상아질에 적용된 재 습윤제가 미세인장 결합강도에 미치는 영향

강희영,조영곤,김종욱,박병철,유상훈,진철희,최희영,기영재 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.2

This study investigated that the effect of rewetting agent on dentinal microtensile bond strength (μTBS). Human molars were sectioned to expose the superficial dentin surfaces. Samples were divided into two groups according to type of adhesives-Single Bond (S) and One-Step (0)], and again subdivided into five groups by different dentin surface treatment-dry for 15s (D) , blot dry (BD) or dry for 15s, and rewet with different rewetting agents[distil1ed water (DW), Gluma Desensitizer (GD) and Aqua-Prep (AP)]for 30s. After application of adhesive, composite resin was built up on the bonding surface. Each tooth was sectioned to obtain stick with 1mm^(2) cross sectional area and the μTBS was determined by EZ test. In the S group, the mean μTBS of GD, AP and BD group was significantly higher than that of DW and D group (p < 0.05). In the 0 group, the mean μTBS of AP, GD, BD and DW group was significantly higher than that of D group (p < 0.05). The data suggested that Gluma Desensitizer and Aqua-Prep could be successfully used as rewetting agents, and Distilled water could be acceptable in aceton based adhesive system only.

법랑질 접착에 대한 습윤 효과

고근호,조영곤,진철희,유상훈,김종욱,박병철,기영재,최희영,김종진 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface, V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15s and rewet with Aqua-Prep F for 20s). Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p〈0.05). but there was no statistically significant difference between group BD and DR (p)0.05). At the enamel-resin interface, group D showed the gap of 2 ㎛ thickness, but group BD and DR showed close adaptation. In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.

단일 단계 접착제의 변연 미세누출

조영곤,정진호,기영재,최희영,진철희,유상훈,김종욱,박병철 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.2

This study evaluated the marginal microleakage of five single step adhesives. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on both buccal and lingual surfaces of extracted human molar teeth. Prepared teeth were randomly divided into five groups and restored using one of the single step adhesives and composite resins: Prompt L-Pop/Filtek Z-250 (Group 1), AQ Bond/Metafil CX (Group 2), One-Up Bond F/Palfique Toughwell (Group 3), Futurabond/Admira (Group 4), Xeno III/Spectrum TPH (Group 5). The restored teeth were thermocycled. Microleakage was assessed by dye penetration using 2% methylene blue dye solution. The teeth were bisected buccolingually and evaluated for microleakage under steromicroscope. The data were statistically analysed by Kruskal-Wallis test and Mann-Whitney tests. The results of this study were as follows; 1. Microleakage of enamel margins in group 3 was statistically higher than that in groups 1, 2, 4, 5 (p < 0.05) 2. Microleakage of dentin margins in group 1 was statistically higher than that in groups 2, 5, and that in group 3 was statistically higher than that in groups 2, 4, 5 (p < 0.05). 3. Dentin marginal microleakage was higher than enamel marginal microleakage in all experimental groups. In conclusion, Prompt L-Pop showed the least leakage at enamel margin, and AQ Bond showed at dentin margin in this study. Marginal miroleakage in dentin was higher than that in enamel.

복합레진의 지연충전이 미세인장 결합강도에 미치는 영향

박현식,조영곤,박병철,김종욱,최희영,김종진,진철희,유상훈,기영재 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

The purpose of this study was to evaluate the effect of immediate or delayed composite resin filling on dentinal microtensile bond strength (μTBS) after applied the adhesive. The coronal dentin of human third molars was exposed. Single-Bond or One-Step was applied on the dentin surfaces, and composite resin were constructed immediately (group 1) or 5 min., 10 min., 15 min., 20 min. and 30 min. (groups 2-6) after an adhesive was applied. The specimens were sectioned and made bar-shaped. Each surface area of them was about l ㎟. The RBS test was performed by EZ test. The results were analysed by One-way ANOVA and Tukey's test at 95 % significance level. The results suggested that the μTBS of Single-Bond to dentin was decreased when the composite resin was constructed 20 min. and 30 min. after Single-Bond was applied. But the μTBS of One-Step was not affected by delayed composite resin filling.

