned non orthogonally.

35. Axial
CoronalSagittal
Volumetrc 3-D

36. PROPERTY
MEDICAL (MULTI – SLICE)
CT
CBCT
COST Expensive Comparatively Cheaper
SOFT TISSUE CONTRAST Better contrast Limited, poor contrast
SCANNING TIME
Lower Speed, requires
multiple rotations
High speed, only one
rotation required.
IMAGE NOISE Lower
Higher
Differences

37. PROPERTY
MEDICAL (MULTI –
SLICE) CT
CBCT
RADIATION DOSE High Low
IMAGE
RESOLUTION
Low (Hard tissue,
teeth)
High (Hard tissue,
teeth)
METAL ARTIFACT
REDUCTION
Less More

38. Thus CBCT had a –
1.More rapid acquisition of a data set of the
entire FOV
2.Less expensive radiation detector.
3.A shorter examination time,
4.Shorter time cause Reduction of image
unsharpness

40. Clinical Analysis
Several steps the clinician must check and analyze for each patient and
clinical situation
Region of interest and field of view: which
anatomical structures are to be visualized
Radiographic Guide: marker showing the exact
location of the desired implant site indicated
Voxel size: Which voxel size would be the best
for this specific situation?
Other: Should the patient’s teeth be in
maximum intercuspal occlusion

41.  PATIENT PREPARATION:
- Patients should be escorted into the scanner
unit and provided with adequate radiation barriers
prior to head stabilization.
- Each CBCT unit has a different mode of head
stabilization..
- Area of interest should be aligned with the
X – ray beam. This reduces radiation exposure
and optimizes image quality.

42. - Facial topographical reference planes are
adjusted to align with the x – ray beam.
- Immediately before scanning, the patient should
be asked to remove all metallic objects from the
head and neck areas.
- Patients should be instructed to be as still as
possible and breathe slowly through the nose,
eyes closed.

43. Patient positioning
• Sitting
• Standing
• Supine
Immobilize patient’s head

44. - Supine  Occupies a larger surface

45. - Sitting  Most comfortable, but fixed seats
may not allow scanning of physically disabled
or wheel – chair bound patients.

46. Erect -Immobilization of the patient’s head
is the most important so that the final
image does not get degraded.

47.  IMAGING PROTOCOLs - This involves a set of
exposure parameters required for image acquisition.
i.) Voxel Size:  Varies from manufacturer to
manufacturer.
ii.) Scan Time/Number of Projections: increase the
number of basis image projections provides better
reconstruction images, but increases the patient
radiation.
iii.) Scanning Trajectory: Reconstructed images
from limited scan trajectories may suffer from the
presence of artifacts.

48. iv.) Field of View:
 Collimation enables limitations of the x – ray
beam to the region of interest alone.

49.  IMAGE REPORTING:
- CBCT imaging not only involves the technical aspect but
interpretation is just as important.
- It includes display of the appropriate region of interest
 ARCHIVING, EXPORT AND DISTRIBUTION:
- The volumetric image data and the generated image report
must be archived and distributed. Export is usually in DICOM
(Digital Imaging and Communications in Medicine)

50. IMAGE ARTIFACTS
 An artifact is any distortion or error that is
unrelated to the subject being studied.
 This is the fundamental aspect that impairs CBCT
image quality.
ARTIFACT
S
Acquisition
Patient -
Related
Cone – Beam
Related
Scanner -
Related

51. - Can be corrected by reducing the field of
view, modifying the patient position and by
separating the dental arches.

52.  PATIENT – RELATED ARTIFACTS:
- Patient motion can cause
misinterpretation of the raw data, which
appears as unsharpness in the
reconstructed image.
- This can be minimized by
restraining the head and using as short a scan
time as possible.

53.  SCANNER – RELATED ARTIFACTS:
- Usually present as circular or ring
streaks resulting from imperfections in scanner
detection or due to poor calibration.

54. - ii.) Undersampling:
 This occurs when there are too few
basis images for image reconstruction.
 Leads to sharp edges, misregistration,
and noisier images. It appears as fine striations
in the image.(Aliasing).

