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National Scientific Advisory Committee Report
Cone Beam Technology
Question to be investigated
What are the specific clinical criteria/conditions under which cone beam technology (CBT)
provides more positive outcomes versus traditional radiographic imaging? (Be sure to include
radiation exposure as part of your review.)
Executive Summary
Cone Beam Computed Tomography (CBCT) was introduced in dental practice more than a
decade ago (1998). There are more than 20 manufacturers on the market that sell either
machines or specialized software to manipulate the CBCT scan data for advanced treatment
planning in several dental disciplines. CBCT has the ability to depict hard tissue structures in
the head and neck area in three planes of space, with minimal distortion or magnification.
Tissues that are difficult to see with conventional radiographs due to superimposition can
often be accurately visualized using CBCT. CBCT does not allow accurate visualization of
soft tissue structures.
No studies have been conducted to evaluate whether CBTs lead to more successful treatment
outcomes. There are a few studies documenting the impact of CBCT on either treatment
planning or diagnostic thinking. Most of the current evidence on CBCT is on diagnostic
accuracy which ranks low as a source for clinical decision making1. As a result, uncertain
benefits in terms of improved procedure outcomes have to be weighed against the known
harms of diagnostic ionizing radiation. The harms of CBCT include:
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Increased cancer risk and mortality caused by the additional radiation dose 2-4. This
harm is relevant when it comes to dentistry due to the high prevalence of dental care.
For instance, close to 50% of children born in the U.S. (or approximately two million
children) undergo orthodontic treatment each year5.
Lack of legislation on CBCT standards may lead to unbridled usage: There is a
common lack of understanding on the part of both medical and dental practitioners
regarding the harms of radiation. For instance, despite the efforts on the part of the
ADA to inform dentists on the harms of ionizing radiation 2-4, many dentists do not
follow the ALARA principle. For instance, D-film use continues to be highly
prevalent in dental practices despite the fact that guidelines have advised against their
use for over two decades now6. The same has occurred in medicine where some have
come to the conclusion that legislation is the only approach to ensure that guidelines
regarding ionizing radiation exposures are followed 7.
More likely occurrence of incidentalomas 8 (definition: incidental findings during
routine dental examinations). These incidentalomas may include false positive
findings, cases of overdiagnosis, and true disease that will progress to clinical
symptoms.
o Overdiagnosis is the diagnosis of histologically verifiable disease that does not
progress to clinical symptoms 9.
o A false positive is the diagnosis of a disease that is determined not be present
upon further diagnostic testing.
o True disease is a clinical condition that is verified as truly present upon further
clinical examination and that will eventually lead to morbidity or mortality.
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-
Incidentalomas may have the following negative consequences:
o Further diagnostic follow-up testing which may include biopsies and
additional diagnostic radiation.
o Psychological harms, temporary or permanent, associated with discovering the
presence of occult disease.
o Legal dilemmas for the practitioner.
We conclude that CBCT may have applications in clinical dentistry for a few specific clinical
conditions only after it has been demonstrated that conventional radiography does not obtain
information that is deemed necessary for therapeutic decision making.
Research sources and thoroughness estimate
In the absence of reliable evidence on benefits and known harms, recommendations for the
use of CBCT in dentistry have been developed or are being developed by organized dentistry.
Most of the current guidelines suffer from the absence of a formal scientific review process.
For instance, the American Academy of Oral and Maxillofacial Radiology does not report the
utilization of accepted systematic review guidelines for the construction of clinical guidelines
and instead appears to rely on expert opinion. Currently, the SEDENTEXCT are the only
evidence-based guidelines that incorporated some aspects of the systematic review process in
the formulation of guidelines.
The absence of a more formal process for the construction of CBCT practice guidelines by
professional guidelines is of concern. The presence of professional biases in the construction
of guidelines has become of increasing concern. The Institute of Medicine (IOM) has
provided suggestions for the development of clinical guidelines. Few of these suggestions
were adhered to in the current CBCT guidelines. For instance, the IOM has suggested that
the development of guidelines for clinical practice should be executed by individuals who are
free from conflicts of interest, and when such individuals are necessary, they should make up
a minority of the panel. 10 The IOM has noted that this is particularly important when
guidelines are created in the absence of evidence which is the case for CBCT guidelines.
Review panels for the American Academy of Oral and Maxillofacial Radiology (AAOMR),
the American Academy of Endodontics (2007), and the SEDENTEXCT (Safety and Efficacy
of a New and Emerging Dental X-ray Modality) project in Europe 11 agree that CBCT scans
should not be used routinely in dentistry. The decision to order a CBCT scan must be based
