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Comparison of Micro-CT and Histology in Dental Caries Diagnosis
e58
OOOOE April 2008
Abstracts
GORHAM DISEASE: A RARE CAUSE OF MASSIVE BONE DESTRUCTION. S.E. Perschbacher, K.A. Perschbacher, M.J. Pharoah, G. Bradley, and L. Lee, University of Toronto Faculty of Dentistry and Princess Margaret Hospital, Toronto, Canada. Background. Gorham disease is a very rare condition that causes severe bone destruction. Also referred to as massive osteolysis and vanishing bone disease, it may progress from 1 to several bones, replacing them with fibrous tissue. Fewer than 40 cases of Gorham disease of the maxillofacial skeleton have been reported.1 Patients are often asymptomatic or present only with mild pain or swelling. Correct diagnosis is difficult and often delayed, because other, more common, diagnoses are considered first. The finding of multiple thin-walled vascular or lymphatic channels in histopathologic samples has led to the belief that vascular proliferation is involved in the etiology of this disease.2 This finding, however, is inconsistent,3 and the causes of Gorham disease remain unknown. Treatment for this condition meets with minimal success and has included bisphosphonate therapy, surgical resection, and radiation therapy. Case report. The case of a 59-year-old man presented with progressive loosening of the teeth in the left maxilla. Examination revealed severe mobility of the entire posterior left maxilla. Plain radiographs and computerized tomography revealed ill defined destruction of the left maxilla without evidence of an associated neoplasm. A provisional diagnosis of Gorham disease was made and confirmed histopathologically. The patient has been treated with a course of radiation therapy with no significant response. Bisphosphonate therapy is currently being considered. This case is unique, because there are no previous reports in the literature of Gorham disease occurring in the maxilla alone, without mandibular involvement.
REFERENCES 1. Mignogna MD, Fedele S, Lo Russo L, Ciccarelli R. Treatment of Gorham’s disease with zoledronic acid. Oral Oncol 2005;41:747-50. 2. Gorham LW, Stout AP. Hemangiomatosis and its relation to massive osteolysis. Trans Assoc Am Physicians 1954;67:302-7. 3. Kawasaki K, Ito T, Tsuchiya T, Takahashi H. Is angiomatosis an intrinsic pathohistological feature of massive osteolysis? Report of an autopsy case and a review of the literature. Virchows Arch 2003;442:400-6.
AN INTERACTIVE COMPUTER PROGRAM TO TEACH PANORAMIC RADIOGRAPHY. S.E. Perschbacher, M. Cash, and D. Dayal, University of Toronto Faculty of Dentistry, Canada. Background. Acquiring good-quality panoramic radiographs is technically demanding and requires an understanding of the concepts of panoramic tomography and the focal trough. Accordingly, it has been found that panoramic radiographs taken in private dental practice are frequently of poor quality.1,2 Interpreting the panoramic image is also difficult, owing to the projection and superimposition of large areas of anatomy of the maxillofacial region. Teaching panoramic radiographic theory, technique, and interpretation to dental students is a challenge facing radiology educators. Good-quality interactive teaching materials that effectively illustrate the concepts of panoramic radiography were desired to enhance our institution’s undergraduate radiology program. Objective. To create an interactive computer program to teach panoramic radiography to undergraduate dental students.
Materials and methods. A Flash-based computer program with video, animation, and interactive components was created. Three modules were designed. First, students are introduced to the theory of tomography and the principles of dental panoramic tomography. They are instructed how to prepare a patient to acquire a panoramic radiograph and shown how errors in patient positioning affect the quality of resultant images. Second, students learn panoramic anatomy through an interactive component. And third, students are introduced to interpretation of panoramic images. They are led through the identification and diagnosis of assorted findings, ranging from variations of normal to malignant neoplasms. Results. An interactive program introducing the theory, acquisition, and interpretation of panoramic radiographs was created. The program was integrated into a Web-based educational resource to be accessed by undergraduate students in their radiology course.
REFERENCES 1. Brezden NA, Brooks SL. Evaluation of panoramic dental radiographs taken in private practice. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1987;63:617-21. 2. Rushton VE, Horner K, Worthington HV. The quality of panoramic radiographs in a sample of general dental practices. Br Dent J 1999;186:630-3.
