• Restorative Dentistry and Endodontics
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• v.42 no.3
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• pp.216-223
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• 2017

Objectives: The aim of this study was to compare the mechanical properties of various nickel-titanium (NiTi) files with similar tapers and cross-sectional areas depending on whether they were surface-treated. Materials and Methods: Three NiTi file systems with a similar convex triangular cross-section and the same ISO #25 tip size were selected for this study: G6 (G6), ProTaper Universal (PTU), and Dia-PT (DPT). To test torsional resistance, 5 mm of the straightened file's tip was fixed between polycarbonate blocks (n = 15/group) and continuous clockwise rotation until fracture was conducted using a customized device. To evaluate cyclic fatigue resistance, files were rotated in an artificial curved canal until fracture in a dynamic mode (n = 15/group). The torsional data were analyzed using 1-way analysis of variance and the Tukey post-hoc comparison test, while the cyclic fatigue data were analyzed using the Mann-Whitney U test at a significance level of 95%. Results: PTU showed significantly greater toughness, followed by DPT and G6 (p < 0.05). G6 showed the lowest resistance in ultimate torsional strength, while it showed a higher fracture angle than the other files (p < 0.05). In the cyclic fatigue test, DPT showed a significantly higher number of cycles to failure than PTU or G6 (p < 0.05). Conclusions: Within the limitations of this study, it can be concluded that the torsional resistance of NiTi files was affected by the cross-sectional area, while the cyclic fatigue resistance of NiTi files was influenced by the surface treatment.

• Archives of Plastic Surgery
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• v.45 no.3
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• pp.207-213
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• 2018

This review article presents an assessment of trends in statistical methods and an evaluation of their appropriateness in articles published in the Archives of Plastic Surgery (APS) from 2012 to 2017. We reviewed 388 original articles published in APS between 2012 and 2017. We categorized the articles that used statistical methods according to the type of statistical method, the number of statistical methods, and the type of statistical software used. We checked whether there were errors in the description of statistical methods and results. A total of 230 articles (59.3%) published in APS between 2012 and 2017 used one or more statistical method. Within these articles, there were 261 applications of statistical methods with continuous or ordinal outcomes, and 139 applications of statistical methods with categorical outcome. The Pearson chi-square test (17.4%) and the Mann-Whitney U test (14.4%) were the most frequently used methods. Errors in describing statistical methods and results were found in 133 of the 230 articles (57.8%). Inadequate description of P-values was the most common error (39.1%). Among the 230 articles that used statistical methods, 71.7% provided details about the statistical software programs used for the analyses. SPSS was predominantly used in the articles that presented statistical analyses. We found that the use of statistical methods in APS has increased over the last 6 years. It seems that researchers have been paying more attention to the proper use of statistics in recent years. It is expected that these positive trends will continue in APS.

• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.276-281
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• 2014

Objectives: The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. Materials and Methods: The apical 3 mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan) or JT-5B (B&L Biotech Ltd.). The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1), J1 (JT-5B / Power-1), K4 (KIS-1D / Power-4), and J4 (JT-5B / Power-4). The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. Results: There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05). The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. Conclusions: Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.360-364
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• 2021

Objectives: The purpose of this study was to evaluate the clinical and radiographic characteristics of idiopathic bone cavity (IBC) to determine the effect of surgical intervention on the process of healing. Materials and Methods: All cases diagnosed with IBC during the period of 2011 to 2020 at our Department of Oral and Maxillofacial Surgery were searched. Ninety cases were retrieved. The features evaluated were sex, age, contour of the lesion, number of teeth involved, site, history of trauma, and postoperative healing pattern. The significance of differences was assessed by Mann-Whitney U test and chi-square test. Results: The female:male ratio showed no predilection toward either sex (0.9:0.8). The mean age of the collected sample was 22.05±14.38 years, and the age ranged from 10 to 58 years. All cases presented in the mandible and showed well-circumscribed radiolucency. Margins were either scalloped or round in shape, and the size varied from one tooth to six teeth involvement. Seventy cases involved three or fewer roots. Three cases showed bilateral lesion. Four cases had a history of trauma at the area of the lesion. Fifty-one cases were followed for six months after surgery, and all showed increased bone density at the lesion. Conclusion: There is no definitive radiological or clinical feature of IBC. Considering the diversity of clinical and radiological features, such a diagnosis relies primarily on surgical findings of an empty bone cavity with no epithelial lining. Our data suggest that surgical intervention be the first choice of treatment as opposed to observation.

