Vital Bleaching이 법랑질 접착에 미치는 영향

김종해,권태엽,권용훈,김교한 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.4

The objective of this in vitro study was to evaluate the effect of bleaching on the composite to enamel bond and surface hardness change. Extracted human premolars were treated with 35% hydrogen peroxide (Sigma Chemical Co, USA) for 1hr/day at 0, 3, 6 and 9 day respectively. For the obsrvation of surface mophology alteration due to the treatment with hydogen peroxide, a SEM (S-4300, Hitachi, Japan) was used. The specimens were ground flat using serial SiC papers and ground ultra-finely using a 0.1㎛ diamond compound paste. To measure the microhardness, five non-carious premolars were ground using SiC papers and ten indentations were made on the surfacd with Vickers hardness tester (FM-7 FUTURE-TEC Inc., Japan). To evaluate shear bond strength, composite was bonded with One Up Bond-F, Prompt L-Pop, AQ Bond to the non-bleached and bleached enamel surface of sixty non-carious premolars. The bonding procedure is postponed for 1 week after bleaching and shear bond strength was measured. All specimens with a SEM. Bleaching created some enamel porosity but the teeth showed nonsignificant morphological chonge as bleaching time increased from SEM analysis. Most microhardness change occured on the first day of bleaching. Bleaching with 35% hydrogen peroxide did not result in significant change in the shear bond strength of composite resin to enamel. In the shear bond strength test, the fractured surfaces of specimens showed mixed adhesive and cohesive failure behavior.

웹서버를 이용한 그룹웨어 시스템의 설계 및 구현

김성연,최용엽 호서대학교 반도체제조장비국산화연구센터 2001 반도체장비학술심포지움 Vol.2001 No.-

이전까지의 결재방식은 직접 결재문서를 들고 결재자로부터 결재를 받는 방식이었으나 이제는 결재자가 집에서 또는 출장 중에 있어서도 웹 상에서 서버에 접속하여 결재자에게 전달되어진 결재문서를 검토, 결재할 수 있도록 하는 그룹웨어시스템이 필요하게 되었다. 본 연구개발의 주된 목적은 사내에서 기존의 결재방식을 웹 상에서 전자결재방식으로 변경하여 문서의 기안작성, 검토 결재 및 결재상황을 실시간으로 파악할 수 있도록 하였으며 또한, 이러한 모든 결재문서들은 데이터베이스에 최근문서, 일반문서, 정형화된 문서로 구분되어 저장되도록 하여서 권한이 부여된 사용자가 필요시 찾고자하는 문서를 실시간으로 검색 될 수 있도록 시스템을 구축하였다.

아동들의 태권도 수련활동참가에 따른 열등감 및 자아존중감의 관계

정재엽,정국현,김지영,김현철,이용국 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.2

The purpose of this study was to identify the relationship between children's Inferiority and self-esteem during Taekwondo practice. In order to achieve this purpose, 480 subject were selected among participants of Taekwondo activity programs in the Seoul area by using the stratified cluster random sampling method. Out of the 480 questionnaires responded to. only 414 were used for data analyses because 66 were responded to incompletely or incorrectly. The instrument for data collection was a questionnaire in which Inferiority and self-esteem consisted of items identified by Jun(1999) and Jun(1993), respectively. The statistical methods utilized in the study for analyzing the collected data were reliability analysis, descriptive statistics, one-way ANOVA, standard multiple regression analysis and the following results were obtained: First, both Inferiority and self-esteem differ statistically and significantly according to both sociodemographic variables. Second, both Inferiority and self-esteem differ statistically and significantly according to Taekwondo practice. Third, Inferiority statistically and significantly influences self-esteem.

상아질 접착제의 적용이 법랑질 접착에 미치는 영향

권태엽,권용훈,김교한,송근배 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.2

The objective of this study was to evaluate the effect of various enamel surface treatments on the bond strength of a composite resin to enamel (n=15). Ground bovine enamel specimens were divided into seven groups. A composite resin (Z250. 3M) was bonded to the specimens using different enamel surface treatments. Four groups examined the effect of application of all-in-one adhesives (Prompt L-Pop (POP), One-Up Bond F (ONE)) with respect to static priming (SP) or dynamic priming (DP). The other two examined use of the POP and ONE after phosphoric acid etching (PE). And the control group provided bond strength of the composite resin to phosphoric acid etched enamel with a resin bonding system (Single bond, SB, 3M). Shear bond strengths for the specimens were measured after 24 hours storage in water at 37 ℃. Effects of various surface treatments on enamel were examined by SEM. Dynamic priming resulted in higher enamel bond strengths than static priming and the best bond strengths were obtained when the enamel was etched with phosphoric acid. SEM analysis showed that depth of etching was related to the bond strengths measured. The enamel etch pattern after static priming showed little retentive surfaces. After dynamic priming, the enamel rod structure has become apparent in the shallow etch. SEM view showed that the resin tags and resin penetration were related to the bond strengths measured. SEM showed minimal resin penetration into enamel following static priming. After application of adhesives to phosphoric acid etched enamel, SEM showed more extended tags that are reflective of the deeper etch pattern.

