• 대한치과기공학회지
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• 제43권3호
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• pp.84-92
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• 2021

Purpose: The purpose of this study was to compare the dimension safety evaluation between a general ultrasonic cleaner and an ultrasonic cleaner equipped with UV-C (ultraviolet-C). Methods: An edentulous model was prepared. A denture base and an occlusal rim were fabricated, and scanning was performed. After scanning, a denture base and full arch artificial teeth were designed. The full arch artificial teeth were printed using a three-dimensional printer (n=10). The residual resin was washed with alcohol and then scanned (reference data). The printed specimens were classified and cleaned using a general ultrasonic cleaner (GU group) and an ultrasonic cleaner equipped with UV-C (UC group). After each washing, a rescan was performed (scan data). Reference data and scan data were superimposed using overlapping software. Data were statistically analyzed using the Mann-Whitney test (α=0.05). Results: In the deviation values of full arch artificial teeth, the GU group showed a high deviation of 18.02 ㎛ and the UC group showed a low deviation of 15.02 ㎛. The two groups demonstrated a statistically significant difference (p<0.05). Conclusion: Full arch artificial teeth prepared using photopolymerized resin were deformed according to the temperature of water generated in the ultrasonic cleaner. It is judged that there is no deformation according to the UV-C ultrasonic cleaner.

• 한국산업보건학회지
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• 제31권4호
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• pp.451-460
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• 2021

Objectives: The purpose of this study is to examine occupational risk factors that affect the mental health (depression, anxiety, anger, insomnia, self-esteem, trauma) of hospital facility workers. Methods: A survey was conducted from November 17, 2020 to December 1, 2020 for 700 non-medical workers (Temporary and contract workers: cleaning, security, information, office workers, etc.) working at a general hospital in Seoul. Results: As a result of the study, the risk of musculoskeletal disorders was found to have a significant effect on depression, anxiety, insomnia, and trauma. Noise had a significant effect on depression and anger, dust hazard had an effect on depression and self-esteem, and high temperature had a significant effect on anxiety and insomnia. Conclusions: Based on these results, it is necessary to examine the influence of occupational risk factors to improve the mental health of non-medical hospital facility workers.

• Journal of Dental Anesthesia and Pain Medicine
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• 제19권3호
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• pp.151-158
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• 2019

Background: This study aimed to examine whether the combination of low-dose ketamine and propofol in deep sedation is clinically useful in controlling the behavior in intellectually disabled patients who are typically extremely noncooperative during dental procedures. Methods: A total of 107 extremely noncooperative intellectually disabled adult patients were analyzed. In all patients, deep sedation was performed using either propofol alone (group P) or using a combination of propofol and 0.2 mg/kg or 0.4 mg/kg ketamine (groups PK0.2 and PK0.4, respectively). The procedures were performed in the order of insertion of nasal cannula into the nostril, attachment of mouth gag, and mouth cleaning and scaling. The frequency of patient movement during the procedures, mean arterial pressure, heart rate, peripheral oxygen saturation, recovery time, discharge time, and postoperative nausea and vomiting were examined. Results: The three groups were significantly different only in the frequency of patient movement upon stimulation during single intravenous injection of propofol and scaling. Conclusion: For propofol deep sedation, in contrast to intravenous injection of propofol alone, prior intravenous injection of low-dose ketamine (0.4 mg/kg) is clinically useful because it neither affects recovery, nor causes side effects and can suppress patient movement and vascular pain during procedures.

• 보존과학회지
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• 제34권6호
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• pp.549-556
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• 2018

In November 2011, various artifacts were excavated from the No. 8 stone-lined tomb in Suchon-ri, Gongju by the Chungnam Institute of History and Culture. These included artifacts with lacquered mainframe and silvery metal ornament. These were recovered together with soil and underwent conservation treatment. In this paper, we discuss the scientific analysis and conservation treatment of the lacquered artifacts excavated from the Suchon-ri site. Among our findings is that the artifacts have three layers of lacquer coating and the metal parts are primarily composed of Ag. As the artifacts were recovered with soil from the site, the soil was removed from underneath and inside the artifacts. The inside of the lacquerware was reinforced with rayon paper using 3% funori, and the metal was treated with acrylic resin after removing the acrylic resin previously used to recover the artifact, followed by cleaning. The metal was also internally reinforced with gauze. Finally, the interior reinforcement was made using PVA and resin in pulp and attached with funori to preserve the shape of the lacquerware, and the exposed rayon was finished with acrylic paint. The main advantages of this study are its review of conservation treatment strategies for lacquer artifacts whose numbers have recently increased, and the application of new conservation treatment methods.

• 한국직업건강간호학회지
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• 제28권4호
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• pp.221-229
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• 2019

Purpose: The aim of this study was to identify core keywords and topic groups of workplace bullying researches in the past 10 years for better understanding research trend. Methods: The study was conducted in four steps: 1) collecting abstracts, 2) extracting and cleaning semantic morphemes, 3) building co-occurrence matrix and 4) analyzing network features and clustering topic groups. Results: 437 articles between 2010 and 2019 were retrieved from 5 databases (RISS, NDSL, Google scholar, DBPIA and Kyobo Scholar). Forty-one abstracts from these articles were extracted, and network analysis was conducted using semantic network module. The most important core keywords were 'turnover', 'intention', 'factor', 'program' and 'nursing'. Four topic groups were identified from Korean databases. Major topics were 'turnover' and 'organization culture'. Conclusion: After reviewing previous research, it has been found that turnover intention has been emphasized. Further research focused on various intervention is needed to relieve workplace bullying in nursing field.

