ER Publications



Evaluation of the accuracy of digital panoramic radiography, multidetector computed tomography and cone beam computed tomography: experimental study with humam dry mandibles.

Ana Cristina Rosário Sobreira Vasconcellos¹, Inêssa da Silva Barbosa¹, Anderson da Silva Maciel¹, Soraya Castro Trindade², Marcos Alan Vieira Bittencourt¹, Patrícia Leite-Ribeiro¹, Viviane Almeida Sarmento¹

¹ School of Dentistry, Federal University of Bahia, Salvador-Bahia/Brazil.

² School of Dentistry, Federal University of Feira de Santana, Feira de Santana-Bahia/Brazil.

E-mail: anacristina_sobreira@.br

Telefhone:557130139336 / 5571991877328

ABSTRACT

Objectives: The aim of this study was to investigate the accuracy of linear measurements of human dry mandibles recorded from digital panoramic radiography (D-PAN) and panoramic reconstructions from Singleslice CT, Four-row multidetector CT (MDCT), 128-row multidetector CT (MDCT); and cone beam CT (CBCT) images with three voxels size (0.2mm; 0.3mm and 0.4mm), generated by post-processing images in the Dolphin Imaging 3D®.

Methods: Linear measurements were evaluated in circumferential bone defects made in ten human dry mandibles. The mandibles were scann using a D-PAN, a CBCT device (with voxels size of 0.2 mm, 0.3 mm and 0.4 mm), a Singleslice CT, a Four-row MDCT and a 128-row MDCT devices. The linear measurements were recorded from panoramic images by two observers and compared with measurements recorded directly from the bone. The measurements errors and intra and interexaminer reliability were calculated for each modality and compared with each other.

Results: The measurements recorded had no statistically significant differences on the accuracy of different image acquisition protocols, although the D-PAN it had the greatest mean of the absolute measurement errors was 0.78 mm, and the lowest mean for the protocols was 0.62 mm for the CBCT voxel 0.2mm. Evaluating the magnitude of the dimensional error was observed only in the D-PAN error mostly remained in the range greater than 1mm (31,25%) and the CT had mostly errors in the range 0 to 0.5mm. The intra and interexaminer reliability was 0.96;

Conclusions: There was no significant difference between the different devices evaluated on the dimensional measurement error, although the error was higher for horizontal measurements and anterior mandible. The D-PAN had the highest mean of absolute measurement error, especially for measurements from the front region of mandible.

Keywords: digital panoramic radiography; cone beam CT; fan beam CT; multiplanar reconstructions.

Introduction

Panoramic radiographs are important images at diagnosis, mainly indicated for visualization of mineralized structures, with one issue more used to allow viewing of both dental arches in a single image. For planning implants is the investigation of choice for providing anatomical view of the area and is often the only imaging examination required to obtain the route metric, which provides information for selecting the type of implant. This images, however, has important deficiencies, such as distortion and non-uniform images magnification and overlapping complex bone structures.1,2

A variety of imaging modalities are available, including panoramic radiography (conventional and digital), tomography, and computed tomography (CT), and have been used for preimplant assesment. Over the last decade, digital panoramic radiography was introduced, and it appears to demonstrate certain advantages compared with film-based panoramic radiography, eg, faster image acquisition, elimination of darkroom procedures, lower radiation exposure and availability of various image-processing tools.³ The digital panoramic radiography system is an effective method that is simple and inexpensive for pre-implant diagnosis and establishing treatment protocol, and it uses a relatively low radiation exposure. The vertical assessment can provide useful, accurate information, however, cross-sectional information cannot be obtained.4

Currently, CT much in demand in the medical field also begins to develop in the dental field, especially in the areas of dental implants, Stomatology, Surgery and Orthodontics.5,6 However, this practice received some criticism due to the level of radiation exposure during image acquisition.7

CT is a method of diagnostic imaging that allows obtaining and playing a section of the human body in any one of the three planes of space: axial, sagittal and coronal, and is an attractive modality for dental imaging because the resulting image data reveal the true three dimensional (3D) relationships between teeth and their supporting tissues.6,8