on the patient’s history and clinical examination, and justified on an individual basis. These
organizations often suggest that clinicians should make a scientific decision on an issue
where no scientific evidence exists; namely that the benefits to the patient outweigh the
potential risks of exposure to ionizing radiation. Making such a decision is especially
challenging for infants, children or young adults in whom the cancer risk subsequent to
ionizing radiation can increase several-fold when compared to adults. The recommendations
typically state that CBCT should only be used when the question for which imaging is
required cannot be answered adequately by lower dose conventional dental radiography or
alternate imaging modalities. Insufficient research has been conducted to provide
probabilistic estimates when such situations arise.
At this time, all CBCT equipment produces dose levels and beam energies (radiation dose
and risk) that are typically higher than conventional dental radiography (intraoral and
panoramic) but lower than conventional CT scans of the dental area. The dose received with
CBCT will depend on the diagnostic need, protocol and scanner used. There is no standard
radiation exposure published for each possible dental application described in this report;
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however, some generalizations can be made. In general, except for endodontic applications
which require a very small field of view1 (FOV) and high resolution, most other applications
(e.g., implant treatment planning, orthodontics and orthognatic surgery planning) can be
accomplished with voxel2 sizes of 0.4 mm 12 , which means lower radiation doses. In
addition, the information obtained from CBCT imaging requires a substantial level of
expertise for interpretation. This implies that the untrained clinician is likely to have a
substantial error rate in the interpretation of CBCT images resulting in a high percentage of
missed or false positive diagnoses 13.
While there may be numerous articles in the literature describing the use of CBCT for
specific dental applications, there are currently no clinical studies demonstrating improved
patient outcomes or systematic reviews of such studies. To the contrary, existing systematic
reviews appear to often point to the absence of good evidence on the benefits of CBCT14,15.
The scientific evidence that the use of CBCT alters diagnosis and improves treatment plans is
starting to be studied16-20. The results of such studies suggest that diagnostic radiography
does not necessarily impact diagnostic thinking, treatment planning, or diagnostic accuracy.
For certain clinical applications, the use of CBCT is justified by the parachute argument (e.g.,
the benefits for the 3-D localization of a cuspid are reported to be so obvious no scientific
studies are needed) 14. Often, specific indications for acquiring CBCT images and protocols
(e.g., doses) are based on anecdotal evidence.
Some of the following recommendations and guidelines were extracted from sources such as
the American Academy of Oral and Maxillofacial Radiology (AAOMR), American Academy
of Endodontics, and the European SEDENTEXCT project. It is expected that in the near
future additional recommendations (e.g., from the American Dental Association) will be
available. Many of the findings and conclusions reported reflect expert opinion of the
involved panels and do not necessarily reflect the opinions of the authors of this document.
Findings and Conclusions
Safety and radiation dose:
CBCT allows for multiplanar reconstruction, non-orthogonal reconstruction and 3dimensional rendering of hard tissue structures. The beam is conical, usually requires one
rotation, and voxel sizes range from 0.4 mm to 0.076 mm. CBCT has an advantage over
medical grade CT as radiation doses from commonly used CBCT acquisition protocols are
lower by an order of magnitude, plus it allows for greater spatial resolution and nonorthogonal reconstruction. The doses of CBCT, however, are significantly higher than the
traditional dental radiography tools.
To provide some estimates of the cancer burden due to diagnostic radiation, the following
two examples are provided. The first example provides a range of radiation doses which are
commonly associated with orthodontic therapy21,22. The below dose estimates show a range
of possible thyroid cancer burdens associated with orthodontic diagnostic radiation. CBCT
can be expected to lead to increases in doses to the thyroid ranging from 1.2 mGray for the ICAT23 to 6.3 mGray for the CB Mercuray 24. The number of individuals developing thyroid
cancer is calculated for the year 1996 where the number of children and adolescents
undergoing orthodontic therapy was approximately 1.5 million.
11
2
The Field of View (FOV) is that part of the skull that is visible through the imaging
A voxel is a volume element in a 3-dimensional space. A voxel is the 3-D equivalent of a pixel in a 2-D space. 3
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Lifetime Attributable Thyroid Cancer Risk (Age at Exposure 10‐19)
Dose
Females
Males
1 mgray
19
2
2.5 mgray
68
10
5 mgray
96
13
10 mgray
193
27
1996 cohort – 1.5 million treated, 65% females
As a second example, the number of orthodontic patients developing leukemia as a
consequence of 2 CBCT and CT is provided. The number of expected cases was calculated
under the same assumptions as the calculations for thyroid cancers.
Lifetime Attributable Leukemia Risk (Age at Exposure: 10)
Dose
Females
Males
CBCT
4
3
CT
19
14
1996 cohort – 1.5 million treated, 65% females
As CBCT use has increased in dentistry (especially amongst orthodontists, oral and
