• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.107-119
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• 1990

The purpose of this study was to evaluate the marginal adaptability of the amalgam restorations in applying the cavity varnish (Copalite$^{(R)}$) and dentin bonding agent (Scotchbond 2$^{(R)}$) under the scanning electron microscope. For this study, eighteen sound extracted human molars were selected. Class I cavities in 12 teeth and class V cavities in 6 teeth were prepared using an air turbine with No. 701 tungsten carbide bur and finished using a low speed handpiece with No. 557 fissure bur. The prepared specimens were then divided into three groups including 4 class I cavities and 2 class V cavities in each group and restored as follows ; Group I. All the prepared cavities were restored with amalgam only (Control). Group II. Two layers of Copalite$^{(R)}$ cavity varnish were applied to the cavities with a gentle stream of air after each application and cavities were restored with amalgam. Group III. The enamel cavity margins were etched with 37% phosphoric acid gel for 60 sec., rinsed for 30 sec. and dried. One layer of visible lightcured Scotchbond Dental Adhesive$^{(R)}$ was applied and immediately cured for 20 seconds with visible light-cure unit and cavities were restored with amalgam. All the specimens were cut at the neck of the teeth and the occlusal halves of specimens were sectioned buccolingually in the longitudinal axis centering the amalgam restorations, using the disk. The cut specimens were ground with sandpapers (400, 600, 800, 1000 grit), and cleaned for 5 minutes in the ultrasonic cleaner (Brason Co. U.S.A.). In the cut surfaces, the amalgam - tooth interfaces were examined under the scanning electron microscope (JSM, 35C type, JEOL). The obtained results were as follows ; 1. The amalgam-tooth interfaces were reduced more significantly in the Copalite$^{(R)}$ and Scotchbond 2$^{(R)}$ application group than in the control group. 2. In the class I cavities, the Scotchbond 2$^{(R)}$ application group showed the findings similar to the Copalite$^{(R)}$ application group in the cavity floor, and the marginal adaptability was better in the side wall than in the cavity floor. 3. In the class I cavities, the Scotchbond 2$^{(R)}$ application group showed better marginal adaptability in the occlusal margin than in the gingival margin. 4. The marginal adaptability was in the order of the Scothbond 2$^{(R)}$ application group, the Copalite$^{(R)}$ application group and the control group.

• 대한치과기공학회지
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• 제37권3호
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• pp.121-127
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• 2015

Purpose: This study was intended to investigate the effect of applying liner for chemical bonding and physical surface roughness created on zirconia by using a sandpaper before sintering on the bond strength between the two materials. Methods: Zirconia blocks were cut using a low-speed cutter. Plate-shaped specimen($6mm{\times}6mm{\times}3mm$) was fabricated by sintering after giving surface roughness according to four kinds of sandpapers. Depending on whether or not to use liner, 60 specimens were divided into two groups ZN(non-liner), ZL(liner), and the two groups were subdivided into four groups respectively in accordance with sandpaper used, totaling eight groups (n=10). The surface roughness (Ra) values and shapes before sintering were observed, and shear bond strength after pressing ceramic plasticity was measured with a universal testing machine. For a test of the significance, a one-way ANOVA was performed, and Tukey's multiple comparison test was conducted. Results: The observation of the surface roughness was SB04($2.22{\pm}1.16{\mu}m$), SB08($2.98{\pm}0.33{\mu}m$), SB12($2.44{\pm}1.32{\mu}m$), SB20($2.34{\pm}0.59{\mu}m$) and SA04($2.34{\pm}0.67{\mu}m$), SA08($1.28{\pm}0.90{\mu}m$), SA12($2.03{\pm}1.60{\mu}m$), SA20($2.19{\pm}1.73{\mu}m$). In the case of ZN Group, the shear bond strength was ZN04($23.26{\pm}3.83MPa$), ZN08($21.76{\pm}2.33MPa$), ZN12($20.49{\pm}3.01MPa$), ZN20($24.98{\pm}4.22MPa$)(p<0.05). As for ZL Group, the shear bond strength was ZL04($25.09{\pm}5.67MPa$), ZL08($22.98{\pm}2.26MPa$), ZL12($21.54{\pm}5.70MPa$), ZL20($23.98{\pm}3.23MPa$)(p<0.05). Conclusion: The research results showed that the bond strength of Zirconia core and Pressing ceramic was further improved by physical surface treatment before sintering, rather than by chemical bonding through liner surface treatment.

