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Uhm, Soo-Hyuk,Kim, Jae-Hong,Jiang, Heng Bo,Woo, Chang-Woo,Chang, Minho,Kim, Kyoung-Nam,Bae, Ji-Myung,Oh, Seunghan JAPANESE SOCIETY FOR DENTAL MATERIALS AND DEVICES 2017 Dental materials journal Vol.36 No.1
<P>The aims of this study were to evaluate the feasibility of 70% reduced inlay and 4-unit bridge models of International Standard (ISO 12836) assessing the accuracy of laboratory scanners to measure the accuracy of intraoral scanner. Four intraoral scanners (CS3500, Trios, Omnicam, and Bluecam) and one laboratory scanner (Ceramill MAP400) were used in this study. The height, depth, length, and angle of the models were measured from thirty scanned stereolithography (STL) images. There were no statistically significant mean deviations in distance accuracy and precision values of scanned images, except the angulation values of the inlay and 4-unit bridge models. The relative errors of inlay model and 4-unit bridge models quantifying the accuracy and precision of obtained mean deviations were less than 0.023 and 0.021, respectively. Thus, inlay and 4-unit bridge models suggested by this study is expected to be feasible tools for testing intraoral scanners.</P>
Uhm, Soo-Hyuk,Lee, Sang-Bae,Song, Doo-Hoon,Kwon, Jae-Sung,Han, Jeon-Geon,Kim, Kyoung-Nam American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.10
<P>We investigated whether a silver coating on an anodic oxidized titania (TiO2) nanotube surface would be useful for preventing infections in dental implants. We used a magnetron sputtering process to deposit Ag nanoparticles onto a TiO2 surface. We studied different sputtering input power densities and maintained other parameters constant. We used scanning electron microscopy, X-ray diffraction, and contact angle measurements to characterize the coated surfaces. Staphylococcus aureus was used to evaluate antibacterial activity. The X-ray diffraction analysis showed peaks that corresponded to metallic Ag, Ti, O, and biocompatible anatase phase TiO2 on the examined surfaces. The contact angles of the Ag nanoparticle-loaded surfaces were significantly lower at 2.5 W/cm2 input power under pulsed direct current mode compared to commercial, untreated Ti surfaces. In vitro antibacterial analysis indicated that a significantly reduced number of S. aureus were detected on an Ag nanoparticle-loaded TiO2 nanotube surface compared to control untreated surfaces. No cytotoxicity was noted, except in the group treated with 5 W/cm2 input power density, which was the highest input of power density we tested for the magnetron sputtering process. Overall, we concluded that it was feasible to create antibacterial Ag nanoparticle-loaded titanium nanotube surfaces with magnetron sputtering.</P>
엄수혁(Soo-Hyuk Uhm),권재성(Jae-Sung Kwon),이정환(Jung-Hwan Lee),이은정(Eun-Jung Lee),김경남(Kyoung-Nam Kim) 대한치과의사협회 2014 대한치과의사협회지 Vol.52 No.12
Since the introduction of non thermal atmospheric pressure plasma in the field of the dentistry, numerous applications have been investigated. Especially with its advantages over existing vacuum plasma in terms of portability, low cost, and non thermal damage, it can be directly applied in the oral cavity, giving number of potentials for dental application. First, possible application of non thermal atmospheric pressure plasma in the field of dentistry is relation to dental caries and periodontal diseases. Teeth and alveolar bones are one of the strongest bony structures in our body, but it cannot be regenerated when they are damaged by dental caries or periodontal disease. Hence many studies to prevent such diseases have been carried out, though no perfect solution has been found yet. With recent studies of modifying surfaces through non thermal atmospheric pressure application that can prevent attachment of bacteria, or studies on bactericidal effects of non thermal atmospheric pressure plasma can be applied here to prevent oral pathogen and ‘biofilm’ attachment to the surface of teeth or directly eliminate the dental caries/periodontal disease causing germs. Secondly, non thermal atmospheric pressure application will be useful on the surface of dental implant. It is well known that the success of dental implant surgery depends on the process known as ‘osseointegration’ that result from osteoblast attachment, proliferation and differentiation. As the application of non thermal atmospheric pressure plasma on the surface of dental implant just before its introduction by the chair side of dental surgery. Despite its long history, the generation of non thermal atmospheric pressure plasma has been greatly increased with its application in dentistry.