maxillofacial surgeons, dentists who perform implants or treat patients with facial pain or
temporomandibular disorders), there is concern about the possible overuse or misuse of this
technology. As endorsed by the American Dental Association25 , the fundamental objective
of diagnostic radiology is summarized in the ALARA principle: radiation doses must be kept
“As Low As Reasonably Achievable”, consistent with the diagnostic needs and goals. All
ionizing radiation is potentially damaging, and thus every prescription for exposure to
ionizing radiation has to be justified. Within this framework, the ADA has engaged into
discussions regarding the most appropriate use of CBCT in dental practice 26 . The ADA
Council on Scientific Affairs is currently developing its own set of guidelines on the use of
CBCT.
Such voluntary guidelines rarely have an impact on clinical practice. Case in point, the
Scientific Council of the American Dental Association recommended in 1984 to abandon the
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use of D-film speed27. These suggestions have not been adhered to according to national
surveys that have subsequently been conducted. Current industry estimates suggest that 70%
of the film is still D-speed film 6. Similarly, while the ADA has recommended the use of
thyroid shields for decades 25,27-29, the prevalence of its utilization has been reported to low30.
The lack of impact of guidelines when it comes to minimizing radiation is driving the call for
legislation in medicine.
At this time, all CBCT equipment produce dose levels and beam energies (radiation dose and
risk) that are higher than conventional dental radiography (intraoral and panoramic), that
expose organs such as brain and thyroid that do not get exposed with other radiographic
projections 11 . Dose is dependent on equipment type and exposure settings, especially the
“field of view” (FOV) selected. The size of the FOV describes the scan volume of the CBCT
machine and is dependent on the detector size and shape, beam projection geometry and the
ability to collimate the beam. Beam collimation limits the x-radiation exposure to the region
of interest and ensures that an optimal FOV can be selected based on disease presentation
(Geist, 2011). . The FOV can range from 10 cm or less scan height for small FOV scanners
(e.g., for individual teeth or quadrant), greater than 10 cm but less than 15 cm of height for
medium FOV scanners (e.g., for both arches including TMJ), and 15 cm or greater scan
height for large FOV scanners (e.g., for full head scan). Selection of the most appropriate
imaging protocol and scanner depends on the diagnostic task at hand. For example, in
endodontics, if it is important to be able to detect disruptions in the periodontal ligament
space, which measures approximately 200μm, and optimal resolution is necessary, a small
FOV scanner would be the one recommended.
Also, doses vary significantly between CBCT machines, as exemplified in the tables below
from the SEDENTEXCT project (2009). Please note that CBCT technology is rapidly
developing as manufacturers are regularly bringing out new models or up-grading existing
software to models that are on the market. Consequently, the doses quoted in the table might
not apply to newer versions of CBCT equipment with the same name. Also, reported
radiation doses measured in idealized phantom situations with optimal collimation rarely
approximate real-life doses.
The conclusion is that careful attention must be paid to the scanner to be used, and voxel size
and FOV needed for a specific dental need in order to help minimize the dose received by the
patient. In addition, the use of the technology requires practical training and protection
measures for office personnel. Clinicians must be trained in use and interpretation of CBCT
scans. Appropriate qualified experts should be consulted prior to and after installation to meet
state and federal requirements, and manufacturer’s recommended calibration routines should
be conducted at the recommended intervals.
Dental CBCT unit
NewTom
Effective dose (μSv)
Craniofacial
Dento-alveolar
41-75
30-78
Accuitomo/ Veraviewepocs
11-102
Galileos
Promax
70-128
488-652
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Prexion
i-CAT
189-388
34-89
48-206
CB MercuRay
407
283-1073
Illuma
98-498
Effective dose (μSv)
Intra-oral radiograph
<8.3
Panoramic radiograph
2.7 - 23
CT maxillo-mandibular
180 - 2100
CT maxilla
1400
31
Guidelines for CBCT use as reported by different organizations:
The SEDENTEXCT (Safety and Efficacy of a New and Emerging Dental X-ray Modality)
project in Europe has established guidelines (Consensus Guidelines of the European
Academy of Dental and Maxillofacial Radiology) for the use of CBCT in dental diagnosis
(2009). The “Basic Principles on the use of Cone Beam CT” according to a consensus
reached by faculty of several European universities are based on the following premises: 32
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CBCT examinations must not be carried out unless a history and clinical examination have
been performed
CBCT examinations must be justified for each patient to demonstrate that the benefits
outweigh the risks
CBCT examinations should potentially add new information to aid the patient’s management
CBCT should not be repeated ‘routinely’ on a patient without a new risk/benefit assessment
having been performed
When accepting referrals from other dentists for CBCT examinations, the referring dentist must
supply sufficient clinical information (results of a history and examination) to allow the CBCT
Practitioner to perform the Justification process
CBCT should only be used when the question for which imaging is required cannot be
answered adequately by lower dose conventional (traditional) radiography