CT can be divided into two categories based on the acquisition geometry of the x-ray beam, namely: a fan beam CT (FBCT), used in the medical diagnostics, or a cone beam CT (CBCT), used in the dentistry. Among the medical equipment, the helical technology replaces the acquisition slice to slice of the first equipment generations. In relation to the singleslice CT equipment, data acquisition by a single row of detectors, has been supplanted by scanners that allow simultaneous capture of multiple detectors at each rotation of the equipment. The multidetector CT (MDCT) scanner refers to a special CT system equipped with a multiple-row detector array to simutaneously collect data at different slice locations. This increases the amount of information obtained at each rotation of the equipment and reduces the dose and duration of the examination.9

The CBCT used in dentistry relate to a device for obtaining exclusive face images of the hard tissues. The basic difference is the acquisition of the entire volume to be scanned in a single spin of the equipment, while the FBCT multiple spins are performed around the patient's head to acquire the data of the desired anatomical segment. The CBCT usually allows the acquisition of images with higher spatial resolution and lower radiation dose compared to FBCT, however the size of the scanned area can be limited in many equipment models, which sometimes restricts the examination to small areas.10

After data acquisition, either in equipment FBCT or CBCT, you need to reformat them to their proper interpretation. In the market many software are able to process and analyze the images generated by these devices and generate different reformatting, including panoramic images. Therefore, the aim of this study was to evaluate the accuracy of digital panoramic radiography (D-PAN) images and CT reformatted panoramic images obtained with different protocols, which were post-processed by Dolphin Imaging 3D® software.

Materials and methods

Preparation of mandibles

This research was submitted to the ethics research committee of College of Dentistry, Federal University of Bahia, Salvador, Bahia, Brazil. Ten human dry mandibles were used in this study and inclusion criteria were observed the integrity of the anatomical structure of the same and, in the case of the presence of teeth, the absence of restorations or metal prosthesis. In each mandible were produced four circumferential standardized bone defects with trephine drills 7,8mm and 11.8 mm in diameters transfix that all bone thickness, in the posterior and front regions of the mandible, bilaterally in a total of four defect in each mandible.

The posterior region, defects were made tangential to a vertical line and a horizontal, perpendicular to each other, the first of which was drawn from the upper end of the coronoid process toward the mandibular base, and the second drawn parallel to the base of the jaw, passing 5 mm above it. In the front region the defects were produced two tangent lines, one vertical and one horizontal, mutually perpendicular also. The vertical line was drawn parallel to the median sagittal plane and far this 5 mm, left or right, and the horizontal line was parallel to the base of the mandible, from 8 mm above this. The distances used to draw reference lines for the fabrication of bone defects were measured with a digital caliper (series 727 - Starrett® Industry and Trade Ltd., Itu, Sao Paulo, Brazil).

Were made in total, forty bone defects, and twenty of them were found with trephine drill 11.8 mm diameter, five jaws, while the other twenty defects were made with a smaller diameter drill of 7.8 mm the other five jaws (Figure 1).

Imaging of the mandibles

The mandibles were radiographed in panoramic device (Rotograph Plus® - Villa Sistemi Medicali, Milano, Italy) with phosphor plates of digital radiographic system VistaScan® (Durr Dental AG, Bietigheim-Bissingen, Germany).

The energy parameters were adjusted and standardized. Digital panoramic radiographs were saved on CD in JPEG format for analysis.

The same mandibles were submitted for examination by singleslice CT (SSCT) (Somatom Spirit®, Siemens, Erlangen, Germany), with slice thickness of 1 mm and 0.5 mm distance between them. Were also scanned MDCT in a four-row device (S4 Asteion ®, Toshiba Medical Systems, Japan), with a slice thickness of 0.5 mm and the distance between them of 0.3 mm and a MDCT equipment 128 channels (Optima CT660®, GE Healthcare, Wisconsin, USA) with a slice thickness of 0,625mm and 5,625mm distance between them.

Volumetric axial sections were obtained in the helical mode with filter for bone and FOV of approximately 250 mm, without gantry inclination.

