• 대한소아치과학회지
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• 제43권3호
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• pp.275-283
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• 2016

본 연구는 복합레진의 연마방법에 따른 표면특성을 평가하기 위해, microhybrid 레진(Filtek$^{TM}$ Z250)과 nanofill 레진(Filtek$^{TM}$ Z350)을 연마 전, abrasive disk(Sof-lex) 연마 후, polishing brush(Occlubrush) 연마 후로 나누어 분석하였다. 그 결과 레진 표면조도는 연마 후 증가하였는데, 미세조도는 연마방법에 따른 차이가 없었으나 거시조도는 Occlubrush를 이용한 경우 현저하게 커졌다(p < 0.05). Sof-lex 연마의 경우 레진의 filler까지 연마되어 표면이 보다 균일한 형상을 보였으나 Occlubrush 연마시편은 기질층이 뜯겨져 나간 불균일한 형상을 보였다. 두 연마방법 간의 미세경도 유의차는 없었으며(p > 0.05), 연마 후 경도 값이 약 25% 상승하였다. 결론적으로, 복합레진의 표면경도 향상을 위하여 적합한 연마가 필요하며, Sof-lex를 이용한 연마가 더 우수한 것으로 사료된다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
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• pp.31-35
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• 2003

Friction in cold forging with mist lubrication is measured with the ring compression test. Small quantity of mist lubricant is sprayed onto the surfaces of cemented tungsten carbide (WC) tools polished to mirror surfaces, and the specimens of pure aluminum are compressed. It is found that spraying small quantity of lubricant $(0.5\;g/m^2)$ is effective to reduce the friction in comparison with the dry condition. The mist particles stick to the tool surface as separated dots, and the behavior of the trapped mist lubricant between the tool and specimen during upsetting is discussed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.921-926
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• 1997

SOI(Silicon On lnsulator) technology is many advantages in the gabrication of MOS(Metal-Oxide Semiconductor) and CMOS(Complementary MOS) structures. These include high speed, lower dynamic power consumption,greater packing density, increased radiation tolearence et al. In smiple form of bonded SOL wafer manufacturing, creation of a bonded SOI structure involves oxidizing at least one of the mirror polished silicon surfaces, cleaning the oxidized surface and the surface of the layer to which it will be bonded,bringing the two cleanded surfaces together in close physical proximity, allowing the subsequent room temperature bonding to proceed to completion, and than following this room temperature joining with some form of heat treatment step,and device wafer is thinned to the target thickness. This paper has been performed to investigate the possibility of the bonded SOI wafer manufacturing Especially, we focused on the bonding quality and thinning method. Finally,we achieved the bonded SOI wafer that Si layer thickness is below 3 .mu. m and average roughness is below 5.angs.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.98-102
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• 1994

There are many difficulties in automatic polishing for die & mold surfaces. Even though the process has been studied in the past 15 years, it has not been achieved yet, but by the process of actual hand work of well-skilled workers. A new magentic assisted polishing process, which is one of the potential method for automation of surface finishing has been studied in the past 10 years by colleagues. The process has many merits, but on the other hand also has demerits, one being low efficiency of gridability by comparision with grinding wheel polish. Therefore, some attempts were tried to improve the grindability by adopting electropolishing, ultra-high speed milling, 5-axis controlled machine etc... most recently by collegues. This study also aims to improve the efficiency of polishing by introducing the easily-polished shape surface milling method equalizing the tool feed per tooth to the pick feed. This milling method was experimentally confirmed to have sufficient grindability to polish milled surface (with 10 .mu. mRmax surface roughness) into mirror surface (with 0.4 .mu. mRmax surface roughness).

• Journal of Dairy Science and Biotechnology
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• 제33권2호
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• pp.139-151
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• 2015

Biofilms are aggregates of microorganisms present in a self-produced matrix of extracellular polymeric substance (EPS) adhered to a surface. Formation of a biofilm in the environment on farms and in dairy plants comprises several stages: attachment, growth (development), and detachment. Generally, biofilms are harmful to humans and need to be controlled. Stainless steel (SS) surfaces that are untreated or are scratched comprise substrata that are especially vulnerable to biofilm formation; therefore, SS surfaces should be polished and sanitized. Various approaches are available for the destruction of biofilms; cleaning-in-place (CIP) is the method mainly used in dairy plants. Further study on optimum detergents, cleaning conditions, and methods for this purpose is needed.

