• The Journal of Korean Society for Radiation Therapy
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• v.24 no.1
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• pp.39-43
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• 2012

Purpose: In hospital image-guided radiation therapy in patients with bladder cancer to enhance the reproducibility of the appropriate amount, depending on the patient's condition, and image-guided injection of saline system (On-Board Imager system, OBI, VARIAN, USA) three of the Cone-Beam CT dimensional matching (3D-3D matching) to be the treatment. In this study, the treatment of patients with bladder cancer at Cone-Beam CT image obtained through the analysis of the bones based matching and matching based on the bladder to learn about the differences, the bladder's volume change injected saline solution by looking at the bladder for the treatment of patients with a more appropriate image matching is to assess how the discussion. Materials and Methods: At our hospital from January 2009 to April 2010 admitted for radiation therapy patients, 7 patients with bladder cancer using a Folly catheter of residual urine in the bladder after removing the amount determined according to individual patient enough to inject saline CT-Sim was designed after the treatment plan. After that, using OBI before treatment to confirm position with Cone-Beam CT scan was physician in charge of matching was performed in all patients. CBCT images using a total of 45 bones, bladder, based on image matching and image matching based on the difference were analyzed. In addition, changes in bladder volume of Eclipse (version 8.0, VARIAN, USA) persuaded through. Results: Bones, one based image matching based on the bladder and re-matching the X axis is the difference between the average $3{\pm}2mm$, Y axis, $1.8{\pm}1.3mm$, Z-axis travel distance is $2.3{\pm}1.7mm$ and the overall $4.8{\pm}2.0mm$, respectively. The volume of the bladder compared to the baseline showed a difference of $4.03{\pm}3.97%$. Conclusion: Anatomical location and nature of the bladder due to internal movement of the bones, even after matching with the image of the bladder occurred in different locations. In addition, the volume of saline-filled bladder showed up the difference between the 4.03 percent, but matched in both images to be included in the planned volumes were able to confirm. Thus, after injection of saline into the bladder base by providing a more accurate image matching will be able to conduct therapy.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.163-169
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• 2013

Purpose: Tonsilloliths are calcifications found in the crypts of the palatal tonsils and can be detected on routine panoramic examinations. This study was performed to highlight the benefits of cone-beam computed tomography (CBCT) in the diagnosis of tonsilloliths appearing bilaterally on panoramic radiographs. Materials and Methods: The sample group consisted of 7 patients who had bilateral radiopaque lesions at the area of the ascending ramus on panoramic radiographs. CBCT images for every patient were obtained from both sides of the jaw to determine the exact locations of the lesions and to rule out other calcifications. The calcifications were evaluated on the CBCT images using Ez3D2009 software. Additionally, the obtained images in DICOM format were transferred to ITK SNAP 2.4.0 pc software for semiautomatic segmentation. Segmentation was performed using contrast differences between the soft tissues and calcifications on grayscale images, and the volume in mm3 of the segmented three dimensional models were obtained. Results: CBCT scans revealed that what appeared on panoramic radiographs as bilateral images were in fact unilateral lesions in 2 cases. The total volume of the calcifications ranged from 7.92 to $302.5mm^3$. The patients with bilaterally multiple and large calcifications were found to be symptomatic. Conclusion: The cases provided the evidence that tonsilloliths should be considered in the differential diagnosis of radiopaque masses involving the mandibular ramus, and they highlight the need for a CBCT scan to differentiate pseudo- or ghost images from true bilateral pathologies.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.260-267
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• 2013

The aim of this study was to analyze the three dimensional characteristics of the size, shape and location of mesiodens and their effect on permanent teeth arrangement using Cone-beam computed tomography(CBCT). 191 patients under 15 years old who had visited the hospital between June 2006 and December 2012 and taken CBCT were investigated. Among them, 43 patients with diastema were analyzed to investigate the correlation between the amount of diastema and the mesiodens. The results showed that mesiodens were found in males 3.9 times more than females and found most in 7 years old. The mean length of mesiodens was 13 mm and the width was 6.8 mm. The conical shape comprised of 52.9%. Many mesiodens were located in the palatal side rather than the labial side and located vertically near the crown. 63.0% of mesiodens were reversed and the common complications were delayed eruption followed by diastema, and teeth rotation. And the amount of diastema had correlation with size and mesiodistal position of the mesiodens. The current study used 3D analysis to show the size and position of mesiodens and occurrence distribution of complication. Among these, the amount of diastema had shown the correlation with the size and mesiodistal position of mesiodens.

