• 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 Technologic Dentistry
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• v.38 no.4
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• pp.327-342
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• 2016

Purpose: The purpose of this study was to investigate the cognition of denture fabrication activities and its cost in National Health Insurance for elderly denture. Methods: A self-administered questionnaire was completed by 41 dental laboratories' owner who was research subjects of HIRA(Health Insurance Review & Assessment Service)'s policy research for elderly denture in 2011. The questionnaire consisted of general characteristics of the subjects, dental technicians' knowledge of national health insurance coverage of elderly denture, job-related changes after national health insurance coverage of elderly denture including validity of denture fabrication activity classification and the cost for each service. Each question was measured by Likert 5 point scale or frequency. The collected data were analyzed by SPSS 16.0. Results: Most of the research subjects had been fabricating national health insurance coverage denture(92.7%), also had ample knowledge of national health insurance coverage denture for elderly. Job-related changes after national health insurance coverage of elderly denture revealed marginal differences in the quality. The validity of fabrication activity classification of resin based complete denture was $3.71{\pm}1.023$ by Likert 5 point scale. Conclusion: The goal of national health insurance for elderly denture is to promote elderly's health and well-being. To fabricate denture is a very important part of the denture treatment. For this reason, denture fabrication activity classification and the cost analysis plan should be duly reflected in the policy of national health insurance for elderly denture.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.260-266
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• 2019

Objectives: Dental implants shorter than 8 mm, called short dental implants (SDIs), have been considered to have a lower success rate than standard length implants. But recent studies have shown that SDIs have a comparable success rate, and implant diameter was more important for implant survival than implant length. Also, SDIs have many advantages, such as no need for sinus lifting or vertical bone grafting, which may limit use in medically compromised patients. Materials and Methods: In this study, 33 patients with 47 implants 7-mm long were examined over the last four years. All patients had special medical history and were categorized into 3 groups: systemic disorders, such as diabetes mellitus (controlled or uncontrolled), mental disability, and uncontrolled hypertension; oral cancer ablation with reconstruction, with or without radiotherapy; diverse osteomyelitis, such as osteoradionecrosis and bisphosphonate-related osteonecrosis of the jaw. Most of these patients have insufficient residual bone quality due to mandible atrophy or sinus pneumatization. Results: The implant diameters were 4.0 (n=38), 4.5 (n=8), and 5.0 mm (n=1). Among the 47 implants placed, 2 implants failed before the last followup. The survival rate of 7-mm SDIs was 95.74% from stage I surgery to the last follow-up. Survival rates did not differ according to implant diameter. The mean marginal bone loss (MBL) at 3 months, 1 and 2 years was significantly higher than at implant installation, and the MBL at 1 year was also significantly higher than at 3 months. MBL at 1 and 2 years did not differ significantly. Conclusion: Within the limitations of the present study, the results indicate that SDIs provide a reliable treatment, especially for medically compromised patients, to avoid sinus lifting or vertical bone grafting. Further, long-term follow-up is needed.

• Korean Journal of Labor Studies
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• v.23 no.2
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• pp.169-193
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• 2017

This study analyzed the determinants that affect employment retention rate in order to diagnose dynamic employment stability in Korea. For this analysis, we constructed multi-level hierarchical data linking Workplace panel survey data and employment insurance job history data. And the determinants were analyzed using a multi-level analysis model suitable for these data. As result of the analysis, it is estimated that the employment stability is very low in Korea due to the widespread existence of the marginal sectors with low wage level and high level of nonstandard employment. In addition, the results of this analysis show that employment structure of Korea occupies considerable area of short-term employment where employment and unemployment are repeated, and overall employment stability is weak. This fact is likely to be a limiting factor for continued growth, as there is limited opportunity for skill development and skills formation at the corporate and individual levels. According to the results of this analysis, it is required to improve the quality of the employment structure for continuous growth and skill formation.

• Health Policy and Management
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• v.31 no.1
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• pp.125-139
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• 2021

Background: In Korea, the health gap widens due to the number of medical resources and access to medical services between metropolitan and rural. The purpose of this study is to identify the impact of residential migration on medical utilization and accessibility. Methods: This study extracted 528,516 claimed cases in the National Health Insurance Service-Cohort Sample Database from 2006 to 2015. Subjects were classified into two groups by the magnitude of the region, the metropolitan and the rural. The inversed probability weights were calculated for each group. And coefficients of the two-part model were estimated by generalized estimation equation. Results: Those who moved region from metropolitan to rural tend to increase the length of stay and inpatients with ambulatory care sensitive conditions (ACSC) disease. Contrariwise, those who moved areas from rural to metropolitan tend to decrease the total medical cost, the adjusted patient days, the number of outpatients and the number of outpatients and inpatients with ACSC disease. Conclusion: This study identified that between the residents who continued to reside in the region and the migrants, there were significant differences in the medical accessibility, quality of primary care, and unmet medical need.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.153-161
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• 2022

This paper analyzes the economic effects when platform provider including CP contributes to broadband universal service and uses broadband bandwidth providing high quality network service. In this model, the contribution rate of broadband universal service is determined by ISP and platform provider sets its price of contents. The main results are as follows. First, the traffic usages is less than social optimum when the market of contents is monopoly. The sum of contribution fee and network usage rate must be less than marginal cost of network operation to get social optimum traffic. Second, the rate set by ISP is equal to social optimum when the market of contents is competitive. Third, when platform provider does not charge contents provided, ISP sets social optimum prices and the network usage rate for contents user is decreasing as advertisement revenue becomes larger. These results suggest that the platform provider should contribute to universal service funding to encourage the network investment of ISP.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.1
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• pp.13-20
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• 2023