COMPARISON OF MICRO-CT AND HISTOLOGY IN DENTAL CARIES DIAGNOSIS. S. Rathore, D. Tyndall, T. Wright, and E. Everett, University of North Carolina, Chapel Hill. Background. Histologic sectioning of extracted teeth has been conventionally used as the gold standard to which new diagnostic modalities are compared. Sectioning is destructive, with demands on both time and personnel. In cariology research there is an increased demand for a nondestructive technique which will not only simplify the investigative procedure but also allow for the preservation of sample for longitudinal use. Micro-computerized tomography (micro-CT) provides 3-dimensional information of the sample which can also be visualized in discrete sections. Objective. To test micro-CT as a possible alternative to histology as the existing gold standard for caries detection. Materials and methods. Sixty extracted teeth (molars and premolars) were scanned using Skyscan 1074 with a 20.4 m resolution. One-half of these teeth had occlusal caries, as tested by visual and dissecting microscope examination. A dynamic range was established for the micro-CT using a set of hydroxyapatite rods. These rods ranged in densities from 50 mg/mL to 1000 mg/mL. The scan settings were established at 1,000 A, 40 kvp, and 600 ms. The images were reconstructed by Nrecon server and viewed with the data viewer. The teeth were then sectioned using a diamond saw into 200 m thin sections and viewed under a stereomicroscope. Three observers graded the presence or absence of caries, and the results were compared with histology of the sectioned teeth. Results. Sensitivity and specificity for micro-CT were established using histology as the gold standard. Sensitivity was 0.89 and specificity 0.78. Interobserver agreement was calculated using kappa and reported as 0.76, with an agreement of 0.88 and standard error of 0.083. Discussion. The initial data suggest that micro-CT can detect occlusal lesions in good agreement with histology. This may provide a viable alternative to histology in caries diagnosis.
OOOOE Volume 105, Number 4 Recent studies suggest similar findings. The use of microtomographic technique in dentistry is relatively new and still has the need for further evaluation to be considered as a true gold standard.
CBCT-SIMULATED PANORAMIC IMAGES FOR THE ASSESSMENT OF MANDIBULAR THIRD MOLAR APICES TO THE INFERIOR ALVEOLAR CANAL. R.L. Snyder, S.S. Chandiramani, W.C. Scarfe, J.P. Scheetz, and A.G. Farman, University of Louisville School of Dentistry, Kentucky. Objectives. Cone-beam volumetric computerized tomography (CBVCT)–simulated panoramic radiographs were used to determine the effect of image layer width on the detection of panoramic features reported to indicate close proximity of impacted mandibular third molar teeth to the inferior alveolar canal (IAC). Materials and methods. CBVCT data sets for 50 patients with impacted mandibular third molar were retrospectively selected. All had been performed using the iCAT (ISI, Hatfield, PA) using a 20 s exposure time with 306 basis images and an isotropic voxel resolution of 0.4 mm. Panoramic reconstructions with 3 different focal trough widths (10, 20, and 40 mm) were developed for each mandibular arch. Six previously reported high-risk radiologic panoramic signs of third molar relationship to the IAN were evaluated by an oral and maxillofacial radiologist and an orthodontist for each impacted third molar at each focal trough width, namely: 1) darkening of root; 2) disruption of canal cortex; 3) canal deviation; 4) root deflection; 5) canal superimposition over roots; and 5) narrowing of canal. Observers subsequently used the CBVCT cross-sections of the mandible to measure the precise distance, in mm, of the mandibular canal to the closest part of the third molar root. Results. The customized image layer of 20 mm width resulted in 2 panoramic radiologic signs found to be statistically significantly indicative of close proximity to the IAN, namely, darkening of the root and narrowing of the canal. None of the reported panoramic signs for root-canal close proximity were significant when using image layer widths of 10 or 40 mm. Discussion. CBVCT-simulated panoramic images indicate that panoramic signs of close proximity of the mandibular third molar to the IAN may well vary with focal trough width. Where the IAN is shown to overlap or be close to the apex of the impacted mandibular third molar, the use of CBVCT is indicated.