CBCT images must undergo a thorough clinical evaluation (‘radiological report’) of the entire
image dataset
Where it is likely that evaluation of soft tissues will be required as part of the patient’s
radiological assessment, the appropriate imaging should be conventional medical CT or MR,
rather than CBCT
CBCT equipment should offer a choice of volume sizes and examinations must use the
smallest that is compatible with the clinical situation if this provides less radiation dose to the
patient
Where CBCT equipment offers a choice of resolution, the resolution compatible with adequate
diagnosis and the lowest achievable dose should be used
A quality assurance programme must be established and implemented for each CBCT facility,
including equipment, techniques and quality control procedures
Aids to accurate positioning (light beam markers) must always be used
All new installations of CBCT equipment should undergo a critical examination and detailed
acceptance tests before use to ensure that radiation protection for staff, members of the public
and patient are optimal
CBCT equipment should undergo regular routine tests to ensure that radiation protection, for
both practice/facility users and patients, has not significantly deteriorated
For staff protection from CBCT equipment, the guidelines detailed in Section 6 of the
European Commission document ‘Radiation Protection 136. European Guidelines on
Radiation Protection in Dental Radiology’ should be followed
All those involved with CBCT must have received adequate theoretical and practical training
for the purpose of radiological practices and relevant competence in radiation protection
Continuing education and training after qualification are required, particularly when new
CBCT equipment or techniques are adopted
Dentists responsible for CBCT facilities who have not previously received ‘adequate
theoretical and practical training’ should undergo a period of additional theoretical and
practical training that has been validated by an academic institution (University or equivalent).
Where national specialist qualifications in DMFR exist, the design and delivery of CBCT
training programmes should involve a DMF Radiologist
For dento-alveolar CBCT images of the teeth, their supporting structures, the mandible and the
maxilla up to the floor of the nose (e.g. 8cm x 8cm or smaller fields of view), clinical
evaluation (‘radiological report’) should be made by a specially trained DMF Radiologist or,
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where this is impracticable, an adequately trained general dental practitioner
20
For non-dento-alveolar small fields of view (e.g. temporal bone) and all craniofacial CBCT
images (fields of view extending beyond the teeth, their supporting structures, the mandible,
including the TMJ, and the maxilla up to the floor of the nose), clinical evaluation
(‘radiological report’) should be made by a specially trained DMF Radiologist or by a Clinical
Radiologist (Medical Radiologist)
Indications for CBCT referrals:
Despite limited high levels of evidence, specific indications for CBCT referral as suggested by
several organizations are summarized below.
Implant site assessment*
Radiographic assessment of the jaw can be a considered useful for implant placement in
certain anatomical areas such as the mandibular region between the mental foramen and the
foramen mandibulare. While it is often stated that panoramic and periapical radiography has
distortion, this is an insufficient justification for switching to CBCT. With the use of
standardization devices such as a fissure bur during radiographic exposure, panoramic
radiographs can provide accurate estimation for the placement of mandibular implants in the
area of the inferior alveolar nerve in the majority of cases33.
The fact that the AAOMR has recommended that all potential implant sites be evaluated with
“cross sectional imaging orthogonal to the site of interest”, referring to planar or computed
tomography 34, may be a reflection of their conflicts of interest, rather than science as other
organizations or expert clinicians have not made such recommendations. Given the
increasing evidence that implant length is not related to implant success 35, CBCT may not be
required to determine the inferior alveolar nerve (IAN) position in clinical settings with more
than 12 mm of bone between the alveolar crest and the inferior alveolar nerve (IAN) can be
identified on a panoramic radiograph. If cross-sectional radiographs are indicated, then
CBCT may be preferred over other tomographic modalities 36 . Radiation dose increases with
increased resolution, and so resolution needs to match the task at hand. Implant treatment
planning can be accomplished generally with voxel sizes of 0.4 mm 12,37.
Often anecdotal evidence is provided to justify CBCT for implant therapy. For instance, one
author in a non-refereed dental journal has suggested that CBCT can be valuable in the
following tasks in implant assessment12:
a) Measuring distances between the alveolar crest and various anatomic landmarks
b) Evaluating the quality of cortical and medullar bone in the potential implant site
c) Visualizing the inclination of the alveolar process to predict a successful path of insertion
d) Providing the basis for treatment planning with the use of special algorithms
Clinical research will be required to determine whether such anecdotal justifications stand up
to an evidence-based assessment.
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According to the SEDENTEXCT project (2009), recommendations for use of CBCT for
implant placement include:
 The use of CBCT is not recommended as a routine imaging technique for all implant
cases

