• Journal of dental hygiene science
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• v.18 no.4
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• pp.210-217
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• 2018

Periodontal disease is a chronic inflammatory disease that affects quality of life and nutrition. Several studies have demonstrated a link between periodontal disease and low bone density, and vitamin D is expected to have a beneficial effect on periodontal disease as well as on bone mineral density and anti-inflammatory effects. The purpose of this study was to identify the association between periodontal disease and vitamin D because the results are different in some studies and there is a lack of research in Korea. In this study, we conducted a multiple linear regression analysis of 8,783 subjects among 23,626 subjects who were older than 20 years of age, who had serum vitamin D levels and periodontal disease, who had three years of the National Health and Nutrition Survey that was conducted in Korea from 2012 to 2014. We examined the relationship between serum vitamin D levels and periodontal disease. Tooth loss and vitamin D levels were negatively correlated (${\beta}=-0.028$, p=0.008). In addition, the prevalence of periodontal disease was found to be higher in men younger than 50 years of age with lower vitamin D levels (Q1: 1.769 [1.125~2.782], Q2: 1.182 [0.743~1.881], Q3: 0.676 [0.400~1.881]; p=0.001). Low vitamin D levels and periodontal disease are common diseases in primary care. Vitamin D supplementation is expected to have favorable effect on periodontal disease and falls, osteoporosis, osteoarthritis, and cancer. Therefore, patients with periodontal disease may benefit from periodic vitamin D management to improve quality of life as well as to manage periodontal disease. In addition, as shown in this study, not only elderly individuals, but also men younger than 50 years of age are related to periodontal disease, so there should be interest in controlling the levels of vitamin D in adults.

• Journal of agricultural medicine and community health
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• v.37 no.4
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• pp.223-232
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• 2012

Objectives: The objective of this study was to identify the relationship between fish consumption and blood mercury levels in a sample of adult Koreans. Methods: The study subjects were 299 residents of Busan (male: 65, female: 234) and 185 residents of Namhae (male: 69, female: 116), South Korea. Demographic characteristics, current smoking, current drinking, fish consumption per week, past history of amalgam treatment, and residential district were recorded by trained interviewers in June and July, 2009. We considered a portion of fish to be equivalent to 70 gm weight, and calculated amounts of fish consumed per week. Using chi-square tests, t-tests, ANOVA, and multiple linear regression analysis, we estimated the relationships between blood mercury levels and amount of fish consumed per week and other factors. Results: The mean blood mercury level of our subjects was 6.61 ${\mu}g/L$, higher than the criterion defined by the United States Environmental Protection Agency (EPA) (5.8 ${\mu}g/L$). In multiple linear regression analysis, residential district and amount of fish consumed per week were associated with blood mercury levels. However, marital status, current drinking, and gender, and age were not associated with blood mercury levels. Conclusions: In conclusion, we suggest the implementation of systematic and periodic population-based studies to decrease the risks of mercury poisoning among South Koreans who consume fish as a regular part of the diet.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.23 no.1
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• pp.34-40
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• 2014

There are several treatment options for rehabilitation of partial edentulism including the use of conventional or implant-retained fixed prostheses. However, such prosthetic options cannot always be possible because of compromised general and oral health (i.e. loss of supporting tissues, medical reasons, extensive surgical protocol and osseointegration failure of dental implant) as well as the affordability of patients. In some cases, removable partial denture provides easier access for oral hygiene procedures and the ability to correct discrepancies in dental arch relationships than implant fixed prosthesis. Recently, Implant Supported Removable Partial Denture (ISRPD) where to place dental implant in strategic position has been suggested to improve the limitation and shortcomings of conventional RPD. ISPRD can overcome mechanical limition of conventional RPD by placing implant in a favorable position and can be cost-effective, prosthetic solution for partially edentulous patients who are not immediate candidates for extensive, fixed implant supported restorations. Incorporation of dental implants to improve the RPD support and retention and to enhance patient acceptance should be considered when treatment planning for RPD. In this case, 59 years old male patient who received dental treatment of implant fixed prosthesis on both side of the upper jaw and implant overdenture on lower jaw showed implant abutment screw fracture on #15i and osseointegration failure on multiple number of implants. After removing failed implants, we planned ISRPD using #15i,24i,25i,26i and #23 natural tooth for RPD abutment. We fabricated #23 surveyed crown,#24i=25i=26i surveyed bridge and #15i gold coping for support,retention and stability for RPD. Periodic follow up check for 2years has been performed since the ISRPD delivery to the patient. No sign of screw loosening, fracture or bone resorption around abutment implants were detected.