• The korean journal of orthodontics
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• v.51 no.5
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• pp.355-362
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• 2021

Objective: This study aimed to establish the prevalence and patterns of nonsyndromic tooth agenesis in patients referred to a tertiary health care facility. Methods: The intraoral records and panoramic radiographs of 9,874 patients aged 12-22 years were evaluated. The study group included 716 patients (371 male, 345 female) with non-syndromic agenesis of at least one tooth (except the third molars). The study data were assessed using descriptive statistics, chi-square test, and Mann-Whitney U test, while patterns were evaluated using a tooth agenesis code (TAC) tool. Results: A total of 1,627 congenitally missing teeth, were found in patients with non-syndromic tooth agenesis, with an average of 2.27 missing teeth per patient. The prevalence of tooth agenesis was 7.25%, and the most commonly missing teeth were the left mandibular second premolars (10.17%). The age group comparison revealed no significant difference in the median number of missing teeth per patient according to the cutoff values for ages between 12 and 22 years. When the missing teeth were examined separately according to quadrants, 114 different tooth agenesis patterns (upper right quadrant = 28, upper left quadrant = 27, lower left quadrant = 31, and lower right quadrant = 28) were identified, and 81 of these patterns appeared only once. Conclusions: This study highlights the benefits of applying the TAC tool in a large sample population. The application of the TAC tool in such studies will enable the development of template treatment plans by determining homogenous patterns of tooth agenesis in certain populations.

• Journal of Obesity & Metabolic Syndrome
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• v.27 no.4
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• pp.233-237
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• 2018

Background: Obesity is a complex, medical condition causally contributing to many chronic diseases and a number of efforts have been made to find the associated markers for novel prevention and treatment of obesity. Our study was to evaluate the relationship between gut immune response and obesity and overweight with use of fecal calprotectin (FC) both in adult and children groups. Methods: Fecal samples were obtained from 74 subjects: 14 non-obese and overweight children (PN), 13 obese and overweight children (PO), 20 non-obese and overweight adults (AN), and 27 obese and overweight adults (AO). FC was measured using a commercial Legend Max quantitative enzyme-linked immunosorbent assay (BioLegend). Mann-Whitney U-test was used for statistical analysis. Results: Median FC concentration was $7.9{\mu}g/g$ (range, $1.9-28.9{\mu}g/g$) for PN, $5.0{\mu}g/g$ (range, $2.6-29.6{\mu}g/g$) for PO, $9.5{\mu}g/g$ (range, $0.8-28.9{\mu}g/g$) for AN, and $10.0{\mu}g/g$ (range, $1.6-25.6{\mu}g/g$) for AO, respectively. In both adults and children age groups, the FC showed no statistically significant difference between AO and AN or PO and PN. However, FC showed statistically significant difference (P<0.05) between AO and PO while not significant between AN and PN. Conclusion: FC level in AO was significantly higher than that in PO, suggestive of different pathophysiologic mechanism between children obesity and adults obesity.

• Journal of Korean Medicine Rehabilitation
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• v.29 no.1
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• pp.63-73
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• 2019

Objectives The purpose of this study is to evaluate the safety of Ojeok-san extract powder and soft extract in healthy male volunteers. Methods Randomized controlled, cross over study was carried out in healthy male volunteers. Total 27 of 31 subjects meeting the inclusion criteria were enrolled and three subjects for waiting were included. To each group 12 subjects were randomly allocated by random number table. Group A took the extract powder in the first period and then took the soft extract in the second period. Group B took the medicine in the opposite order. Trial was conducted through two times of hospitalizations and all subjects had a seven-days of wash out period. Vital sign and laboratory test were checked before and after the medication. The mean difference of safety evaluation variables were analyzed by paired t-test (p<0.001) or wilcoxon signed rank test (p<0.05). The mean difference between two groups were analyzed by independent t-test (p<0.05) or Mann whitney test (p<0.05). Results As a result of all data related to vital sign and laboratory test in both group, There were no significant differences associated with the clinical trial drug between before and after the medication. And there was no adverse event associated with the clinical trial drug. Conclusions Both Ojeok-san extract powder and soft extract were found to be safe for healthy male volunteers.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.105-111
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• 2019