Seo, Sang-Hee,Uhm, Soo-Hyuk,Kwon, Jae-Sung,Choi, Eun Ha,Kim, Kwang-Mahn,Kim, Kyoung-Nam American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.3
<P>Titanium oxide nanotube layer formed by plasma electrolytic oxidation (PEO) is known to be excellent in biomaterial applications. However, the annealing process which is commonly performed on the TiO2 nanotubes cause defects in the nanotubular structure. The purpose of this work was to apply a non-thermal atmospheric pressure plasma jet on diameter-controlled TiO2 nanotubes to mimic the effects of annealing while maintaining the tubular structure for use as biomaterial. Diameter-controlled nanotube samples fabricated by plasma electrolytic oxidation were dried and prepared under three different conditions: untreated, annealed at 450 °C for 1 h in air with a heating rate of 10 °C/min, and treated with an air-based non-thermal atmospheric pressure plasma jet for 5 minutes. The contact angle measurement was investigated to confirm the enhanced hydrophilicity of the TiO2 nanotubes. The chemical composition of the surface was studied using X-ray photoelectron spectroscopy, and the morphology of TiO2 nanotubes was examined by field emission scanning electron microscopy. For the viability of the cell, the attachment of the osteoblastic cell line MC3T3-E1 was determined using the water-soluble tetrazolium salt assay. We found that there are no morphological changes in the TiO2 nanotubular structure after the plasma treatment. Also, we investigated a change in the chemical composition and enhanced hydrophilicity which result in improved cell behavior. The results of this study indicated that the non-thermal atmospheric pressure plasma jet results in osteoblast functionality that is comparable to annealed samples while maintaining the tubular structure of the TiO2 nanotubes. Therefore, this study concluded that the use of a non-thermal atmospheric pressure plasma jet on nanotube surfaces may replace the annealing process following plasma electrolytic oxidation.</P>
Park, Da-Ryeong,Uhm, Soo-Hyuk,Kim, Kyung-Nam,Bae, Ji-Myung,Kim, Jeong-Mi,Jung, Soo-Ha,Kim, Jae-Hong,Oh, Seunghan American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11
<P>Zirconia-based restoration has been used for obtaining high compressive strength and excellent esthetics, even though it exhibits technical complications with delamination and/or porcelain chipping from the zirconia core. The shear bond strength between the zirconia core and the veneer ceramic plays a critical role in the longevity and sustainability of the zirconia-based restoration. This study aims at evaluating the effects of surface treatment based on a selective infiltration etching (SIE) technique using a mixture comprised of zirconia nanoparticles and a glass conditioner on the shear bond strength between the zirconia core and the veneer ceramic with 20,000 times of thermocycling. Examinations of the surfaces and the shear bond strengths of five different samples having different amounts of zirconia nanoparticles and the glass conditioner (60, 70, 80, 90, and 100 wt% of glass conditioner) were carried out in order to determine the optimum mixing ratio. Field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX) analyses indicated that the zirconia nanoparticles were well dispersed in the samples with 80 and 90 wt% glass conditioner. The thickness of the interfacial layer was found to be similar to 200 mu m. Shear bond strength test with 20,000 times of thermocycling resulted that the strength value of 80, 90, and 100 wt% glass conditioner groups were significantly higher than that of the control and 60 and 70 wt% glass conditioner groups. Bonding deterioration on thermocycling was not observed on the SIE treated samples. Thus, SIE with zirconia nanoparticles is expected to be a reliable surface treatment method in order to activate the surface of the zirconia block and improve the bond strength between the zirconia core and the veneer ceramic.</P>