55. Orthodontist related

56. Classification of CBCT systems
 According to the available FOV or selected scan volume
height CBCT systems can be categorized as
 Localized region: approximately 5 cm or less (eg,
dentoalveolar, temporomandibular joint)
 Single arch: 5 cm to 7 cm (eg, maxilla or mandible)
 Interarch: 7 cm to 10 cm (eg, mandible and superiorly to
include the inferior concha)
 Maxillofacial: 10 cm to 15 cm (eg, mandible and
extending to Nasion)
 Craniofacial: greater than 15 cm (eg, from the lower
border of the mandible to the vertex of the head)

58. Choice of Field of view

59. FIND THE SUPERNUMERY

61. Applications

63.  IMPLANT SITE ASSESSMENT:
- This has been the greatest impact of CBCT till date.

64. LOCALIZATION OF THE INFERIOR ALVEOLAR
CANAL:
-

65.  TEMPOROMANDIBULAR JOINT:
- CBCT provides multiplanar and 3D
images of the condyle and the surrounding structures
to facilitate the analysis and diagnosis of bone
morphologic features, joint space and dynamic
functions.
ML dos Anjos Pontua et al, Evaluation of bone changes in the
temporomandibular joint using cone beam CT, Dentomaxillofacial
Radiology, (2012), 41, 24 - 29

66. PERIAPICAL
DISEASE
PERIODONTAL
DISEASE

67. ROOT FRACTURE/ALVEOLAR BONE LOSS
SUPERNUMERARY TEETH

68. TRITICEOUS CARTILAGE
AND THYROID
CALCIFICATIONS
CAROTID ARTERY AND STYLOID
CALCIFICATIONS

69. DEMONSTRATION OF FRACTURE

70.  RAPID PROTOTYPING:
-processes from which physical scale models can
be fabricated directly from 3D computer data

71. CBCT; In Clinical
Orthodontic Practice

72. Howcasesarerecordedin
foreignsetups

76. CBCT offers precise location of impacted
teeth in three dimensions

77. Cleft Lip and Palate
3D volumetric
reconstructions of a
patient with bilateral
CL/P are useful in
obtaining detailed
information on the
magnitude of the
defect and the status
and position of teeth
at the defect site

78. Orthognathic and craniofacial anomalies
surgical planning and implementation

79. Asymmetry
Mirroring on a mid-sagittal plane for quantitation of mandibular asymmetry. A midsagittal
plane was defined for this patient based on Na, Ba, and ANS. The left ramus was
mirrored onto the right side using this plane.

80. Root resorption

81. Alveolar boundary conditions

82. TMJ degeneration, progressive bite changes
functional shifts, and responses to therapy
3D can help in the identification of pathologic changes, including sclerosis, flattening, erosions, osteophytes,
abnormalities in joint spaces, and responses of the joint tissues to forces

83. Reconstructed pan from a 3-D scan
reconstructed pan can also give a much better view of root alignment

84. Reconstructed ceph from a 3-D scan

85. ROOT ANGULATION

86. Sinus And Airway Airway assessment

89. Measuring bone dimensions for miniimplant
placement

90. LOST TADS

91. Assessment Rapid maxillary expansion

92. CAD planning software for orthodontics

93. Everythingcomeswitha
price

95. CONCLUSION
The introduction of CBCT imaging systems have provide a better
environment for the clinician in terms of providing accurate, submillimeter
resolution images at lower doses, costs and scanning time, when compared to
CT. The availability of this technology is increasing day by day and its capability
in providing the practitioner with a 3D representation has changed the face of
dentistry over the years. Maxillofacial imaging has shifted gears from the art of
diagnosis to the guidance of operative and surgical procedures, thanks to CBCT.

96. References
1)WHAT IS CONE-BEAM CT AND HOW DOES IT WORK? WILLIAM C. SCARFE, BDS,
FRACDS, MSA,*, ALLAN G. FARMAN, BDS, PHD, DSC, MBAB
2)CBCT; IN CLINICAL ORTHODONTIC PRACTICE
PROF. DR. NEZAR WATTED*, PROF. DR. DR.PETER PROFF ,**DR. VADIM REISER***, DR.
BENJAMIN SHLOMI***, DR. MUHAMAD ABU-HUSSEIN****,DR.DROR SHAMIR*****
3)CLINICAL RECOMMENDATIONS REGARDING USE OF CONE BEAM COMPUTED
TOMOGRAPHY IN ORTHODONTICS. POSITION STATEMENT BY THE AMERICAN ACADEMY
OF ORAL AND MAXILLOFACIAL RADIOLOGY -AMERICAN ACADEMY OF ORAL AND
MAXILLOFACIAL RADIOLOGY
4)USING CONE BEAM TECHNOLOGY IN ORTHODONTICS-EDWARD LIN
5)THE USE OF CBCT IN ORTHODONTICS: RECOMMENDATIONS FOR CLINICAL PRACTICE
-ALBERTO CAPRIOGLIO
6)CBCT – AN ADVANCED DIAGNOSTIC TOOL FOR ORTHODONTICS AND OTHER
SPECIALTIES IN DENTISTRY – A SYSTEMATIC REVIEW- A VISHVANATH
7)CBCT IN ORTHODONTICS: THE WAVE OF FUTURE - JCDP

97. THANK YOU