• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3316-3318
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• 1999

PMMA(poly-methyl methacrylate) microlens array is fabricated using transparent acrylic resin. PMMA is commonly used material for plastic lens due to its excellent visibility larger than 90% and other optical characteristics so much close to those of glass. Orthodontic resin (DENTSPLY International Inc.), commonly used in dentistry, is an transparent acrylic resin kit including MMA liquid and polymerization powder. Their mixture results in PMMA through polymerization. Using the resin PMMA layer is formed on the substrate through spin-coating. Designed pattern of lens structure is transferred to PMMA layer by RIE (Reactive Ion Etching) with oxygen plasma. Final lens shape is formed by thermal treatment that causes PMMA to reflow, The thickness of PMMA spun on the substrate is $17{\mu}m$ that is also final sag of microlens, Designed diameters of the microlenses are $200{\mu}m$, $300{\mu}m$,and $500{\mu}m$, respectively.

• 대한치과보철학회지
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• 제39권6호
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• pp.589-598
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• 2001

The fracture of acrylic resin dentures remains an unsolved problem. Therefore, many investigations have been performed and various approaches to strengthening acrylic resin, for example, the reinforcement of heat-cured PMMA resin using glass fibers, have been suggested over the years. The aim of the present study was to investigate the effect of short glass fibers treated with silane coupling agent on the transverse strength of heat-polymerized PMMA denture base resin. To avoid fiber bunching and achieve even fiber distribution, glass fiber bundles were mixed with PMMA powder in conventional mixer whose blade was modified to be blunt. Composite of glass fiber($11{\mu}m$ diameter, 3mm & 6mm length, silane treated) and PMMA resin was made. Transverse strength and Young's modulus were estimated. Glass fibers were incorporated with 1%, 3%, 6% and 9% by weight. Plasticity and workability of dough was evaluated. Fracture surface of specimens was investigated by SEM. The results of this study were as follows 1. 6% and 9% incorporation of 3mm glass fibers in the PMMA resin enhanced the transverse strength of the test specimens(p<0.05). 2. 6% incorporation of 6mm glass fibers in the PMMA resin increased transverse strength, but 9% incorporation of it decreased transverse strength(p<0.05). 3. When more than 3% of 3mm glass fibers and more than 6% of 6mm glass fibers were incorporated, Young's modulus increased significantly(p<0.05). 4. Workability decreased gradually as the percentage of the fibers increased. 5. Workability decreased gradually as the length of the fibers increased. 6. In SEM and LM, there was no bunching of fibers and no shortening of fibers.

• 대한치과재료학회지
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• 제44권4호
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• pp.311-318
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• 2017

본 연구의 목적은 2가지 임시 수지 (Bis-acryl resin composite 및 polymethyl methacrylate (PMMA))의 굴곡 강도 및 미세 경도에 대한 경화 순서 및 중합 온도의 영향을 조사하는 것에 있다. 중합은 대기 중 $25^{\circ}C$ (대조) 및 온수 (40, 50, 60, 70 그리고 $80^{\circ}C$)에서 다양한 조건하에 수행되었다. 굴곡 강도 시험은 ISO-4049에 따라 수행되었다. 또한, 누프 경도를 측정 하였다. Bis-acryl resin의 경우, $50^{\circ}C$까지의 온도는 굴곡 강도와 bis-acryl resin composite의 경도를 증가시키지 않았지만 (p> 0.05), 온도가 높을수록 강도가 증가 하였다. PMMA 수지의 경우 굴곡 강도는 최대 $70^{\circ}C$의 온도에서 증가하고 약간 감소합니다. Bis-acryl resin은 PMMA 수지보다 기계적 특성이 더 컸다. 열의 영향은 Bis-acryl resin에서 PMMA 수지보다 더 두드러졌다(p <0.05).

• 디지털융복합연구
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• 제18권4호
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• pp.341-346
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• 2020

가철성 교정장치에서 주로 사용하고 있는 자가중합 레진인 Polymethyl methacrylate (PMMA)는 현대 치의학 분야에서 주로 쓰이고 있는 아크릴릭 레진이다. 장점으로 색과 체적의 조직 친화성, 안정성 등 있어 치과에선 교정장치 재료로 오랫동안 사용해 왔다. PMMA의 제작은 활성화 방법에 따라 자가중합방식과 열중합 방식으로 나눌 수 있다. 자가중합 레진은 치과 교정장치로 오래동안 사용되고 있다. 레진의 주입방법은 크게 적층법(sprinkle-on method)와 혼합법(mixing method)이 있다. 본 연구에서는 교정장치의 레진 주입방법에 따른 기계적 특성인 강도, 탄성계수 경도, 표면조도를 실험 해보고자 한다. Orthodontic PMMA 의 직사각형 시편 (1.4×3.0×19.0 mm)에 3점 굽힘강도 실험한 결과 강도에선 유의한 차이가 없었다. 경도 역시 유의한 차이가 없었다. 표면조도도 큰 차이가 보이지 않았다. Orthodontic PMMA는 교정용 장치의 레진주입 방식에 따른 기계적 특성의 유의한 차이가 없음을 확인하였다.