• Management & Information Systems Review
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• v.35 no.1
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• pp.51-68
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• 2016

In this paper, we aim to analyze the effect of accounting policy change subsequent to the adoption of K-IFRS in Korea, whereby the firms are required to recognize impairment losses on goodwill on a periodic basis rather than to amortize over a specific period. As a principle-based accounting standard, the K-IFRS expands the scope of fair value measurement with a view to enhance the relevance and timeliness of accounting information. In the same vein, intangibles with indefinite useful life, of which goodwill is an example, are subject to regulatory impairment tests at least once a year. Related literature on the impact of mandatory change in goodwill policy document that impairment recognition is more likely to be practiced opportunistically, mainly because managers have a greater discretion to conduct the tests under K-IFRS. However, existing literature examined the frequency and/or magnitude of the goodwill impairment before versus after the K-IFRS adoption, failing to notice the impairment symptoms at individual firm level. Borrowing the definition of impairment symptoms suggested by Ramanna and Watts(2012), this study performs a series of tests to determine whether the goodwill impairment recognition achieves the goal of communicating timelier information under the K-IFRS regime. Using 947 firm-year observations from domestic companies listed in KRX and KOSDAQ markets from 2008 to 2011, we document overall delays in recognizing impairment losses on goodwill after the adoption of K-IFRS relative to prior period, based on logistic and OLS regression analyses. The results are qualitatively similar in robustness tests, which use alternative proxy for goodwill impairment symptom. Afore-mentioned results indicate that managers are likely to take advantage of the increased discretion to recognize the impairment losses on goodwill rather than to provide timelier information on impairment, inconsistent with the goal of regulatory authority, which is in line with the improvement of timeliness and relevance of accounting information in conjunction with the full implementation of K-IFRS. This study contributes to the extant literature on goodwill impairment from a methodological viewpoint. We believe that the method employed in this paper potentially diminishes the bias inherent in researches relying on ex post impairment recognition, by conducting tests based on ex ante impairment symptoms, which allows direct examination of the timeliness changes between before and after K-IFRS adoption.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.117-123
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• 2010

Tooth eruption is the movement of the tooth from the developing place in the alveolar bone to the functional position in the oral cavity. The permanent incisors originate from the dental lamina on the lingual side of preceding deciduous tooth and erupt to the level of the occlusion through the well developed gubernacular cord. Ectopic eruption is a developmental disturbance in the eruption pattern of the permanent dentition. Most of the ectopically erupted lower incisor has been found in lingual side. The ectopically erupted tooth could be repositioned by orthodontic force in the early mixed dentition, which could help preventing the problems of loss of space and the lingual tilting of the lower anterior teeth. An eight-year-old girl visited the department of pediatric dentistry, Yonsei Dental University Hospital, for the evaluation and the treatment of the lower right lateral incisor, which was horizontally erupted in the lingual side, parallel to the mouth floor. Her tongue was placed on the labial side of that tooth. There was no previous dental history of dental caries or trauma on the pre-occupied primary incisor. Clinical and radiographic examinations including the computed tomography(CT), showed no evidence of dilacerations on root. Therefore, we decided to start active orthodontic traction of the lower right lateral incisor. We designed the fixed type of buccal arch wire and the lip bumper with hook for the traction. Button was attached to the lingual side of the ectopically positioned tooth. Elastic was used between the appliance and the button on that tooth. After the tooth become upright over the tongue level, appliance was change to the removable type and periodic check-up with occlusal guidance was followed to monitor the position of the tooth. In this case using the fixed appliance with modified form of lip bumper and hook embedded in acrylic part instead of extraction was very efficient up-righting the ectopically erupted tooth toward the occlusal plane.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.1
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• pp.39-45
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• 2018

