• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.61-68
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• 2007

The purpose of this study was to compare the centering abilities of four root canal instrument systems and the amounts of dentin removed after root canal shaping using them. The mesial canals of twenty extracted mandibular first molars having $10-20^{\circ}$ curvature were scanned using X-ray micro-computed tomography (XMCT)-scanner before root canals were instrumented. They were divided into four groups (n = 10 per group). In Group 1, root canals were instrumented by the step-back technique with stainless steel K-Flexofile after coronal flaring. The remainders were instrumented by the crown-down technique with Profile (Group 2), ProTaper (Group 3) or K3 system (Group 4). All canals were prepared up to size 25 at the end-point of preparation and scanned again. Scanned images were processed to reconstruct three-dimensional images using three-dimensional image software and the changes of total canal volume were measured. Pre-and post-operative cross-sectional images of 1, 3, 5, and 7 mm from the apical foramen were com pared. For each level, centering ratio were calculated using Adobe Photoshop 6.0 and image software program. ProTaper and K3 systems have a tendency to remove more dentin than the other file systems. In all groups, the lowest value of centering ratio at 3 mm level was observed. And except at 3 mm level, ProTaper system made canals less centered than the other systems (p < 0.05).

• Journal of the Korean Fracture Society
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• v.30 no.4
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• pp.186-191
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• 2017

Purpose: The purpose of this study was to investigate the radiological and epidemiological characteristics, as well as the clinical course of pelvic insufficiency fractures in the elderly population. Materials and Methods: At a Haeundae Paik Hospital, we retrospectively reviewed patients with pelvic insufficiency fractures between March 2010 and May 2017. The demographic data of patients were analyzed, and bone mineral density and bone turnover markers were evaluated to estimate the metabolic status of the bone. The radiological characteristics were evaluated by comparing the simple x-ray images with the computed tomography images, and the types of fractures were classified via computed tomography images. For clinical course evaluation, we investigated comorbid complications, and compared the walking ability scale before and 6 months after the fracture. Results: A total of 42 patients were included, with an average age of 76.5 years. All were female except one case. In 5 cases where the initial medical examination was from another institution, the fracture was not found in 3 cases. All cases received conservative treatment. After the diagnosis of pelvic bone fracture using a simple x-ray imaging, additional fractures were found in 81.0% of the study population using a computed tomography. Initiation of gait occurred at an average of 2.8 weeks, and every case except 1 (97.6%) fully recovered their gait ability. Conclusion: We concluded that there was a limitation with diagnosing pelvic insufficiency fracture using only a simple x-ray imaging technique. In general, cases in this study showed conservative treatment yielded favorable clinical outcome with relatively less critical complications.

• Archives of Craniofacial Surgery
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• v.18 no.1
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• pp.21-24
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• 2017

Background: In evaluation of craniosynostosis patients in terms of neurodevelopmental delay, positron emission tomography computed tomography (PET-CT) scan can be used to assess brain abnormalities through glucose metabolism. We aimed to determine the unnecessity of PET-CT in this study. Methods: Thirty-eight patients diagnosed with craniosynostosis who underwent distraction osteogenesis from October, 2010 to November, 2013 were reviewed. Magnetic resonance imaging (MRI) and PET-CT scan were carried out for evaluation of the brain structure and function, whereas X-ray and CT scan were taken for evaluation of the skull. Results: Nine patients reported abnormal MRI findings which were not significant, and five patients showed local problem on brain on PET-CT scan. No correlation was found among them. Conclusion: PET-CT evaluation of possible abnormal brain findings do not affect surgical planning or require additional therapy. Preoperative PET-CT scan is not the essential study to get any etiologic information of the disease consequences or to establish the treatment plan.

