• Imaging Science in Dentistry
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• v.41 no.3
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• pp.115-121
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• 2011

Purpose : This article is to describe a modified device for intraoral radiography which was developed to obtain reproducible radiographic images for assessment of distal osseous defects of the mandibular second molar (2 Mm) after impacted third molar (3 Mm) surgery. Materials and Methods : A commercial available alignment system for posterior region was modified by adding a reference gauge pin (millimetric) and threading a hollow acrylic cylinder at the ring of the radiographic positioner to attach the X-ray collimator. The design included customized resin acrylic stent for the occlusal surface of the 2Mm in maximum intercuspal position, individualizing the biteblock positioner. Periapical radiographs were taken before and after surgical extraction of 3 Mm, employing the radiographic technique of parallelism described by Kugelberg (1986) with this modified film holder and inserting the gauge pin on the deepest bone probing depth point. Results : This technique permitted to obtain standardized periapical radiographs with a moderate to high resolution, repeatability, and accuracy. There was no difference between the measurements on the pre- and post-operative radiographs. This technique allowed better maintenance of the same geometric position compared with conventional one. The insertion of the gauge pin provided the same reference point and localized the deepest osseous defect on the two-dimensional radiographs. Conclusion : This technique allowed better reproducibility in posterior radiographic records (distal surface of 2 Mm) and more accurate measurements of radiographic bone level by the use of a millimetric pin.

• Imaging Science in Dentistry
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• v.40 no.3
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• pp.115-121
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• 2010

Purpose : The purpose of this study was to accurately analyze the radiographic characteristics of dentigerous cyst (DC) with multiplanar images of cone beam computed tomography (CBCT). Materials and Methods : Thirty eight radiographically and histopathologically proven cases of DCs were analyzed with panoramic radiograph and CBCT, retrospectively. The radiographic CT pattern, symmetry of radiolucency around the unerupted tooth crown, ratio of long length to short length, degree of cortical bone alternation, effects on adjacent tooth, and cyst size were analyzed. Relative frequencies of these radiographic features were evaluated. In order to compare the CBCT features of DC with those of odontogenic keratocyst (OKC), 9 cases of OKCs were analyzed with the same method radiographically. Results : DCs consisted of thirty unilocular cases (79.0%), seven lobulated cases (18.4%) and one multilocular case (2.6%). Eight were asymmetric (21.0%) and thirty were symmetric (79.0%). Maxillary DC showed rounder shape than mandibular DC (L/S ratio; maxilla 1.32, mandible 1.67). Alternations of lingual cortical bone (14 cases, 48.2%) were more frequent than those of buccal side (7 cases, 24.1%). CBCT images of DC showed definite root resorption and bucco-lingual tooth displacement. These findings were hardly observed on panoramic radiographs of DCs. Comparison of CBCT features of DC with those of OKC showed several different features. Conclusions : CBCT images of DC showed various characteristic radiographic features. Therefore, CBCT can be helpful for the diagnosis of DC radiographically.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.429-436
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• 2008

Purpose: The goal of periodontal regenerative therapy is to replace bone, cementum, and periodontal ligament on a previously diseased root surface, which has suffered the loss of these supporting structures. To accomplish the regeneration, a number of surgical procedures have been advocated throughout the years. There seems to be a potential for some spontaneous periodontal tissue regeneration in the bottom of periodontal defect following open flap debridement alone. The aim of this study was to analyse the radiographic bone changes over 2-year after flap operation. Material and Methods: Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients had clinical and radiographic evidence of infrabony defect(s). forty two sites of 33 patients aged 26 to 65 (mean age 45.5) were treated by flap operation with or without osseous surgery. Baseline and over 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, gender, defect depth, defect angle) using the paired t-test were examined. Result: We observed 0.74 mm of bone fill, 0.66 mm of crestal resorption, 1.40 mm of defect resolution, and 27% of percentage of defect resolution. Mandible, women, deeper initial defect depth, narrower initial defect angle showed greater bone fill, defect resolution, and % of defect resolution. Conclusion: The results of this study suggest that the use of flap operation did enhance the outcome in terms of radiographically detectable bone fill. Both treatment resulted in some loss of crestal bone height.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.437-444
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• 2008

