3d Imaging

Limited Field Cone Beam Computed
Tomography (CBCT) in Dentistry©

Martin D. Levin, DMD
Diplomate, American Board of Endodontics
Chevy Chase, Maryland

Adjunct Associate Professor of Endodontics
University of Pennsylvania, School of Dental Medicine
Philadelphia, Pennsylvania

© 2010, EndoNet Consulting, LLC All Rights Reserved.

Agenda*

1. What is CBCT and
How Does it Work?
2. Applications of CBCT
3. Summary

*Sponsored by Carestream/Henry Schein Software of Excellence

1.What is CBCT and How Does it Work?

Principals of CBCT: What is it?
CBCT utilizes a
pyramidal or cone
shaped x-ray beam
and an area detector
that acquires a full
volume of images in
a single rotation,
with no need for
patient movement.

Principals of CBCT: VOXEL
Imaging Area
50 mm

37mm
A voxel (VOlume piXEL),
represents the smallest
distinguishable box-shaped
.076m
part of a 3D image, similar .076m m

to a pixel representation in m
.076m
2D data. m
Isotropic Voxel

Principles of CBCT: Optimal voxel size
Unpublished ex vivo research investigated
the effect of increasing voxel resolution
on the detection rate of multiple
observers of the MB2 canal on 24
maxillary first molars by CBCT.
Compared to the overall prevalence of
MB2 canals (92% prevalence), CBCT
detection rates increased from 60% to
93.3% with increasing resolution
suggesting that if CBCT is to be used, then
resolutions in the order of 0.125 mm or
less are optimal.

Bauman M. The effect of CBCT voxel resolution on the detection of canals in the mesiobuccal roots of permanent maxillary first molars. MS Thesis.
University of Louisville School of Dentistry Masters in Oral Biology, Louisville, Kentucky, May, 2009.

This reconstructed view shows the cylindrical volume of data in a CBCT volume of the mandibular anterior teeth of a
patient referred for endodontic evaluation. Typically, limited field of view (FOV) is defined as 5 cm x 5 cm or less.

Principals of CBCT: Measurement
Simulated bone defects in the
human mandible proved that
CBCT is an accurate way to
measure osseous lesion
size and volume.

Pinsky H, Dyda S, Pinsky RW, Misch KA, Sarment DP: Accuracy of three-dimensional measurements using CBCT. Dentomaxillofac
Radiol 2006:35;410-416.

Principals of CBCT: Field of view (FOV)

Large
Medium
Focused


Large
Medium
Limited


Large
Medium
Limited
Stitched

Naturally-Occurring
“Background” Radiation
We are exposed to radiation from natural sources all the
time: Average in US is 3 mSv per year from naturally
occurring radioactive materials and cosmic radiation
from outer space.

The added dose from cosmic rays during a 5 hour flight
in a commercial airplane is about 0.03 mSv.

In the US, the largest source of background
radiation comes from radon gas in our homes (about
2 mSv per year). Like other sources of background
radiation, exposure to radon varies widely from one part
of the country to another.

NCRP Report #160
In 2006, Americans were
exposed to 7 times more
ionizing radiation than in
the early 1980s.
The increase was result of
growth of medical imaging,
especially CTs (67 million)
and nuclear medicine (18
million).

Principals of CBCT: Dosimetry
CT of maxilla and mandible 243

CBCT large FOV 31

FMX 18.3

Bitewings (4) 4.6

Kodak 9000 3D mand posterior 38.3 µSv 5

Kodak 9000 3D mand anterior 21.7 µSv 3

Kodak 9000 3D panoramic 14.7 µSv 2

Kodak 9000 3D max anterior/posterior… 1
Time period for equivalent effective dose
from natural background radiation in days
Intraoral periapical 0.61

0 50 100 150 200 250
Ludlow JB: Dosimetry of Kodak 9000 3D Small FOV CBCT and Panoramic Unit, Proceedings of the AAOMR, 2008.

Principals of CBCT: Dosimetry
Level
“The Kodak 9000 3D provides s
doses that are substantially 2
lower than previously reported 3
doses produced by medium and 4
large FOV CBCT units.” 5
The digital panoramic mode 6
provides a low dose alternative 7
for panoramic examinations of the 9
jaws using the same unit.

Rando the Radiology Phantom
27 Thermoluminescent Sensors

Ludlow JB: Dosimetry of Kodak 9000 3D Small FOV CBCT and Panoramic Unit, University of N Carolina School of Dentistry, Chapel Hill, NC, 2008.