Purpose: The purpose of this study was to evaluate the clinical effects of erythritol powder air polishing device (EPAP) in addition to scaling and root planing (SRP) in non-surgical periodontal treatment in moderate chronic periodontitis patients. Materials and Methods: Clinical evaluation was performed at 21 sites treated with SRP (control) and 21 sites treated with the addition of SRP+EPAP (test). All examinations were performed before treatment, 1 month after treatment, and 3 months after treatment. Depth of the periodontal pocket, gingival recession, clinical attachment level, plaque index, and bleeding of probing were measured as clinical parameters. Results: In both test and control groups, there was a significant decrease in the depth of the periodontal pocket, plaque index, bleeding of probing, increased gingival recession, and gain of clinical attachment level at 1 month and 3 months after treatment. However, there was no significant clinical difference between the test group and the control group. Clinical result was improved after 1 month compared to the baseline; in contrast, results at 3 months after treatment were worse than at 1 month after treatment. Conclusion: In this study, we cannot suggest that SRP + EPAP is clinically more effective than SRP alone as non-surgical periodontal treatments. Periodic periodontal therapy, at intervals of at least every three months, is important for sustaining effects of this treatment.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.329-342
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• 2003

Most of the existing multicast routing protocols for ad-hoc networks do not take into account the efficiency of the protocol for the cases when there are large number of sources in the multicast group, resulting in either large overhead or poor data delivery ratio when the number of sources is large. In this paper, we propose a multicast routing protocol for ad-hoc networks, which particularly considers the scalability of the protocol in terms of the number of sources in the multicast groups. The proposed protocol designates a set of sources as the core sources. Each core source is a root of each tree that reaches all the destinations of the multicast group. The union of these trees constitutes the data delivery mesh, and each of the non-core sources finds the nearest core source in order to delegate its data delivery. For the efficient operation of the proposed protocol, it is important to have an appropriate number of core sources. Having too many of the core sources incurs excessive control and data packet overhead, whereas having too little of them results in a vulnerable and overloaded data delivery mesh. The data delivery mesh is optimally reconfigured through the periodic control message flooding from the core sources, whereas the connectivity of the mesh is maintained by a persistent local mesh recovery mechanism. The simulation results show that the proposed protocol achieves an efficient multicast communication with high data delivery ratio and low communication overhead compared with the other existing multicast routing protocols when there are multiple sources in the multicast group.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.83-96
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• 2017

