• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.263-273
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• 2007

Statement of problem: Alteration of tooth function is assumed to be changed by stress/strain on the adjacent alveolar bone, producing changes in morphology similar to those described for other load-bearing bones. When teeth are removed, opposing teeth will not be functioned. When edentulous area is restored by implant prostheses, opposing teeth will be received physiologic mechanical stimuli. Purpose: The aim of this study was to evaluate the bone changes around the teeth opposing implant restoration installed mandibular posterior area. Material and method: Eight patients who had mandibular posterior edentulous area were treated with implants. Radiographs of the opposing teeth were taken at implant prostheses delivery(baseline), 3 months, and 6 months later. Customized film holding device was fabricated to standardize the projection geometry for serial radiographs of opposing teeth. Direct digital image was obtained. Gray values of region of interest at each digital image were measured and compared according to time lapse. Repeated measured analysis of variance and post-hoc Scheffe's test were performed at the 95% significance level. Results: Alveolar bone changes around the natural teeth opposing the posterior implant in mandible showed statistically significant difference compared to control group(P<0.05). And gray values of alveolar bone around the teeth opposing implants were increased. There were no statistically significant differences of alveolar bone changes between crestal group and middle group and between mesial group and distal group according to time lapse(P>0.05). There were no statistically significant differences of alveolar bone changes among mesial-crestal group, mesial-middle group, distal-crestal group, distal-middle group, and control group(P>0.05). Conclusion: Alveolar bone around the natural teeth opposing the implant prosthesis showed gradual bony apposition.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.3
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• pp.306-313
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• 2012

Class III malocclusion or anterior crossbite is commonly seen in Asian. This problem is easily recognized by dentists and parents. During the primary dentition period, anterior crossbite with functional shift and deep overbite could develop to skeletal protrusive mandible. So, early and proper diagnosis of anterior crossbite which needs prompt treatment is important. These cases showed the early management of crossbite with functional shift in primary dentition using intraoral removable appliance resulting in improvement of intermaxillary relationship. And I analyzed the positional change and the dimensional change during treatment with lateral cephalometric x-ray analysis. Our patients showed vertical dimensional change of lower anterior facial height and clockwise rotation which results crossbite correction in 1 year of treatment period.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.4
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• pp.349-365
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• 2006

State of problem : A number of investigation about increase of surface area via various surface treatments and modification of surface constituent have been carried out. Purpose : The surface characteristics and stability of implants treated with anodic oxidation, fluoride ion incorporation, and groups treated with both methods were evaluated. Material and method : Specimens were divided into six groups, group 1 was the control group with machined surface implants, groups 2 and 3 were anodic oxidized implants (group 2 was treated with 1M $H_2SO_4$ and 185V, group 3 was treated with 0.25M $H_2SO_4$ and $H_3PO_4$ and 300V). Groups 4, 5 and 6 were treated with fluoride. Group 4 was machined implants treated with 0.1% HF, and groups 5 and 6 were groups 2 and 3 treated with 10% NaF respectively. Using variable methods, implant surface characteristics were observed, and the implant stability was evaluated on rabbit tibia at 0, 4, 8 and 12 weeks. Result : 1. In comparison of the surface characteristics of anodic oxidized groups, group 2 displayed delicate and uniform oxidation layer with small pore size containing Ti, C, O and showed mainly rutile, but group 3 displayed large pore size and irregular oxidation layer with many crators. 2. In comparison of the surface characteristics of fluoride treated groups 4, 5, 6 and non-fluoride treated groups 1, 2, 3, the configurations were similar but the fluoride treated groups displayed rougher surfaces and composition analysis revealed fluoride in groups 4, 5, 6. 3. The fluoride incorporated anodic oxidized groups showed the highest resonance frequency values and removal torque values, and the values decreased in the order of anodic oxidized groups, fluoride treated group, control group. 4. According to implant stability tests, group 2 and 3 showed significantly higher values than the control group (P<.05). The fluoride treated groups showed relatively higher values than the non fluoride treated groups and there were significant difference between group 4 and group 1 (P<.05). Conclusion : From the results above, it can be considered that the anodic oxidation method is an effective method to increase initial bone stability and osseointegration and fluoride containing implant surfaces enhance new bone formation. Implants containing both of these methods should increase osseointegration, and reduce the healing period.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.1
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• pp.12-20
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• 2020