• 공업화학
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• 제32권3호
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• pp.332-339
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• 2021

최근 화석 연료 고갈과 지구 온난화를 가속화하는 온실 가스 배출에 대한 우려로 온실 가스를 배출하지 않는 청정 에너지원인 수소 에너지 기술의 중요성이 강조되고 있다. 그 중 물을 전기분해하여 수소를 얻는 수전해 기술은 그린 수소 기술로 궁극적인 청정 미래 에너지 자원으로 주목받고 있다. 본 연구에서는 양이온 교환막 수전해(proton exchange membrane water electrolysis, PEMWE)의 셀 구성요소 중 하나인 확산층(porous transport layer, PTL)을 sandpaper를 이용한 표면 처리를 통하여 표면 특성을 제어하였으며, 이러한 표면 특성 개선을 통하여 과전압을 줄이고 성능과 안정성을 높이기 위한 연구를 진행하였다. Sandpaper 400, 180, 100방을 준비하여 PTL 표면을 sanding하여 처리하였으며, 처리 후 1000방의 고른 sandpaper로 표면을 매끄럽게 처리하였다. 준비된 확산층은 물접촉각을 측정하여 친수성 정도를 분석하였으며, SEM 분석을 통하여 표면 형태를 관찰하였다. 전기화학적 특성 분석을 위하여 I-V 성능곡선, 임피던스 측정을 진행하여 성능 개선 여부를 확인하였다.

• Restorative Dentistry and Endodontics
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• 제31권4호
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• pp.312-322
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• 2006

본 연구는 복합레진의 표면 연마에 의한 표면 거칠기가 표면 색상과 투명도에 어떤 영향을 미치는가를 알아보고자 시행하였다. Charisma (Heraeus Kulzer GmbH, Domagen, Germany)의 B1과 A3, Esthet-X (DENTSPLY Caulk, Milford, USA)의 B1과 B3 레진으로 거칠기에 따른 표면 색상을 평가하기위한 직경 8 mm, 두께 5 mm의 시편을 제작하고, Sof-Lex finishing & polishing system (3M, ESPE Dental Products, St. Paul, USA)의 C, M, F 및 SF 디스크로 시편의 한쪽 면을 연마하였으며, 연마 전 Mylar strip으로 압축된 면을 대조군으로 하였다 . 거칠기에 따른 투명도의 차이를 평가하기위한 두께 1 mm의 시편을 Charisma 의 A3로 제작하여, 한쪽 면을 600, 1000. 1500 및 2000번 사포로 연마하였다. 각 시편의 연마 전과 후, 연마면의 CIE $L^{*}a^{*}b^{*}$ 값과 1 mm 시편의 백색과 흑색 배경판 상에서의 Y값을 spectrophotometer 인 Spectrolino (GretagMacbeth, Regensdorf, Switzerland)를 사용해 측정 분석하였으며, 각 시편의 연마 전과 후의 평균 표면 조도 (Ra)값을 Surface Roughness Tester SJ-301 (Mytutoyo, Tokyo, Japan)로 측정했다. $L^{*}$값은 재료와 색상에 상관없이 가장 거친 Sof-lex C 디스크로 연마한 군에서 가장 높은 값을 보였으며 (p < 0.05), Esthet-X B3군을 제외한 모든 군에서 Ra값이 감소함에 따라 $L^{*}$값도 낮아졌다. $a^{*}$값은 표면 거칠기에 따라 특정한 변화양상을 보이지 않았으며, $b^{*}$값은 Esthet-X B1군을 제외한 모든 군에서 Sof-lex SF 디스크로 연마 시 가장 높은 값을 보였으며 (p < 0.05), Charisma B1과 Esthet-X B3군에서 Ra값과 비교적 높은 상관관계를 보였다. Contrast ratio 는 1000번과 1500번 사포로 연마한 군 간을 제외한 모든 군 간에 유의한 차이를 보였으며 (p < 0.05), 표면 거칠기가 감소함에 따라 contrast ratio도 감소하였다 (R2 = 0.801).