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CURRENT THERAPY
J Oral Maxillofac Surg
66:791-796, 2008
Applications of Cone Beam Computed
Tomography in the Practice of Oral and
Maxillofacial Surgery
Faisal A. Quereshy, MD, DDS,* Truitt A. Savell, DDS, MD,†
and J. Martin Palomo, DDS, MSD‡
Providing imaging in 3 dimensions, computed tomography (CT) has had a profound effect on surgical and
medical practice since its introduction in 1973.1 Practitioners at that time certainly marveled at the new technology, but likely were at a loss as to how to apply it or
what exactly the images meant. It was only after years of
research, as well as the development of a whole new
aspect of radiology, that we have been able to apply this
technology for the benefit of our patients.
In oral and maxillofacial surgery, we are accustomed
to using CT in patients with trauma and pathological
conditions in the hospital setting; however, in dental
practice, practitioners depend almost entirely on 2-dimensional plain films. The applications and advantages
of CT in dentistry remain largely unrealized.
Cone beam CT (CBCT) was first developed for use
in angiography. In 1998, Mozzo et al2 reported the
first CBCT unit developed specifically for dental use,
the NewTom 9000 (Quantitative Radiology, Verona,
Italy). Other similar devices introduced at around that
time included the Ortho-CT, which was renamed the
3DX (J. Morita Mfg Corp, Kyoto, Japan) multi-image
micro-CT in 2000.3,4 In 2003, Hashimoto et al4 reported that the 3DX CBCT produced better image
quality with a much lower radiation dose than the
newest multidetector row helical CT unit (1.19 mSv
vs 458 mSv per examination).
CBCT machines have 2 major differences compared
with so-called “medical” CT scanners. First, CBCT
uses a low-energy fixed anode tube, similar to that
used in dental panoramic x-ray machines. Second,
CBCT machines rotate around the patient only once,
capturing the data using a cone-shaped x-ray beam.
These changes allow for a less expensive, smaller
machine that exposes the patient to approximately
20% of the radiation of a helical CT, equivalent to the
exposure from a full-mouth periapical series.5-8
All of the CBCT scanners currently on the market use
the same technology, with only slight differences. The
major difference is in the detector used, either an amorphous silicon flat-panel detector or a combination of an
image intensifier and a charge-coupled device (CCD)
camera. Both these technologies have been proven to
be accurate and reliable and to provide sufficient resolution for the needs of dental medicine (Fig 1).
Within every field, the introduction of new technology raises several fundamental questions, including identifying the practical applications of the new technology
and determining whether it is truly superior to existing
modalities. These questions are not easily answered, but
require research and comparison. This article explores
the possible applications of this new CBCT technology
and the ongoing research in these areas, with the goal of
applying CBCT data in an evidence-based manner.
Received from the School of Dental Medicine, Case Western Reserve University, University Hospitals Case Medical Center, Cleveland, OH.
*Program Director, Department of Oral and Maxillofacial Surgery.
†Former Resident, Department of Oral and Maxillofacial Surgery.
‡Associate Professor of Orthodontics and Director, Craniofacial
Imaging Center.
Address correspondence and reprint requests to Dr Quereshy:
Department of Oral and Maxillofacial Surgery, School of Dental
Medicine, Case Western Reserve University, 2123 Abingdon Road,
Cleveland, OH 44106; e-mail: [email protected]
Implant Dentistry
The advantages of CBCT in visualizing the alveolus in 3 dimensions and making precise measurements before surgery are obvious in the field of
implant dentistry (Fig 2). With conventional panoramic radiography, it is not unusual to anticipate
adequate bony support preoperatively, only to be
disappointed in the reflection of tissue. Obviously,
having this information preoperatively greatly reduces the likelihood of the need to change the
treatment approach intraoperatively. This gives the
surgeon the ability to anticipate implant placement
and even to place implants in a virtual model in
© 2008 American Association of Oral and Maxillofacial Surgeons
0278-2391/08/6604-0026$34.00/0
doi:10.1016/j.joms.2007.11.018
791
792
CONE BEAM COMPUTED TOMOGRAPHY
FIGURE 1. Some currently available CBCT scan devices. A,
NewTom 3G (courtesy of Aperio
Services, Sarasota, FL). B, i-Cat
(courtesy of Imaging Sciences,
Hatfield, PA). C, ILUMA (courtesy
of IMTEC Corp, Ardmore, OK).
