• The Journal of Advanced Prosthodontics
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• 제11권2호
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• pp.81-87
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• 2019

PURPOSE. The purpose of this study was to evaluate the effects of various protocols and systems for finishing and polishing monolithic zirconia on surface topography, phase transformation, and bacterial adhesion. MATERIALS AND METHODS. Three hundred monolithic zirconia specimens were fabricated and then treated with three finishing and polishing systems (Jota [JO], Meisinger [ME], and Edenta [ED]) using four surface treatment protocols: coarse finishing alone (C); coarse finishing and medium polishing (CM); coarse finishing and fine polishing (CF); and coarse finishing, medium polishing, and fine polishing (CMF). Surface roughness, crystal phase transformation, and bacterial adhesion were evaluated using atomic force microscopy, X-ray diffraction, and streptococcal biofilm formation assay, respectively. One-way and two-way analysis of variance with Tukey post hoc tests were used to analyze the results (${\alpha}=.05$). RESULTS. In this study, the surface treatment protocols and systems had significant effects on the resulting roughness. The CMF protocol produced the lowest roughness values, followed by CM and CF. Use of the JO system produced the lowest roughness values and the smallest biofilm mass, while the ME system produced the smallest partial transformation ratio. The ED group exhibited the highest roughness values, biofilm mass, and partial transformation ratio. CONCLUSION. Stepwise surface treatment of monolithic zirconia, combined with careful polishing system selection, is essential to obtaining optimal microstructural and biological surface results.

• The Journal of Advanced Prosthodontics
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• 제9권2호
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• pp.138-142
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• 2017

In restorative treatment using fixed dental prostheses, dentists should select appropriate restoration material among various types of dental materials. The strength, marginal fit, esthetics, wear resistance, biocompatibility, and cost are important factors in the choice of restoration materials. The present case showed a surface stain on a monolithic zirconia restoration that was due to wear between the monolithic zirconia restoration and the base metal alloy restoration. This phenomenon was confirmed by surface roughness measurement and electron probe micro-analysis.

• Journal of Pharmaceutical Investigation
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• 제19권2호
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• pp.87-92
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• 1989

The multilayered monolithic type transdermal delivery device has been designed and analyzed by a numerical analysis. The device consists of three layered polymer matrices which posess the different diffusion parameters, respectively. The purpose of this study was to design an ideal transdermal drug delivery device which is capable of initial burst and zero order release later on. Numerical modelings were simulated for a dispersed and a dissolved multilayered monolithic system. The results showed that the dispersed multilayered monolithic system could meet the requirements for an ideal transdermal delivery device.

• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.296-304
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• 2013

PURPOSE. The aim of this study was to evaluate the effect of polishing and glazing on the color and spectral distribution of monolithic zirconia. MATERIALS AND METHODS. Forty-five monolithic zirconia specimens ($16.3mm{\times}16.4mm{\times}2.0mm$) were fabricated and divided into 5 groups according to the number of A2-coloring liquid applications (Group I to V). Each group was divided into 3 subgroups according to the method of surface treatments (n=3): N: no treatment; P: polishing; G: glazing. Color and spectral distribution of five different areas of each specimen were measured according to CIELAB color space in the reflectance mode relative to the standard illuminant D65 on a reflection spectrophotometer. Data were analyzed using one-way ANOVA followed by Tukey's HSD test, Pearson correlation and regression analysis (${\alpha}$=.05). RESULTS. There was a significant difference in CIE $L^*$ between Subgroup N and P, and in CIE $b^*$ between Subgroup P and G in each group. Spectral reflectance generally decreased in Subgroup P and G in comparison with Subgroup N. Color differences between Subgroup P and G were within the perceptibility threshold (${\Delta}E{^*}_{ab}$ < 3.7) in most groups. Highly significant correlation was found between CIE $b^*$ and each subgroups as the number of coloring liquid applications increased ($R^2$ >0.88, P<.001). CONCLUSION. A perceptible color difference can be detected after polishing of monolithic zirconia. Polishing decreases the lightness, and glazing also decreases the lightness, but increases the yellowness of monolithic zirconia.

• 대한치과기공학회지
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• 제41권3호
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• pp.187-193
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• 2019

Purpose: The purpose of this study was to compare two-dimensional fitness of the monolithic zirconia prosthesis by using different type of scanner. Methods: No. 26 abutment tooth of FDI system was selected for the study. Using the extraoral scanner and intraoral scanner, the abutment tooth was scanned 10 times and the scanned files were saved as STL files. CAD/CAM system was used to produce the monolithic zirconia prosthesis. marginal and internal gap of the monolithic zirconia prosthesis were measured by digital microscope(x160) and applied silicone replica technique was applied. t-test, a statistical software, was used to perform data analysis. Results: Marginal gap $mean{\pm}SD$ of the monolithic zirconia prosthesis was $33{\pm}7.5{\mu}m$ with extra oral scanner and $34.7{\pm}11.1{\mu}m$ with intraoral scanner. axial gap mean was $40.5{\pm}3.5{\mu}m$ with extra oral scanner and $44.6{\pm}11.6{\mu}m$ with intraoral scanner. occlusal gap mean was $110.1{\pm}25.4{\mu}m$ with extra oral scanner and $64{\pm}9.7{\mu}m$ with intraoral scanner. Conclusion: In this study, fabricating zirconia prosthesis with different type of scanner was clinically applicable.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3233-3240
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• 2012