CBCT is justified for cross-sectional imaging prior to implant placement as an
alternative to existing cross-sectional techniques where the radiation dose is shown to be
lower

The advantage of CBCT with adjustable fields of view, compared with conventional CT,
becomes greater where the region of interest is a localized part of the jaw, as a similar
sized field of view can be used
TMJ evaluations
Decisions on radiograph exposures of the TMJ are often based on the need to establish a
diagnosis 38. A systematic review of TMJ imaging concluded that CBCT provides the same
diagnostic accuracy regarding degenerative condylar changes as CT, at lower cost and
radiation dosage 39. To what extent a diagnosis of a degenerative condylar changes
contributes to better patient outcomes is unclear.
Regarding other TMJ diseases (e.g., neoplasia of the condyle) CBCT has been reported to
have similar sensitivity and specificity to CT 40.

According to the SEDENTEXCT project (2009);
Where the existing imaging modality for examination of the TMJ is conventional CT,
CBCT should be considered as an alternative where radiation dose is shown to be lower
.
Orthodontics
Despite the increasing popularity of CBCT in orthodontics, the effects of information derived
from these images in altering diagnosis and treatment decisions has not been demonstrated. It
has, therefore, been recommended that CBCT not be used routinely during orthodontic
treatment (American Association of Orthodontists Resolution 26–10H, 2010), but be used
only in select cases in which conventional radiography cannot supply satisfactory diagnostic
information. According to Kapila et al13 , these cases include cleft palate patients, assessment
of unerupted tooth position, supernumerary teeth, identification of root resorption, and for
planning orthognatic surgery. Once again, it should be realized that justification for using
CBCT for these special cases is anecdotal.
The need to image other types of cases – according to Kapila - should be made on a case-bycase basis following an assessment of benefits vs. risks of scanning in these situations.
Orthodontic or orthognatic surgical planning can be accomplished generally with voxel sizes
of 0.4 mm 37.
Orthodontics is of particular concern when it comes to CBCT usage because of the high
prevalence of orthodontic care in the U.S. population and the typical age of care 5. Several
organs in children and adolescents are more sensitive to radiation than are adults. For
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instance, the radiosensitivity of the thyroid varies significantly as a function of age and
gender (red for females, and green for males).
The Academy of Oral and Maxillofacial Radiology (AAOMR) and the American Association
of Orthodontists are working together to develop guidelines and selection criteria for the use
of CBCT in orthodontics with special consideration for minimizing radiation dose in children
(as orthodontics involves a course of treatment over a period of time with multiple
radiographic exposures).
According to the SEDENTEXCT project (2009):
 Large volume CBCT should not be used routinely for orthodontic diagnosis