D, ProMax 3D (courtesy of Planmeca Oy, Helsinski, Finland). E,
CB MercuRay (courtesy of Hitachi
Medical System America Inc,
Twinsburg, OH). F, Dental CBCT
(courtesy of TeraRecon Inc, San
Mateo, CA). G, 3D Accuitomo
(courtesy of J Morita USA, Irvine,
CA). H, Sirona Galileos (courtesy
of Sirona Dental Systems North
America, Charlotte, NC).
Quereshy, Savell, and Palomo.
Cone Beam Computed Tomography. J Oral Maxillofac Surg
2008.
terms of bone height, bone width, nerve position,
and even objective measures of bone quality.9
With regard to a traditional panoramic radiography,
the average machine produces approximately 25%
magnification, which must be accounted for when
planning implant placement. Preliminary studies on
CBCT, specifically the NewTom 9000, have concluded that the CBCT image underestimates the actual
distances; however, these differences were significant
FIGURE 2. Images produced
from a single exposure for the purpose of dental implant planning.
The images selected here are panoramic and cross-sectional views
with the mandibular nerve marked,
as well as a surface and radiographic (maximum intensity projection) view with the stent in place.
Quereshy, Savell, and Palomo.
Cone Beam Computed Tomography. J Oral Maxillofac Surg 2008.
only for the skull base. Imaging within the dentomaxillofacial regions was found to be quite reliable, demonstrating no significant differences.10 The fact that
measurements from the CBCT are routinely accurate
throughout the maxilla and mandible makes this an
excellent modality for planning implant placement.11
Conventional multislice CT has been used for implant planning and in fabrication of a stent used intraoperatively for precise implant placement in pre-
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QUERESHY, SAVELL, AND PALOMO
FIGURE 3. CBCT images of a
patient with a mandibular cyst. A,
Mesial view of right half of the mandible in a surface mode. B, Anterior
view of the mandible in the surface
mode (measurements in mm). C,
Lingual view of the mandible in surface mode (measurements in mm).
D, Radiographic cross-sectional
view of the maxilla and mandible.
E, Panoramic view.
Quereshy, Savell, and Palomo.
Cone Beam Computed Tomography. J Oral Maxillofac Surg 2008.
determined locations. The stent can be fabricated on
top of a CT image without the need for patient contact, allowing for precise placement of implants, prefabrication of the prosthesis and abutments, and delivery of the prosthesis on the same day as surgery.12
CBCT images have similar capabilities with the benefit of less radiation exposure to the patient.
Oral and Maxillofacial Pathology
Conventional CT is used routinely in the diagnosis of
maxillofacial pathology. Given the higher resolution,
lower radiation dose, and lower cost of CBCT in imaging
the maxillofacial region, it stands to reason that CBCT
can easily replace conventional CT in this regard. Threedimensional imaging of cysts and tumors of the maxillofacial region can give the surgeon the vital information
necessary for planning surgery; with volumetric analysis, this can help anticipate the need for and volume of a
potential graft for reconstruction (Fig 3). CBCT data also
can be useful in creating a stereolithic model of the area
of interest.
Temporomandibular Joint Disorders
The diagnosis and treatment planning of temporomandibular joint (TMJ) disorders often are quite challenging. Although magnetic resonance imaging remains
the gold standard for imaging the intra-articular components of the TMJ, evaluation of the bony components is
often left to conventional panoramic radiographs. Panoramic radiographs can provide a general impression of
the joint in 2 dimensions but have low sensitivity in
evaluating changes in the condyle, poor reliability, and
low accuracy in evaluating the temporal components of
the joint.13 The imaging offered by current CBCT machines has been shown to provide a complete radiographic evaluation of the bony components of the TMJ
(Fig 4). The resulting images are of high diagnostic
quality. Given the significantly reduced radiation dose
and cost compared with conventional CT, CBCT may
soon become the investigational tool of choice for evaluating bony changes of the TMJ.14
Craniofacial Surgery
Treatment planning for patients with cleft lip and
palate entails many unique considerations. Due to the
young age of the patients and concerns about radiation
exposure, conventional CT is not always used. Timing of
alveolar cleft repair is often determined based on panoramic and occlusal radiographs. Other considerations
include palatal expansion as well as segmental alignment. CBCT should allow better evaluation of dental
age, arch segment positioning, and cleft size compared
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CONE BEAM COMPUTED TOMOGRAPHY
FIGURE 4. Different possible
views of the TMJ complex using
CBCT. A, Surface mode. B, Radiographic mode. C, Close up of
the radiographic view. D, Crosssectional view in the radiographic
mode.