3D RECONSTRUCTION FROM FEW RADIOGRAPHIC PROJECTIONS ACQUIRED IN ARBITRARY GEOMETRY. R.K.W. Schulze, U. Heil, D. Groß, O. Weinheimer, D.D. Bruellmann, E. Thomas E, U. Schwanecke, and E. Schoemer, Johannes Gutenberg-University, Mainz, and University of Applied Sciences, Wiesbaden, Germany. Background. At present, cone-beam computerized tomography (CBCT) is the hottest topic in dental radiography, because it enables a true 3-dimensional (3D) representation of the objects under evaluation. Owing to the high number of projections required to compute 3D structure in CBCT, however, the patient dose is not negligible. Also, CBCT machines are rather expensive devices, owing to complex requirements concerning hard- and software. Alternative low-cost solutions to obtain 3D information with less radiation, such as tuned-aperture CT (TACT), have been successfully introduced1 and widely evaluated2-8 already. When using radiographic projections from off-the-shelf ma-
Abstracts e59 chines, one major problem is to calculate the imaging geometries a posteriori by image analysis. We have introduced a very flexible technique (reference sphere method [RSM]9,10) that allows the use of virtually arbitrary projection geometries for subsequent 3D reconstruction. Using only 3 reference spheres, RSM-3D enables registration of normal radiographic projections exposed in arbitrary geometries into a single coordinate system for reconstruction of a 3D volume. The projections may be obtained from ubiquitously available radiographic units. Objectives. The aim of the present investigation was to evaluate the RSM-3D technique for different radiographic input devices. Material and methods. The current C⫹⫹-implementation of the RSM-3D software allows for automated RSM registration of radiographic projections and a subsequent algebraic reconstruction technique (ART).11-14 Projection radiographs (5 to 9) of human teeth, a dry mandible, a dry skull, and a frozen bird were acquired on a dental CCD sensor, a storage phosphor plate, and a medical amorphous selenium detector. Fast ART reconstructions based on conjugate gradients or the method of steepest descent were computed on the graphics processing unit integrated in a Pentium PC. Results. RSM-3D volume reconstructions are presented as slices and surface-rendered display. Additional mathematical constraints in the ART reconstruction render higher reconstruction quality. Discussion. TACT has proved its efficiency in processing 3D information from only a very few radiographs in various studies.2,3,5,6,8,15-21 An advantage of RSM-3D is that it can handle a very flexible imaging geometry.9,22 Six to eight degrees of freedom in an arbitrary imaging system may be registered a priori. Like other techniques, RSM-3D is still being developed further. Yet there is indication that it may provide a cheap, low-dose, and versatile alternative to established 3D techniques, such as CT or CBCT, for some distinct dental/medical applications.
REFERENCES 1. Webber RL, Horton RA, Tyndall DA, Ludlow JB. Tuned-aperture computed tomography (TACT). Theory and application for three-dimensional dento-alveolar imaging. Dentomaxillofac Radiol 1997;26:53-62. 2. Liang H, Tyndall DA, Ludlow JB, Lang LA. Cross-sectional presurgical implant imaging using tuned aperture computed tomography (TACT). Dentomaxillofac Radiol 1999;28:232-7. 3. Nair MK, Nair UP, Gröndahl H-G, Webber RL. Accuracy of tuned aperture computed tomography in the diagnosis of radicular fractures in nonrestored maxillary anterior teeth—an in vitro study. Dentomaxillofac Radiol 2002;31:299-304. 4. Nair MK, Nair UP, Gröndahl H-G, Webber RL, Wallace JA. Detection of articially induced vertical radicular fracture using tuned aperture computed tomography. Eur J Oral Sci 2001;109:375-79. 5. Sakata M, Hareyama M, Heil TA, Henson MM, Henson OW Jr, Webber RL, et al. High-resolution in situ imaging of cochlear implant electrode arrays in cat temporal bones using tuned aperture computed tomography (TACT). Ear Hear 2007;28:435-43. 6. Shi X-Q, Han P, Welander U, Angmar-Månsson B. Tunedaperture computed tomography for detection of occlusal caries. Dentomaxillofac Radiol 2001;30:45-9. 7. Webber RL, Underhill HR, Freimanis RI. A controlled evaluation of tuned-aperture computed tomography applied to digital spot mammography, J Digit Imaging 2001;13:90-97. 8. Webber RL, Messura JK. An in vivo comparison of diagnostic information obtained from tuned-aperture computed tomography and conventional dental radiographic imaging modalities. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88:239-47. 9. Schulze R, Brüllmann DD, Röder F, d’Hoedt B. Determination
OOOOE April 2008