자가 산부식 프라이머의 적용시간이 상아질의 미세인장 결합강도에 미치는 영향

조영곤,이영곤,김종욱,박병철,김종진,최희영,진철희,유상훈 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.5

This study evaluated the influence of application time of self-etching primers on microtensile bond strength (μTBS) to dentin using three self-etching primer adhesive systems. Dentin surfaces were exposed from forty-eight human molars. They were conditioned with three self-etching primers (Clearfil SE Bond [SE], Unifil Bond [UF], Tyrian SPE + One Step Plus [TY]) and different primining times (10s, 20s, 30s and 40s). Composite resins were bonded to dentin surfaces and specimens were made. μTBS was tested and statistically compared using by one-way ANOVA and Tukey's Test. The results of this study presented that priming time for 10s in SE and UF groups and for 30s and 40s in TY group was highly decreased μTBS to dentin.

공정능력지수를 이용한 제조공정관리 실증분석

김희철 남서울대학교 2008 남서울대학교 논문집 Vol.14 No.-

From the subdivision of this analysis, basic plan needs the side of the quality control. In this paper, we discuss process capability analysis using process capability indexs. This paper‘s method is a system design and related industries to process their workers the ability to utilize the quality analyzes information in advance to help improve the quality of life, and the distribution of choice, there are one measure of using models can be used. The used software failure time data for capability analysis of process is Manufacturing Process Management data, the result of analysis listed on this chapter 3. The practical use is presented. Key Words : Process capability index elease Policies, Manufacturing Process Management data, Target Value, U. L

무한고장 소프트웨어 신뢰성장 모형에 대한 최소자승법 모수추정에 관한 연구

김희철 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.4

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, Weibull distribution reliability model was reviewed. Parameter Estimation by least squares study for Infinite failure software reliability growth Model was employed. The numerical example by Minitab software random data was illustrated. Key words : Least squares, Finite failure NHPP model, reliability growth

패널 데이터모형을 이용한 직업별 취업자 수 결정요인 추정에 관한 연구

김희철 남서울대학교 2010 남서울대학교 논문집 Vol.16 No.1-1

The employment number by occupational job is composed of various factors for groups and time series. In this paper, we use the panel data for finding various variables and using this. we analyzed the factors that is major influence to employment number by occupational job. For analysis, we looked at employment number by occupational job of 5 groups such as expert/skill/administration manager, business worker, service/sale worker, agriculture / forestry / skillful worker, faculty / machine operation / assembly / sin labor worker. In this analysis we looked at employment number by occupational job during the period from 2005.01 to 2009.12. We examined the data in relation to the employment number by occupational job, unemployment rate , monthly household income, preceding business composite index, consumer price index, composite stock price index. In looking at the factors which determine employment number by occupational job, evidence was produced supporting the hypothesis that there is a significant positive relationship between the consumer price index. The unemployment rate and monthly household income are significant negative relationship, preceding business composite index is negative relationship and composite stock price index positive relationship, they are not significant variables in terms of employment number by occupational job. Key Words : Fixed effect model, One-Way Error Component Regression Model, Lagrange Multiplier

반-로지스틱 분포 특성을 이용한 NHPP 소프트웨어 신뢰성장 모형에 관한 연구

김희철 남서울대학교 2012 남서울대학교 논문집 Vol.18 No.2

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rate per fault (hazard function). This infinite non-homogeneous Poisson process is model which reflects when correcting or modifying the software. In this paper, half Logistic distribution property have been proposed, which can efficiency application for software reliability. Algorithm for estimating the parameters used to maximum likelihood estimator and bisection method. Model selection based on mean square error and the coefficient of determination for the sake of efficient model were employed. In numerical example, half-Logistic distribution model were applied using failure interval time. Because half Logistic distribution property model is more efficient in terms of reliability, half Logistic distribution model as an alternative to the existing model also were able to confirm that can use in this area. Key Words : NHPP, Half-Logistic Distribution Property, Coefficient of Determination

일반화지수분포와 지수화 지수분포를 이용한 유한고장 소프트웨어 신뢰성장 모형에 관한 비교 연구

김희철 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.4

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, Goel‘s generalized and the exponentiated exponential distribution reliability model which maked out efficiency substituted for Gamma and weibull model (2 parameter shape illustrated by Gupta and Kundu ) was reviewed. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on SSE for the sake of efficient model, was employed. Analysis of failure using real data set for the sake of proposing shape parameter of the generalized exponential distribution and the exponentiated exponential distribution reliability model was employed. Key words : exponentiated exponential distribution, NHPP, SSE