Where the current imaging method of choice for the assessment of cleft palate is MSCT,
CBCT may be preferred where radiation dose is lower. The smallest volume size
compatible with the situation should be selected because of reduced radiation dose

For complex cases of skeletal abnormality, particularly those requiring combined
orthodontic/surgical management, large volume CBCT may be justified in planning the
definitive procedure, particularly where MSCT is the current imaging method of choice

Research is needed to define robust guidance on clinical selection for large volume
CBCT in orthodontics, based upon quantification of benefit to patient outcome
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Oral Surgery
The ability to depict the dento-alveolar complex in three dimensions can help localize
structures. It has been suggested that CBCT can help better visualize impacted third molars
(which should minimize the risk of complications; 41), help reposition the condyle during
fracture surgeries (reducing postoperative complications; 42), etc. However, due to the poor
ability of CBCT to depict soft tissues, it is not indicated for fractures with extension into the
cranium or tumors with soft tissue involvement 43.

According to the SEDENTEXCT project (2009):
For the localized assessment of an impacted tooth (including consideration of resorption
of an adjacent tooth) where the current imaging method of choice is MSCT, CBCT may
be preferred because of reduced radiation dose

For the localized assessment of an impacted tooth (including consideration of resorption
of an adjacent tooth) where the current imaging method of choice is conventional dental
radiography, CBCT may be used when the information cannot be obtained adequately by
lower dose conventional (traditional)radiography

For the localized assessment of an impacted tooth (including consideration of resorption
of an adjacent tooth), the smallest volume size compatible with the situation should be
selected because of reduced radiation dose. The use of CBCT units offering only large
volumes (craniofacial CBCT) requires very careful justification and is generally
discouraged