Purpose: This study was designed to analyze the relationship between the presence and severity of depression and chewing problems (CPs) in a representative sample of the general population. Materials and Methods: Health surveys and examinations were conducted on a nationally representative sample (n = 8150) of Korean was conducted. CPs was determined by a simple survey response concerning "Do you feel uncomfortable about chewing your food because of problems with your mouth such as teeth, dentures and gums?" Depression was defined as individuals with a total score ≥ 10 on the Patient Health Questionnaire (PHQ)-9 survey. Data regarding demographics, socioeconomic history and comorbid health conditions were used to analyze adjusted logistic regression models. Results: In the Korean population, the prevalence of depression was significantly greater in individuals with CP (17.2%) than in those without CP (10.2%). On multivariate logistic regression analysis, the presence of depression was significantly associated with CPs (adjusted odd ratio [aOR]: 1.90, P < 0.001). The risk of CPs increased with increasing severity of depression as follows: severe depression (OR: 2.62, P < 0.001), moderately severe depression (OR: 2.19, P < 0.001). Conclusion: The presence of depression was significantly associated with CPs, especially in severely depressed individuals. Depression screening should be considered in treating CP patients.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.1
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• pp.355-384
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• 2017

In Korea, a Law on Airport Noise Prevention and Noise Control Area Support has been in effect since 2010. And also, airport noise measures project and residents support project conducted following the Law on Airport Noise Prevention and Noise Control Area Support. However, a Law on Airport Noise Prevention and Noise Control Area Support does not apply to military airfield. Many city residents already complain about military airport noise, but there are no countermeasures. They claim the noise from the military airfield is an intrusion on their lives, and some people brought a class action against the government. In the 20th National Assembly, some congressmen already proposed some legislations that aims to support residents adjacent to the military airfield. Nevertheless, relevant legislations are currently pending at the 20th National Assembly. Legislation preventing aircraft noise and providing support measures is essential to residents life who near by military airfield. At first, this study looked at legislations proposed by congressmen in the 20th National Assembly. And also, this study looked at A Law on the Improvement of Living Environment around the Defence Facilities of Japan. Based on this study, we did an analysis of the problem of legislation and proposed improvement suggestion. I hope so that this study could someday help congressmen make a legislation about military airfield noise. We hope the 20th National Assembly will pass the legislation finally to help the residents who near by military airfield relieve their pain by noise and restore their human dignity.

• Journal of the Economic Geographical Society of Korea
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• v.19 no.4
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• pp.694-711
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• 2016

This study analyzes the spatial characteristics of knowledge industry which has shown relatively rapid growth in the low-growth economy situation in recent years. In particular, we catch hold of the locational characteristics of the knowledge service industry which occupies the highest ratio by professional-expert jobs favoured by young generations, as well as estimate their occupational employment opportunities. By applying Location Quotient(LQ) and LISA, we reveal the spatial distribution patterns of publishing business, information service business and education service business in the Seoul Metropolitan area, and examine the changes in the spatial patterns during the last ten years. In order to understand the socio-economic factors which explain their locations, we apply the stepwise multiple regression analysis. Furthermore, we predict the changes distribution of Knowledge service industrial employment by applying Markov Chain Model. As the result, we found their clusters at the specific locations, while there is the significant variations in the socio-economic variables related their locations respectively. The related job opportunities of the knowledge service businesses in the Seoul Metropolitan area are predicted steady growth trend for the next four years, even though dull or stagnant trend is expected for other industries. This study provides basic resources to the planning for young generation employment problem.