• 대한치과보철학회지
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• 제45권4호
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• pp.457-468
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• 2007

Statements of problem: The fracture of acrylic resin dentures remains an unsolved problem. Therefore, many investigations have been performed and various approaches to strengthening acrylic resin, for example, the reinforcement of heat-cured acrylic resin using glass fibers, have been suggested over the years. Silane is important for bonding between glass fiber and resin. Purpose: The aim of the present study was to investigate the effect of various silane on the strength of PMMA resin and roughness of resin-glass fiber complex after abrasion test. Material and methods: 3mm glass fiber (Chopped strand, Hankuk fiber Co., Milyang, Korea) was treated with 3 kinds of silane (MPS, EPS, APS) (Sila-ace, Chisso chemical, Tokyo, Japan) and mixed with PMMA resin(Vertex RS, Vertex Dental B.V., Zeist, Netherlands). Transverse strength and Young's modulus was measured using Instron (Instron model 4466, Instron, Massachusetts, USA). After abrasion test (The 858 Mini Bionix II Test System, MTS System Co., Minnesota, USA) surface roughness was evaluated using tester (Form Talysurf plus, Taylor Hopson Ltd., Leicester England). Examination of scanning electron microscope was also performed. Results: Within this study, the following conclusions were drawn. 1. Surface treatment of glass fiber with MPS and APS increased transverse strength of PMMA resin complex, but surface treatment with EPS decreased transverse strength of PMMA resin complex (p<0.05). 2. Silane treated glass fiber increased Young's modulus of PMMA resin complex compared to desized glass fiber (p<0.05). 3. Roughness increased after abrasion test in case of PMMA resin reinforced with desized glass fiber (p<0.05). 4. Roughness change was not observed after abrasion test in case of PMMA resin reinforced with silane treated glass fiber (p>0.05).

• 구강회복응용과학지
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• 제37권3호
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• pp.101-110
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• 2021

목적: 본 연구에서는 3D 프린팅 레진과 임시 수복용 레진의 열순환 처리에 따른 전단결합강도의 변화를 연구하고자 하였다. 연구 재료 및 방법: DLP 방식을 이용하여 3D 프린팅 레진으로 표본을 제작하였다. 표본은 상부에 부착한 임시 수복용 레진(PMMA, bis-acryl resin) 및 열순환 처리 횟수(대조군, 2,000, 3,000, 5,000회)에 따라 8개의 군으로 분류하였다. 만능 재료시험기 상에서 결합된 표본들의 전단결합강도를 측정하였다. 결과: 열순환 처리의 횟수가 증가함에 따라 3D 프린팅 레진에 대한 PMMA와 bis-acryl resin의 전단결합강도는 PMMA에서 3,000회와 5,000회 간을 제외하고 모두 감소하였다. PMMA 그룹에서는 3,000회 미만의 열순환 처리 횟수 간에서 유의한 전단결합강도의 차이를 보였으며(P < 0.05), 3,000회 이상의 열순환 처리 횟수 간에는 유의한 차이를 보이지 않았다(P > 0.05). Bis-acryl resin 그룹에서는 대조군과 2,000회 간, 대조군과 3,000회 간, 대조군과 5,000회 간의 열순환 처리에는 유의한 전단결합강도의 차이가 있었으며(P < 0.05), 2,000회와 3,000회 간, 3,000회와 5,000회 간에는 유의한 차이가 없었다(P > 0.05). 결론: 3D 프린팅 레진에 대한 임시 수복용 레진의 전단결합강도는 열순환 처리를 한 경우 결합강도가 낮아지는 경향을 보였다.

• The Journal of Advanced Prosthodontics
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• 제4권1호
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• pp.1-6
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• 2012

PURPOSE. The aim of this study was to compare the flexural strength of polymethyl methacrylate (PMMA) and bis-acryl composite resin reinforced with polyethylene and glass fibers. MATERIALS AND METHODS. Three groups of rectangular test specimens (n = 15) of each of the two resin/fiber reinforcement were prepared for flexural strength test and unreinforced group served as the control. Specimens were loaded in a universal testing machine until fracture. The mean flexural strengths (MPa) was compared by one way ANOVA test, followed by Scheffe analysis, using a significance level of 0.05. Flexural strength between fiber-reinforced resin groups were compared by independent samples t-test. RESULTS. For control groups, the flexural strength for PMMA (215.53 MPa) was significantly lower than for bis-acryl composite resin (240.09 MPa). Glass fiber reinforcement produced significantly higher flexural strength for both PMMA (267.01 MPa) and bis-acryl composite resin (305.65 MPa), but the polyethylene fibers showed no significant difference (PMMA resin-218.55 MPa and bis-acryl composite resin-241.66 MPa). Among the reinforced groups, silane impregnated glass fibers showed highest flexural strength for bis-acryl composite resin (305.65 MPa). CONCLUSION. Of two fiber reinforcement methods evaluated, glass fiber reinforcement for the PMMA resin and bis-acryl composite resin materials produced highest flexural strength. Clinical implications. On the basis of this in-vitro study, the use of glass and polyethylene fibers may be an effective way to reinforce provisional restorative resins. When esthetics and space are of concern, glass fiber seems to be the most appropriate method for reinforcing provisional restorative resins.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.332-335
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• 2004