• Journal of Korean Foot and Ankle Society
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• v.18 no.4
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• pp.165-172
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• 2014

Purpose: We evaluated the correlation of postoperative clinical outcomes and radiologic findings using computed tomography and simple X-ray in intra-articular calcaneal fractures. Materials and Methods: The current study is based on 41 feet, 38 patients with displaced intra-articular fracture who underwent surgical treatment with at least one year of follow-up. Evaluation of clinical outcome included American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, visual analogue scale (VAS) score, and subjective satisfaction. A simple X-ray was used in evaluation of preoperative and postoperative Gissane angle, B${\ddot{O}}$hler angle, and calcaneal fracture width. Computed tomography scan was performed for evaluation of preoperative and postoperative articular step-off and articular gap in all cases. Finally, we evaluated the correlation of the postoperative clinical outcomes and radiologic findings based on the measurement. Results: The average postoperative AOFAS score and VAS score was $84.1{\pm}8.5$ and $2.2{\pm}2.2$. Subjective satisfaction was excellent in 15 cases, good in 19 cases, and fair in seven cases. The average B${\ddot{O}}$hler angle was restored from $11.1^{\circ}$ to $24.7^{\circ}$(p<0.05), Gissane angle was changed from $121.0^{\circ}$ to $119.0^{\circ}$ (p>0.05), and the average width was restored from 45.8 to 35.0 mm (p<0.05). The average articular step-off and gap were decreased from 6.3 to 2.0 mm and from 11.1 to 4.6 mm, respectively (p<0.05). No significant correlations were observed between the clinical outcome and Gissane angle, B${\ddot{O}}$hler angle, and width, and there was no significant correlation between the clinical outcome and Sanders classification. However, postoperative articular step-off showed correlation with VAS and AOFAS score and articular gap showed correlation with VAS score. Conclusion: The clinical outcome did not show correlation with B${\ddot{O}}$hler angle and Gissane angle but did show correlation with anatomical reduction of the posterior facet joint.

• Imaging Science in Dentistry
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• v.41 no.2
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• pp.79-84
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• 2011

Purpose : The aim of the present study was to investigate the disagreement of cephalometric analysis depending on the reference determination of midsagittal plane on three-dimensional computed tomography. Materials and Methods : A total of 102 young women with class III dentofacial deformity were evaluated using three-dimensional computed tomography. The cranial and facial midsagittal planes were defined and the amounts of jaw deviation were calculated. The amounts of jaw deviation were compared with paired t-test (2-tailed) and Bland-Altman plot was drawn. Results : The landmark tracing were reproducible ($r{\ge}.978$). The jaws relative to the cranial midsagittal plane were 10-17 times more significantly deviated than to the facial midsagittal plane (P<.001). Bland-Altman plot demonstrated that the differences between the amounts of jaw deviation from two midsagittal planes were not normally distributed versus the average of the amounts of jaw deviation from two midsagittal planes. Conclusion : The cephalometric analyses of facial asymmetry were significantly inconsistent depending on the reference determination of midsagittal plane. The reference for midsagittal plane should be carefully determined in three-dimensional cephalometric analysis of facial asymmetry of patients with class III dentofacial deformity.

• Journal of Veterinary Clinics
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• v.32 no.4
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• pp.313-318
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• 2015

The lung opacity on radiography is influenced by various factors. The physical density of the lung and the attenuation ensured on computed tomography (CT) scans is determined by three components : lung tissue, blood, and air. Temporary right lateral recumbency may responsible for the increase of opacity on ventrodorsal projection view. Thus, our aim is to demonstrate that the effect of right lateral recumbency posture on right lung opacity using radiograph and CT scan. In this study, 62 dogs without clinical or radiologic signs of cardiopulmonary disease are selected. Thorax radiographs per 30 seconds for 2 minutes (30s, 60s, 90s, 120s) were performed for 62 dogs. After discussion of the radiographic findings of lung field by two radiologists and a student at Chungbuk national university veterinary medical center a consensus opinion was recorded. Computed tomography per a minute (1 min, 2 min) for 2 minutes were performed for 2 dogs. Mean x-ray attenuation of lung was measured quantitatively using software at two levels (aortic arch and basal level). Among 62 dogs with radiograph comparison, 9.3% of dogs showed influence by postural effect. However, all 2 dogs with computed tomography comparison, showed influence by postural effect. In conclusion, position dependent changes of lung density in CT exam are not consistent with thoracic radiograph.