Principals of CBCT – What is it?
2D Planar Imaging 3D Volumetric Imaging

With 2D imaging, the letters are With volumetric imaging, it is like
superimposed making it difficult removing a particular pane (slice) to
to make out detail. examine it clearly and accurately.

Limitations of 2D Imaging
Intraoral radiography is based on
the transmission, attenuation and
recording of X-rays on an analog
film or digital receptor, and
requires an optimized geometric
configuration of the X-ray
generator, tooth and sensor to
produce an accurate projection.

The image produced is a 2D
representation of a 3D object.

Scarfe WC, Levin MD, Gane D, Farman AG. Use of Cone Beam Computed Tomography in Endodontics. Int J of Dent, 2009.

Principals of CBCT: Limitations of 2D imaging
Goldman et al. showed that in
evaluating the healing of periapical
lesions using 2D periapical
radiographs, there was only 47%
agreement between 6 examiners.
When those same examiners
evaluated the same films at two
different times, they only had 19%–
80% agreement between the two
evaluations.

M. Goldman, A. H. Pearson, and N. Darzenta, ―Endodontic success—who’s reading the radiograph?‖ Oral Surgery, Oral Medicine, Oral Pathology,
vol. 33, no. 3, pp. 432–437, 1972.

Principals of CBCT: Limitations of 2D imaging
CBCT is a tomographic
scanning technology that
allows us understand the
maxillofacial complex and
the spacial relationship of
anatomic structures.

Pinsky HM, Dyda S, Pinsky RW, Misch KA, Sarment DP: Accuracy of three-dimensional measurements using CBCT. Dentomaxillofac Radiol 2006.
35;410-416.

Advantages of Limited Field CBCT

1. Higher resolution and diagnostic potential
2. Focused on anatomical area of interest
3. Less radiation exposure
4. Less time required to
read the image (4.5 vs 17 min)
5. Smaller area of responsibility

Simonton JD, Trevino E, Azevedo: Small v Large Volume CBCT in Endodontics, Table Clinic, AAE, Vancouver, 2008.

Principals of CBCT: Visualization

Axial

Coronal Sagittal

Principals of CBCT: Visualization

Axial Transaxial

Coronal Sagittal

What Percentage of Patients
Are Scanned?
% of All Endodontic
Referrals (ALARA)

42
58

Cone beam scan
No cone beam scan

Offices of Drs. Levin and Mischenko, Chevy Chase, Maryland

What Procedures Are Scanned?
100% 11.3 Mand anterior
15
80% Max anterior
34.6
60% Mand posterior
40% Max posterior
47.3
20%
0%
CBCT Data Capture

Offices of Drs. Levin and Mischenko, Chevy Chase, Maryland

Principals of CBCT: Radiology Over-Reads

“It is the responsibility of the
practitioner obtaining the CBCT
images to interpret the findings of
the examination. Just as a pathology
report accompanies a biopsy, an
imaging report must accompany a
CBCT scan.”

American Academy of Oral and Maxillofacial Radiology (AAOMR) Executive opinion statement on performing diagnostic CBCT

2-D Digital Radiography Systems
Odontogenic
lesions normally
initiate around a
specific tooth and
spread from the
cancellous to
cortical bone as
the lesion
expands.

2-D Digital Radiography Systems
“The Kodak filtered,
Schick filtered, Op-
Time unfiltered,
Schick unfiltered,
and Dexis filtered
images were
significantly
better at lesion
detection
compared with D-
speed film.”

Hadley DL, Replogle KJ, Kirkam JC, Best AM: A Comparison of five radiographic systems to D-speed film in the detection of artificial bone lesions. J of Endod 34(9):1111-14, 2008.

2-D Radiography Systems: Comparison
“Comparisons of the
filtered and unfiltered
images in the digital
systems revealed
differences between the
systems. Kodak filtered
images had the greatest
probability of lesion
detection.”

Hadley DL, Replogle KJ, Kirkam JC, Best AM: A Comparison of five radiographic systems to D-speed film in the detection of artificial bone lesions. J of Endod 34(9):1111-14, 2008.

2-D Radiography Systems: Comparison
Resolution: 9lp/mm v >20 lp/mm
Active Area: 10% more for size 2 sensor
Sensor shape: rounded corners
Cable attachment: robust

IntraOral Camera: WiFi 1024 x 768 resolution

Levin, M: Digital Technology in endodontic practice. Pathways of the Pulp, Ed 10, Elsevier, St. Louis, 2010.