Quereshy, Savell, and Palomo.
Cone Beam Computed Tomography. J Oral Maxillofac Surg
2008.
with traditional radiography (Fig 5). Volumetric analysis
promises to offer better prediction in terms of the morphology of the defect, as well as the volume of graft
material necessary for repair. Questions abound regard-
FIGURE 5. CBCT images of a
patient with a cleft palate. A, Anterior view of the maxilla in the
surface mode. B, Anterior view of
the maxilla in the radiographic
mode. C, Occlusal view of the
maxilla in the surface mode. D,
Occlusal view of the maxilla in the
radiographic mode.
Quereshy, Savell, and Palomo.
Cone Beam Computed Tomography. J Oral Maxillofac Surg
2008.
ing the stability of the arch after grafting, the quality of
the bone graft over time, and the effect on overall facial
growth; CBCT provides a means to investigate these
issues in depth.
QUERESHY, SAVELL, AND PALOMO
795
FIGURE 6. Preoperative and
postoperative CBCT images of a
patient who underwent bilateral
split saggital osteotomy. A, Preoperative soft tissue profile view in
surface mode. B, Preoperative radiographic view of the patient’s
right half. C, Preoperative radiographic view of the patient’s left
half. D, Postoperative soft tissue
profile view in surface mode. E,
Postoperative radiographic view
of the patient’s right half. F, Postoperative radiographic view of
the patient’s left half.
Quereshy, Savell, and Palomo.
Cone Beam Computed Tomography. J Oral Maxillofac Surg
2008.
FIGURE 7. CBCT images of a
patient with an impacted supranumerary tooth. A, Anterior view of
the maxilla in the radiographic
mode. B, View of the right half of
the maxilla in the radiographic
mode. C, Surface view of the anterior right segment of the maxilla.
D, Anterior view of the maxilla in
the surface mode. E, Occlusal
view of the maxilla in the radiographic mode.
Quereshy, Savell, and Palomo.
Cone Beam Computed Tomography. J Oral Maxillofac Surg
2008.
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Orthognathic Surgery
Clinicians have long evaluated the usefulness of
3-dimensional imaging in orthodontics and orthognathic surgery, with a major concern being the
correlation between soft tissue and hard tissue
changes.15 For decades, lateral cephalography has
been the standard modality for diagnosing skeletal
and dental deformities, as well as for use in surgical
prediction and treatment planning. These applications are made possible by the early growth studies of
the mid-1970s that set the stage for current cephalometric analysis and prediction.16,17 In like fashion, it
stands to reason that before a 3-dimensional model
can be reliably adopted for orthodontic and orthognathic analysis and surgical prediction, extensive research is needed to characterize the landmarks and
relationships that this technology allows us to measure.
As useful as cephalometric analysis can be, its imaging accuracy is inadequate in such deformities as
hemifacial microsomia, severe facial asymmetries, and
occlusal cant. Three-dimensional imaging of the hard
and soft tissue makes all of the data available (Fig 6);
the only question is how best to apply and manipulate
that data for more accurate surgery and treatment
planning.
Impacted Teeth
The identification, treatment planning, and evaluation of potential complications of impacted teeth
are greatly improved by adding the third dimension
through CBCT. The site evaluation becomes not
only less invasive and less time-consuming, but also
more complete. The relationship of impacted third
molars to the mandibular canal, adjacent teeth, sinus walls, and cortical borders is important diagnostic information that can directly impact the outcome of surgery.18
Using CBCT to locate and evaluate impacted cuspids and supernumerary teeth seem to make the surgical procedure more efficient and less invasive (Fig
7).19 Because the anatomic structures adjacent to the
region of interest can be seen in 3 dimensions, this
additional information may reduce the morbidity and
potential complications during surgery, contributing
to a better outcome.
In summary, with the continued decreasing cost of
CBCT technology, it is only a matter of time until
CBCT finds its way into the average oral and maxillofacial surgery practice. The increased diagnostic capa-
CONE BEAM COMPUTED TOMOGRAPHY
bility combined with the lower radiation dose also
will help bring this technology into the mainstream.
The applications described herein are merely the beginning. We are now capable of obtaining significantly more data to characterize a patient’s condition.
The next step is to establish how best to use these
additional data in the most effective manner.
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