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IV형 경석고와 경화처리된 IV형 경석고 그리고 폴리우레탄 수지 치형재의 표면경도와 미세구조 특성의 비교
이완선,김지환,김태석,김남식,유진호,Lee, Wan-Sun,Kim, Ji-Hwan,Kim, Tae-Suk,Kim, Nam-Sic,Yu, Chin-Ho 대한치과기공학회 2012 대한치과기공학회지 Vol.34 No.3
Purpose: This study compared the surface hardness (Vickers) and microstructural characteristics between a type IV stone with and without die hardening treatment, a polyurethane die material. Methods: Materials used were a type IV stone(MG Crystal Rock), two die hardeners (Hardening bath, Epox-it), and a polyurethane resin material(Polyluck). Six specimens per group were prepared according to manufacturer's directions. The prepared specimens were tested by means of hardness test, one-way ANOVA analysis, scanning electron microscopic(SEM) observations and energy dispersive spectroscopic(EDS) analysis. Results: In the hardness test and its statistical analysis, there was no significant difference in the surface hardness between a type IV stone and type IV stone with die hardener coating, type IV stone mixed with an epoxy like material instead of water. In contrast, polyurethane resin material exhibited significantly greater surface hardness than other specimen groups (p<0.05). Conclusion: By considering the results of the hardness test, SEM observations and EDS analysis, although the die hardeners on type IV stone did not show remarkable improvement in surface hardness, the die hardener coating on the surface of type IV stone material did show decrease of microporous and improvement of surface defects.
Evaluation of internal fit of interim crown fabricated with CAD/CAM milling and 3D printing system
이완선,이두형,이규복 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.4
PURPOSE. This study is to evaluate the internal fit of the crown manufactured by CAD/CAM milling method and 3D printing method. MATERIALS AND METHODS. The master model was fabricated with stainless steel by using CNC machine and the work model was created from the vinyl-polysiloxane impression. After scanning the working model, the design software is used to design the crown. The saved STL file is used on the CAD/CAM milling method and two types of 3D printing method to produce 10 interim crowns per group. Internal discrepancy measurement uses the silicon replica method and the measured data are analyzed with One-way ANOVA to verify the statistic significance. RESULTS. The discrepancy means (standard deviation) of the 3 groups are 171.6 (97.4) μm for the crown manufactured by the milling system and 149.1 (65.9) and 91.1 (36.4) μm, respectively, for the crowns manufactured with the two types of 3D printing system. There was a statistically significant difference and the 3D printing system group showed more outstanding value than the milling system group. CONCLUSION. The marginal and internal fit of the interim restoration has more outstanding 3D printing method than the CAD/CAM milling method. Therefore, the 3D printing method is considered as applicable for not only the interim restoration production, but also in the dental prosthesis production with a higher level of completion.
Evaluation of different approaches for using a laser scanner in digitization of dental impressions
이완선,김웅철,김혜영,김욱태,김지환 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.1
PURPOSE. This study aimed to investigate the potential clinical application of digitized silicone rubber impressions by comparing the accuracy of zirconia 3-unit fixed partial dentures (FPDs) fabricated from 2 types of data (working model and impression) obtained from a laser scanner. MATERIALS AND METHODS. Ten working models and impressions were prepared with epoxy resin and vinyl polysiloxane, respectively. Based on the data obtained from the laser scanner (D-700; 3Shape A/S, Copenhagen, Denmark), a total of 20 zirconia frameworks were prepared using a dental CAD/CAM system (DentalDesigner; 3shape A/S, Copenhagen, Denmark / Ener-mill, Dentaim, Seoul, Korea). The silicone replicas were sectioned into four pieces to evaluate the framework fit. The replicas were imaged using a digital microscope, and the fit of the reference points (P1, P2, P3, P4, P5, P6, and P7) were measured using the program in the device. Measured discrepancies were divided into 5 categories of gaps (MG, CG, AWG, AOTG, OG). Data were analyzed with Student’ t-test (α=0.05), repeated measures ANOVA and twoway ANOVA (α=0.05). RESULTS. The mean gap of the zirconia framework prepared from the working models presented a narrower discrepancy than the frameworks fabricated from the impression bodies. The mean of the total gap in premolars (P=.003) and molars (P=.002) exhibited a statistical difference between two groups. CONCLUSION. The mean gap dimensions of each category showed statistically significant difference. Nonetheless, the digitized impression bodies obtained with a laser scanner were applicable to clinical settings, considering the clinically acceptable marginal fit (120 μm).
이완선,김소연,김지환,김웅철,김혜영 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.5
PURPOSE. The purpose of this study is to mix dental ceramic powder in varying ratios and evaluate the effect of the mixing ratio on color and translucency. MATERIALS AND METHODS. The ceramic powder of shade A3 of the same product was mixed with the shade A2 of three products: IPS e.max Ceram (Ivoclar Vivadent, Schaan, Liechtenstein), Vintage Halo (SHOFU Inc., Kyoto, Japan), and Ceramco 3 (Ceramco-Dentsply, Burlington, NJ, USA) in the following fixed ratios (0 wt%, 25 wt%, 50 wt%, 75 wt%, and 100 wt%) and then fired. A total of 150 specimen of ceramic fired were manufactured in a regular size (W: 8.5 mm, L: 10.5 mm, and H: 1.5 mm). For color and translucency, L*, a*, and b* were measured and Two-way analysis of variance (ANOVA) and One-way analysis of variance (ANOVA) were used for data analysis (α=0.05). RESULTS. The higher the mixing ratio was, L*, a*, and b* of IPS e.max Ceram were all increased, and L* of Vintage Halo was reduced and a* and b* were increased. L* and a* of Ceramco3 were reduced and b* of Ceramco3 was increased. Color difference (ΔE*ab) was increased in all three products as the mixing ratio got higher. Increased mixing ratios resulted in decreased translucency parameter (TP) values for IPS e.max Ceram but increased TP values for Vintage Halo and Ceramco3. CONCLUSION. In this limited study, CIE L*, a*, and b* were influenced by the mixing ratio of the A3 powders and porcelain powder mixtures represented a various color and translucency.
이완선,유미애,조환규 한국생명과학회 2002 생명과학회지 Vol.12 No.4
The difficulties in dealing with the Bioinformatics data come more from its idiosyncrasies than from its quantity Currently researchers need to an easy method for data exchange, manage, update. In order to integrate and manage all kinds of biological data, it is reasonable to adopt XML as standard tool since XML is independent of operating system, programming language and hardware platform. Although XML in Bioinformatics has been used widely as a standard notation abroad, however it is the beginning step in the domestic research. This article reviews a basic concept of XML and how to apply XML modeling in Bioinformatics. In addition we present XML applications for genomic sequences, structures and genetic network modeling.