• The Journal of Advanced Prosthodontics
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• 제3권2호
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• pp.81-84
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• 2011

PURPOSE. The aim of this in vitro study was to investigate the adhesion of initial colonizer, Streptococcus sanguis, on resin, titanium and zirconia under the same surface polishing condition. MATERIALS AND METHODS. Specimens were prepared from Z-250, cp-Ti and 3Y-TZP and polished with $1 {\mu}m$ diamond paste. After coating with saliva, each specimen was incubated with Streptococcus sanguis. Scanning electron microscope, crystal violet staining and measurement of fluorescence intensity resulting from resazurin reduction were performed for quantifying the bacterial adhesion. RESULTS. Surface of resin composite was significantly rougher than that of titanium and zirconia, although all tested specimens are classified as smooth. The resin specimens showed lower value of contact angle compared with titanium and zirconia specimens, and had hydrophilic surfaces. The result of scanning electron microscopy demonstrated that bound bacteria were more abundant on resin in comparison with titanium and zirconia. When total biofilm mass determined by crystal violet, absorbance value of resin was significantly higher than that of titanium or zirconia. The result of relative fluorescence intensities also demonstrated that the highest fluorescence intensity was found on the surface of resin. Absorbance value and fluorescence intensity on titanium was not significantly different from those on zirconia. CONCLUSION. Resin specimens showed the roughest surface and have a significantly higher susceptibility to adhere Streptococcus sanguis than titanium and zirconia when surfaces of each specimen were polished under same condition. There was no significant difference in bacteria adhesion between titanium and zirconia in vitro.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.171-174
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• 2000

We have investigated the CMP slurry properties of silicate oxide thin films surface on CMP cleaning process. The metallic contaminations by CMP slurry were evaluated in four different oxide films, such as plasma enhanced tetra-ethyl-ortho-silicate glass(PE-TEOS), $O_3$ boro-phospho silicate giass( $O_3$-BPSG), PE-BPSG, and phospho-silicate glass(PSG). All films were polished with KOH-based slurry prior to entering the post-CMP cleaner. The Total X-Ray Fluorescence(TXRF) measurements showed that all oxide surfaces are heavily contaminated by potassium and calcium during polishing, which is due to a CMP slurry. The polished $O_3$-BPSG films presented higher potassium and calcium contaminations compared to PE-TEOS because of a mobile ions gettering ability of phosphorus. For PSG oxides, the slurry induced mobile ion contamination increased with an increase of phosphorus contents.

• 한국전기전자재료학회논문지
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• 제13권2호
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• pp.131-136
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• 2000

We have investigated the slurry induced metallic contaminations of undoped and doped silicate oxides surface on CMP cleaning process. The metallic contaminations by CMP slurry were evaluated in four different oxide films, such as plasma enhanced tetra-ethyl-orthyo-silicate glass(PE-TEOS), O3 boro-phos-pho-silicate glass(O3-BPSG), PE-BPSG, and phospho-silicate glass(PSG). All films were polished with KOH-based slurry prior to entering the post-CMP cleaner. The Total X-Ray fluorescence(TXRF) measurements showed that all oxide surfaces are heavily contaminated by potassium and calcium during polishing which is due to a CMP slurry. The polished O3-BPSG films presented higher potassium and calcium contaminations compared to PE-TEOS because of a mobile ions gettering ability of phosphorus. For PSG oxides, the slurry induced mobile ion contamination increased with an increase of phosphorus contents. In addition, the polishing removal rate of PSG oxides had a linear relationship as a function of phosphorus contents.

• The Journal of Advanced Prosthodontics
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• 제10권4호
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• pp.300-307
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• 2018

PURPOSE. To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS. Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: $3000{\times}5^{\circ}C/3000{\times}55^{\circ}C$; ML: $1.2{\time}10^6$ cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, ${\alpha}=.05$). RESULTS. All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between $1214{\pm}293N$ (NPT) and $1324{\pm}498N$ (NGT), differing significantly ($P{\leq}.003$) from the polished reference EPT ($2044{\pm}302N$). Fracture forces in implant groups varied between $934{\pm}154N$ (NGI_L) and $1782{\pm}153N$ (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant ($P{\geq}.066$) between crowns of identical materials and abutment support. CONCLUSION. Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.

• 구강회복응용과학지
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• 제17권2호
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• pp.107-112
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• 2001

The prosthodontic treatment of severely resorbed edentulous patients has been one of the frustrating areas due to extensive loss of tissues. The integrated neuromuscular balance among tongue, lip, and cheek is compromised. The retention, stability, and support are the three major factors to influence the clinical outcome. Fish described a denture as having three surface, with each surface playing an independent and important role in the over all fit, stability, and comfort of the denture. He recommended that the polished surface should be a series of inclines so that pressure from muscular activity will retain dentures. Within the denture space there is an area that has been termed the neutral zone. The neutral zone is that area in the mouth where, during function, the forces of the tongue pressing outward are neutralized by the forces of the cheeks and lips pressing inward. According to Jacobson and Krol, neuromuscular control interacts to provide retention and the relationship of polished surface of denture base to the surrounding muscular structure of orofacial capsule facilitates the stability and retention. This neutral zone concept has been demonstrated with various modification by a number of authors. The theory used to develop the denture base contours is based on the belief that the muscle should functionally mold not only the border but the entire polished surface. Lott and Walsh reported the clinical success on complete mandibular dentures with application of neutral zone concept. A number of studies demonstrated that denture stability and retention are more dependent on correct position of the teeth and correct contour of external surfaces of the denture in a severely resorbed alveolar ridge. This article presents a prosthodontic approach to treatment of a edentulous patient using neutral zone technique to improve the retention and stability of the prosthesis.