• Imaging Science in Dentistry
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• v.51 no.3
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• pp.223-235
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• 2021

Purpose: This study aimed to summarize the impact of neck and head radiation treatment on maxillofacial structures detected on panoramic radiographs. Materials and Methods: In this systematic review, the authors searched PubMed Central, Embase, Scopus, Cochrane Central Register of Controlled Trials, Web of Science, and Google Scholar for original research studies up to February 2020 that included the following Medical Subject Headings keywords: words related to "radiotherapy" and synonyms combined with keywords related to "panoramic radiography" and "oral diagnosis" and synonyms. Only original studies in English that investigated the maxillofacial effects of radiotherapy via panoramic radiographs were included. The quality of the selected manuscripts was evaluated by assessing the risk of bias using Cochrane's ROBINS-I tool for non-randomized studies. Results: Thirty-three studies were eligible and included in this review. The main objectives pertained to the assessment of the effects of radiation on maxillofacial structures, including bone architecture alterations, periodontal space widening, teeth development abnormalities, osteoradionecrosis, and implant bone loss. The number of participants evaluated ranged from 8 to 176. Conclusion: The interaction between ionizing radiation and maxillofacial structures results in hazard to the tissues involved, particularly the bone tissue, periosteum, connective tissue of the mucosa, and endothelium. Hard tissue changes due to radiation therapy can be detected on panoramic radiographs.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.235-243
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• 2013

Purpose: This study was performed to assess the correlation of calcified carotid atheromatous plaque (CCAP), the mandibular cortical index, and periodontal bone loss in panoramic radiographs. Materials and Methods: One hundred eighty-five panoramic radiographs with CCAP and 234 without this finding were evaluated by 3 observers for the presence of osseous changes related to osteoporosis and periodontal bone loss. Chi-squared and Mann-Whitney U tests were used to compare the two groups for an association of CCAP with the mandibular cortical index and periodontal bone loss, respectively. Results: There was a statistically significant coincidence of CCAP and osseous changes related to osteopenia/osteoporosis, with a p-value <0.001. There was no statistically significant coincidence of CCAP and periodontal bone loss. When comparing the 2 groups, "With CCAP" and "Without CCAP", there was a statistically significant association with the mean body mass index (BMI), number of remaining teeth, positive history of diabetes mellitus, and vascular accidents. There was no statistically significant association with gender or a history of smoking. Conclusion: This study identified a possible concurrence of CCAP and mandibular cortical changes secondary to osteopenia/osteoporosis in panoramic radiographs. This could demonstrate the important role of dental professionals in screening for these systemic conditions, leading to timely and appropriate referrals resulting in early interventions and thus improving overall health.

• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.385-391
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• 2013

X-ray computed tomography is a very powerful nondestructive technique in safety inspection of historic timber building. But, in field, various testing condition makes it difficult to carry out X-ray CT testing. Limited size in X-ray digital detector is one of the problems. In this study, a pitch pine disk with two holes was used to know how imperfection in X-ray projection affects CT image resolution. Using various number of projections, CT image was reconstructed by filtered back projection method, and then it was investigated how many projection is required to identify the holes in different location. Two artificial holes could be differently detected according to their location in cross section of specimen. One hole in center part of specimen was identified using more than 9 radiographs, but the other one which located in outer part of cross section could not be detected until more than 36 projections were used. Even though there is data missing in outer part of cross section due to limited size of detector, the center part of CT image could be reconstructed well and the resolution of outer part became higher with increase of the number of projections. For field application, the number of projections for CT image reconstruction needs to be decided with consideration of another nondestructive testing and the location of interest.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.271-278
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• 1987

The purpose of the present study was to investigate associations between periapical and bitewing techniques by assessing the crestal alveolar bone. This article also reports the ability of these two techniques to correctly detect evidence of interproximal dental caries, and comparison between the interproximal overlapping of teeth. Bitewing and periapical radiographs were used from posterior quardants of 243 dental students in Seoul National University. The distance from cemento-enamel junction to the alveolar crest (CEJ-AC) was measured for each proximal surface from the distal of cuspid to the distal of second molar. Data were arranged according to the proximal surface examined, and bitewing and periapical measurements were compared using paired tests. The obtained results were as follows: 1. In maxilla, a significant t ratio with a P value of 0.05 or less reached for 100% and in mandible, reached for 94%. 2. The anatomic limitations imposed on periapical radiographic technique, most often result in somewhat foreshortened radiographic images. This situation would tend to be accentuated by the anatomical restrictions of the hard palate. 3. Consequently, since the significant differences frequently exist between measurements obtained from bitewing and periapical techniques, it is important to define which technique is used. 4. The number of the interproximal overlapping was the largest medial side of the maxillary second molar, while the smallest at the distal side of the mandibular second premolar. And the overall number of the interproximal overlapping was more (538) in the periapical technique than in the bitewing technique (372). 5. The interproximal dental carious lesions were detected more (74) on the bitewing films than on the periapical ones (23). The fact was resulted from the small number of interproximal overlapping and relative easi- ness of obtaining horizontal angulation in taking the bitewing radiographs.

