• Journal of Korean Neurosurgical Society
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• v.49 no.5
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• pp.273-277
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• 2011

Objective : A single balloon extrapedicular kyphoplasty has been introduced as one of the unilateral approaches for thoracic compression fractures; however, the unilateral extrapedicular technique in the lumbar area needs a further understanding of structures in the lumbar area. The purpose of the present study is to describe methods and pitfalls of this procedure based on the anatomy of the lumbar area and to analyze clinical outcome and complications. Methods : Anatomical evaluation was performed with 2 human cadavers. A retrospective review of unilateral extrapedicular approaches yielded 74 vertebral levels in 55 patients that were treated with unilateral extrapedicular vertebroplasty and kyphoplasty. Radiographic assessment included the restoration rate of vertebral height and correction of kyphosis. Results : Anatomical evaluation indicates that the safe needle entry zone of bone for the extrapedicular approach was located in the supero-lateral aspect of the junction between the pedicle and vertebral body. The unilateral extrapedicular procedure achieved adequate pain relief with a mean decreases in pain severity of $7.25{\pm}1.5$ and $2.0{\pm}1.4$, respectively. Complications were 1 retroperitoneal hematoma, 6 unilateral fillings and 3 epidural leak of the polymethylmethacrylate. Conclusion : The method of a unilateral extrapedicular approach in kyphoplasty and vertebroplasty in the lumbar area might be similar to that in thoracic approach using a route via the extrapedicular space. However, different anatomical characteristics of the lumbar area should be considered.

• Restorative Dentistry and Endodontics
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• v.26 no.2
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• pp.153-161
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• 2001

The purpose of this study was to evaluate microleakage of six current dentin bonding systems. In this in vitro study, class V cavities were prepared on buccal and lingual surfaces of thirty extracted human molars. Each margin was on enamel and dentin/cementum. Experimental teeth were randomly divided into six groups of 5 each. Group 1 : Scotchbond Multi-Purpose; Group 2 : Single Bond; Group 3 : Prime&Bond NT ; Group 4 : Clearfil Liner Bond 2 ; Group 5 : MAC Bond II ; Group 6 : One-up Bond F. The bonding agent and composite resin were applied to class V cavities according to manufacturer's directions. After thermocycling, the specimens were immersed in 0.5% basic fuchsin dye solution for 6 hours and sectioned longitudinally through the center of the restoration with a low speed diamond saw. The degree of microleakage was measured as the extent of dye penetration under the stereomicroscope at $\times$20. The data were analyzed using one way ANOVA. When significant differences found. multiple comparisons were made using Duncan's Multiple Range Test. The results of this study were as follows: 1. In all groups, leakage value seen at the enamel margin was significantly lower than that seen at the dentin margin(P<0.001). 2. At the enamel margin, none of the dentin bonding systems used in this study showed statistically significant difference in leakage values(P<0.05). 3. At the cementum margin, group 3 showed the highest leakage value, and others were decreased as group 5, 6, 4 in that order, and group 1, 2 showed the lowest leakage value. There was statistically significant difference between group 3 and the other groups except for group 5(P<0.05).

• Journal of Periodontal and Implant Science
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• v.50 no.4
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• pp.260-267
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• 2020

Purpose: The aim of this study was to compare the prevalence, amount, and rate of supraeruption of the maxillary second molar according to sex, age, and history of periodontitis. Methods: Data were collected retrospectively from the charts and panoramic radiographs of 65 patients who were scheduled to undergo implant placement at the site of the mandibular second molar. The amount of supraeruption of the maxillary second molar and the alveolar bone level of the neighboring teeth were measured on digital panoramic radiographs. The prevalence was evaluated in each group, and univariate and multivariate logistic regression analyses were used to identify factors influencing the prevalence of supraeruption. The amount and the rate of supraeruption were compared between pairs of groups using the Mann-Whitney U test. For all tests, P values <0.05 were considered to indicate statistical significance. Results: Supraeruption occurred in 78% of the patients. The prevalence of supraeruption was affected by sex, age, and history of periodontitis. The mean amount of supraeruption was 0.91 mm and the mean rate of supraeruption was 0.14 mm/month. The amount and the rate of supraeruption showed no significant differences according to sex, age, or the distance from the cementoenamel junction to the alveolar bone crest (P>0.05). Conclusions: These results show that the amount of supraeruption on the maxillary second molar was similar to the thickness of the enamel on the occlusal surface. When a single implant is scheduled to be placed on the mandibular second molar, supraeruption of the antagonist should be considered.

• Journal of the Optical Society of Korea
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• v.19 no.2
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• pp.136-143
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• 2015

Image deblurring by a deconvolution method requires accurate knowledge of the blur kernel. Existing point spread function (PSF) models in the literature corresponding to lens aberrations and defocus are either parameterized and spatially invariant or spatially varying but discretely defined. In this paper, a parameterized model is developed and presented for a PSF which is spatially varying due to lens aberrations and defocus in an imaging system. The model is established from the Seidel third-order aberration coefficient and the Hu moment. A skew normal Gauss model is selected for parameterized PSF geometry structure. The accuracy of the model is demonstrated with simulations and measurements for a defocused infrared camera and a single spherical lens digital camera. Compared with optical software Code V, the visual results of two optical systems validate our analysis and proposed method in size, shape and direction. Quantitative evaluation results reveal the excellent accuracy of the blur kernel model.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.1
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• pp.67-70
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• 2009

