Cone beam computed tomography Carm CT Cone beam volume CT Flat panel CT Extra-oral imaging system specifically designed for three dimensional imaging of the oral and maxillofacial structures ALARA Principle Principal of cbct- Field of view voxel

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Cone beam computed tomography
Carm CTCarm CT
Cone beam volume CTCone beam volume CT
Flat panel CTFlat panel CT
GUIDED BY:
DR.RAHUL MARIA
PRESENTED BY:
DR. ANUBHUTI
Dental Institute
RIMS

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Introduction
Extra-oral imagingExtra-oral imaging
system specificallysystem specifically
designed fordesigned for threethree
dimensional imagingdimensional imaging
of the oral andof the oral and
maxillofacialmaxillofacial
structuresstructures
ISSN: 2161-1122 Dentistry 2

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The ALARA Principle
 As
Low
As
Reasonably
Achievable

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Produces cone-shaped
beam that irradiates a
patient mouth and jaw as
the arch rotates
cesium iodide
scinilltor coverts x ray
into visible lights
Photosesitive pixels covert
scinillator's light into electric
signals. On- chip circuit turns
electric current to digital output
digital data is
sent to
computer
Cone Beam-Computed Tomography in Endodontics,American Association of Endodontists 5

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Classification of CBCT
According to the dimensions of their FOV or scan
volume.
The following categorization has been proposed:
Small volume (also referred to as focused,
Small field, limited field or limited volume)
systems have a maximum scan volume height of
5 cm

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Principal of
cbct- Field
of view
Detector size
and shape
Beam
projection
geometry
Ability to
collimate the
beam
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CBCT
Localized
region
inter-arch
CBCT
maxillofacial
CBCT
craniofacial
CBCT
Single arch
CBCT
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• Localized region-Small
volume
(also referred to as
focused, small field, limited
field or limited volume)
systems have a maximum
scan volume height of 5
cm.Dent Clin N Am 52 (2008) 707–730 11

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Based on the
patient
position during
the scan
Based on the
patient
position during
the scan
supinesupine sittingsitting standingstanding
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functionality
of the systems
functionality
of the systems
multimodal and have
a digital panoramic tomograph (DPT)
function
multimodal and have
a digital panoramic tomograph (DPT)
function
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Effective dose
• One of the major advantages of CBCT over CT is
the significantly lower effective radiation dose to
which patients are exposed
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A cone-shaped X-ray beam and the detector rotate once
around the patient and captures a cylindrical volume of
data (field of view)
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Software is used to reconstruct images for this dataset

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Just as a digital
radiograph is
subdivided into:
The CBCT
images are
composed of :
ENDODONTOLOGY 17

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• A voxel is a 3D
• pixel.
A voxel is a 3D pixel.
It represents the smallest
distinguishble part of a ENDODONTOLOGY 18

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ENDODONTOLOGY 19

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Three orthogonal planes axial, sagittal and coronal

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The three views can be assessed simultaneously, raversing
through one plane simultaneously alters the other two planes.

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It allows the area of interest to be dynamically traversed in
‘real time’.
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• One significant problem, which can affect the image quality
and diagnostic accuracy of CBCT images is the scatter and
beam hardening caused by high density neighbouring
structures, such as enamel, metal posts and restorations
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The use of CBCT in the management of endodontic
problems
• Cone beam computed tomography overcomes several
limitations of conventional radiography.
• Slices can be selected to avoid adjacent anatomical noise.
For example, the roots of maxillary posterior
teeth and their periapical tissues can be visualized
separately and in all three orthogonal planes without
superimposition of the overlying zygomatic buttress,
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Detection of apical
periodontitis
• Cone beam computed tomography enables
radiolucent endodontic lesions to be detected before
they would be apparent on conventional radiographs
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Pre-surgical assessment
• By selecting relevant views and slices of data, the
thickness of the cortical plate, the cancellous bone
pattern, fenestrations, as well as the inclination of the
roots of teeth planned for surgery can be accurately
determined preoperatively (Nakata et al. 2006)
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A periapical radiograph of
the lower left first molar with
a failing root canal treatment
and a large periapical
radiolucency, periapical
microsurgery is planned..
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A cone beam computed tomography scan is taken, from
this data orthogonal images can be reconstructed
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Volume rendering allows
true three-dimensional
assessment of the roots,
periapical tissues and
adjacent inferior dental
nerve to be assessed
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finally a rapid
prototyping anatomical
model has been
manufactured, which
allows the operator to
tangibly assess the area
to be treated.IEJ-1365-2591.2008