• The korean journal of orthodontics
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• v.47 no.4
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• pp.222-228
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• 2017

Objective: To evaluate soft- and hard-tissue changes in the mandibular angle area after the administration of botulinum toxin type A (BoNT-A) injection to patients with masseteric hypertrophy by using three-dimensional cone-beam computed tomography (3D-CBCT). Methods: Twenty volunteers were randomly divided into two groups of 10 patients. Patients in group I received a single BoNT-A injection in both masseter muscles, while those in group II received two BoNT-A injections in each masseter muscle, with the second injection being administered 4 months after the first one. In both groups, 3D-CBCT was performed before the first injection and 6 months after the first injection. Results: Masseter muscle thicknesses and cross-sectional areas were significantly reduced in both groups, but the reductions were significantly more substantial in group II than in group I. The intergonial width of the mandibular angle area did not change significantly in either group. However, the bone volume of the mandibular gonial angle area was more significantly reduced in group II than in group I. Conclusions: The repeated administration of BoNT-A injections may induce bone volume changes in the mandibular angle area.

• Imaging Science in Dentistry
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• v.52 no.3
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• pp.245-258
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• 2022

Purpose: This study compared the root canal anatomy between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) images before and after biomechanical preparation and root canal filling. Materials and Methods: Isthmus-containing mesial roots of mandibular molars(n=14) were scanned by micro-CT and 3 CBCT devices: 3D Accuitomo 170 (ACC), NewTom 5G (N5G) and NewTom VGi evo (NEVO). Two calibrated observers evaluated the images for 2-dimensional quantitative parameters, the presence of debris or root perforation, and filling quality in the root canal and isthmus. The kappa coefficient, analysis of variance, and the Tukey test were used for statistical analyses(α=5%). Results: Substantial intra-observer agreement (κ=0.63) was found between micro-CT and ACC, N5G, and NEVO. Debris detection was difficult using ACC (42.9%), N5G (40.0%), and NEVO (40%), with no agreement between micro-CT and ACC, N5G, and NEVO (0.05<κ<0.12). After biomechanical preparation, 2.4%-4.8% of CBCT images showed root perforation that was absent on micro-CT. The 2D parameters showed satisfactory reproducibility between micro-CT and ACC, N5G, and NEVO (intraclass correlation coefficient: 0.60-0.73). Partially filled isthmuses were observed in 2.9% of the ACC images, 8.8% of the N5G and NEVO images, and 26.5% of the micro-CT images, with no agreement between micro-CT and ACC, and poor agreement between micro-CT and N5G and NEVO. Excellent agreement was found for area, perimeter, and the major and minor diameters, while the roundness measures were satisfactory. Conclusion: CBCT images aided in isthmus detection and classification, but did not allow their classification after biomechanical preparation and root canal filling.

• Journal of Periodontal and Implant Science
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• v.47 no.3
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• pp.154-164
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• 2017

Purpose: Measurement of the root surface area (RSA) is important in periodontal treatment and for the evaluation of periodontal disease as a risk factor for systemic disease. The aim of this study was to measure the RSA at 6 mm below the cementoenamel junction (CEJ) using the Mimics software (Materialise, Leuven, Belgium). Methods: We obtained cone-beam computed tomography (CBCT) data from 33 patients who had visited the Department of Oral and Maxillofacial Radiology of Dankook University Dental Hospital. The patients comprised 17 men and 16 women aged from 20 to 35 years, with a mean age of 24.4 years. Only morphologically intact teeth were included in our data. Because the third molars of the maxilla and mandible have a high deformation rate and were absent in some participants, they were not included in our research material. Results: The CBCT data were reconstructed into 3-dimensional (3D) teeth models using the Mimics software, and the RSA at 6 mm below the CEJ was separated and measured using 3-Matic (Materialise). In total, 924 3D teeth models were created, and the area at 6 mm below the CEJ could be isolated in all the models. The area at 6 mm below the CEJ was measured in all teeth from the 33 patients and compared based on sex and position (maxilla vs. mandible). Conclusions: In this study, we demonstrated that it was feasible to generate 3D data and to evaluate RSA values using CBCT and the Mimics software. These results provide deeper insights into the relationship between periodontal inflammatory burden and systemic diseases.

• The korean journal of orthodontics
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• v.46 no.5
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• pp.269-279
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• 2016