Purpose: This study presents the use of mini implants for fixed restoration and implant supported overdenture to enable the practitioner to overcome the anatomic obstacles of ridge width and narrow interdental space. Patients and methods: This study consisted of 9 patients who required single implants for one or two teeth replacement and 1 patient who required implant supported overdenture after mandiblectomy, iliac bone graft due to ghost cell tumor. The ages ranged from 29 to 70 years (mean 51). All patients were in good health. Clinical and radiographs were taken pretreatment, postoperatively, during rehabilitation, and at follow ups. Results: Total implant survival rate was 94.7%. One implant was removed due to its mobility as a result of bad bone quality (Type IV) and patient's carelessness (Heavy smoker). All patients except one reported complete satisfaction regarding to function, aesthetics, and phonetics. Radiographic follow up every 3months postoperatively showed success in achieving function and maintaining marginal bone level. Conclusion: Clinician can overcome both severe ridge deficiency and small interdental space with mini implant.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.28 no.2
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• pp.74-85
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• 2019

The aesthetic restoration of dental implants in the anterior maxilla is a challenge for clinicians because it requires proper harmony in three following conditions; reconstruction of hard tissue, soft tissue, and aesthetic prosthesis. A newer technique, VIP-CT (Vacularized Interpositional Periosteal Connective Tissue) graft has been introduced as an alternative to these technique which allows the clinicians perform large volume soft tissue augmentation in esthetic sites with a single procedure. The advantages of the VIP-CT graft technique are that it allows the reconstruction of large soft tissue deficiency, with little constriction postoperatively. Furthermore, it facilitates improved hard tissue augmentation due to the additional blood supply and improved bone healing by mesenchymal cells. Moreover, this technique reduces patient discomfort and treatment time. This clinical report describes the procedure of bone augmentation during immediate implantation in facial dehiscence defect, especially Vascularized Interpositional Periosteal Connective Tissue(VIP-CT) graft for aesthetic anterior soft tissue.

• Polymer(Korea)
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• v.33 no.6
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• pp.620-624
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• 2009

Biomedical metal implants have been used clinically for replacement, restoration, or improvement of injury bodies based on high mechanical properties, but it has some risks such as the inflammatory, late thrombosis, or restenosis due to the low biocompatibility and toxicity. In various techniques of surface treatment developed to preserve these drawbacks, this study examined the electrospray coating technology with biodegradable poly (lactic-co-glycoic acid) (PLGA) on metal surface. Based on fundamental examination of electrospraying and solution parameters, the surface morphology of coated film was closely related to the boiling point of solvent, in-flight distance, and droplet size. The thickness of polymer film was linearly proportional to the emerged volume. This result exhibits that the polymeric droplets were continuously deposited on the polymer film. Therefore, the electrospray coating technology might be applied into the fabrication of single/multi-layered polymer film in nano-/micro-thickness and the control of the topology for biomedical metal implants including stents.

• The Journal of the Korean dental association
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• v.51 no.4
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• pp.190-197
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• 2013

A titanium based screw shaped dental implant was first introduced by Branemark and a treatment protocol where the restoration of edentulous area by connecting abutment after the osseointegration of the titanium surface of the implant and surrounding bone structure has been proposed. Although this protocol is widely accepted as a standard up to date, the healing duration of 3-6 months as well as the need for provisional prostheses during this period present as a major drawback. Immediate loading has been accomplished through the advent of various implant designs, enforced surface treatments, diverse forms of abutment, and delicate surgical techniques together with the increase in demand from the patients. The success rate of the immediate loading technique has been first reported as 85.7% by Dr. Schnitman in 1990 which recently has been reported up to 100% in the case of immediate loading in single tooth by Dr. Kan. To ameliorate the success rate of immediate loading technique, selection of patients presenting a sound bone quality and quantity, acquiring primary stability through delicate surgical techniques and fabrication of prostheses which accounts for biological stabilities should all be taken into consideration. This presentation introduces the understanding of biological stability of immediate loading, various methods for measurement of stability and clinical cases regarding immediate loading technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2067-2072
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• 2016

Recently, due to the development of attack techniques that can circumvent existing information protection systems, continuous threats in a form unrecognized by the user have threatened information assets. Therefore, it is necessary to support the prompt responses to anticipated attempts of APT attacks, bypass access attacks, and encryption packet attacks, which the existing systems have difficulty defending against through a single response, and to continuously monitor information protection systems with a defense strategy based on Indicators of Attack (IOA). In this paper, I suggest a centralized intelligent information protection system to support the intelligent response to a violation by discerning important assets through prevention control in a performance impact assessment about information properties in order to block the attack routes of APT; establishing information control policies through weakness/risk analyses in order to remove the risks in advance; establishing detection control by restricting interior/exterior bypass networks to server access and monitoring encrypted communications; and lastly, performing related corrective control through backup/restoration.

• 사회경제평론
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• v.31 no.1
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• pp.25-61
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• 2018

Nowadays 87 regimes born in the same year with the Korean Association for Political Economy(KAPE in abbreviation) have ended historically. This paper surveys the research trends of KAPE after 2007 for the 30th founding anniversary. This survey is expected to help research way forward of KAPE. The main contents of the surveys are as follows. Global finance crisis caused by subprime mortgage crisis in 2007 expanded to global economic crisis resulting in the crisis of economics. KAPE criticized the mainstream economics with different approach and methodology as well as political economy copying with the crisis of economics and then focused on economics of inequality. However, the progressive economics is depressed under the conservative regime after 2007. As a result, the progressive economics have experienced the crisis of reproduction of knowledge and have become the peripheral science in Korea. With new regimes after 87 regimes, more important than restoration of the progressive economics is rebirth as the progressive economics corresponding to new regime and new era. This is responsibility of KAPE as the single association of the progressive economics in Korea.