Purpose: A number of techniques and materials have been used for periodontal regeneration and bone graft procedures with guided tissue regeneration(GTR) have been suggested as alternatives to osseous surgery in the management of local infra-bony defects. However, the long-term stability and treatment outcome following bone graft procedure of infra-bony defects is poorly documented. The purpose of this study was to assess radiographic change in infra-bony defects over 2 years after bone graft procedures with various graft materials. Material and Methods: Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients showed clinical and radiographic evidence of infra-bony defect(s). 44 sites of 34 patients aged 31 to 69 (mean age 48.3) were treated by bone graft procedure with a bone graft material. Baseline and 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, defect depth, defect angle, bone graft materials) using the paired t-test were examined. Result: We observed $1.15{\pm}1.95\;mm$ of bone fill, $0.40{\pm}1.19\;mm$ of crestal resorption, $1.55{\pm}1.77\;mm$ of defect resolution, and $40{\pm}44%$ of percentage of defect resolution. Deeper initial defect depth, narrower initial defect angle showed significantly greater bone fill, defect resolution, and % of defect resolution. But no significant difference was observed in graft sites and graft materials. Conclusion: If good oral hygiene maintenance and periodic recall check of patients is assured, bone graft procedure using various graft materials is one of the appropriate treatment modality for regenerative therapy of infra-bony defects.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.670-678
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• 2014

This paper presents a method to extract objects in radiographic images where all the allowable combinations of segmented regions are compared to a target object using Fourier descriptor. In the object extraction for usual images, a main problem is occlusion. In radiographic images, there is an advantage that the shape of an object is not occluded by other objects. It is because radiographic images represent the amount of radiation penetrated through objects. Considering the property of no occlusion in radiographic images, the shape based descriptors can be very effective to find objects. After all, the proposed object extraction method consists of three steps of segmenting regions, finding all the combinations of the segmented regions, and matching the combinations to the shape of the target object. In finding the combinations, we reduce a lot of computations to remove unnecessary combinations before matching. In matching, we employ Fourier descriptor so that the proposed method is rotation and shift invariant. Additionally, shape normalization is adopted to be scale invariant. By experiments, we verify that the proposed method works well in extracting objects.

• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.146-153
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• 2013

Objectives: Aluminum step wedge (ASW) equivalent radiodensity (eRD) has been used to quantify restorative material's radiodensity. The aim of this study was to evaluate the effects of image acquisition control (IAC) of a digital X-ray system on the radiodensity quantification under different exposure time settings. Materials and Methods: Three 1-mm thick restorative material samples with various opacities were prepared. Samples were radiographed alongside an ASW using one of three digital radiographic modes (linear mapping (L), nonlinear mapping (N), and nonlinear mapping and automatic exposure control activated (E)) under 3 exposure time settings (underexposure, normal-exposure, and overexposure). The ASW eRD of restorative materials, attenuation coefficients and contrasts of ASW, and the correlation coefficient of linear relationship between logarithms of gray-scale value and thicknesses of ASW were compared under 9 conditions. Results: The ASW eRD measurements of restorative materials by three digital radiographic modes were statistically different (p = 0.049) but clinically similar. The relationship between logarithms of background corrected grey scale value and thickness of ASW was highly linear but attenuation coefficients and contrasts varied significantly among 3 radiographic modes. Varying exposure times did not affect ASW eRD significantly. Conclusions: Even though different digital radiographic modes induced large variation on attenuation of coefficient and contrast of ASW, E mode improved diagnostic quality of the image significantly under the underexposure condition by improving contrasts, while maintaining ASW eRDs of restorative materials similar. Under the condition of this study, underexposure time may be acceptable clinically with digital X-ray system using automatic gain control that reduces radiation exposure for patient.

• Journal of Periodontal and Implant Science
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• v.49 no.2
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• pp.90-104
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• 2019

Purpose: The aim of this study was to evaluate clinical and radiographic changes and the survival rate after periodontal surgery using deproteinized bovine bone mineral (DBBM) with 10% collagen or DBBM with a collagen membrane in endo-periodontal lesions. Methods: A total of 52 cases (41 patients) with at least 5 years of follow-up were included in this study. After scaling and root planing with or without endodontic treatment, periodontal regenerative procedures with DBBM with 10% collagen alone or DBBM with a collagen membrane were performed, yielding the DBBM + 10% collagen and DBBM + collagen membrane groups, respectively. Changes in clinical parameters including the plaque index, bleeding on probing, probing pocket depth, gingival recession, relative clinical attachment level, mobility, and radiographic bone gains were evaluated immediately before periodontal surgical procedures and at a 12-month follow-up. Results: At the 12-month follow-up after regenerative procedures, improvements in clinical parameters and radiographic bone gains were observed in both treatment groups. The DBBM + 10% collagen group showed greater probing pocket depth reduction ($4.52{\pm}1.06mm$) than the DBBM + collagen membrane group ($4.04{\pm}0.82mm$). However, there were no significant differences between the groups. Additionally, the radiographic bone gain in the DBBM + 10% collagen group ($5.15{\pm}1.54mm$) was comparable to that of the DBBM + collagen membrane group ($5.35{\pm}1.84mm$). The 5-year survival rate of the teeth with endo-periodontal lesions after periodontal regenerative procedures was 92.31%. Conclusions: This study showed that regenerative procedures using DBBM with 10% collagen alone improved the clinical attachment level and radiographic bone level in endo-periodontal lesions. Successful maintenance of the results after regenerative procedures in endo-periodontal lesions can be obtained by repeated oral hygiene education within strict supportive periodontal treatment.