2. Endodontic Applications of CBCT

Endodontic Applications of CBCT
1. Diagnosis of endodontic pathosis
Canal morphology
Assessment of pathosis of non-endodontic
origin
Evaluation of root fractures and trauma
Analysis of external and internal root
resorption and extraradicular invasive
cervical resorption
Pre-surgical planning
Implant planning

Cotton TP, Geisler TM, Holden DT, Schwartz SA, Schindler WG. Endodontic applications of cone beam volumetric tomography, J Endod 2007;33:1121–1132.

Diagnosis of endodontic pathosis
2. Canal morphology
origin
cervical resorption
Implant planning


Canal morphology
3. Assessment of pathosis of non-endodontic
origin
cervical resorption
Implant planning


Canal morphology
origin
4. Evaluation of root fractures and trauma
cervical resorption
Implant planning


Canal morphology
origin
5. Analysis of external and internal root
cervical resorption
Implant planning


Canal morphology
origin
cervical resorption
6. Pre-surgical planning
Implant planning


Canal morphology
origin
cervical resorption
7. Implant planning


Pre-Operative Assessment

“Imaging achieves
visualization of dental and
alveolar hard tissue
morphology and pathologic
alterations to assist correct
diagnosis.”

Scarfe WC, Levin MD, Gane D, Farman AG. Use of Cone Beam Computed Tomography in Endodontics. Int J of Dent, submitted Jul 29, 2009.

3 Month Check-Up: CBCT Axial View

3 Month Check-Up: CBCT Sagittal View

Clinical Decision Making: Missed Lesions

“CBCT showed
significantly more
lesions (34%, p 0.001)
than PA radiography.”

Low KMT, Dula K, Bürgin W, von Arx T. Comparison of periapical radiography and limited cone-beam tomography in posterior maxillary
teeth referred for apical surgery. J Endod 2008;34:557–562.


“Detecting lesions with PA
radiography alone was
most difficult in second
molars or in roots in
close proximity to the
maxillary sinus floor.”



“Only 1 out of 14 [artificial]
furcation defects in maxillary
teeth were seen on PA
radiography because of
overlapping roots, whereas
HR-CT scans were able to
identify all furcal defects.”

Fuhrmann RA, Bucker A, Diedrich PR. Furcation involvement: comparison of dental radiographs and HR-CT-slices in human specimens.
J Periodontal Res 1997;32:409 –18.

Fuhrmann compared artificial
bone defects in the antral floor
(1-2 mm to the denudation of
the entire antral surface). PA
radiography was unable to
detect any of the defects,
whereas 62.5% of the defects
were detected with CT scans.


Lesion Detection
Patel, et al. used 2 mm diameter
defects placed in the cancellous bone
at the apices of 10 first molar teeth on
six partially dentate intact human dry
mandibles.
They found a detection rate of
24.8% for intraoral radiography
and 100% CBCT imaging.

Patel S, Dawood A, Mannocci F, Wilson R, Pitt Fort T. Detection of periapical bone defects in human jaws using CBCT and intraoral radiogrpahy. Int J Endod 2009;42:507-515.

Lofthag-Hansen, et al.
compared the accuracy of 3
observers using focused field
CBCT to PA radiography.
While CBCT and intraoral
radiographs identified 53 roots
with lesions, CBCT identified
an additional 33 roots with
lesions (62%).

Lofthag-Hansen S, Huumonen S, Grondahl HG. Limited CBCT and intraoral radiography for the diagnosis of periapical pathology. Oral Surg Oral Med Oral Path Oral
Radiol Endod 2007;103:114-119.


Lofthag-Hansen S, Huumonen S, Grondahl HG. Limited CBCT and intraoral radiography for the diagnosis of periapical pathology. Oral Surg Oral Med Oral Path Oral
Radiol Endod 2007;103:114-119.

Maxillary Sinusitis of Dental Origin
When a dental infection extends
directly through the mucosal floor
causing a secondary maxillary sinus
infection.
Abrahams, et al., infections of maxillary
posterior teeth show maxillary sinus
pathosis: 60%
Matilla found mucosal hyperplasia; 80%.
Dental infections cause 10-15% of acute
maxillary sinusitis, and is much higher in
chronic cases.

Ingle JI, Bakland LK: Endodontics. 5th ed. Hamilton, Ont.; BC Decker; 2002.

Clinical Decision Making: Missed Canals

Persistent Idiopathic Facial Pain (PIFP)

Pain in face, present daily, persists all
or most of day.
Poorly localized, unilateral deep ache.
Not associated with sensory loss or
other physical signs, normal lab and
imaging studies.
Psychiatric symptoms of depression
and anxiety prevalent and compound
conundrum.

