Construction of the dental attachment manufacturing system made from the Fe-Pt-Nb magnetic alloy by CAD/CAM

研制出了由Fe-39.5mol%Pt-0.75mol%Nb磁性合金和磁性不锈钢组成的新型假体矫形器。Fe-Pt-Nb磁体具有与Sm-Co磁体相当的高能量积，并且具有优异的耐腐蚀性。Kanno等人展示了Fe-Pt磁铁合金牙科铸造的可能性。然而，Fe-Pt-Nb磁性合金的磁性能对铸造过程的热历史非常敏感。临床使用的磁性合金具有良好的研磨性。此外，如果磁性合金可以很容易地通过牙科CAD/CAM系统加工，就有可能避免与铸造时不可避免的熔化材料相关的问题。本研究对铸造Fe-Pt-Nb磁性合金和磁性不锈钢的磨削性能进行了评价，并与常规牙科铸造合金的磨削性能进行了比较。此外，采用积分有限元法对内、外帽模型的三维磁场进行了分析，确定了Fe-Pt磁体可移动冠桥系统的设计和磁化的最佳方法。在500 m min^<-1>时，固溶处理的Fe-Pt-Nb磁性合金与时效处理的Fe-Pt-Nb磁性合金的磨削速率无显著差异。在较高的磨削速度下，时效Fe-Pt-Nb磁性合金的磨削速率明显降低。结果表明，时效Fe-Pt-Nb磁性合金和不锈钢在低速下的磨削速率均高于常规铸造合金。当外帽顶厚度为1.5mm，外帽侧长度为4.0 ~ 3.5mm时，临床可获得最佳的吸引力。模型-1的吸引力优于模型-2.5。当磨牙咬合垂直尺寸较低时，两种模型中外帽顶的厚度比外帽边的长度更重要。少

New prosthetic appliances composed of outer and inner crowns, each made of Fe-39.5mol%Pt-0.75mol%Nb magnetic alloy and magnetic stainless steel, have been developed. The Fe-Pt-Nb magnet has high energy product almost equivalent to the Sm-Co magnet, and excellent corrosion resistance. Kanno et al. showed the possibility of dental casting of the Fe-Pt magnet alloy. However, there remains a problem that the magnetic properties of the Fe-Pt-Nb magnetic alloy are very sensitive to the thermal history of the casting process.Good grindability is desirable in magnetic alloys for clinical use. Furthermore, if the magnetic alloys could be readily machined by a dental CAD/CAM system, it would be possible to avoid problems related to melting the material, which are inevitable when casting. In this study, the grindability of the cast Fe-Pt-Nb magnetic alloy and the magnetic stainless steel was evaluated and compared with that of conventional dental casting alloys. Furthermore, using the integral el … More ement method, the 3-dimensional magnetic field of the outer and inner cap model were analyzed to determine the optimal method for the design and magnetization of removable crown and bridge system made of the Fe-Pt magnet.CONCLUSION1. There was no significant difference in the grinding rate between the solution treated and aged Fe-Pt-Nb magnetic alloys at 500 m min^<-1>. However, the grinding rate of aged Fe-Pt-Nb magnetic alloy was significantly lower at the higher grinding speeds.2. It was found that the grinding rate of the aged Fe-Pt-Nb magnetic alloy and the stainless steel were higher than those of conventional casting alloys at lower speed.3. When the thickness of outer cap top was 1.5mm and the length of outer cap side was 4.0-3.5mm, the optimum attractive force were obtained clinically.4. The attractive force of model-1 was more excellent than that of model-2.5. When the occlusal vertical dimension of the molar was low, it was suggested that the thickness of outer cap top was more important than the length of outer cap side in both models. Less