Axial sectional images of the mandibles were acquired parallel to the axial base of the mandible and the mandible entire height was included in the test, with a margin of 1.5 cm above and below the area of interest. The axial sectional generated presented as thin as possible for each device. The images were exported in DICOM (Digital Imaging and Communication in Medicine) for filed in a compact disk (CD-ROM).

The mandibles were also examined in a CBCT device (I-CAT® Imaging, Sciences International, Inc., Hatfield, Pennsylvania, USA) with voxels in three different sizes (0.2mm, 0.3mm and 0.4mm) and 8 cm FOV. For images acquisition mandibles were positioned with its base parallel to the horizontal plane being fixed with foam and duct tape. The images were exported in DICOM (Digital Imaging and Communication in Medicine) for filed in a compact disk (CD-ROM).

A reformatting software (Dolphin Imaging 3D®, v. 11.5, Dolphin Imaging & Management Solutions, Chatsworth, CA, USA), operating in a desktop computer with Windows 7® (Microsoft Corp., USA), with Corel Intel i5 with off-board video card, 15-inch monitor, SuperVGA (resolution of 1024 x 768 pixels) and 32-bit was used to obtain panoramic images of the mandibles. In the software, the steps for generation of CT panoramic reformattion were standardized and was selected the axial section in the most central region of the upper-lower direction of each mandible.

Then, the reference curve in this axial section was drawn in order to remain equidistant from the buccal and lingual cortical. We selected a uniform thickness of 20 mm and chosen the Dolphin 1 filter.

The CT images were reformatted by only one of the evaluators and were filed for both evaluators later did the analysis of horizontal and vertical measurements of the four defects in each panoramic image generated. Figure 2 is a sample of the reformatted panoramic images obtained by the respective protocols and Figure 3 is a sample of the digital panoramic radiography acessed in the software.

Recording of measurements

Linear measurements (vertical and horizontal) of the bone defects were performed in the posterior and front regions of the dry mandibles (gold standard) with the aid of a digital caliper (Series 727- Starrett® Industry and Trade LTD, Itu, São Paulo, Brazil) (Figure 1), which was positioned at the linear circumferential flaw located in the central portion of the bone defects.

The same measurements were recorded in digital panoramic radiographs and the panoramic CT reformation, with its own eletronic rules of the Dolphinn Imaging 3D® software (Figure 2 and 3). The record of the measures on the images was performed in the darkroom.

During the measurement of the images no tool to enhance the brightness or contrast of panoramic radiographs and panoramic reformation was not applied. To correct the inherent magnification digital panoramic radiograph, was subtracted 20% of each measure obtained in these images, in accordance with the appliance manufacturer's information.

Measurements of bone defects correspond to the distance horizontal and vertical of each of the four defects per jaw, which are circumferential defects, measurements were made in the median position of the circle.

All measurements were made by two observers, twice, with an interval of at least seven days between assessments.

Statistics

Descriptive statistics were calculated for the differences between the measurements obtained from the images and those obtained by directly measuring the bone (the gold standard). Intra- and interexaminer reliability were evaluated with linear correlation test of Pearson and confirmed by the calculation of Dahlberg's test.

To evaluate the accuracy of the measurements was calculated average of the two measurements obtained by one of the examiners, and then was performed ANOVA with post hoc Dunnett, in the measurements obtained the dry mandible (gold standard) and images of the measures corresponding. This evaluation was performed for the set of measures, and also separately for vertical or horizontal measures and the measures of the anterior region or later of the jaws. The significance level was 95% (p 0.05).

In the table 2 demonstrated the analyzy of the measures according to their direction, the results showed no statistical differences for horizontal and vertical measurements betwen all groups in relation to the gold standard.

In the table 3 were also compared the measurements with respect to its regions in the mandible, posterior or front. There was no statistically significant difference compared to the gold standard.