• Journal of Korean Biological Nursing Science
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• 제23권3호
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• pp.170-179
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• 2021

Purpose: The aim of this study was to identify core keywords and topic groups in the 'Diabetes mellitus and mobile applications' field of research for better understanding research trends in the past 20 years. Methods: This study was a text-mining and topic modeling study including four steps such as 'collecting abstracts', 'extracting and cleaning semantic morphemes', 'building a co-occurrence matrix', and 'analyzing network features and clustering topic groups'. Results: A total of 789 papers published between 2002 and 2021 were found in databases (Springer). Among them, 435 words were extracted from 118 articles selected according to the conditions: 'analyzed by text network analysis and topic modeling'. The core keywords were 'self-management', 'intervention', 'health', 'support', 'technique' and 'system'. Through the topic modeling analysis, four themes were derived: 'intervention', 'blood glucose level control', 'self-management' and 'mobile health'. The main topic of this study was 'self-management'. Conclusion: While more recent work has investigated mobile applications, the highest feature was related to self-management in the diabetes care and prevention. Nursing interventions utilizing mobile application are expected to not only effective and powerful glycemic control and self-management tools, but can be also used for patient-driven lifestyle modification.

• 대한치위생과학회지
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• 제4권2호
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• pp.99-111
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• 2021

Background: This study aimed to investigate the changes of the amount of P. gingivalis in saliva by professional preventive treatment of periodontal disease by dental hygienists. Methods: A total of 109 subjects participated in this study with informed consent. The control group (38 subjects) performed oral hygiene management individually. The periodontal treatment group (35 subjects) underwent root planning once every 3 weeks for a total of 4 times. The professional periodontal prevention group (36 subjects) underwent interdental cleaning and professional tooth brushing once every 3 weeks for a total of 4 times. Paired T test and analysis of variance were performed to compare the difference among the groups in the amount of P. gingivalis. Results: The copies of P. gingivalis in the professional periodontal prevention group decreased from 773.62±1,198.09 to 241.40±430.40 after treatment significantly. The control group decreased from 525.22±582.54 to 244.29±385.88 after treatment. The periodontal treatment group showed insignificant change of P. gingivalis. Conclusions: This study showed the professional periodontal prevention was more effective than periodontal treatment in decrease of P. gingivalis.

• 한국치위생학회지
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• 제22권5호
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• pp.347-354
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• 2022

Objectives: This study aimed to evaluate the relationship between pit and fissure sealants of the molars, and caries prevalence and experience to assess the effect of sealants on caries prevention. Methods: Data from 16,119 people were extracted from the seventh Korean national health and nutrition examination survey, which was conducted from 2016 to 2018. Demographic, socioeconomic, oral health-related behavioral, and oral examination survey data were collected as independent variables. SAS statistics for complex samples and multiple logistic regression analysis (Windows ver. 9.4) was used for the statistical analyses. Results: Caries prevalence and experience were significantly associated with age, sex, daily toothbrushing frequency, interdental cleaning, and having molar sealant. Multiple logistic regression analysis revealed a significant association between having molar sealants and the caries prevalence and experience among participants under 30 years of age after adjusting socio-economic variables and toothbrushing-related factors. Conclusions: This study confirmed the effect of molar sealants on caries prevention in Korea. Our results support that the application of molar sealants in children, adolescents, and young individuals is effective in preventing caries.

• 한국치위생학회지
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• 제23권4호
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• pp.227-234
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• 2023

Objectives: Cetylpyridinium chloride CPC-based mouthwashes are well known to have no harmful ingredients in the mouth and can be used for a long time. The purpose of this study was to evaluate the effect of using CPC-based mouthwashes to suppress the biofilm formation and antibiotics for handling orthodontic appliances. Methods: To measure the antibacterial effect, Streptococcus mutans (S. mutans) cultured orthodontic appliances were precipitated in Gargreen and Polident for 5 minutes, incubated at 37℃ for 24 hours(h). In order to measure the biofilm removal effect, the degree of biofilm formation on the orthodontic appliances was stained with a methylene blue and the difference before and after was compared using image J software program (NIH Image J; NIH, Bethesda, MD). Results: The viability of S. mutans according to the concentration showed that Gargreen and Polident inhibited colony formation compared to the control, respectively (p<0.01). The degree of biofilm formation was significantly higher in the control, however both Gargreen and Polident significantly reduced it compared to the before and after condition on removable orthodontic appliances (p<0.01). Conclusions: This study suggests that the use of Gargreen, a cetylpyridinium chloride based oral cleaning cleanser, could be replaced by Polident for antibacterial effect and biofilm formation on removable orthodontic appliances.

• Membrane and Water Treatment
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• 제13권1호
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• pp.39-49
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• 2022

Seawater desalination is doubtlessly a viable option to supply fresh drinking water. Nevertheless, RO (reverse osmosis) desalination plants in specific areas may be intermittently operated to match the imbalance between water demand and supply. Although a handful of works have been done on other membrane systems, few studies have attempted to mitigate fouling in intermittent RO systems. Accordingly, the objectives of this paper were to examine the effect of the intermittent operation on RO fouling; and to compare four intermittent operation modes including feed solution recirculation, membrane storage in the feed solution, deionized water (DI) recirculation, and membrane storage in DI water. Results showed that intermittent operation reduced RO fouling under several conditions. However, the extents of fouling mitigation were different depending on the feed conditions, foulant types, and membrane lay-up methods. When the feed solution was recirculated during the lay-up, the restoration of the flux was less significant than that by the feed solution feed-up. The use of deionized water during the lay-up was effective to restore flux, especially when the feed solution contains scale-forming salts (CaSO₄) and/or colloidal silica.