PURPOSE. Limited data is available regarding the differences for possible microleakage problems and fitting accuracy of zirconia versus titanium abutments with various connection designs. The purpose of this in vitro study was to investigate the effect of connection design and abutment material on the sealing capability and fitting accuracy of abutments. MATERIALS AND METHODS. A total of 42 abutments with different connection designs [internal conical (IC), internal tri-channel (IT), and external hexagonal (EH)] and abutment materials [titanium (Ti) and zirconia (Zr)] were evaluated. The inner parts of implants were inoculated with $0.7{\mu}L$ of polymicrobial culture (P. gingivalis, T. forsythia, T. denticola and F. nucleatum) and connected with their respective abutments under sterile conditions. The penetration of bacteria into the surrounding media was assessed by the visual evaluation of turbidity at each time point and the number of colony forming units (CFUs) was counted. The marginal gap at the implant- abutment interface (IAI) was measured by scanning electron microscope. The data sets were statistically analyzed using Kruskal-Wallis followed by Mann-Whitney U tests with the Bonferroni-Holm correction (${\alpha}=.05$). RESULTS. Statistically significant difference was found among the groups based on the results of leaked colonies (P<.05). The EH-Ti group characterized by an external hexagonal connection were less resistant to bacterial leakage than the groups EH-Zr, IT-Zr, IT-Ti, IC-Zr, and IC-Ti (P<.05). The marginal misfit (in ${\mu}m$) of the groups were in the range of 2.7-4.0 (IC-Zr), 1.8-5.3 (IC-Ti), 6.5-17.1 (IT-Zr), 5.4-12.0 (IT-Ti), 16.8-22.7 (EH-Zr), and 10.3-15.4 (EH-Ti). CONCLUSION. The sealing capability and marginal fit of abutments were affected by the type of abutment material and connection design.

• The Journal of Korean Academic Society of Nursing Education
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• v.25 no.2
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• pp.216-226
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• 2019

Purpose: This study aimed to investigate child abuse awareness and reporting intention among nursing and education students and correlations among the variables involved. Methods: A cross-sectional study was conducted by administering an online questionnaire to 70 nursing college students and 70 education college students. Data were analyzed using descriptive statistics, t-test, chi-squared test, the Mann-Whitney U test, and Pearson's correlation in SPSS 21.0 (IBM, Armonk, NY). Results: The mean score of child abuse awareness was $3.61{\pm}0.32$ for nursing students and $3.60{\pm}0.36$ for education students. The mean score of reporting intention was $5.65{\pm}0.90$ for nursing students and $5.38{\pm}1.03$ for education students. Females presented higher scores than males in the awareness of sexual abuse. The awareness of emotional abuse was higher in students who knew of reporting obligations or who had experienced abuse. Child abuse awareness and reporting intention were significantly positively correlated. Also, the number of times having received child abuse education was correlated with reporting intention in both mild and severe cases of abuse. Conclusion: Reporting intention is not only related to having received education, but also to the frequency of that education. Child abuse education is important to increase reporting intention and should be delivered repeatedly.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.454-459
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• 2020

The main cause of oral disease is the formation of tooth surface bacteria, and a chemical mouthwash is used as a suppression method. However, chemical preparations have side effects, so we tried to verify the antibacterial effect of bamboo extract against oral microbes. Subjects were 15 college students as a control group and an experimental group, and the changes in oral microbes before and after the use of distilled water and bamboo extract were compared. Analysis of SPSS Windows ver. 20.0 was used (p<0.05). Results The total number of pathogenic microorganisms further decreased after using bamboo extract solution after using gargling solution between groups.