The measurement error for each test device was calculated as the mean test measurement (first examiner) minus the mean direct bone measurement. Thus, a negative error value indicated the measurement recorded from the image was smaller than the gold standard and vice versa.36

In the table 4 was evaluated the mean of the absolute and relative measurement error for each test in relation to the gold standard measures. The results showed no statistical significant difference (p = 0.85) between the groups.

Evaluating the dimensional error, relative to the direction of measurement (horizontal or vertical), there was no statistical difference (p = 0.91 and 0.30, respectively). When performed the dimensional error, regarding the region of the measure (posterior or front regions), there was a significant difference between groups (p = 0.026 and p 0.05) were detected when comparing measurements performed with and without metallic artefacts. With respect to the CBCT, dental metallic artefact produced an increase of 6% in bone thickness and a reduction of 0.68% in bone height. No significant differences (p>0.05) were observed when comparing measurements performed with and without metallic artefacts. However in this study were selected mandibles without metallic artifacts to avoid changes in exams.

The overview of CBCT reformatting may undergo changes depending on the image acquisition process, the voxel size or due to image processing by the program.17,30,31

In the present study the positioning of the dry mandibles was standardized between different equipment, so as to reproduce the position of an in vivo examination. In surveys of FBCT additionally, no gantry tilt, as recommended.5 However, Tomasi et al.32 assessed the influence of inclination of the object on the reliability and reproducibility of linear measurements of anatomic structures of the mandible on images obtained using CBCT. The results revealed high reability of measurements performed on CBCT images independently from object position, examiner's experience and high reproducibility in repeated measurements settings.

In this study the software Dolphin Imaging 3D® version 11.5 was used to access digital panoramic images and build the panoramic reformatted CT images, to be a software with extensive functionality and applicability in orthodontics, implantology and maxillofacial surgery. This software has been used by other studies. 22,33

Another methodological concern was to evaluate the inter and intra-examiner reproducibility. Several previous studies investigating CT measures, reported on intra-examiner reliability, including research dental, height and thickness of the alveolar bone, root length and the transverse dimensions of the mandibular canal and jaw.19,22,27,34 These studies found intra-examiner correlation ranging from 0.93 to 0.99, showing excellent reliability. In this study the intra-examiner correlation was 0.90, indicated an extremely strong intra-examiner agreement, demonstrating the reproducibility of the method. Regarding the variability inter-examiner the correlation coefficient was r= 0.96, very strong, confirming calibration of examiners and confirming the previous studies.

The results of this study revealed that there was no significant statistical difference in linear measurements assessed for all image acquisition protocols for the measures carried out directly in dry mandibles. This finding is in agreement with the results of Correia et al.10, that evaluated the accuracy of linear measurements in cross-sectional images of anterior and posterior teeth head cadavers CBCT scans and found no statistically significant differences between the measurements of the images in the program i-CATVision® and direct measurements with calipers.

In this study, the CBCT voxel was less than the thickness of the FBCT images. The best spatial resolution of CBCT images but did not influence the accuracy of measurements.

When the horizontal and vertical absolute errors were evaluated separately, the results for vertical measurements showed no difference between measurements obtained from panoramic radiographs or reformatting of CT. Kim et al.4 with the purpose of the determine the magnification rate of digital panoramic radiographs and its effectiveness for pre-operative assessment of dental implants, observed no significant difference between the planned implant length and actual inserted implant length (p>0.05) and the magnification rate of the width and length of the inserted implants, seen in the digital panoramic radiographs, was 127.28 + 13,47% and 128.22 + 4.17%, respectively. This finding is similar to the results of the present study, in which no statistical difference of vertical measurements.

However, Schulze et al.15 evaluated the precision and accuracy of digital measurements in digital panoramic radiography observed that the vertical measurements were less reproducible than horizontal measures. The difference did not exceed 0.1mm. The authors report that examiners find it easier to implement horizontal measures the vertical with the mouse cursor. In this present study, the examiners did not have this difficulty.

