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변상기,장성규,이충엽,전언찬 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.2
Cuttingability of carbide step drill is highly progressing the step drill with more then twice diameter rate is so difficult in regrinding and very easy to damage during machining. As the machining of step drill for blind hole is occur to breakage at small diameter position, so it is very difficult to machining. In this experiments, we investigate roundness and surface roughness by machining distance and were identified that the first distance, 5∼10m, was fine with 7㎛ but the around of 15m was happened so much alternation. And we were identified that after 20m was happend stable machining. The surface roughness was happened the same conditions. So application of step drill, we think that the selection of cutting conditions need lots consideration and the study of step drill's diameter ratio is carried out.
3차원 유한요소법적 분석을 이용한 5종의첨형 임플랜트에 발생하는 응력의 비교연구
변상기,박원희,이영수,Byun, Sang-Ki,Park, Won-Hee,Lee, Young-Soo 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.5
Statement of problem : Dental implant which has been developed gradually through many experiments and clinical applications is presently used to various dental prosthetic treatments. To conduct a successful function of implant prosthesis in oral cavity for a long time, it is important that not only structure materials must have the biocompatibility, but also the prosthesis must be designed for the stress, which is occurred in occlusion, to scatter adequately of load support. Therefore, it is essential to give the consideration about the stress analysis of supporting tissues for higher successful rates. Purpose : Recently, many implant manufacturing company produce various taper design of root form implant, the fixture is often selected. However, the stress analysis of taper form fixture still requires more studies. Material and method : This study we make the element models that five implant fixture; Branemark system(Nobel Biocare, Gothenberg, Sweden), Camlog system(Altatec, Germany), Astra system(Astra Tech, Sweden), 3i system(Implant Innovations Inc, USA), Avana system(Osstem, Korea) were placed in the area of mandibular first premolar and prosthesis fabricated, which we compared with stress distribution using the three-dimension finite element analysis under two loading condition. Results : This study compares the aspect of stress distribution of each system with the standard of Von mises stress, among many resulted from finite element analysis so that this research gets the following results. 1. In all implant system, oblique loading of maximum Von mises stress of implant, alveolar bone and crown is higher than vertical loading of those. 2. Regardless of loading conditions and type of system, cortical bone which contacts with implant fixture top area has high stress, and cancellous bone has a little stress. under the vertical loading, maximum Von mises stress is more higher in order of Branemark, Camlog, Astra, 3i, Avana. under the horizontal loading, maximum Von mises is more higher in order of Camlog, Branemark, Astra, 3i, Avana.