Abstracts
GORHAM DISEASE: A RARE CAUSE OF MASSIVE BONE DESTRUCTION. S.E. Perschbacher, K.A. Perschbacher, M.J. Pharoah, G. Bradley, and L. Lee, University of Toronto Faculty of Dentistry and Princess Margaret Hospital, Toronto, Canada. Background. Gorham disease is a very rare condition that causes severe bone destruction. Also referred to as massive osteolysis and vanishing bone disease, it may progress from 1 to several bones, replacing them with fibrous tissue. Fewer than 40 cases of Gorham disease of the maxillofacial skeleton have been reported.1 Patients are often asymptomatic or present only with mild pain or swelling. Correct diagnosis is difficult and often delayed, because other, more common, diagnoses are considered first. The finding of multiple thin-walled vascular or lymphatic channels in histopathologic samples has led to the belief that vascular proliferation is involved in the etiology of this disease.2 This finding, however, is inconsistent,3 and the causes of Gorham disease remain unknown. Treatment for this condition meets with minimal success and has included bisphosphonate therapy, surgical resection, and radiation therapy. Case report. The case of a 59-year-old man presented with progressive loosening of the teeth in the left maxilla. Examination revealed severe mobility of the entire posterior left maxilla. Plain radiographs and computerized tomography revealed ill defined destruction of the left maxilla without evidence of an associated neoplasm. A provisional diagnosis of Gorham disease was made and confirmed histopathologically. The patient has been treated with a course of radiation therapy with no significant response. Bisphosphonate therapy is currently being considered. This case is unique, because there are no previous reports in the literature of Gorham disease occurring in the maxilla alone, without mandibular involvement.
REFERENCES 1. Mignogna MD, Fedele S, Lo Russo L, Ciccarelli R. Treatment of Gorham’s disease with zoledronic acid. Oral Oncol 2005;41:747-50. 2. Gorham LW, Stout AP. Hemangiomatosis and its relation to massive osteolysis. Trans Assoc Am Physicians 1954;67:302-7. 3. Kawasaki K, Ito T, Tsuchiya T, Takahashi H. Is angiomatosis an intrinsic pathohistological feature of massive osteolysis? Report of an autopsy case and a review of the literature. Virchows Arch 2003;442:400-6.
AN INTERACTIVE COMPUTER PROGRAM TO TEACH PANORAMIC RADIOGRAPHY. S.E. Perschbacher, M. Cash, and D. Dayal, University of Toronto Faculty of Dentistry, Canada. Background. Acquiring good-quality panoramic radiographs is technically demanding and requires an understanding of the concepts of panoramic tomography and the focal trough. Accordingly, it has been found that panoramic radiographs taken in private dental practice are frequently of poor quality.1,2 Interpreting the panoramic image is also difficult, owing to the projection and superimposition of large areas of anatomy of the maxillofacial region. Teaching panoramic radiographic theory, technique, and interpretation to dental students is a challenge facing radiology educators. Good-quality interactive teaching materials that effectively illustrate the concepts of panoramic radiography were desired to enhance our institution’s undergraduate radiology program. Objective. To create an interactive computer program to teach panoramic radiography to undergraduate dental students.
Materials and methods. A Flash-based computer program with video, animation, and interactive components was created. Three modules were designed. First, students are introduced to the theory of tomography and the principles of dental panoramic tomography. They are instructed how to prepare a patient to acquire a panoramic radiograph and shown how errors in patient positioning affect the quality of resultant images. Second, students learn panoramic anatomy through an interactive component. And third, students are introduced to interpretation of panoramic images. They are led through the identification and diagnosis of assorted findings, ranging from variations of normal to malignant neoplasms. Results. An interactive program introducing the theory, acquisition, and interpretation of panoramic radiographs was created. The program was integrated into a Web-based educational resource to be accessed by undergraduate students in their radiology course.
REFERENCES 1. Brezden NA, Brooks SL. Evaluation of panoramic dental radiographs taken in private practice. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1987;63:617-21. 2. Rushton VE, Horner K, Worthington HV. The quality of panoramic radiographs in a sample of general dental practices. Br Dent J 1999;186:630-3.