CBCT imaging has broadned opportunities for examining morphologic aspects of the craniofacial complex, including alveolar bone, but limitations of the technology have yet to be defined. In a study were to investigate the accuracy and reliability of buccal alveolar bone height and thickness measurements derived from CBCT images and was demonstrated the intrarater reliability was high as were interrater correlations for all measurements (> 0.97) except CBCT buccal bone thickness (0.90). CBCT measurements did not differ significantly from direct measurements.22 This results agree of this study.

Wood et al.³³ using the Dolphin Imaging 3D® and OsiriX® programs, evaluated the accuracy of height measurements, in cross-sections of CBCT with voxel of 0.2 mm and 0.4 mm. The results showed differences averages close to zero and that the accuracy of measurements of the vestibular alveolar bone from images with soft tissue CBCT with 0.2 mm voxel showed better accuracy. In this study there was no difference in the accuracy of linear measurements in relation to the spatial resolution of the CBCT image, similar results were found by Ganguly et al.20 that evaluated the accuracy of linear measurements of bone height in cross-sectional images of CBCT with voxel 0.15 mm in the presence of soft tissues.

Timock et al.²² investigated the accuracy and reliability of buccal alveolar bone height and thickness measurements derived from CBCT images with voxel size 0.3 mm and the mean of absolute errors were 0.30mm in buccal bone height and and 0.13 mm in buccal bone thickness with 95% limits of agreement of -0.77 to 0.81 mm, and -0.32 to 0.38 mm, respectively. Agreement between the two methods was higher for the measurements of buccal bone height than buccal bone thickness. In the present study the vertical and horizontal measures were also accurate.

In this study, evaluation differences in relation to the measurement region, on the front or posterior mandible regions. The results showed no statistically significant differences. This finding is in agreement with the results of Veyre-Goulet et al.17 which was evaluated the CBCT images in the posterior maxillary and found no clinically significant differences between the direct measurements and reformatted images.

Comparing the dimensional error between the various devices and protocols, it is observed that there was no statistical difference between them, although the dimensional mean error was lower for CBCT with voxel size 0.2 mm (0.62 mm) and added to the panoramic radiograph (0.78 mm), it differs from the study of Al-ekrish & Ekram36 that compared the accuracy and reliability of linear measurements of jaws recorded from 16-row MDCT images and CBCT voxel size 0.29 mm, obtained the mean of the CBCT absolute errors (0.49 mm) was smaller than that of the MDCT absolute errors (0.75 mm), and this difference was considered statistically significant.

In the study by Gribel et al.21 the linear measurements were performed on axial reformation, sagittal and coronal CBCT with thickness 0.3 mm and the average absolute error was 0.1 mm. And the study of Timock et al.22 using CBCT at 0.3 mm voxel size. Buccal alveolar bone height and thickness measurements of 65 teeth were made in standardized radiographic axial and sagital slices and compared with direct measurements made by dissection. The mean absolute differences were 0.30 mm in bucal bone height and 0.13 mm in bucal bone thickness. In this study the mean absolute error were higher. To CBCT with slice thickness 0.2; 0.3 and 0.4 mm were 0.62; 0.73, 0.68 mm, respectively, and Singleslice CT and four-row MDCT were 128 and 0.74; 0.73 and 0.72 mm, respectively. However this study was conducted with panoramic images, while most of the others was done with cross-sections of the jaws.

Assessing the horizontal measures separately from the vertical, there was no significant difference in the dimensional error between these two groups, although the horizontal error of average was higher than the average vertical error in all cases.

Bahlis et al.¹² evaluating bone height (vertical) measurements in the mental foramen region, using periapical, conventional panoramic radiography (25% constant magnification) and Singleslice CT found mean differences of 0.33 mm, 0.85 mm and 0.35 mm, respectively. The authors obtained better accuracy in periapical radiography and Singleslice CT. In this present study, Singleslice CT had an average error for the vertical measurements of 0.34 mm and a panoramic radiograph of 0.40 mm, and there was no statistical difference between the methods.