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The exact nature and severity of
alveolar and luxation injuries can
be assessed from just one scan
from whic multiplanar views can
be selected and assessed with no
geometric distortion or anatomical
noise
Assessment of traumatic
dental injuries
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sagittal anaxial views reveal the presence and exact
location of the fractured portion of the crown fragment
(white arrow)
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The scan also reveals an oblique fracture of tooth 21
(red arrow)
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• In addition to detecting the true nature of the
injuries sustained by the tooth, the CBCT scans were
able to detect cortical bone fractures, which were
not diagnosed from the clinical or conventional
radiographic examination.
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Assessment of root canal
anatomy
• Because of the two-dimensional nature of
radiographs they do not consistently reveal the
actual number of canals present in teeth.
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• Assessment of
internal and
external root
resorption
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cone beam computed tomography scans reveal that lesion in actually
internal resorption, because of its location on the periphery of the
root canal (yellow arrow) it can be easily be mistaken for external
cervical resorption with conventional radiographs.
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Determination of Second MesiobuccalDetermination of Second Mesiobuccal
Canal inCanal in
Maxillary Second MolarMaxillary Second Molar
Preoperative periapical radiograph of maxillary right second molar
depicts radiolucent lesions around the Palatal and buccal roots
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Intraoperative CBCT demonstrates absence of MB2 in MB root
(arrows) in both axial and coronal planes
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Postoperative periapical radiograph of nonsurgical root
canal treatment.
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• Cone beam computed tomography
reconstructed scans are invaluable
for assessing teeth with unusual
anatomy, such as teeth with an
unusual number of roots,
dilacerated teeth and dens in dent
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An invaginated lower left secondAn invaginated lower left second
incisor tooth with an associatedincisor tooth with an associated
periapical radiolucency.periapical radiolucency.
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Taurodontism
Sagittal CBCT image of maxillary right first molar demonstrating
extent of pulp chamber extension and depth of furcation.

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Sagittal image with extent of mucositis in the sinus measured.

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Axial images demonstrating C-shaped anatomy and presence
of 4 canal systems.

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Separated Instruments
Determining the Location of a Separate
Instrument to Enable Bypass and Removal

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Advantages of cone-beam CT in
dentistry
1. Three dimensional rendition
2. Geometrically accurate images
3.Increased sensitivity and specificity for caries, periodontal
and periapical lesions
4. Patient comfort - no intra-oral placement of film or sensor.
5.Soft tissue rendition
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Disadvantages
1.Expensive
2.Inferior resolution
3.Beam scatter and hardening by high density materials
cause artifacts
4.Dentist/DSA needs to be computer savvy
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Limitations of CBCT
At present the images produced with CBCT technology
do not have the resolution of conventional radiographs.
The spatial resolution of conventional direct-action
packet film and digital sensors is in the order of 15–20
line pairs mm)1 (Farman & Farman 2005).
CBCT images only have a spatial resolution of 2 line pairs
mm)1 (Yamamoto et al. 2003).
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Conclusion
Radiological examination is a key tool for the diagnosis
and management of endodontic disease.
At present it is done by two-dimensional intra-oral
radiography which has limitations. CBCT can overcome
some of these limitations and help in improved decision
making thus improving the outcome of endodontic
treatment.

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REFERENCES
1. Cone Beam Computed Tomography in Endodontics Dr. SF
LEUNG ,VOL.15 NO.3 MARCH 2010
2. Clinical Applications of Cone-Beam Computed Tomography in
Dental Practice,William C. Scarfe,JCDA • www.cda-adc.ca/jcda
February 2006, Vol. 72, No. 1 • 75
3. Applications of Cone Beam Computed Tomography in the Practice
of Oral and Maxillofacial Surgery,J Oral Maxillofac Surg,Faisal A.
Quereshy et.al 66:791-796, 2008

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4.Cone Beam Computed Tomography in Endodontics,Conor
DURACK Shanon PATEL,Braz Dent J (2012) 23(3): 179-191
5.Applications of Cone Beam Computed Tomography in
Endodontics: A Review Meena N* and Kowsky RD,Dentistry
ISSN,Volume 4 Issue 7 1000242
6.CBCT & endodontics: Get it right the first time with
CBCT,Emanuele Ambu et.al,Dental Economics-volume101/
issue7

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7.What is Cone-Beam CT and How Does it Work? William C. Scarfe,Dent Clin N Am
52 (2008) 707–730
8.Cone beam computed tomography Wikipedia, the free encyclopedia
9.ConebeamComputed Tomography:Legal Considerations Bernard Friedland
9.Cone Beam-Computed Tomography in Endodontics,American Association of
Endodontists
10.Maxillofacial cone beam computed tomography: essence, elements and steps
to interpretation,WC Scarfe,Australian Dental Journal 2012; 57:(1 Suppl): 46–
60

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11.Intraoperative Endodontic Applications of Cone-Beam Computed
Tomography,Ball et al,JOE — Volume 39, Number 4, April 2013
12.Endodontic Applications of Cone Beam Computed
Tomography,Thomas V. McClammy,Dent Clin N Am 58 (2014)
545–559
13.Possibilities and limits of imaging endodontic structures with
CBCT,Marie-Theres Weber,SWISS DENTAL JOURNAL SSO VOL 125
3 P 2015

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