• Imaging Science in Dentistry
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• v.51 no.1
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• pp.27-34
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• 2021

Purpose: This study was performed to compare the ability of limited- and large-volume cone-beam computed tomography (CBCT) to display isthmuses in the apical root canals of mandibular molars. Materials and Methods: Forty human mandibular first molars with isthmuses in the apical 3 mm of mesial roots were scanned by micro-computed tomography (micro-CT), and their thickness, area, and length were recorded. The samples were examined using 2 CBCT systems, using the smallest voxels and field of view available for each device. The Mann-Whitney, Friedman, and Dunn multiple comparison tests were performed (α=0.05). Results: The 3D Accuitomo 170 and i-Cat devices detected 77.5% and 75.0% of isthmuses, respectively (P>0.05). For length measurements, there were significant differences between micro-CT and both 3D Accuitomo 170 and i-Cat(P<0.05). Conclusion: Both CBCT systems performed similarly and did not detect isthmuses in the apical third in some cases. CBCT still does not equal the performance of micro-CT in isthmus detection, but it is nonetheless a valuable tool in endodontic practice.

• Imaging Science in Dentistry
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• v.52 no.3
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• pp.303-308
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• 2022

Purpose: This technical report aims to describe and detail the use of micro-computed tomography for a reliable evaluation of the bulk-fill composite/tooth interface. Materials and Methods: Bulk-fill composite restorations in tooth cavities were scanned using micro-computed tomography to obtain qualitatively and quantitatively valuable information. Two-dimensional information was processed using specific algorithms, and ultimately a 3-dimensional (3D) specimen reconstruction was generated. The 3D rendering allowed the visualization of voids inside bulk-fill composite materials and provided quantitative measurements. The 3D analysis software VG Studio MAX was used to perform image analysis and assess gap formation within the tooth-restoration interface. In particular, to evaluate internal adaptation, the Defect Analysis addon module of VG Studio Max was used. Results: The data, obtained with the processing software, highlighted the presence and the shape of gaps in different colours, representing the volume of porosity within a chromatic scale in which each colour quantitatively represents a well-defined volume. Conclusion: Micro-computed tomography makes it possible to obtain several quantitative parameters, providing fundamental information on defect shape and complexity. However, this technique has the limit of not discriminating materials without radiopacity and with low or no filler content, such as dental adhesives, and hence, they are difficult to visualise through software reconstruction.

• Anatomy and Cell Biology
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• v.56 no.2
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• pp.185-190
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• 2023

The root canal morphology undergoes aging-related changes, and relevant quantitative analyses have not yet been reported. We compared the cone beam computed tomography (CBCT) and micro-computed tomography (microCT) scans of extracted mandibular incisors to check the accuracy of morphological measurements. Thereafter, the root canal morphology and aging-related changes in the mandibular incisors of Japanese individuals were assessed using CBCT. Six extracted teeth were fixed in a phantom head and imaged using CBCT and micro-CT. The correlation between the findings of the two imaging modalities was examined. Further, CBCT reconstructed images of the mandibular incisors of 81 individuals were observed. Age-related changes of the root canals were compared between participants aged <30 years and those aged ≥30 years. The CBCT and micro-CT findings regarding the root canals of the extracted teeth coincided in 94.4% of the cases. Mandibular incisors exhibiting two root canals in either cross-section accounted for 9.9% of central incisors and 12.4% of lateral incisors. Mandibular central incisors with two root canals were observed in two (6.3%) individuals aged <30 years and six (12.2%) aged ≥30 years. Mandibular lateral incisors with two root canals were observed in one (3.1%) individual aged <30 years and nine (18.4%) aged ≥30 years. CBCT allows accurate evaluation of complex root canal morphologies and is useful for endodontic preoperative assessment. Mandibular incisors have more frequent occurrence of two root canals with aging.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.516-522
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• 2014

Old architectural wood materials damaged by a fire were evaluated on the basis of wood species and scanning electron microscopy (SEM) observation of wood tissues in combination with energy dispersive X-ray spectroscopy (EDXS) analysis. Results of SEM observation showed that tracheid wall thickness of burned parts was very thin compared with undamaged and sound wood, and tylosoid in the resin canals disappeared after the exposure to fire. SEM-EDXS analysis indicated that carbon and oxygen peaks occurred in the original energy band, and the carbon peak was higher than that of the oxygen in the burned part. A computerized tomography was also undertaken to investigate the carbonization layer formed by fire and possible internal defects.