Transcript Application of Cone Beam Computed Tomography Imaging to

Application of Cone Beam Computed
Tomography Imaging to Dental and
Maxillofacial Practice.
ABSTRACT ID NO: IRIA-1162
Radiographs for maxillofacial practice
Images of maxillofacial skeleton demonstrating 2 Dimensional view, haziness, overlapping,
artefacts, distortion etc.
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Introduction
Imaging is an important diagnostic adjunct
• to the clinical assessment of the dental patient and
• guidelines for the selection of appropriate radiographic procedures for patients
suspected of having dental and maxillofacial diseases are available.
• Although combination of plain X-ray transmission projections and panoramic
radiography can be adequate in a number of clinical situations, radiographic
assessment may sometimes be facilitated by multiplanar images including
computed tomographs.
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• For most dental practitioners, the use of advanced imaging has been limited because
of
• cost,
• Availability and
• radiation dose considerations.
However, the introduction of Cone Beam Computed Tomography [CBCT] specifically
dedicated to imaging the maxillofacial region heralds a true paradigm shift from
1. 2D to 3D approach to data acquisition and
2. Also provides opportunities for dental practitioners to request multiplanar
imaging.
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• Dental practitioners are familiar with the thin-size images produced in the
axial plane by conventional helical fan-beam CT.
• CBCT allows the creation in ‘Real Time’ of images not only in the axial plane
but also 2-dimensional images in the coronal, sagittal and even oblique or
curved image planes- a process referred to as multiplanar reformation[MPR].
• In addition, CBCT data are amenable to reformation in a volume, rather than
a slice providing 3- dimensional information and expanding the role of
imaging from diagnosis to image guidance of operative and surgical
procedures by way of applications software.
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Advantages and limitations of Cone Beam
Computed Tomography
Advantages
Limitations
• X-ray beam limitation
• Image accuracy
• Rapid scan time
• Dose reduction
• Reduced image artefacts
• Display modes unique to
maxillofacial imaging
• Currently- poor soft tissue
contrast.
• Artifacts
• Partial volume averaging
• Under sampling
• Image noise
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Cone Beam CT Technical Fundamentals
Image production can be done in
Components of CBCT image
• Sitting position
• Standing position
• Supine position
• Acquisition configuration
• Image detection
• Image reconstruction
• Image display
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X-ray beam projection scheme comparing acquisition geometry of
conventional or fan beam geometry and cone beam imaging geometry.
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An overview of the unique image display capabilities of maxillofacial
CBCT systems and to illustrate specific applications in dental and
maxillofacial practice.
• Root calcification
• Odontogenic cyst of the maxilla
• Root fracture
• Mandibular jaw fracture
• Canine tooth impaction
• Condylar neck of the mandibular bone fracture.
• Post-operative assessment of maxillofacial trauma patient.
• Virtual implant placement.
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Pre-surgical anatomic assessment of
mandibular fracture.
FOV: 200mm x 100mm
Panoramic image demonstrating a well defined
radiolucent line present on right body of mandible extending
interdentally between 43,44 extending downwards, backwards
to lower border of mandible suggesting a fracture.
Coronal, sagittal and axial section showing the fracture
involvement of buccal and lingual cortical plates and its close
proximity to mental foramen.
CBCT imaging of maxillofacial region provides opportunities for
3 D viewing and Multiplanar imaging.
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Pre-surgical assessment of
canine impaction
• 3D Panoramic view showing
bilateral canine impaction.
• The sagittal view shows the
direction of the tooth. i e the root
more close to the lingual cortex
• The coronal section showing the
approximity of the impacted
canine tooth to the adjacent tooth
structures.
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Post-operative assessment of
maxillofacial trauma patient.
1. To check the fixation of
hard ware
2. To check for anatomic
reduction of fractured bone
fragments
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Use of CBCT in virtual implant
placement for a lower molar
tooth.
CBCT scan can assess bone height, bone
profile, associated anatomy and to aid the
implant placement in the correct
angulation.
CBCT with virtual implant, healing abutment
and crown showing the ideal final result.
The measurement from the apex of the
virtual implant to the mandibular canal is
1.81mm.
3 Dimensional view of the virtual implant.
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Discussion
• Diagnostic information directly influences clinical decisions.
• Accurate data lead to better treatment-planning decisions and potentially
more predictable outcomes.
• CBCT is an emerging technology that can offer the clinician clinically relevant
information that cannot be gathered from conventional radiography.
• The ability to assess an area of interest in 3 dimensions eliminates the
superimposition that is inherent in conventional radiographic imaging.
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• The cases outlined in this paper exemplified clinical situations that might
benefit from further imaging information to provide the best clinical
care.
• 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. However, it should be prescribed only after weighing the
cost of radiation exposure with the benefit of the diagnostic information
that can be obtained from the scan.
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