CBCT may be justifiable in the assessment of dento-alveolar trauma in selected cases,
where conventional radiographs provide inadequate information for treatment planning

Where conventional radiographs suggest a close relationship between a mandibular third
molar and the inferior dental canal, and when a decision to perform surgical removal
has been made, CBCT is justified.
It should be noted that this latter guideline may be outdated. A recent systematic review
suggested that there are only two studies that compared CBCT and panoramic
radiographs with a valid reference method and presented the results in terms of
percentage of correct diagnoses14. While there was a trend for better sensitivity results
with CBCT, the difference was not significant.

CBCT may be justified for pre-surgical assessment of an unerupted tooth in selected
cases where conventional radiographs fail to provide the information required

For maxillofacial fracture assessment, where cross-sectional imaging is judged to be
necessary, CBCT may be used as an alternative imaging modality to conventional CT
where radiation dose is shown to be lower and soft tissue detail is not required

CBCT should not be used routinely for imaging the craniofacial skeleton
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
CBCT may be used, in selected cases, where only bone information is required, for
obtaining three-dimensional datasets of the craniofacial skeleton
Endodontics
Radiography has historically been considered important for the successful diagnosis of
odontogenic and non-odontogenic pathoses, treatment of the pulp chamber and canals of a
compromised tooth, biomechanical instrumentation, evaluation of final canal obturation, and
assessment of healing. With the development of new diagnostic instruments (apex locators)
the use of ionizing radiation in endodontics may also come under re-evaluation.
In a joint position statement of the American Association of Endodontists and the American
Academy of Oral and Maxillofacial Radiology44, it was concluded that CBCT must NOT be
used routinely for endodontic diagnosis or for screening purposes in the absence of clinical
signs and symptoms. The patient’s history and clinical examination must justify the use of
CBCT by demonstrating that the benefits to the patient outweigh the potential risks. It is
unclear if such a situation exists since dental implant can eliminate the need for CBCTs.
Clinicians have been advised to use the CBCT when the need for imaging cannot be
answered adequately by lower dose conventional dental radiography or alternate imaging
modalities. Endodontics usually requires high resolution and voxel size less than 0.4 mm
are generally needed (Farman et al., 2010). However, every effort should be made to reduce
the effective radiation dose to the patient for endodontic-specific tasks. Using the smallest
possible FOV, the smallest voxel size, the lowest mA setting and the shortest exposure time
in conjunction with a pulsed exposure mode of acquisition is recommended (in fact small or
limited FOV units are probably the most adequate for this as they can provide a resolution as
low as 0.076 voxel size). If extension of pathology beyond the area surrounding the tooth
apices or a multifocal lesion with possible systemic etiology is suspected, and/or a nonendodontic cause for devitalization of the tooth is established clinically, appropriate larger
field of view protocols may be employed on a case-by-case basis. Limited field of view
CBCT systems can provide images of several teeth from approximately the same radiation
dose as two periapical radiographs, and they may provide a dose savings over multiple
traditional images in complex cases. In fact, for most endodontic applications, limited
volume CBCT is preferred over large volume CBCT for the following reasons:
a) Increased spatial resolution to improve the accuracy of endodontic-specific tasks such
as the visualization of small features including accessory canals, root fractures, apical
deltas, calcifications, etc.
b) Highest possible spatial resolution that provides a diagnostically acceptable signal-tonoise ratio for the task at hand.
c) Decreased radiation exposure to the patient.
d) Time savings due to smaller volume to be interpreted.
According to the joint report of the AAOMR and AAE (2010), the use of CBCT in
endodontics should be limited to the assessment and treatment of complex endodontic
conditions such as:
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a) Identification of potential accessory canals in teeth with suspected complex morphology
based on conventional imaging.
b) Identification of root canal system anomalies and determination of root curvature.
c) Diagnosis of dental periapical pathosis in patients who present with contradictory or
nonspecific clinical signs and symptoms, who have poorly localized symptoms associated
with an untreated or previously endodontically treated tooth with no evidence of pathosis
identified by conventional imaging, and in cases where anatomic superimposition of roots
or areas of the maxillofacial skeleton is required to perform task-specific procedures.
d) Diagnosis of non-endodontic origin pathosis in order to determine the extent of the lesion
and its effect on surrounding structures.
e) Intra- or post-operative assessment of endodontic treatment complications, such as
overextended root canal obturation material, separated endodontic instruments, calcified
canal identification, and localization of perforations.
f) Diagnosis and management of dento-alveolar trauma, especially root fractures, luxation
and/or displacement of teeth, and alveolar fractures.
g) Localization and differentiation of external from internal root resorption or invasive
cervical resorption from other conditions, and the determination of appropriate treatment
and prognosis.
h) Pre-surgical case planning to determine the exact location of root apex/apices and to
evaluate the proximity of adjacent anatomical structures.