• Tuberculosis and Respiratory Diseases
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• v.55 no.5
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• pp.526-530
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• 2003

Bronchogenic cysts are generally presented as a well defined mass that have thin and smooth wall in the intrapulmonary or mediastinal area by simple chest radiographs. We present the case of a 20-year-old man with a ill-defined left upper lobe mass, found by chest radiographs. At the preoperative examinations, chest computed tomography showed ill-defined mass with Hounsfield Number 26, and nonspecific findings were shown by the bronchoscopy and percutaneous needle aspiration. The patient was undertaken the left upper lobectomy. The surgical specimen contained a ill-defined mass, measuring $2{\times}3$ cm. On the section of the mass, a cyst containing dark brown thick materials was noted. The cyst was unilocular, and the wall showed a trabeculation. Microscopically, the cystic mass was lined with ciliated pseudostratified columnar epitheliums and surrounded by smooth muscle and cartilage.

• Imaging Science in Dentistry
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• v.32 no.4
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• pp.213-219
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• 2002

Purpose : Computed radiography (CR) has been used in cephalometric radiography and many studies have been carried out to improve image quality using various digital enhancement and filtering techniques, During CR image acquisition, the frequency rank and type affect to the image quality. The aim of this study was to compare the diagnostic quality of conventional cephalometric radiographs to those of computed radiography. Materials and Methods : The diagnostic quality of conventional cephalometric radiographs (MO) and their digital image counterparts were compared, and at the same time, six modalities (M1-M6) of spatial frequency-processed digital images were compared by evaluating the reproducibility of 23 cephalometric landmark locations. Reproducibility was defined as an observer's deviation (in mm) from the mean between all observers. Results and Conclusion: In comparison with the conventional cephalometric radiograph (MO), Ml showed statistically significant differences in 8 locations, M2 in 9, M3 12, M4 in 7, M5 in 12, and M6 showed significant differences in 14 of 23 landmark locations (p < 0.05). The number of reproducible landmarks that each modality possesses were 7 in M6, 6 in M5, 5 in M3, 4 in M4, 3 in M2, 2 in Ml, and 1 location in MO. The image modality that observers selected as having the best image quality was M5.

• Journal of Oral Medicine and Pain
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• v.18 no.2
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• pp.43-53
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• 1993

The aim of this study was to investigate the relationship between the presence or absence of anterior tooth contact and the changes in temporomandibular joint space. The study sample consisted of 32symptom-free dental students and 79 craniomandibular disorders patients with unilateral joint dysfunction. The two groups were categorized into control group or experimental group, respectively. Recordings of the number and distribution of occlusal contacts were made by T-Scan system. Transcranial radiographs were taken with using of accurad-100 head positioner. Measured items in transcranial radiographs were anterior, superior, posterior joint space and relative condylar position to deepest position of glenoid folla. According to the presence or absence of anterior tooth contact, each group was subdivided and compared with each other with respect to TM joint space. Data were processed and tested with SPSS/PC + package. The results of the study showed that the joint space in control group were wider than those of experimental group and the difference of the width of joint space was more remarkable in subjects with anterior contact between control group and experimental group. However, in same group whether the presence of anterior tooth contact could hardly affect the difference of the width of joint space. And anterior tooth contact in grouip are more frequent than in experimental group.

• Imaging Science in Dentistry
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• v.45 no.4
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• pp.233-240
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• 2015

Purpose: This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT) Materials and Methods: A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Results: Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Conclusion: Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images.

• Imaging Science in Dentistry
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• v.38 no.2
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• pp.103-107
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• 2008

Purpose: The purpose of this study was to evaluate the relationship between the position of mesiodens and its complications. Materials and Methods: The subjects for this study consisted of 172 patients with mesiodens. Panoramic radiographs and cross-sectional tomography were taken of all of the subjects. Their clinical records and radiographs were analyzed in order to study the direction and vertical and sagittal position of mesiodens, as well as complications caused by mesiodens. Results: The number of mesiodens was one in 112 cases (65.1%) and two in 60 cases (34.9%). Complications were found in 121 mesiodentes (52.2%), with being median diastema the most frequent. The incidence of complications was high in erupted mesiodens (75.0%), in horizontal mesiodens (89.8%) and in mesiodens located within the arch (75.7%), but was low in mesiodens impacted above apex (29.8%), in normal position (34.4%) and in palatally positioned mesiodens (46.5%). Conclusion: It was suggested that the frequency of complications was different according to the vertical position, the direction of the crown and the sagittal position.

• Journal of information and communication convergence engineering
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• v.21 no.4
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• pp.322-328
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• 2023

The number of senior citizens with large bowel obstruction is steadily growing in Korea. Plain radiography was used to examine the severity and treatment of this phenomenon. To avoid examiner subjectivity in radiography readings, we propose an automatic segmentation method to identify fluid-filled areas indicative of large bowel obstruction. Our proposed method applies the Hough transform to locate suspicious areas successfully and applies the possibilistic fuzzy c-means unsupervised learning algorithm to form the target area in a noisy environment. In an experiment with 104 real-world large-bowel obstruction radiographs, the proposed method successfully identified all suspicious areas in 73 of 104 input images and partially identified the target area in another 21 images. Additionally, the proposed method shows a true-positive rate of over 91% and false-positive rate of less than 3% for pixel-level area formation. These performance evaluation statistics are significantly better than those of the possibilistic c-means and fuzzy c-means-based strategies; thus, this hybrid strategy of automatic segmentation of large bowel suspicious areas is successful and might be feasible for real-world use.