Evaluating the error regarding the region of the measure (in the posterior or front mandible regions), contrary there was statistical difference between the error of panoramic radiographs and CT reformation, especially in the posterior region. In this region, the average error was 0.76 mm for the PAND and did not exceed 0.28 mm in panoramic CT reformatting. The lowest average error was for the panoramic reformatting obtained from CBCT with voxel of 0.2 mm (0.17 mm). As for the error of panoramic radiographs, these data are at odds with expectations. This is because the outer regions of the panoramic radiograph (branch and mandibular condyles) are areas of higher magnification image. In this present study, the posterior region of the bone defects were created in the mandible ramus, but the average error is greater in the front region, in relation to the posterior region.

The measures of D-PAN were generally larger than those of the gold standard (data not shown), but after the fix applied (20% subtraction), have become smaller on average, differing significantly from the measures panoramic CT reformatting. The underestimation of the measures in the panoramic radiograph was greater than overestimation and this finding is in agreement with the results of Bahlis et al.¹². This shows that this correction factor is inappropriate for panoramic radiographs. To Carvalho (2008), the panoramic radiograph obtained by rotational system, where beam of X-ray film and move synchronously, image distortion is inevitable and this factor, unlike the expansion, can not be corrected.

The study Suomalainen et al.34 evaluated the accuracy of linear measurements in the posterior mandible in CBCT images with 2D voxel 0,125mm and four-row MDCT, with or without soft tissue, and dose reduction. The authors found significant differences in the dimensional error between the methods studied (p = 0.022): 4.7% for CBCT and 8.8% for TCMC with dry jaw; and 2.3% and 6.6%, respectively, for soft tissue to the jaws; and 5.4% to TCMC with dose reduction. The CBCT was more accurate than a four-row MDCT. The above results are similar in part to this research because here the error of statistical difference of the measures of the angle mandible was attributed to the panoramic radiograph, with no difference in error between CBCT and the four-row MDCT. However, the mean error was at most four channels CT (3.2%), compared to the average error of 0.2 CBCT; 0.3 and 0.4mm (1.7%, 2.3% and 2.5%, respectively). In this study, for the measures in the front region, in contrast, the average error was greater in the panoramic reformatted CT (ranging from 1.06 to 1.25 mm), in relation to D-PAN (0.81 mm average error). The region selected for carrying out the above measures is really critical because, unlike the angle region (mandibular branch) whose thickness is more uniform in front region can observe a wide variation in bone thickness, but substantially wider near the base mandible and narrower at the upper portion of the alveolar process. This feature may have hindered the selection of the central area of the jaw for making the panoramic reconstruction in the software used. In the mandibular branch, bone thickness practically remained at full height, facilitating the design of panoramic cut equidistant to the buccal and lingual cortical. Thus the image of the bone defects of the anterior mandible in panoramic CT reconstructions can not be represented adequately the real structure.

It is noteworthy however that in all groups the average error was greater than 0.5 mm but not exceeding 1 mm. In absolute numbers, except for the PAND, the dimensional errors were mostly located in the range between 0 and 0.5 mm. Evaluating the error greater than 1 mm, more or less, the frequency ranged from 18.8 to 23.8% for CT scans, and was 33.75% for the D-PAN. This may be clinically important, for some situations in dentistry, such as the placement of implants in areas near noble anatomical structures.

In conclusion, the results of this study showed no significant difference in the accuracy of linear measurements between the different evaluated tests and the gold standard, in all protocols; there was no significant difference between the different evaluated tests on the dimensional error, although the error was higher for horizontal measures in the front mandible regions; digital panoramic radiograph showed the highest dimensional error means, especially for measurements of front mandible regions.

Acknowledgements: This study was financed by the Brazilian agency Foundation of support the state´s research of BAHIA (Fundação de amparo à pesquisa do estado da Bahia/FAPESB).

References

1. Abrahams JJ. Dental CT Imaging: A Look at the Jaw. Radiol 2001; 219: 334-345.

2. Liang X, Jacobs R, Hassan B, Li L, Pauwels R, Corpas L, et al. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part I. On subjective image quality. Eur J of Radiol 2010;75: 265-269.

3. Angelopulus C, Thomas S, Hechler S, Parissis N, Hlavacek M. Comparison between digital panoramic radiography and cone-beam computed tomography for the identification of the mandibular canal as part of presurgical dental implant assessment. J Oral Maxillofac Surg 2008; 66: 2130-2135.