According to the SEDENTEXCT project (2009):
CBCT should not be used routinely for identification of periapical pathosis

CBCT may be considered for periapical assessment, in selected cases, when conventional
radiographs give a negative finding when there are contradictory positive clinical signs
and symptoms

Where CBCT images include the teeth, care should be taken to check for periapical
disease when performing a clinical evaluation (report)

CBCT should not be used routinely for endodontic diagnosis

CBCT may be justifiable for selected cases, where intraoral radiographs provide
information on root canal anatomy that is equivocal or inadequate for planning
treatment, most probably in multi-rooted teeth

CBCT may be justifiable for selected cases, where endodontic treatment is complicated
by concurrent factors, such as resorption lesions, combined periodontal/endodontic
lesions, perforations and atypical pulp anatomy

CBCT may be justifiable for selected cases when planning surgical endodontic
procedures. The decision should be based upon potential complicating factors, such as
the proximity of important anatomical structures
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Other Applications:
According to the SEDENTEXCT project (2009):
 CBCT should not be used as a routine method of caries detection and diagnosis. But,
where CBCT images include the teeth, care should be taken to check for caries when
performing a clinical evaluation (report)

CBCT should not be used as a routine method of imaging periodontal bone support

CBCT may be useful in selected cases of infra-bony defects and furcation lesions, where
clinical and conventional radiographic examinations do not provide the information
needed for management.

Where CBCT images include the teeth, care should be taken to check for periodontal
bone levels when performing a clinical evaluation (report)
Conclusions
CBCT must not be used routinely for dental care. Systematic reviews indicate that there is
currently no evidence to suggest better patient outcomes when CBCT is used. Clinicians should
use CBCT only if appropriately trained and when the need for imaging cannot be answered
adequately by lower dose conventional dental radiography or alternate imaging modalities.
Strength of the Evidence
There is a great need for future research regarding the contribution of CBCT to dental
applications. In areas where the use of CBCT may appear logical (as described above, CBCT
may be useful), the specific indications for acquiring CBCT images and protocols (e.g., doses) to
be used for imaging and extracting appropriate information have not been resolved. In absence of
other sources, the recommendations provided in this report were extracted from sources such as
the American Academy of Oral and Maxillofacial Radiology (AAOMR), American Academy of
Endodontics, and the European SEDENTEXCT project. It is expected that in the near future
additional recommendations (e.g., from the American Dental Association) will be available.
These professional guidelines were formulated in the absence of high-level evidence on the
usefulness of diagnostic tests, without adhering to principles of guideline formulation as
stipulated by the institute of medicine. Until clinical trials demonstrate that CBCTs do improve
the oral health related quality of life, it may be prudent to obtain informed consent. This
informed consent should inform the patient regarding the organ-specific radiation doses,
expected cancer risks, risk for discovering incidentalomas, and expected benefits in terms of
providing a successful procedure outcome.
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