Objectives: Ultra-wide implants may be used as a replacement if existing implants fail. This study was conducted to evaluate the factors influencing the prognosis and failure of ultra-wide implants. Patients and Methods: This study evaluated whether sex, age, site, diameter, length, additional surgery, implant stability (primary and secondary), and reason for ultra-wide implant placement affect the 5-year survival and success rates and marginal bone loss (MBL) of ultra-wide implants. Seventy-eight ultra-wide implants that were placed in 71 patients (39 males and 32 females) from 2008 to 2010 were studied. One-way ANOVA analysis was conducted to evaluate the statistical significance of MBL according to the patient's sex, implant site, and diameter. Independent sample t-tests were used to determine the statistical significance of MBL analysis which was used to determine the significance of the 5-year success and survival rates related to the variables. One-way ANOVA was conducted to evaluate the statistical significance of sex, implantation site, diameter, and MBL. Independent sample t-tests were used to evaluate the correlation between implantability and MBL for implantation reasons, while additional surgery, length, and Kaplan-Meier analysis were used to evaluate 5-year survival and success rates. Results: The mean age of patients was 54.2 years with a survival rate of 92.3% and a success rate of 83.3% over a mean 97.8-month period of observation. MBL averaged 0.2 mm after one year of prosthetic function loading and 0.54 mm at the time of final observation. Success rates correlated with primary stability (P=0.045), survival rates correlated with secondary stability (P=0.036), and MBL did not correlate with any variables. Conclusion: Ultra-wide implants can be used to achieve secure initial fixation in the maxillary and mandibular molar regions with poor bone quality or for alternative purposes in cases of previous implant failure.

• Korean Journal of Agricultural Science
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• v.13 no.1
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• pp.44-51
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• 1986

A total number of 916 fruiting bodies of Ganoderma lucidum (Fr.) Karsten grown naturally in Korea were collected to investigate the morphological characters and some other useful characters related to the quality of the fungus and the results obtained are summarized as follows; The host tree showing the highest parasitic rate by the Genoderma lucidum(Fr.) Karsten was oak tree and the parasitic rate of the tree was 86.2%. The order of parasitic rate of the host trees by the fungus next to the oak was peach, chestnut, persimmon and acasia. The size, shape and color of fruiting bodies were varied according to the host trees. The average size of fruiting bodies collected was 40 to 100 mm by 30 to 80mm. The fruiting bodies with pileus size of 60 by 45 mm, pileus thickness of over 10mm, pileus minor axis/stipe length ratio of over 0.65 and pileus thickness/pileus minor axis ratio of over 0.22 were considered having higher commerical values. The external shape of the fruiting body was very important criterion to evaluate the quality of the Ganoderma lucidum (Fr.) Karsten. A great variation in characters such as pileus shape, color, marginal shape, zonation of pileus, pileus thickness, poroid layer of fruiting bodies and shape of stipe were observed from the fruiting bodies of G. lucidum collected in Korea. Further studies will be necessary for the genetic nature of these characters.

• Journal of Periodontal and Implant Science
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• v.34 no.1
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• pp.101-112
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• 2004

Osseointegrated implnats have proven to be successful in both full and partial edentulous patients since the 1960s and recently have shown successful results when used to restore single tooth missing. However, in most studies reporting the success of single implants, single implants replacing anterior teeth are more frequently mentioned than posterior single implants. Moreover, in studies regarding posterior single implants, the replaced region seemed to be variable; the maxilla, mandible and areas from the first premolar to the second molar were mentioned. However, considering the difference in bone quality in the mandible and maxilla, and the increased occlusal force in the posterior region, the success rates in each region may be different. In this study, the cumulative success rates and amount of bone loss of single implants replacing the mandibular first and second molar, respectively, were compared and analyzed to come to the following conclusion. 1. The 20 (20 persons) single implants that were placed in the mandibular first molar region were all successful and showed a 100% 5 year cumulative success rate. Among the 27 (24 persons) single implants replacing the mandibular second molar, 8 failed (27.63%) showing a 5 year cumulative success rate of 70.37%. 2. Among the 8 failed implants, one showed symptoms of postoperative infection and one complained of parenthesia. 6 implants failed after functional loading; 5 showed mobility and one resulted in fixture fracture. 3. After the attachment of the prosthesis, there was no significant statistical difference regarding the marginal bone loss in group 1 and group 2 during the checkup period (P>0.05). In conclusion, restoration of the mandibular first molar using single implants was found to be an excellent treatment modality, and when replacing mandibular second molars with single implants, poor bone quality and risk of overloading must be considered.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.3
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• pp.272-279
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• 2013

The concept of implant stability was basically originated from the relative condition of bone-implant interface and has some meanings for evaluation of that interface. In addtion, it has been used for the investigation of initial bone healing process after fixture installation because a degree of micromotion around interface can affect unfavorable clinical results. The purpose of this study is to investigate the mode of initial bone healing from fixture installation through prospective trial. Thirty fixtures were consecutively installed in mandibles of 26 patients with single tooth loss area and then healing abutment were secured for one-stage surgery meothod. Resonance frequency analysis was performed with one week interval during 12 weeks and periapical radiographs were taken at each month. Although marginal bone level change was not shown through observation period (P>0.05), statistical difference of implant stability was shown through 4 and 6 week (P<0.05) and was not shown after 6 week (P>0.05) according to the bone quality. Initial bone healing process is a successive process of bone resorption and favorable bone healing result might be postulated at 4 week interval after installation through RFA.