|Year : 2017 | Volume
| Issue : 4 | Page : 100-103
The accuracy of linear and angular measurements in the different regions of the jaw in cone-beam computed tomography views
Mehrdad Abdinian1, Homa Baninajarian2
1 Department of Oral and Maxillofacial Radiology, Dental Implants Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
2 Dental Students’ Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
|Date of Web Publication||29-Nov-2017|
Dental Students’ Research Center, School of Dentistry, Isfahan University of Medical Sciences, Hezarjerib St, Isfahan
Source of Support: None, Conflict of Interest: None
Introduction: The use of cone-beam computed tomography (CBCT) has increased lately. The aim of this study was to evaluate the accuracy of linear and angular measurements by CBCT in the different areas of the jaws. Materials and Methods: In this study, the mesiodistal width and height as well as the angular measurements were ascertained in four different sites of the mandibular and maxillary jaws (anterior, canine, premolar, and molar regions). Each area was outlined by gutta-percha as opaque markers. The measurements were obtained by a digital caliper (as gold standard) and on CBCT views including “three-dimensional” and “panaroma” (section thickness of 5 and 10 mm). Data were analyzed by the one-way analysis of variance (ANOVA). Results: The means [standard deviation (SD)] of measurement accuracy of all groups were more than 90%. There was no significant difference between the means (SD) of measurement accuracy of all views (oneway ANOVA, P > 0.05). The means (SD) of measurement accuracy of all views in four regions of the jaws had no significant difference (one-way ANOVA, P > 0.05). Conclusion: This study showed that CBCT imaging has a high degree of measurement accuracy in all three horizontal, vertical, and angular measurements as well as the “panorama” (5- and 10-mm thicknesses) and “three-dimensional” views in all the areas of the jaws. Therefore, the use of CBCT in the linear and angular measurements of the dentomaxillofacial region can be recommended.
Keywords: Angular measurement, CBCT, jaw, linear measurement
|How to cite this article:|
Abdinian M, Baninajarian H. The accuracy of linear and angular measurements in the different regions of the jaw in cone-beam computed tomography views. Dent Hypotheses 2017;8:100-3
|How to cite this URL:|
Abdinian M, Baninajarian H. The accuracy of linear and angular measurements in the different regions of the jaw in cone-beam computed tomography views. Dent Hypotheses [serial online] 2017 [cited 2018 Apr 20];8:100-3. Available from: http://www.dentalhypotheses.com/text.asp?2017/8/4/100/219446
| Introduction|| |
Cone-beam computed tomography (CBCT) is a novel modality that constructs the image by a cone-shaped beam of X-ray, which is rotating around the subject. CBCT provides three-dimensional images with considerable reductions in radiation dose and metal-induced artifacts, and higher spatial resolution compared to computed tomography (CT).,,, The use of CBCT in various research and clinical situations has been increasing in the recent years.,, The indications of CBCT imaging include planning for implant surgery, computer-guided implant placement, and maxillofacial surgeries.,,,
By using CBCT, images can be produced in orientations other than the conventional axial plane with special algorithms that can generate multiplanar, reformatted two-dimensional, three-dimensional, and panoramic reconstructions on a personal computer. It should be considered that detector quality, imaging setting, voxel size, and hardware/software characteristics affect CBCT image quality, which may have an effect on the linear and angular measurements.
The linear measurement is used for many reasons including to measure the height of the remaining bone, the periphery of the anatomical structures such as the maxillary sinus, inferior alveolar canal, and distance to the root of the other teeth, or other anatomical structures.,,, Additionally, the angular measurement is used for determining the orientation degree of the root, crown, or impacted teeth. It is also used for evaluating the edentulous areas before dental implant placement.,
Because of the increasing use of CBCT in different dental operations and the importance of the linear and angular measurements, this study aimed to evaluate the accuracy of the linear and angular measurements in the different areas of the jaws in CBCT images.
| Materials and Methods|| |
In this study, 10 dry human skulls of unknown age, sex, and race were used. Four regions of the mandible and maxilla including the anterior, canine, premolar, and molar areas were considered for the linear and angular measurements.