Polymethyl Methacrylate(PMMA) mortars using EPS solution-based binders are prepared with various unsaturated polyester resin(UP) contents of binder, and tested for working life. heat exothorm temperature, length change. compressive strength and temperature dependence of compressive strength. As a result, the working life of PMMA mortar is lengthened with raising UP content of binder. Length change of the mortar was condensed from expansion to shrinkage with increasing UP content, and non shrinkage of the mortar is obtained at about UP content of $2.5\%$. The compressive strength of the mortar is increased with an increase in the UP content and reach maximum at UP content of $5\%$. However thermal resistance improvement of the mortar by increasing UP content was not recognized. UP resin was recommended as an effective agent for shrinkage control and strength development of PMMA mortar.

• The Journal of Advanced Prosthodontics
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• 제8권3호
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• pp.167-171
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• 2016

PURPOSE. This study inspects the effect of incorporating halloysite nanotubes (HNTs) into polymethyl methacrylate (PMMA) resin on its flexural strength, hardness, and Young's modulus. MATERIALS AND METHODS. Four groups of acrylic resin powder were prepared. One group without HNTs was used as a control group and the other three groups contained 0.3, 0.6 and 0.9 wt% HNTs. For each one, flexural strength, Young's modulus and hardness values were measured. One-way ANOVA and Tukey's test were used for comparison (P<.05). RESULTS. At lower concentration (0.3 wt%) of HNT, there was a significant increase of hardness values but no significant increase in both flexural strength and Young's modulus values of PMMA resin. In contrast, at higher concentration (0.6 and 0.9 wt%), there was a significant decrease in hardness values but no significant decrease in flexural strength and Young's modulus values compared to those of the control group. CONCLUSION. Addition of lower concentration of halloysite nanotubes to denture base materials could improve some of their mechanical properties. Improving the mechanical properties of acrylic resin base material could increase the patient satisfaction.

• The Journal of Advanced Prosthodontics
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• 제11권4호
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• pp.193-201
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• 2019

PURPOSE. The aim of the present study was to evaluate the color changes of an autopolymerizing PMMA resin used for interim fixed restorations, reinforced with $SiO_2$ nanoparticles. MATERIALS AND METHODS. Silica nanoparticles were blended with the PMMA resin powder through high-energy ball milling. Four shades of PMMA resin were used (A3, B3, C3, D3) and total color differences were calculated through the equations ${\Delta}E_{ab}=[({\Delta}L*)^2+({\Delta}a*)^2+({\Delta}b*)^2]^{1/2}$ and ${\Delta}E_{00}=[(\frac{{\Delta}L^{\prime}}{K_LS_L})^2+(\frac{{\Delta}C^{\prime}}{K_CS_C})^2+(\frac{{\Delta}H^{\prime}}{K_HS_H})^2+R_T(\frac{{\Delta}C^{\prime}}{K_CS_C})(\frac{{\Delta}H^{\prime}}{K_HS_H})]^{1/2}$. Statistically significant differences between ${\Delta}E_{ab}$ and the clinically acceptable values of 3.3 and 2.7 and those between ${\Delta}E_{00}$ and the clinically acceptable value of 1.8 were evaluated with one sample t-test (P<.05). Differences among the different shades were assessed through One-Way ANOVA and Bonferroni multiple comparison tests. RESULTS. Significantly lower values were detected for all groups concerning ${\Delta}E_{ab}$ compared to the intraorally clinical acceptable values of 3.3 and 2.7. Significantly lower mean values were detected for groups B3, C3, and D3, concerning ${\Delta}E_{00}$ compared to the intraorally clinical acceptant value of 1.8. Color pigments in red-brown (A3) and red-grey (D3) shades affect the total color change to a greater extent after the reinforcement with $SiO_2$ nanoparticles compared to the red-yellow (B3) shade. CONCLUSION. Within the limitations of this in vitro study, it can be suggested that reinforcing PMMA with $SiO_2$ nanoparticles at 0.25 wt% slightly affects the optical properties of the PMMA resin without being clinically perceivable.