A constructed sea stream in Yeongdo, Busan, Republic of Korea is mostly static due to the lifted stream bed and tidal characters, and receives domestic wastewater nearby, causing a consistent odor production and water quality degradation. Bioaugmentation of a microbial consortium was proposed as an effective and economical restoration technology to restore the polluted stream. The microbial consortium activated on site was augmented on a periodic basis (7~10 days) into the most polluted site (Site 2) which was chosen considering the pollution level and tidal movement. Physicochemical parameters of water qualities were monitored including pH, temperature, DO, ORP, SS, COD, T-N, and T-P. COD and microbial community analyses of the sediments were also performed. A significant reduction in SS, COD, T-N, and COD (sediment) at Site 2 occurred showing their removal rates 51%, 58% and 27% and 35%, respectively, in 13 months while T-P increased by 47%. In most of the test sites, population densities of sulfate reducing bacterial (SRB) groups (Desulfobacteraceae_uc_s, Desulfobacterales_uc_s, Desulfuromonadaceae_uc_s, Desulfuromonas_g1_uc, and Desulfobacter postgatei) and Anaerolinaeles was observed to generally decrease after the bioaugmentation while those of Gamma-proteobacteria (NOR5-6B_s and NOR5-6A_s), Bacteroidales_uc_s, and Flavobacteriales_uc_s appeared to generally increase. Aerobic microbial communities (Flavobacteriaceae_uc_s) were dominant in St. 4 that showed the highest level of DO and least level of COD. These microbial communities could be used as an indicator organism to monitor the restoration process. The alpha diversity indices (OTUs, Chao1, and Shannon) of microbial communities generally decreased after the augmentation. Fast uniFrac analysis of all the samples of different sites and dates showed that there was a similarity in the microbial community structures regardless of samples as the augmentation advanced in comparison with before- and early bioaugmentation event, indicating occurrence of changing of the indigenous microbial community structures. It was concluded that the bioaugmentation could improve the polluted water quality and simultaneously change the microbial community structures via their niche changes. This in situ remediation technology will contribute to an eco-friendly and economically cleaning up of polluted streams of brine water and freshwater.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.2
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• pp.204-210
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• 1999

Purpose: We assessed the nutritional status and the alterations of oral diets during anti-cancer chemotherapy in pediatric oncology patients. Methods: Twenty children with malignancy were evaluated from day 0 until day 21 of post-chemotherapy. Nutritional status was assessed by body weight and biochemical parameters. The amount and calories of oral diets were assessed and food preference before and during chemotherapy were analysed by questionnelle. Results: 1) The underlying diseases of 20 patients were 11 acute lymphoblastic lekemia, 2 non-Hodgkin's lymphoma, 2 Langerhans cell histiocytosis, 2 Wilm's tumor, 2 brain tumor, 1 rhabdomyosarcoma. 2) There were weight loss during chemotherapy in 8 patients (40.0%), weigt gain in 5 patients (25.0%), and no significant changes in 7 patients (35.0%). 3) Biochemical parameters showed no significant interval changes during chemotherapy except elevation of serum ALT level. 4) The daily caloric intakes of oral diets during chemotherapy were 310~600 Kcal which was much lower than average of daily recommended calory for Korean children. 5) The most favorate food was altered by chemotherapy, from meats to carbonated beverages and unfavorate food was not altered as vegetables. Conclusion: The periodic assessment of nutritional status and dietary supplements according to preferred foods of patients will be required for the optimal nutrition care in cancer patients.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.124-134
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• 2011

Purpose : We have tried to search all concerning data on the policies of hepatitis B vaccination or surveillance of medical equipments that can transmit blood mediated diseases, including disposable syringe, in Republic of Korea, to propose references to other medical professionals. Methods : Data from domestic journals, government websites, computerized newspapers, etc. were reviewed. The data were arranged into four categories (governmental policies on hepatitis B control, hepatitis B mass immunization program in school, using process of hepatitis B vaccine, and policies on medical equipments surveillance, including disposable syringes, which is considered as source of blood mediated infection), and the periodic changes on each subjects in policies were reviewed. Results : Due to growing social concerns on hepatitis B in early 1980s, swift introduction and production of hepatitis B vaccine was made. After establishment of "5 year project for eradication of hepatitis B" in late 1983, number of vaccinated population jumped up to 6 million within 2 years (1984-85). However, since the immunization targets were mainly adult, not infant, this project was annulled in late 1985. Following this project, hepatitis B mass immunization program in school was carried out. In year 1995, hepatitis B vaccine was included in national immunization program. The use of disposable syringe was recommended from year 1980 but legislated in year 1985, finally. Conclusion : The mainstay in controlling hepatitis B in Republic of Korea was coordination of prompt introduction of vaccine, mass immunization, high vaccination coverage rate, or use of disposable syringes. However, since there is lack of official data available, it is urgent to arrange and computerize all government data related to infectious diseases.