Headache Classification Subcommittee of the International Headache Society, 2004)

Persistent Idiopathic Facial Pain (PIFP)

Diagnosis and Treatment Planning:
Maxillary sinusitis of dental origin

Osteoperiostitis
Occasionally, apical
periodontitis will not
penetrate the antral
floor, but will displace
the periosteum, which
will deposit new bone
(periapical
osteoperiostitis or
“halo”).

Osteoperiostitis

Incidental Findings

Mucus retention pseudocyst Antrolith

Diagnosis and Treatment Planning

Diagnosis of Endodontic Pathosis

b c d

Diagnosis of Endodontic Pathosis

e f

Principals of CBCT: Missed canals
Matherne, et al. compared the ability of three board certified
endodontists to detect the number of root canals on intraoral digital
(both CCD and PSP) images with CBCT in 72 extracted teeth in 3 equal
groups of maxillary molars, mandibular premolars, and mandibular
incisors. Observers failed to detect at least one root canal in 40%
of teeth using 2D imaging.
Number of Canals in Number of Canals in Mandibular Number of Canals in Mandibular
Maxillary Molars Premolars Incisors

CBCT 3.58 1.21 1.5
CCD 3.1 1.0 1.0
PSP 3.0 1.1 1.3

Matherne RP, Angelopoulos C, Kulild JC, Tira D. Use of CBCT to identify root canal systems in vitro. J Endod 2008;34:87-89.

Acute Periradicular Periodontitis
In a 150 patients,
17 accessory
mental foramina
were located in
the area of the,
area of mesial
root of the
mandibular first
molar.

Katakami K, Mishima AT, Shiozaki K, Shimoda S, Hamada Y, Kobayashi K. Characteristics of accessory mental foramina observed on limited CBCT
images, published online 13 Oct 2008. AAE, Elsevier, Inc.

Root Fracture, Horizontal
Bernardes, et al. [65]
retrospectively compared
conventional periapical
radiographs and CBCT
images for 20 patients
with suspected root
fractures. They found
that CBCT was able to
detect fractures in 90%
of patients whereas PAs
could only detect
fractures in 30% to 40%
of cases.
Bernardes RA, de Moraes IG, Duarte MA, Azevedo BC, de Azevedo JR, Bramante CM. Use of cone-beam volumetric tomography in the diagnosis of
root fractures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009 Mar 7.[Epub ahead of print]..

Root Fracture, Vertical
Hassan, et al. compared the
accuracy of 4 observers in
detecting ex vivo vertical root
fractures (VRFs) on CBCT and
periapical images. They
found an overall higher
accuracy for CBCT because
mesio-distal fractures are
almost impossible to detect
with 2D imaging - the x-ray
beam must be within 4 of
the fracture plane.

Hassan B, Metska ME, Ozok AR, van der Stelt P, Wesselink PR. Detection of vertical root fractures in endodontically treated teeth by a cone
beam computed tomography scan. J Endod 2009;35:719-722.

Root Fracture, Vertical

Hassan B, Metska ME, Ozok AR, van der Stelt P, Wesselink PR. Detection of vertical root fractures in endodontically treated teeth by a cone
beam computed tomography scan. J Endod 2009;35:719-722.

Resorption

Common complications of trauma are pulp necrosis, pulp canal obliteration,
periapical pathosis and root resorption. Types of root resorption: repair-related
(surface), infection-related (inflammatory), ankylosis-related (osseous
replacement) or extraradicular invasive cervical resorption are among the
most common.

Resorption, External

c
d

b

a

e

Extraradicular
Invasive Cervical
Resorption
“CBCT has been used
successfully to confirm
the presence of IRR and
differentiate it from
ERR.”


“CBCT has been used
successfully to confirm
the presence of IRR and
differentiate it from
ERR.”


Periradicular Pathosis
Estrela, et al. compared the accuracy of
CBCT, panoramic and periapical
radiographs from 888 imaging exams
showing periapical pathosis.
3 observers reviewed a total of 1,014
images taken from 596 patients. They
found that CBCT imaging detected
54.2% more periradicular lesions
than intraoral radiography alone.

Estrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of CBCT and panoramic and periapical radiography for detection of apical periodontitis. J Endod 2008;34:273-279.

Why Embrace 3D?

“Diagnostic information directly
influences clinical decisions.
Accurate data lead to better
treatment planning decisions and
potentially more predictable
outcomes.”


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