For linear measurements in both horizontal and vertical dimensions (mesiodistal width and height), the opaque gutta-percha points were attached to the specified sites by glue (Super Glue, Razi, Iran). This meant that the first marker in the deep area of the buccal embrasure was attached to the alveolar crest, and the second marker was attached to the most apical part of the alveolar ridge, precisely parallel to the first marker. The liner measurements (horizontal and vertical) were made by a digital caliper (Guanglu and Vazigeve, China), with an accuracy of 0.01 mm. For angular measurements, two gutta-percha points with uncertain angles were glued (Super Glue, Razi, Iran) to each site. To measure the angles, they were drawn on the paper by a parchment and a pen and were then measured by a protractor.
The temporomandibular joint was rehabilitated between the glenoid fossa and the mandibular condyle by covering them with a piece of baseplate wax of 0.01-mm thickness. The jaws were fixed in central occlusion by a paper tape. To rehabilitate the spine and stabilize the position of the head, a pipe made of polyvinyl plastic was placed into the foramen magnum on one side and attached to a camera tripod on the other side (630 Zeiss Universal Tripod FT, Ogerkochen, Germany). Then, the images were captured using a CBCT system (Soredex, Helsinki, Finland). For this purpose, the skull was placed in a CBCT device in an optimum position: the Frankfurt line was set parallel to the horizontal plane and the device midline was set according to the skull midline. The ear rods were then fixed in the skull, and the skull was scanned with an exposure setting of 12.6 s, 89 KvP, and 6 mA.
The images were rebuilt by “On Demand 3D Dental” software. The images were observed on an LG, 22-inch screen monitor (LG, Seoul, Korea) with a resolution of 1440 × 900 pixels at 32-bit color using the CBCT software (GALAXIS Viewer, Sirona Dental Systems, NC, USA). The intended measurements were made by the devices mounted on the software (linear and angular measurements in the device menu). All measurements were made separately in three views including “three dimensions” and in the two sections for the “panorama” view (5- and 10-mm thicknesses).
Statistical analysis was conducted using the Statistical Package for the Social Sciences version 20.0 software (IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.). The measurement accuracy was calculated as follows:
One-way analysis of variance (ANOVA) was used to assess the means [standard deviation (SD)] of measurement accuracy between the groups.
| Results|| |
The means (SD) of measurement accuracy of all the views in all measurements and in all four regions of the jaws were high (more than 90% in all groups) [[Table 1] and [Table 2]].
|Table 1: The mean (SD) accuracy of the measurements in the linear (horizontal and vertical) and angular measurements|
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|Table 2: The mean (SD) accuracy of the measurements in the different regions|
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The “three-dimensional” and “panorama, 10-mm thickness” views show the highest means (SD) of measurement accuracy in the linear (horizontal and vertical) and angular measurements, respectively. The “panorama, 5-mm thickness” view shows the lowest means (SD) of measurement accuracy in all measurements. However, there was no significant difference between the means (SD) of measurement accuracy of all views (one-way ANOVA, P > 0.05) [Table 1].
The vertical linear measurement had the highest mean (SD) of accuracy of the measurement for all views. The horizontal liner measurement and angular measurement for the “panorama, 5-mm thickness” and “three-dimensional” views had the lowest mean (SD) accuracy of measurement, respectively. However, there was no significant difference in this respect (one-way ANOVA, P > 0.05) [Table 1].
The mean (SD) accuracy of measurement in the “panorama” (5-mm thickness) view for the anterior, canine, premolar, and molar regions were 94.7 (4.9), 96.4 (3.1), 94.1 (4.2), and 94.1 (5.3), respectively (one-way ANOVA, P = 0.058). Furthermore, the mean (SD) accuracy of measurement in the “panorama” (10-mm thickness) view for the anterior, canine, premolar, and molar regions were 94.7 (6.5), 96.7 (3.4), 96.0 (2.1), and 94.9 (5.6), respectively (one-way ANOVA, P = 0.052). Additionally, the mean (SD) accuracy of measurement in the “three-dimensional” view for the anterior, canine, premolar, and molar regions were 95.8 (3.2), 96.9 (3.1), 96.4 (3.5), and 96.2 (3.8), respectively (one-way ANOVA, P = 0.320). However, the canine area showed the highest mean (SD) accuracy of measurement in all views [Table 2].
| Discussion|| |
This study examined the accuracy of linear and angular measurements in CBCT views. This study showed that CBCT imaging has a high degree of measurement accuracy in all three horizontal, vertical, and angular dimensions as well as the “panorama” and “three-dimensional” views in all areas of the jaws. These findings were consistent with the results of other studies.
