CBCT views and its anatomical structures

2. What is CBCT and what do we use it for?

3. Applications of CBCT in dentistry
Endodontics
Oral and
maxillofacial
dentistry
Pedodontics
Orthodontics
General
dentistry
Research
Forensic
Dentistry
Implants
Periodontics
TMJ imaging

4. Different views of
CBCT

5. 1. Axial plane

10. 2. Sagittal
plane

11. Sphenoid bone
Nasal bone
Red : ANS
Yellow : PNS
Blue : hard palate
Orange :sphenoid sinus
Green : sella turcica

13. 3. Coronal plane
(Frontal - AP)

20. Differences between CBCT and CT
CT ( COMPUTERIZED TOMOGRAPHY
)
CBCT ( CONE-BEAM COMPUTED
TOMOGRAPHY )
 CT scanner was invented by Godfrey Newbold
Hounsfield in Hayes, England
 A CT scan makes use of computer-processed
combinations of many X-ray images taken from
different angles to produce cross-sectional
(tomographic) images.
 CBCT is a variation on traditional computed tomography
(CT) in which an X-ray tube and detector panel rotate
around the patient capturing data with a cone-shaped X-
ray beam instead of the "slices" CTs are typically known
for.
 Images are then reconstructed using algorithms to
produce 3-dimensional images at high resolution.

21.  A CT scanner consists of an x-ray tube that
emits a finely collimated fan shaped x-ray beam
directed through a patient to a series of
scintillation detectors.
 These detectors measure the number of photons
that exit the patient.
 The detectors form a continuous ring around the
patient and the x-ray tube moves in a circle within
the fixed detector ring.
 This information is used to construct a cross-
sectional image of the patient.
 All CBCT scanners consists of an x ray source
and detector mounted on a rotating gantry.
 During rotation of the gantry, the x ray source
produces a divergent cone shaped radiation,
while the receptor records the residual x rays
after attenuation by patients' tissues
 The x ray source and detector moves through an
arc of 180 to 360 degree to produce multiple
planar projection images.
 Theses images constitute the raw primary data
which is then reconstructed by a computer
algorithm to generate cross sectional images
Fig.1 Fig.2
How it works?

22. Fig.1

24. Fig.2

25.  For the image reconstruction to occur ; many
scans are progressively taken as the object is
gradually passed through the gantry.
 They are combined by the mathematical
procedure known as tomographic
reconstruction.
 Components of image production are X-ray
generation and X-ray detection: Image
sensor- PSP (photo stimulable phosphorus
plates), CCD sensors, FPD (flat panel
detector.
 Image formed

27. CT CBCT
 Evaluation of extent of any
suspected pathology in the head and
neck, including tumors, cysts and
infection.
 Determination of location and extent
of facial fractures.
 Radiographic pre surgical evaluation
for implant placement.
In the Developing Dentition :
 Localization of an unerupted tooth .
 Assessment of external resorption in
relation to unerupted teeth .
 Localized assessment of an impacted
tooth .
 Assessment of cleft palate .
 Planning complex orthodontic/surgical
management of maxillofacial skeletal
abnormalities .

28. In restoring The Dentition
 Assessment of periodontal infra-bony
defects and furcation lesions.
 Periapical assessment.
 Assessment of root canal anatomy in
multi-rooted teeth .
 Planning surgical endodontic
procedures .
 Endodontic treatment complicated
by resorption lesions, combined
perio-endo lesions, perforations and
atypical pulp anatomy.
 Assessment of dental trauma
(suspected root fracture).

29. In surgical applicants
 Assessment of lower third molars where an
intimate relationship with the inferior dental
canal is suspected .
 Assessment of unerupted teeth.
 Cross-sectional imaging prior to implant
placement.
 Assessment of pathological lesions affecting
the jaws including cysts, tumors, giant cell
lesions and osseous dysplasia.
 Assessment of facial fractures where soft
tissue detail is not required.
 Planning orthognathic surgery to obtain
three-dimensional datasets of the craniofacial
skeleton.
 Assessment of the bony elements of the TMJ.

30. CT CBCT
 CT eliminates the superimposition of
images of structures outside the area of
interest.
 Because of the inherent high-contrast
resolution of CT, differences between
tissues that differ in physical density by
less than 1% can be distinguished.
 Data from a single CT imaging
procedure consisting of either multiple
contiguous or one helical scan can be
viewed as images in the axial, coronal,
or sagittal planes, depending on the
diagnostic task. This is referred to as
multiplanar reformatted imaging.
 Rapid scan time.
 Beam limitation.
 Image accuracy.
 Reduction in patient radiation dose
when compared to medical CT.
 Multiplanar reformatting
3-dimensional volume.
 Better images with good spatial
resolution.
 Economical, comfortable and safe.

31. CT CBCT
Disadvantage
s
 Time consuming.
 Expensive for routine clinical
use.
 High radiation exposure.
 Expensive equipment and
hence is not always
accessible.
 Poor contrast resolution,
thus soft tissue cannot be
viewed.
 Artifacts.
 Image noise.

32. CT CBCT
 Traditional CT uses a high-output, rotating
anode X-ray tube.
 Cone beam tomography utilizes a low-
power, medical fluoroscopy tube that
provides continuous imaging throughout the
scan.
 Produces a single slice image per scan.
Each slice must overlap slightly in order to
properly reconstruct the images
 Produces the complete volume image in a
single rotation
 Slower due to spiral motion.
 Scan time is longer.
 The single-turn motion image capture used
in CBCT is quicker than traditional spiral
motion of CT.
 Average time for one bet scan may vary
from 7-30 seconds.

33. CT CBCT
 Has high radiation dose.
 The average medical CT scan of the oral
and maxillofacial area can reach levels of
1,200- 3,300 micro sieverts to collect
adequate formation.
 Has lower radiation dose as a result of no
overlap of slices.
 Radiation exposure using the standard full
field of view from a CBCT machine is 36
micro sieverts.
 there is overlapping of radiation  No overlap of slices

34. CT CBCT
 Only one jaw can be visualized at
one time.
 Both jaws can be imaged at the
same time.

35. CT CBCT
 High contrast resolution  Low contrast resolution

36. CT CBCT
 Cost is high  Cost of equipment about 3 5 times less than
traditional medical CT
 Can cause claustrophobia  The open design of the cone beam CT
eliminates claustrophobia and enhance
patient comfort and acceptance
 2D fan shaped x ray beam  Cone shaped x ray beam
 Database compromised of 2D slices  Volumetric data set
 High radiation dose  low radiation exposure

37. Thanks!