We demonstrated the combined applications of online protein digestion using trypsin immobilized enzyme reactor (IMER) and dual tandem mass spectrometry with collisionally activated dissociation (CAD) and electron transfer dissociation (ETD) for tryptic peptides eluted through the trypsin-IMER. For the trypsin-IMER, the organic and inorganic hybrid monolithic material was used. By employing the trypsin-IMER, the long digestion time could be saved with little or no sacrifice of the digestion efficiency, which was demonstrated for standard protein samples. For three model proteins (cytochrome c, carbonic anhydrase, and bovine serum albumin), the tryptic peptides digested by the IMER were analyzed using LC-MS/MS with the dual application of CAD and ETD. As previously shown by others, the dual application of CAD and ETD increased the sequence coverage in comparison with CAD application only. In particular, ETD was very useful for the analysis of highly-protontated peptide cations, e.g., ${\geq}3+$. The combination approach provided the advantages of both trypsin-IMER and CAD/ETD dual tandem mass spectrometry applications, which are rapid digestion (i.e., 10 min), good digestion efficiency, online coupling of trypsin-IMER and liquid chromatography, and high sequence coverage.

• 한국세라믹학회지
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• 제34권11호
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• pp.1129-1138
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• 1997

Al2O3/20 vol%YAG composite containing equiaxed grains and Al2O3/20 vol%LaAl11O18 composite containing elongated grains were fabricated using Al2O3-Y2O3 composition and Al2O3-La2O3 composition, respectively, by hot-pressing. In order to investigate the influence of microstructural control of second phase on toughening effect of toughened ceramic composites, AE (acoustic emission) measurements have been coupled with fracture toughness experiments(SENB and SEPB method). A separation of the fracture toughness and analysis of toughening mechanism was possible using the AE technique. The fracture toughness of hot-pressed materials was estimated to be 3.2 MPam0.5 for monolithic alumina, 4.7 MPam0.5 for Al2O3/20 vol%YAG composite and 6.2 MPam0.5 for Al2O3/20 vol%LaAl11O18 composite. In monolithic Al2O3, toughening does not occur as a result of either microcracking or grain bridging, whereas, composites exhibit toughening effects by both microcracking in the frontal zone and gain bridging in the wake zone, resulting in an improvement of fracture toughness as compared with monolithic Al2O3. The fracture toughness of Al2O3/20 vol%LaAl11O18 composite is higher than that of Al2O3/20 vol%YAG composite. It may be attributed to the elongated microstructure of Al2O3/20 vol%LaAl11O18 composite, resulting relatively greater bridging effect.

• 한국연초학회지
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• 제32권1호
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• pp.35-40
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• 2010

This study was carried out to enhance the analytical methods of phenolic compounds in mainstream cigarette smoke using high efficiency column and RRLC(Rapid Resolution Liquid Chromatography) system, and to compare these methods. RRLC system offers significantly faster results with higher data quality of phenolic compounds than conventional HPLC, but it is disadvantage that it is expensive. On the other hand, the method using monolithic column offers faster results by the use of conventional HPLC system without new equipment introduction. In this study, we used the linear type smoking machine and Health Canada method for pre-treatment process of phenolic compounds. The analysis time of phenolic compounds using RRLC and monolithic column was individually 8 and 15 minutes, whereas in the conventional HPLC it was 45 minutes. These new methods were accompanied with the minimal solvent consumption and had lower analysis costs. Also, we proved that there were no difference between new methods and conventional method in accuracy by statistic.

• 대한치과보철학회지
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• 제57권4호
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• pp.321-327
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• 2019

목적: 본 연구는 단일구조 지르코니아 크라운의 소결 후 소성 과정이 변연 및 내면 적합도에 미치는 영향에 대하여 3차원으로 평가해 보고자 하였다. 재료 및 방법: 타이타늄 지대치 모형을 제작하여 10개의 단일구조 지르코니아 크라운을 제작하였다. 제작된 단일구조 지르코니아 크라운을 소결 한 상태를 대조군으로, 소결 후 광택을 위해 추가적인 소성단계를 거친 후를 실험군으로 설정하였다. 각 군에서 triple-scan protocol을 이용하여 협설과 근원심으로 단면을 형성하고 변연 및 내면 적합도를 계측하여 통계 분석하였으며, 삼차원 표면 비교를 시행하였다 (${\alpha}=.05$). 결과: 변연과 내면 적합도를 분석한 결과 근심 축벽에서 대조군($32.0{\pm}24.3{\mu}m$)과 실험군 간($17.0{\pm}10.8{\mu}m$)의 통계적 유의한 차이가 있었고 (P < .020), 원심 축벽에서 대조군($60.2{\pm}24.3{\mu}m$)과 실험군($71.8{\pm}21.5{\mu}m$)간의 통계적으로 유의한 차이가 있었다 (P < .01). 나머지 측점지점에서는 통계적으로 유의한 차이가 없었다. 결론: 단일구조 지르코니아 크라운에서의 소결 후 추가적인 소성은 내면의 변형에 큰 영향을 미치지 않았고 임상적으로 허용 가능한 범위에 있었다.

• 한국세라믹학회지
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• 제37권7호
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• pp.617-624
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• 2000

Abnormal grain growth in alumina was investigated during sinter-HIP process for better understanding of pressure effect on microstructural development. Abnormal grain growth of monolithic alumina was observed near surface region rather than interior region of specimen. Finite element analysis was used to estimate the pressure distribution developed in the specimen. Pressure distribution analysis was in good agreement with grain size distributjion in the specimen. The results of finite element analysis provided that abnormal grain growth monolithic alumina was resulted from the inhomogeneous pressure distribution in the specimen. MgO addition in alumina was effective for the suppression of abnormal grain growth in alumina under inhomogeneous pressure distribution during sinter-HIP process.