COMPARISON OF MICRO-CT AND HISTOLOGY IN DENTAL CARIES DIAGNOSIS. S. Rathore, D. Tyndall, T. Wright, and E. Everett, University of North Carolina, Chapel Hill. Background. Histologic sectioning of extracted teeth has been conventionally used as the gold standard to which new diagnostic modalities are compared. Sectioning is destructive, with demands on both time and personnel. In cariology research there is an increased demand for a nondestructive technique which will not only simplify the investigative procedure but also allow for the preservation of sample for longitudinal use. Micro-computerized tomography (micro-CT) provides 3-dimensional information of the sample which can also be visualized in discrete sections. Objective. To test micro-CT as a possible alternative to histology as the existing gold standard for caries detection. Materials and methods. Sixty extracted teeth (molars and premolars) were scanned using Skyscan 1074 with a 20.4 m resolution. One-half of these teeth had occlusal caries, as tested by visual and dissecting microscope examination. A dynamic range was established for the micro-CT using a set of hydroxyapatite rods. These rods ranged in densities from 50 mg/mL to 1000 mg/mL. The scan settings were established at 1,000 A, 40 kvp, and 600 ms. The images were reconstructed by Nrecon server and viewed with the data viewer. The teeth were then sectioned using a diamond saw into 200 m thin sections and viewed under a stereomicroscope. Three observers graded the presence or absence of caries, and the results were compared with histology of the sectioned teeth. Results. Sensitivity and specificity for micro-CT were established using histology as the gold standard. Sensitivity was 0.89 and specificity 0.78. Interobserver agreement was calculated using kappa and reported as 0.76, with an agreement of 0.88 and standard error of 0.083. Discussion. The initial data suggest that micro-CT can detect occlusal lesions in good agreement with histology. This may provide a viable alternative to histology in caries diagnosis.
OOOOE Volume 105, Number 4 Recent studies suggest similar findings. The use of microtomographic technique in dentistry is relatively new and still has the need for further evaluation to be considered as a true gold standard.
CBCT-SIMULATED PANORAMIC IMAGES FOR THE ASSESSMENT OF MANDIBULAR THIRD MOLAR APICES TO THE INFERIOR ALVEOLAR CANAL. R.L. Snyder, S.S. Chandiramani, W.C. Scarfe, J.P. Scheetz, and A.G. Farman, University of Louisville School of Dentistry, Kentucky. Objectives. Cone-beam volumetric computerized tomography (CBVCT)–simulated panoramic radiographs were used to determine the effect of image layer width on the detection of panoramic features reported to indicate close proximity of impacted mandibular third molar teeth to the inferior alveolar canal (IAC). Materials and methods. CBVCT data sets for 50 patients with impacted mandibular third molar were retrospectively selected. All had been performed using the iCAT (ISI, Hatfield, PA) using a 20 s exposure time with 306 basis images and an isotropic voxel resolution of 0.4 mm. Panoramic reconstructions with 3 different focal trough widths (10, 20, and 40 mm) were developed for each mandibular arch. Six previously reported high-risk radiologic panoramic signs of third molar relationship to the IAN were evaluated by an oral and maxillofacial radiologist and an orthodontist for each impacted third molar at each focal trough width, namely: 1) darkening of root; 2) disruption of canal cortex; 3) canal deviation; 4) root deflection; 5) canal superimposition over roots; and 5) narrowing of canal. Observers subsequently used the CBVCT cross-sections of the mandible to measure the precise distance, in mm, of the mandibular canal to the closest part of the third molar root. Results. The customized image layer of 20 mm width resulted in 2 panoramic radiologic signs found to be statistically significantly indicative of close proximity to the IAN, namely, darkening of the root and narrowing of the canal. None of the reported panoramic signs for root-canal close proximity were significant when using image layer widths of 10 or 40 mm. Discussion. CBVCT-simulated panoramic images indicate that panoramic signs of close proximity of the mandibular third molar to the IAN may well vary with focal trough width. Where the IAN is shown to overlap or be close to the apex of the impacted mandibular third molar, the use of CBVCT is indicated.