금합금의 프라이머 처리가 교정용 브라켓의 접착에 미치는 영향

류동범,권태엽,권용훈,김교한 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.3

The purpose of this study was to compare the bonding strength and the interfacial micromorphology of two surface modification of gold alloys in direct bonding of orthodontic brackets. Flat tab of cast gold alloys (n= 120) were subjected to either of two surface treatments: 1.50㎛ aluminum oxide sandblasting, and 2. sandblasting plus adhesive primer for noble metal. Orthodontic brackets (RMO Co.) were bonded directly with Superbond C&B (Sun Medical Co. Ltd.), or Transbond XT (3M Unitek), or Ortho One (Bisco). All specimens were stored in distilled water at 37℃ for 24 hours, and then the tensile bond strength testing was performed in a Instron test machine. Bond failure sites were classified by a modified Adhesive Remnant Index (ARI) system. The results showed that sandblasting plus adhesive primer for noble metal produced stronger bonds to gold alloy than sandblasting only in all cases (Superbond C&B, Transbond XT, Ortho One). Superbond provided significantly stronger bonds to gold alloy than the others. Bond failure of Superbond to sandblast only and sandblast plus adhesive primer for noble metal to gold alloy occurred at the bracket/adhesives interface, whereas bond failure of the others occurred at the gold/adhesive interface. The clinical implications of these findings are discussed.

임플란트 보철물에서 임시 접착용 시멘트의 인장결합강도 비교

서경숙,권태엽,권용훈,김교한 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.4

The major disadvantage of cement-retained implant-supported superstructure is difficulty of retrievability. Sometimes, it is recommended that proetheses be provisionally cemented to implant abutment in order to ebaluate occlusion, screw loosening and tissue reaction. The retention of the provisional luting cementedusually employed in this case is considered to be important. This study compared tensile bond strength of gold crowns cemented to machined titanium implant abutments with three provisional luting cements. Also the effect of petrolatum and thermocycling on tensile bond stength were evaluated. Tensile bond strength of provisional luting cement were as follows with the decreasing order of Eugenol (13.06±1.544 kgf), Temp-Bond (9.41±0.737 kgf), Cavex (8.04±0.974 kgf), and Temp-bond with petrolatum (5.28±0.800 kgf). The addition of petrolatum in Temp-bond decreased tensile bond strength significantly (p<0.01). After thermocycling of 1,500 cycles, the tensile bond strengths of the cements were decreased with the order of Nogenol (10.87±3.031 kgf), Temp-Bond (8.1±0.667 kgf), Cavex (7.33±1.103 kgf), Temp-bond with petrolatum (4.88±1.348 kgf). The mocycling decreased the bond strength of Temp-Bond significantly, with no effects no other cements (p<0.01).

Role of cold water and beta-effect in the formation of the East Korean Warm Current in the East/Japan Sea: a numerical experiment

Kim, Yong-Yub,Cho, Yang-Ki,Kim, Young Ho Springer-Verlag 2018 Ocean dynamics Vol.68 No.8

A multi-year climate prediction system based on CESM2

Yong-Yub Kim,June-Yi Lee,Axel Timmermann,Yoshimitsu Chikamoto,Sun-Seon Lee,Eun Young Kwon,Wonsun Park,Nahid A. Hasan 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.4

A comparative study of dissolving hyaluronic acid microneedles with trehalose and poly(vinyl pyrrolidone) for efficient peptide drug delivery

Kim, Hong Kee,Lee, Soo Hyeon,Lee, Boo Yong,Kim, Sung Jin,Sung, Chang Yub,Jang, Na Keum,Kim, Jung Dong,Jeong, Do Hyeon,Ryu, Hyeon Yeol,Lee, Somin The Royal Society of Chemistry 2018 Biomaterials Science Vol.6 No.10

<P>We studied the role of the additives trehalose and poly(vinyl pyrrolidone) in the physical and pharmacokinetic properties of peptide drug incorporated hyaluronic acid microneedles. Poly(vinyl pyrrolidone) increases the mechanical strength of microneedles and ameliorates drug bioavailability <I>in vivo</I>, suggesting that poly(vinyl pyrrolidone) can be a promising additive in the fabrication of peptide drug-encapsulated fully dissolving microneedles.</P>

Magnesium phosphate ceramics incorporating a novel indene compound promote osteoblast differentiation <i>in vitro</i> and bone regeneration <i>in vivo</i>

Kim, Ju Ang,Yun, Hui-suk,Choi, Young-Ae,Kim, Jung-Eun,Choi, So-Young,Kwon, Tae-Geon,Kim, Young Kyung,Kwon, Tae-Yub,Bae, Myung Ae,Kim, Nak Jeong,Bae, Yong Chul,Shin, Hong-In,Park, Eui Kyun IPC Science and Technology Press 2018 Biomaterials Vol.157 No.-

<P><B>Abstract</B></P> <P>Incorporating bioactive molecules into synthetic ceramic scaffolds is challenging. In this study, to enhance bone regeneration, a magnesium phosphate (MgP) ceramic scaffold was incorporated with a novel indene compound, KR-34893. KR-34893 induced the deposition of minerals and expression of osteoblast marker genes in primary human bone marrow mesenchymal stem cells (BMSCs) and a mouse osteoblastic MC3T3-E1 cell line. Analysis of the mode of action showed that KR-34893 induced the phosphorylation of MAPK/extracellular signal-regulated kinase and extracellular signal-regulated kinase, and subsequently the expression of bone morphogenetic protein 7, accompanied by SMAD1/5/8 phosphorylation. Accordingly, KR-34893 was incorporated into an MgP scaffold prepared by 3D printing at room temperature, followed by cement reaction. KR-34893-incorporated MgP (KR-MgP) induced the expression of osteoblast differentiation marker genes <I>in vitro</I>. In a rat calvaria defect model, KR-MgP scaffolds enhanced bone regeneration and increased bone volume compared with MgP scaffolds, as assessed by micro-computed tomography and histological analyses. In conclusion, we developed a method for producing osteoinductive MgP scaffolds incorporating a bioactive organic compound, without high temperature sintering. The KR-MgP scaffolds enhanced osteoblast activation <I>in vitro</I> and bone regeneration <I>in vivo</I>.</P>