Objective: Rapid maxillary expansion (RME) is used to expand the maxilla and increase arch perimeter; yet, there are few reports on its effects on the sphenoid bone. With cone-beam computed topography (CBCT), it is possible to visualize sphenoid bone changes. The purpose of this study was to investigate sphenoid bone changes observed in conjunction with RME treatments, using CBCT. Methods: Sixty patients (34 women and 26 men, aged 11-17 years) underwent RME as part of their orthodontic treatment. Patients were randomly assigned to one of three groups: a tooth-anchored group, a bone-anchored group, or a control group. Initial CBCT scans were performed preceding the RME treatment ($T_1$) and again directly after the completion of expansion ($T_2$). Statistical analysis included ANOVA, descriptive statistics, and the intraclass correlation coefficient (ICC). Results: The reliability of the landmark location was at least 0.783, and the largest ICC mean measurement error was 2.32 mm. With regard to distances, the largest change was 0.78 mm, which was not statistically significant (p > 0.05). Statistical significance was established in patient groups of the same sex and treatment type for the following distance measurements: right anterior lateral pterygoid plate to the right edge of the hypophyseal fossa ($d_2$), anterior distance between the medial pterygoid plates ($d_4$), and anterior distance between the left medial and lateral plates ($d_8$). Conclusions: In this study, there were no clinically significant changes in the sphenoid bone due to RME treatments regardless of sex or treatment type.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.4
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• pp.168-174
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• 2013

Objectives: The aim of this study is to investigate the correlation between 2-dimensional (2D) cephalometric measurement and 3-dimensional (3D) cone beam computed tomography (CBCT) measurement, and to evaluate the availability of 3D analysis for asymmetry patients. Materials and Methods: A total of Twenty-seven patients were evaluated for facial asymmetry by photograph and cephalometric radiograph, and CBCT. The 14 measurements values were evaluated and those for 2D and 3D were compared. The patients were classified into two groups. Patients in group 1 were evaluated for symmetry in the middle 1/3 of the face and asymmetry in the lower 1/3 of the face, and those in group 2 for asymmetry of both the middle and lower 1/3 of the face. Results: In group 1, significant differences were observed in nine values out of 14 values. Values included three from anteroposterior cephalometric radiograph measurement values (cant and both body height) and six from lateral cephalometric radiographs (both ramus length, both lateral ramal inclination, and both gonial angles). In group 2, comparison between 2D and 3D showed significant difference in 10 factors. Values included four from anteroposterior cephalometric radiograph measurement values (both maxillary height, both body height) and six from lateral cephalometric radiographs (both ramus length, both lateral ramal inclination, and both gonial angles). Conclusion: Information from 2D analysis was inaccurate in several measurements. Therefore, in asymmetry patients, 3D analysis is useful in diagnosis of asymmetry.

• Imaging Science in Dentistry
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• v.40 no.4
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• pp.171-178
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• 2010

Purpose : The purpose of this study is to develop a surgical stent for dental implant procedure that can be easily applied and affordable by using cone beam computerized tomography (CBCT). Materials and Methods : Aluminum, Teflon-PFA (perfluoroalkoxy), and acetal (polyoxymethylene plastic) were selected as materials for the surgical stent. Among these three materials, the appropriate material was chosen using the CBCT images. The surgical stent, which could be easily placed into an oral cavity, was designed with chosen material. CBCT images of the new surgical stent on mandible were obtained using Alphard-3030 dental CT system (Asahi Roentgen Co., Ltd., Kyoto, Japan). The point of insertion was prescribed on the surgical stent with the multiplanar reconstruction software of OnDemand3D (CyberMed Inc., Seoul, Korea). Guide holes were made at the point of insertion on the surgical stent using newly designed guide jig. CBCT scans was taken for the second time to verify the accuracy of the newly designed surgical stent. Results : Teflon-PFA showed radiologically excellent image characteristics for the surgical stent. High accuracy and reproducibility of implantation were confirmed with the surgical stent. Conclusion : The newly designed surgical stent can lead to the accurate implantation and achieve the clinically predictable result.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.4
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• pp.256-261
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• 2017

Objectives: The concept of natural head position (NHP) was first introduced by Broca in 1862, and was described as a person's stable physiologic position "when a man is standing and his visual axis is horizontal." NHP has been used routinely for clinical examination; however, a patient's head position is random during cone-beam computed tomography (CBCT) acquisition. To solve this problem, we developed an accelerometer to record patients' NHP and reproduce them for CBCT images. In this study, we also tested the accuracy and reproducibility of our accelerometer. Materials and Methods: A total of 15 subjects participated in this study. We invented an accelerometer that measured acceleration on three axes and that could record roll and pitch calculations. Recorded roll and pitch data for each NHP were applied to a reoriented virtual image using three-dimensional (3D) imaging software. The data between the 3D models and the clinical photos were statistically analyzed side by side. Paired t-tests were used to statistically analyze the measurements. Results: The average difference in the angles between the clinical photograph and the 3D model was $0.04^{\circ}$ for roll and $0.29^{\circ}$ for pitch. The paired t-tests for the roll data (P=0.781) and the pitch data (P=0.169) showed no significant difference between the clinical photographs and the 3D model (P>0.05). Conclusion: By overcoming the limitations of previous NHP-recording techniques, our new method can accurately record patient NHP in a time-efficient manner. Our method can also accurately transfer the NHP to a 3D virtual model.