자석어태치먼트 sealing용 스테인리스강의 표면개질

모웅남,이용준 조선대학교 구강생물학연구소 2003 口腔生物學硏究 Vol.27 No.1

Dental magnetic attachment have been applied to removable prosthetic appliances, maxillofacial prostheses, obturator and dental implant but they still have some problems such as low corrosion resistance in oral environments. To increase the corrosion resistance of dental magnetic materials, Nd-Fe-B materials were sealed with stainless steel, but pitting corrosion, intergranular corrosion and erosion corrosion occurred predominantly at welded zone and center of magnetic attachment in corrosive environment and mechenical wear condition. In order to develop corrosion resistance of magnetic materials, the surface modification of stainless steel for magnetic attachment sealing materials were investigated by utilizing potentiostat. Stainless steels containig 0.1~1.0 wt%Ti were fabricated with 12㎜ thickness by using vacuum furnace and roller. An then stainless steel were solutionized for 1hr at 1050℃. Samples were ion nitrided at 380℃ and 500℃ for 10, 20, and 30hrs. Electrochemical corrosion test were performed in 2 kinds of electrolyte solutions (0.9% NaCl, and 0.1MH_2S0. The surface and corrosion morphology of ion nitrided stainless steel were analyzed by utilizing optical microscopy SEM, XRD and WDX. It was found that Plasma nitriding at 380℃ compared with 500℃, Produced a good corrosion resistance as nitriding time increased. whereas stainless steel containing low Ti content showed that Pitting potential and corrosion potential decreased. Pitting corrosion resistance improved significantly in the case of plasma nitrided SS containing 100.0wt% Ti at 500℃ because that Ti act to retard the formation of carbides and to form a protective layer on surface which is responsible for the aggresive Clion. The nucleation rate and number of pit in the plasma nitriding at 500℃ decreased as Ti content increased owing to retard a nucleation and growth of chromium carbide or nitride in gram boundary.

전자빔 진공증착을 이용한 치과용 임플란트재의 표면 전처리법에 따른 HA코팅효과

모웅남,이용준 조선대학교 구강생물학연구소 2003 口腔生物學硏究 Vol.27 No.1

The dental implant materials required good mechanical roperties, such as fatigue strength, combined with a high resistance to corrosion. For increasing fatigue resistance and delaying onset of stress corrosion cracking, shot peening has been used for > 50 years to extend service life of metal components. However, there is no information on the electrochemical behavior of shot peened and hydroxyapatite(HA) coated Ti-6Al-4V alloys. To increase fatigue strength, good corrosion resistance , and biocompatibility, the electrochemical characteristics of Ti/TiN/HA coated and shot peened Ti-6Al-4V alloys by EB-PVD have been researched by various electrochemical method in 0.9.%NaCl. The coated layer and surface showed the formation of dense and uniform surface in the case of TiN/HA and Ti/TiN/HA ftlm coated samples. The hardness of shot peened Ti-6Al-4V alloys(SPA) increased as SP treatment time increased. Electrochemical measurements showed that, in the case of shot Peened Ti-6Al-4V alloys, the corrosion and pitting potential increased due to the SP induced removal of defects, such as inclusion, scratch, and pore on the surface, whereas passivation and active current density decreased as the SP time increased. For the HA coated samples, pitting and repassivation potential increased in the order of Ti/TiN/HA > TiN/HA > Ti/HA > HA coated SPA. Results suggest that the best pitting corrosion behavior is shown by Ti/TiN/HA coated SPA with a fatigue strength and biocompatability.

