3d Imaging

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

Martin D. Levin, DMDDiplomate, 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.

1. What is CBCT and How Does it Work?

2. Applications of CBCT3. Summary

Agenda*

*Sponsored by Carestream/Henry Schein Software of Excellence

1.What is CBCT and How Does it Work?

CBCT utilizes a pyramidal or coneshaped 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: What is it?

A voxel (VOlume piXEL), represents the smallest distinguishable box-shaped part of a 3D image, similar to a pixel representation in 2D data.

Principals of CBCT: VOXEL

Imaging Area

50 mm

37mm

.076mm.076m

m

.076mm

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Unpublished ex vivo research investigated the effect of increasing voxel resolution on the detection rate of multiple observers of the MB2 canal on 24 maxillary first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 resolutionsuggesting 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

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

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

Principals of CBCT: Field of view (FOV)

Large

Medium

Focused


Large

Medium

Focused


Large

Medium

Limited


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 flightin 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

0 50 100 150 200 250

Intraoral periapical

Kodak 9000 3D max anterior/posterior …

Kodak 9000 3D panoramic 14.7 µSv

Kodak 9000 3D mand anterior 21.7 µSv

Kodak 9000 3D mand posterior 38.3 µSv

Bitewings (4)

FMX

CBCT large FOV

CT of maxilla and mandible

0.61

1

2

3

5

4.6

18.3

31

243

Time period for equivalent effective dose from natural background radiation in days

Ludlow JB: Dosimetry of Kodak 9000 3D Small FOV CBCT and Panoramic Unit, Proceedings of the AAOMR, 2008.

Principals of CBCT: Dosimetry

2

3

4

5

6

7

9

Level

s“The Kodak 9000 3D provides doses that are substantially lower than previously reported doses produced by medium and large FOV CBCT units.”

The digital panoramic mode provides a low dose alternative for panoramic examinations of the jaws using the same unit.

Rando the Radiology Phantom27 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?

With 2D imaging, the letters are superimposed making it difficult to make out detail.

With volumetric imaging, it is like removing a particular pane (slice) to examine it clearly and accurately.

2D Planar Imaging 3D Volumetric 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.

Limitations of 2D Imaging

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









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









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

CBCT is a tomographic scanning technology that allows us understand the maxillofacial complex and the spacial relationship of anatomic structures.














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

Coronal Sagittal

Transaxial

What Percentage of PatientsAre Scanned?

5842

% of All Endodontic Referrals (ALARA)

Cone beam scanNo cone beam scan

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

What Procedures Are Scanned?

0%

20%

40%

60%

80%

100%

CBCT Data Capture

47.3

34.6

1511.3 Mand anterior

Max anterior

Mand posterior

Max posterior

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

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 Digital Radiography Systems

“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

2-D Radiography Systems: Comparison

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.


1. Diagnosis of endodontic pathosis

Canal morphology





Implant planning



Diagnosis of endodontic pathosis

2. Canal morphology





Implant planning




Canal morphology

3. Assessment of pathosis of non-endodontic origin




Implant planning




Canal morphology


4. Evaluation of root fractures and trauma



Implant planning




Canal morphology


4. Evaluation of root fractures and trauma



Implant planning




Canal morphology



5. Analysis of external and internal root resorption and extraradicular invasive cervical resorption


Implant planning




Canal morphology




6. Pre-surgical planning

Implant planning




Canal morphology





7. Implant planning


“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.

Pre-Operative Assessment





3 Month Check-Up: CBCT Axial View

3 Month Check-Up: CBCT Sagittal View

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

Clinical Decision Making: Missed Lesions

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.

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








“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, 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%).





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)

Ectodermal Dysplasia

Diagnosis and Treatment Planning: Maxillary sinusitis of dental origin

Diagnosis and Treatment Planning: Osteoperiostitis

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

Diagnosis and Treatment Planning: Osteoperiostitis

Diagnosis and Treatment Planning: Incidental Findings

AntrolithMucus retention pseudocyst

Diagnosis and Treatment Planning

Diagnosis of Endodontic Pathosis

b c d

Diagnosis of Endodontic Pathosis

fe

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 inMaxillary Molars

Number of Canals in Mandibular Premolars

Number of Canals in Mandibular 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.

Principals of CBCT: Missed canals

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.

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

Acute Periradicular Periodontitis

Revision Therapy

Revision Therapy

Revision Therapy

Root Fracture, Horizontal

Bernardes RA, de Moraes IG, Duarte MA, Azevedo BC, de Azevedo JR, Bramante CM. Use of cone-beam volumetric tomography in the diagnosis ofroot fractures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009 Mar 7.[Epub ahead of print]..

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.

Root Fracture, VerticalHassan, 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

Resorption, External

d

a

b

c

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.”


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


Resorption, Cervical

Resorption, Cervical

Intra-Operative

Intra-Operative

Surgical Assessment

3. Why Embrace 3D?

Periradicular PathosisEstrela, 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.

“Diagnostic information directly influences clinical decisions.

Accurate data lead to better treatment planning decisions and potentially more predictable outcomes.”


Why Embrace 3D?

Summary

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