• Journal of Veterinary Clinics
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• v.40 no.2
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• pp.119-123
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• 2023

Although various imaging evaluation methods have been developed and utilized, thoracic radiography remains essential and is the top priority for diagnosing and managing cardiac diseases. Thoracic radiographic measurements associated with the vertebral heart scale (VHS) and caudal vena cava (CVC) can objectively diagnose cardiac disease in many animals. In particular, VHS measurement is primarily used to evaluate the dimensions of the heart size on thoracic radiographs and can measure cardiomegaly more objectively. Additionally, the value of the CVC compared with the aorta (Ao) and the length of vertebrae (VL) can be used as valuable parameters in right congestive heart failure. To describe the CVC/Ao and CVC/VL ratios in 10 long-tailed gorals (Naemorhedus caudatus) without subjective radiographic evidence of cardiac diseases. The VHS, CVC, Ao, and VL of gorals were measured in the right lateral (RL) view of the thoracic radiographs. In the RL view of 10 gorals, the VHS was 9.31 ± 0.55 vertebrae (v), the CVC/Ao ratio was 0.84 ± 0.13, and the CVC/VL ratio was 0.67 ± 0.09. Additionally, the thoracic morphology of gorals was determined to be intermediate (thoracic depth-to-width ratio, 1.04 ± 0.09, 0.75-1.25). This study confirmed that VHS was significantly correlated with CVC and Ao, and measuring and comparing each value would help diagnose cardiac diseases in gorals. The radiographic measurements in this study will allow veterinarians to diagnose several cardiac diseases in gorals.

• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.565-572
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• 2023

This study was conducted to analyze the status radiological imaging examinations assessment in Korea medical institutions conducted in the public sector and suggest a direction for improvement. Among the assessment of medical institutions, the main assessment related to radiographic imaging examinations are the certification evaluation of medical institutions and the adequacy assessment of radiographic imaging examinations. The certification evaluation of medical institutions evaluates the image inspection operation process, provision of accurate results, and compliance with safety management procedures. In the assessment of adequacy of radiographic imaging examinations, structural indicators related to manpower and equipment, patient evaluation implementation rate, and exposure reduction programs were included. However, for safer and higher-quality radiological imaging examinations, it is necessary to increase the participation rate of medical institutions in certification evaluations. In addition, it is necessary to improve the manpower indicator, and incentive payments can be considered to induce quality improvement of medical institutions in the future. Integrated management of radiation exposure at the national level should also be carried out simultaneously.

• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.49.1-49.11
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• 2020

Objectives: The aim of this study was to perform a clinical and radiographic analysis of endodontically treated teeth (ETT) restored with cast metal posts (CMPs) or prefabricated glass fiber posts (GFPs) and crowns. Materials and Methods: Fifty ETT were restored with 25 CMPs and 25 GFPs at a private dental clinic between 2001 and 2016. The restorations consisted of 12 all-ceramic crowns, 31 metal-ceramic crowns, and 7 composite resin crowns. Demographic data, type of teeth, type of post-and-core system, time of placement, crown restorations, the number of proximal contacts, the type of antagonist, and reports of any complications after post-and-core placement were recorded for each patient. Assessments were performed at baseline (radiographic) and follow-up (radiographic and clinical). Data were analyzed by the McNemar test, the Pearson χ² test, and Kaplan-Meier survival curves (α = 0.05). The mean follow-up was 67.6 months. Results: No significant difference was observed for any of the radiographic parameters when the baseline and final radiographs were compared. In the clinical evaluation, anatomical form (p = 0.009) and occlusion (p = 0.001) showed significant differences according to the type of crown restoration; specifically, metal-ceramic and all-ceramic crowns outperformed composite resin crowns. Conclusions: CMPs and GFPs showed favorable results for restoring ETT after 6 years of follow-up. All-ceramic and metal-ceramic crowns showed higher survival rates and better clinical outcomes.