• Journal of Environmental Policy
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• v.12 no.4
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• pp.71-92
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• 2013

Unlike general public investment projects, when it comes to environmental public investment projects, there is a gap between those who pay the costs, and those who receive the benefits. This is because of the long term nature of environmental investments, which entails that the majority of the costs are paid by the current generation, while the benefits are reaped by future generations. Because of this, when the social discount rate is set at a standard, singular rate, an issue of relative underestimation of the benefits reaped by future generations may occur during the analytic process. This paper begins with the recognition of this problem, and attempts to estimate a suitable social discount rate that can be applied to environmental investment projects. Taking into account recent economic situations, the social discount rate is currently being estimated at between 2.9 ~ 4.9%. Also, this paper used preliminary feasibility studies that took place so far, to analyze the standard pattern of benefit generation. This revealed that alterations in social discount rates can bring significant changes in economic feasibility test results. Simulation results showed that roughly 6% of B/C ratios could be increased by 1%p. resulting in a decrease in social discount rates. Also if we use hyperbolic discount rates, instead of using the current singular rate, there would be a meaningful increase in the benefits for the future generation.

• KDI Journal of Economic Policy
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• v.14 no.3
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• pp.23-48
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• 1992

The Korea's Consumer electronics industry has exhibited a spectacular growth in the last three decades, expanding into one of the most important industries in Korea in many respects. One interesting aspect of the industry is the dominant role played by the Big Three of the industry, Gumsung, Samsung, and Daewoo. Since 1984, the three companies have accounted for about 90% of the sales in key items such as color TV, VTRs, refrigerators, and washers. The Big Three not only dominated the manufacturing stage, but also the distribution stage of the industry through their networks of exclusive dealers that constitute the major part of the distribution market. In this study, we analyzed the effects of the exclusive dealing by the Big Three on the efficiency of the Korean economy. We find that exclusive dealing by the Big Three could seriously constrain competition in both the manufacturing and distribution stages of the industry. Exclusive dealing by the Big Three effectively forcecloses the market for most other manufacturers as well as deterring entry into the manufacturing stage by potential entrants. Further, it impedes the growth of distributors that achieve the economies of scale and scope and restricts competition by the Big Three. In contrast, we could find little evidence that exclusive dealing by the Big Three is pro-competitive or enhances welfare. As a remedy to this problem, we suggest that the Fair Trade Commission of Korea should regulate the exclusive dealing by the Big Three, thus opening the door for the growth of distributors that are not bound by an exclusive dealing relationship with any of the Big Three. Put differently, we urge the Korean Fair Trade Commission to apply the Article 23 (5) to the exclusive dealing by the Big Three. Article 23 (5) that states that unfair restrictive dealing is illegal has never been clarified by the FTC. We believe that our analysis could also serve as a basic for the clarification of the article in general.

• Journal of the Korea Institute of Building Construction
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• v.15 no.1
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• pp.43-51
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• 2015

At present, in the case of small and medium window manufacturers in South Korea, glazing and window frame manufacturers are divided into separate businesses. However, in the fenestration energy consumption efficiency rating system and the energy-saving design criteria for buildings, the coefficient of overall heat transmission standard for windows is defined by window sets, which integrate glazing and window frames. At most construction sites, windows are constructed by installing separately supplied glass and frames. Research that can integrate the reality and the system is therefore necessary. The present study first investigated and analyzed the on-site situation of the fenestration energy consumption efficiency rating system. According to the results, while overall understanding of the fenestration energy consumption efficiency rating system was high, satisfaction with it was low, and the general practice at construction sites was to use windows assembled on site rather than integrated window systems manufactured at factories, thus making it difficult to confirm that the current rating system was well applied on site. Consequently, the reality of industrial sites must be reviewed and a realistic alternative to the fenestration energy consumption efficiency rating system must be presented instead of focusing on theory.

• Journal of the Korea Institute of Building Construction
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• v.15 no.5
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• pp.507-514
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• 2015

In recent years, the number of construction projects carried out to repair and reinforce newly built structures and facilities has been on the rise compared to the number of new construction projects, accounting for more than 90 percents of all construction projects carried out by specialty construction companies. However, as some of the ordering parties fill out the required tasks incorrectly, the wrong information on construction bids is announced, and the specialty construction companies that hold a license and technology are unable to get the job at the right time. As such, it is critical to prevent unnecessary time and expense related to the correction of incorrect bid announcements by providing accurate information and definitions, because the tasks of each specialty construction work stipulated in the framework act of construction industry are vague. Therefore, the causes and problems were analyzed based on the correction cases of bid information, and a plan that can address the problem will be proposed. The result of this study can be utilized as fundamental data to achieve an institutional improvement in the bidding service for the specialty construction companies.