Pinsky et al. studied the size of bone defects resulting from periodontal and periapical diseases. They reported that the CBCT could be a practical, noninvasive, reliable, and accurate modality for diagnosing the bone lesions. Stratemann et al. studied the accuracy of linear measurements by NewTom QR DVT 9000 and the Hitachi MercuRay devices. In both the devices, a high degree of accuracy was reported in the linear measurements. Lascala et al. assessed the linear measurements in 13 anatomical points in the internal and external anatomical site. Their result showed that the linear measurements were less than the actual one in CBCT images. However, the difference was only significant in the base of the skull and not in other dentomaxillofacial structures. Therefore, the linear measurement is reliable for other structures such as the dentoalveolar region. In the study performed by Moshfeghi et al., the mean difference with respect to the gold standard was negative but not statistically significant in the axial and coronal planes, except in measurements made in the axial section with high resolution. They also concluded that the linear measurement of CBCT images, in the different regions of the maxillofacial structure, is highly accurate and reproducible. Kamburoglu et al. assessed the accuracy of the linear measurements in 13 points of the skull by Iluma and 3D Accuitomo devices. They reported similar accuracy of image measurements with real measurement in the different regions of the mandibular, maxillary, and skull bases. In an investigation of the posterior maxilla, Shahbazian et al. showed that CBCT was better than panoramic radiography for measuring the distance between the maxillary sinus floor and maxillary teeth. In addition, Vujanovic-Eskenazi et al. compared the panoramic and CBCT images to assess the anterior loop position of the mental nerve. They reported no significant difference between the two devices. However; because of the less accurate and reliable information obtained by two-dimensional imaging, they recommended the use of CBCT. In this study, the measurement accuracy in all regions were reported to be high. However, the highest mean measurement accuracy was obtained for the canine region in both the upper and lower jaws.
The reason for the slight differences in this study in comparison with other studies is likely to be related to how the study was conducted (observer performance and calibration or hardware/software capabilities of the different systems tested). It should also be noticed that in this study measurements were made only in the dentoalveolar regions and between specified artificial markers, and not in the whole skull.
Shokri and Khajeh compared the effects of difference in section thickness on the accuracy of linear measurements. Their results showed the highest degree of measurement accuracy for the horizontal dimension with 4-mm thickness and vertical dimension with 5-mm thickness. In addition, Moshfeghi et al. studied the effect of section thickness on the measurement accuracy of linear dimension. The results showed a significant difference between reality and images in different thicknesses, but because these differences were less than 1 mm, they were clinically accepted. In this study, the 5- and 10-mm thicknesses were examined in the panorama views. The results showed that the accuracy of the mean measurements was high, and these measurements were not significantly different from the actual ones. The reason for the differences in the findings is probably related to the study method and the selected regions. Further studies are recommended in this respect.
One of the limitations of this study was the nonsimulation of soft tissue, because the dispersed radiation emitted from the soft tissue made changes in the measurements. Future studies are suggested to perform measurements using a phantom with materials mimicking soft tissue that reduces the radiation dose. In addition, in this study, the measurements were performed on the external anatomy of the jaws. More studies for evaluating the accuracy of measurement of the internal anatomy of the dentomaxillofacial structures are also recommended.
| Conclusion|| |
This study showed that CBCT imaging has a high degree of measurement accuracy in all three horizontal, vertical, and angular measurements as well as the panorama (5- and 10-mm thicknesses) and three-dimensional views in all areas of the jaws. Therefore, the use of CBCT in the linear and angular measurements of the dentomaxillofacial region could be recommended.
Financial support and sponsorship
This study was supported financially by the Vice Chancellery of Research and Technology, Isfahan University of Medical Sciences, Isfahan, Iran (Grant #395438).
Conflicts of interest
Authors declare that they have no significant competing financial, professional, or personal interests that might have influenced the performance or presentation of the work described in this manuscript.
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[Table 1], [Table 2]