4. Kim YK, Park JY, Kim SG, Kim SJ and Kim JD. Magnification rate of digital panoramic radiographs and its effectiveness for pre-operative assessment of dental implants. Dentomaxillofacial Radiology 2011; 40: 76-83.

5. Meurer MI, Meurer E, Silva JVL, Bárbara AS, Nobre LF, Oliveira MG, et al. Acquisition and manipulation of computed tomography images of the maxillofacial region for biomedical prototyping. Radiol Bras 2008; 41(1): 49–54.

6. Garib DG, Raymundo Jr. R, Raymundo MV, Raymundo DV, Ferreira SN. Tomografia computadorizada de feixe cônico (Cone Beam): entendendo este novo método de diagnóstico por imagem com promissora aplicabilidade na ortodontia. R Dental Press Ortondon Ortop Facial 2007; 12(2): 139-156.

7. Benavides E, Rios HF, Ganz SD, An CH, Resnik R, Reardon GT, et al. Use of Cone Beam Computed Tomography in Implant Dentistry: The International Congress of Oral Implantologists Consensus Report. Implan dentist 2012; 21(2): 78-86.

8. Tohnak, Mehnert AJH, Mahoney M and Crozier S. Dental CT metal artefact reduction based on sequential substitution. Dentomaxillofac Radiol 2011; 40: 184–190.

9. Hu H. Multi-slice helical CT: Scan and reconstruction. Med Phys 1999; 26(1): 5-18.

10. Correia F and Salgado A. Tomografia computadorizada de feixe cônico e a sua aplicação em medicina dentária. Rev Port Estomatol Med Dent Cir Maxilofac 2012; 53(1): 47-52.

11. Angelopoulus C, Bedard A, Katz JO, Karamanis S, and Parissis N. Digital Panoramic Radiography: An Overview. Semin Orthod 2004; 10: 194-203.

12. Bahlis A, Mezzomo LA, Boeckel D, Costa NP, Teixeira ER. Accuracy of periapical radiography, panoramic radiography and computed tomography for examining the mental foramen region. Rev Odonto Ciênc 2010; 25(3): 282-287.

13. Correa LR, Spin-Neto R, Stavropoulos A, Schropp L, da Silveira HED, Wenzel A. Planning of dental implant size with digital panoramic radiographs, CBCT-generated panoramic images, and CBCT cross-sectional images. Clin Oral Implants Res 2014; 25(6): 690-5.

14. Parck JB. The evaluation of digital panoramic radiographs taken for implant dentistry in the daily practice. Med Oral Patol Oral Cir Bucal 2010; 1; 15(40): e663-6.

15. Schulze R, Krummenauer F, Schalldach F, d´Hoedt B. Precision and accuracy of measurements in digital panoramic radiography. Dentomaxillofac Radiol 2000; 29: 52-56.

16. Yasar F, Apaydin B, Yilmaz HH. The effects of image compression on quantitative measurements of digital panoramic radiographs. Med Oral Patol Oral Cir Bucal 2012,1; 17(60): 1074-1081.

17. Veyre-Goulet S, Fortin T, Thietty A. Accuracy of linear measurement provided by cone beam computed tomography to assess bone quantity in the posterior maxilla: A human cadaver study. Clin Implant Dent Relat Res 2008;10(4):226-30.

18. Gahleitner A, Kuchler U, Homolka P, Heschl J, Watzek G, Imhof H. High-resolution CT of transplanted teeth: imaging technique and measurement accuracy. Eur Radiol 2008; 18: 2975–80.

19. Kamburoglu K, Kiliç C, Özen T, Yuksel SP. Measurements of mandibular canal region obtained by conebeam computed tomography: a cadaveric study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 107: 34-42.

20. Ganguly R, Ruprecht A, Vincent S, Hellstein J, Timmons S, Qian F. Accuracy of linear measurement in the Galileos cone beam computed tomography under simulated clinical conditions. Dentomaxillofac Radiol 2011; 40: 299–305.