3D RECONSTRUCTION FROM FEW RADIOGRAPHIC PROJECTIONS ACQUIRED IN ARBITRARY GEOMETRY. R.K.W. Schulze, U. Heil, D. Groß, O. Weinheimer, D.D. Bruellmann, E. Thomas E, U. Schwanecke, and E. Schoemer, Johannes Gutenberg-University, Mainz, and University of Applied Sciences, Wiesbaden, Germany. Background. At present, cone-beam computerized tomography (CBCT) is the hottest topic in dental radiography, because it enables a true 3-dimensional (3D) representation of the objects under evaluation. Owing to the high number of projections required to compute 3D structure in CBCT, however, the patient dose is not negligible. Also, CBCT machines are rather expensive devices, owing to complex requirements concerning hard- and software. Alternative low-cost solutions to obtain 3D information with less radiation, such as tuned-aperture CT (TACT), have been successfully introduced1 and widely evaluated2-8 already. When using radiographic projections from off-the-shelf ma-
Abstracts e59 chines, one major problem is to calculate the imaging geometries a posteriori by image analysis. We have introduced a very flexible technique (reference sphere method [RSM]9,10) that allows the use of virtually arbitrary projection geometries for subsequent 3D reconstruction. Using only 3 reference spheres, RSM-3D enables registration of normal radiographic projections exposed in arbitrary geometries into a single coordinate system for reconstruction of a 3D volume. The projections may be obtained from ubiquitously available radiographic units. Objectives. The aim of the present investigation was to evaluate the RSM-3D technique for different radiographic input devices. Material and methods. The current C⫹⫹-implementation of the RSM-3D software allows for automated RSM registration of radiographic projections and a subsequent algebraic reconstruction technique (ART).11-14 Projection radiographs (5 to 9) of human teeth, a dry mandible, a dry skull, and a frozen bird were acquired on a dental CCD sensor, a storage phosphor plate, and a medical amorphous selenium detector. Fast ART reconstructions based on conjugate gradients or the method of steepest descent were computed on the graphics processing unit integrated in a Pentium PC. Results. RSM-3D volume reconstructions are presented as slices and surface-rendered display. Additional mathematical constraints in the ART reconstruction render higher reconstruction quality. Discussion. TACT has proved its efficiency in processing 3D information from only a very few radiographs in various studies.2,3,5,6,8,15-21 An advantage of RSM-3D is that it can handle a very flexible imaging geometry.9,22 Six to eight degrees of freedom in an arbitrary imaging system may be registered a priori. Like other techniques, RSM-3D is still being developed further. Yet there is indication that it may provide a cheap, low-dose, and versatile alternative to established 3D techniques, such as CT or CBCT, for some distinct dental/medical applications.
REFERENCES 1. Webber RL, Horton RA, Tyndall DA, Ludlow JB. Tuned-aperture computed tomography (TACT). Theory and application for three-dimensional dento-alveolar imaging. Dentomaxillofac Radiol 1997;26:53-62. 2. Liang H, Tyndall DA, Ludlow JB, Lang LA. Cross-sectional presurgical implant imaging using tuned aperture computed tomography (TACT). Dentomaxillofac Radiol 1999;28:232-7. 3. Nair MK, Nair UP, Gröndahl H-G, Webber RL. Accuracy of tuned aperture computed tomography in the diagnosis of radicular fractures in nonrestored maxillary anterior teeth—an in vitro study. Dentomaxillofac Radiol 2002;31:299-304. 4. Nair MK, Nair UP, Gröndahl H-G, Webber RL, Wallace JA. Detection of articially induced vertical radicular fracture using tuned aperture computed tomography. Eur J Oral Sci 2001;109:375-79. 5. Sakata M, Hareyama M, Heil TA, Henson MM, Henson OW Jr, Webber RL, et al. High-resolution in situ imaging of cochlear implant electrode arrays in cat temporal bones using tuned aperture computed tomography (TACT). Ear Hear 2007;28:435-43. 6. Shi X-Q, Han P, Welander U, Angmar-Månsson B. Tunedaperture computed tomography for detection of occlusal caries. Dentomaxillofac Radiol 2001;30:45-9. 7. Webber RL, Underhill HR, Freimanis RI. A controlled evaluation of tuned-aperture computed tomography applied to digital spot mammography, J Digit Imaging 2001;13:90-97. 8. Webber RL, Messura JK. An in vivo comparison of diagnostic information obtained from tuned-aperture computed tomography and conventional dental radiographic imaging modalities. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88:239-47. 9. Schulze R, Brüllmann DD, Röder F, d’Hoedt B. Determination