레이저가공법으로 제조된 치과용 골 고정판의 표면특성

모웅남,최한철,고영무 대한치과재료학회 2005 대한치과기재학회 학술대회 Vol.2005 No.11

키토산을 첨가한 콤포짓트 레진의 기계적 성질과 항균성에 관한 연구

최낙찬,모웅남,이용준 조선대학교 구강생물학연구소 2003 口腔生物學硏究 Vol.27 No.1

The purpose of this study was to evaluate the mechanical and anti-microbial properties of newly prepared chitosan G for human gingival fibroblast. Compressive strength, diametral tensile strength and tensile strength of specimens of resin composite, with or without chitosan G incorporated, were measured. Using a SEM (S-4700, Hitach, Japan), pictures of microbes were taken and adherent capability of microbes to the surface of resin composite was investigated. The results were as follows; 1. The values of compressive strength, diametral tensile strength and tensile strength, composite resin containing 7㎎/㎖ chitosan G were higher than the control group(p>0.05) but composite resin containing 40 ㎎/㎖ chitosan G were either the same or lower than the control group(P<0.05) 2. The MIC of newly prepared chitosan G for S mutans KCTC 3065 and C albicans KCTC 7965 were more than 2 ㎎/㎖. 3. The adherent capability of microbes significantly decreased as the amount of chitosan G increased in the test specimens compared to the control group for C aibicans KCTC 7965 (P<0.05) but there was no statistical significance for S mutans KCTC 3065(p>0.05) . 4. The cytotoxicity of newly prepared chitosan G for human gingival fibroblast was not showed. In conclusion, resin composite with chitosan G incorporated did not show any statistically significant difference for mechanical properties (p>0.05) but it showed a significant antimicrobial effect against C albicans (P<0.05).

최과 교정용 스테인리스 강 선재의 신선 가공법이 내식성에 미치는 영향

고영무,모웅남,최한철 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.1

The dental orthodontic wire requires good mechanical properties, such as elastic strength, combined with a high resistance to corrosion. For increasing elastic strength and delaying onset of stress corrosion cracking, drawing methods(one-step and two-step drawing) have been used in this study to extend service life of metal components, However, there is no information on the electrochemical corrosion behavior of drawn wires for orthodontics. To increase elastic strength, good corrosion resistance, and biocompatibility, the electrochemical characteristics of drawn wire have been researched by field emission scanning microscope and potentiodynamic method in 0.9% NaCl solution. The one-step drawn wire showed the formation of rough surface. The hardness and tensile strength of two-step drawn wire increased. Electrochemical measurements showed that, in the case of two-step drawn wire, the corrosion resistance and pitting potential increased compared with two-step drawn wire due to the drawing induced small surface roughness, such as scratch, whereas passivation and active current density decreased as the reduction in area for drawing increased.

스테인리스강 소결체를 이용한 치과용 임플란트 개발(Ⅰ) : 치과용 소결체의 제작과 물성을 중심으로 Fabrication and Physical Properties of Sintered Stainless Steel

최한철,고영무,모웅남 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.3

The first factor to decide the success of dental implantation is sufficient, osseointegration between implant fixture and its surrounding bone tissue. Thus many studies about this have been under actively. In recent, one of them is to increase the roughness of the surface of an implant fixture by treating the surface of an implant fixture in various ways, increase the contact area between an implant fixture and its surrounding bone tissue and so induce a sufficient osseointegration between them. The roughness of the surface on an implant fixture can be increased by coating the smooth surface of an implant fixture with hydroxyapatite or titanium particles or by treating the surface with acid. But these ways can cause the failure of implantation in the long run due to the separatation of coated particles from an implant fixture and sometime; can't attain the sufficient osseointegration because of emitting ion into the surrounding bone tissue. To develop dental implant materials, fabrication and physical properties of sintered stainless steel have studied using hardness tester, tensile tester, SEM, TEM, EPMA, EDX. Stainless steel compacts containing Cu (2-10 wt%) were prepared either by electroless Cu-plating method which result in the increased homogenization in alloying powder or by Cu-elemental powder addition method on the stainless steel powder Experimental investigation foucusing on mechanical property was performed for Cu-added samples to study the effects of Cu content, electroless Cu-plating method, and Cu-elemental powder addition method on the surface characteristics of sintered stainless steel in Mo and Cu in sintered stainless steel on the mechanical behaviors. Microstructural characterization revealed that Cu-addition by electroless Cu-plating method resulted in less porous material compared that prepared by Cu-elemental powder addition method. Since Cu is blown to be effective in reducing the precipitation of chromium carbide at sensitization temperature, Cr concentration in electroless Cu-plating method was uniformly distributed in the grain boundary and in the matrix. The sintered density in electroless Cu-plating method increased with reducing porosity as a result of the Cu-uniform distribution due to electroless Cu plating during the sintering process. The amount of Cu added in the sintered stainless steel affected significantly tensile strength which increased with 4 wt% Cu and decreased with more than 7 wt% Cu.

레이저가공으로 제조된 골 고정판의 표면특성에 미치는 TiN코팅의 영향

김진수(Jin-Soo Kim),모웅남(Woong-Nam Mo),배현숙(Hyun-Sook Bae),최한철(Han-Cheol Choe),고영무(Yeong-Mu Ko) 대한치과재료학회 2005 대한치과재료학회지 Vol.32 No.4