21. Gribel BF, Gribel MN, Fraza DC, Mcnamara JA, Manzie FR. Accuracy and reliability of craniometric measurements on lateral cephalometry and 3D measurements on CBCT scans. Angle Orthod. 2011; 81: 26–35.

22. Timock AM, Cook V, Mcdonald T, Leo MC, Crowe J, Benninger BL, et al. Accuracy and reliability of buccal bone height and thickness measurements from cone-beam computed tomography imaging. Am J Orthod Dentofacial Orthop 2011; 140: 734-44.

23. Al-Ekrish AA. Effect of exposure time on the accuracy and reliability of cone beam computed tomography in the assessment of dental implant site dimensions in dry skulls. Saudi Dent J 2012; 24: 127–34.

24. Benninger B, Peterson A, Cook V. Assessing validity of actual tooth height and width from cone beam images of cadavers with subsequent dissection to aid oral surgery. J Oral Maxillofac Surg 2012; 70: 302-6.

25. Patcas R, Meuller L, Ullrich O, Peltomeaki T. Accuracy of cone-beam computed tomography at different resolutions assessed on the bony covering of the mandibular anterior teeth. Am J Orthod Dentofac Orthop. 2012; 141: 41-50.

26. Torres MGG, Campos PSF, Segundo NP, Navarro M, Crusoé-Rebello. Accuracy of linear measurements in cone beam computed tomography with different voxel sizes. Implant Dent 2012; 21(2): 150-5.

27. Zhang Z, Cheng J, Li G, Zhang J, Zhang Z, Chen X. Measurement accuracy of temporomandibular joint space in Promax 3-dimensional cone-beam computerized tomography images. Oral Surg Oral Med Oral Pathol Oral Radiol. 2012; 114: 112-117.

28. Hanazawa T, Sano T, Seki K, Okano T. Radiologic measurements of the mandible: a comparison between ct-reformatted and conventional tomographic images. Clin Oral Impl Res 2004; 15: 226–32.

29. Cremonini CC, Dumas M, Pannuti CM, Neto JBC, Cavalcanti MGP, Lima LA. Assessment of linear measurements of bone for implant sites in the presence of metallic artefacts using cone beam computed tomography and multislice computed tomography. Int J Oral Maxillofac Surg 2011; 40: 845–50.

30. Kobayashi K, Shimoda S, Nakagawa Y, Yamamoto A. Accuracy in measurament of distance using limited cone-beam computerized tomography. Int J Oral Maxillofac Implants. 2004; 19: 228-31.

31. Farman AG, Scarfe WC. Development of imaging selection criteria and procedures should precede cephalometric assessment with cone-beam computed tomography. Am J Orthod Dentofacial Orthop. 2006; 130(2): 257-65.

32. Tomasi C, Bressan E, Corazza B, Mazzoneli S, Stellini E, Lith A. Reliability and reproducibility of linear mandible measurements with the use of a cone-beam computed tomography and two object inclinations. Dentomaxillofac Radiol. 2011; 40: 244–250.

33. Wood R, Sun Z, Chaudhry J, Tee BC, Kim DG, Leblebicioglu B, ENGLAND G. Factors affecting the accuracy of buccal alveolar bone height measurements from cone-beam computed tomography images. Am J Orthod Dentofacial Orthop 2013; 143: 353-63.

34. Suomalainen A, Vehmas T, Kortesniemi M, Robinson S, Peltola J. Accuracy of linear measurements using dental cone beam and conventional multislice computed tomography. Dentomaxillofac Radiol 2008; 37: 10–17.

35. Scarfe WC, Farman AG, Sukovic P. Clinical Applications of cone-bean computed tomography in dental practice. J Can Dent Assoc. 2006; 72: 75-80.

36. Al-ekrish AA, Ekram M. A comparative study of the accuracy and reliability of multidetector computed tomography and cone beam computed tomography in the assessment of dental implant site dimensions. Dentomaxillofac Radiol 2011; 40: 67-75.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download