Fischer-Brandies Helge, Es-Souni Mohammed, Kock Norman, Raetzke Klaus, Bock Ole
Department of Orthodontics, University of Kiel, Germany.
J Orofac Orthop. 2003 Mar;64(2):88-99. doi: 10.1007/s00056-003-0062-8.
The aim of this study was to characterize five selected commercial NiTi archwires in terms of their transformation behavior, chemical composition, surface topography and mechanical properties (at temperatures of 22 degrees C, 37 degrees C and 60 degrees C).
The rectangular orthodontic archwires investigated were Neo Sentalloy F80 (GAC, Central Islip, NY, USA), 35 degrees C Thermo-Active Copper NiTi (A-Company/Ormco, Glendora, CA, USA), Rematitan "Lite" (Dentaurum, Pforzheim, Germany), Titanol SE S (Forestadent, Pforzheim, Germany) and Titanal (Lancer, San Marcos, CA, USA) in size 0.016" x 0.022". The chemical composition and surface topography were analyzed by energy dispersive X-ray spectroscopy using an analytical scanning electron microscope (XL30, EDAX SUTW Saphire Detector; Philips, Eindhoven, Netherlands). The transition temperatures were measured by means of differential scanning calorimetry (DSC; Perkin-Elmer Pyris 1, Perkin-Elmer, Fremont, CA, USA) in a range of - 80 degrees C to + 80 degrees C. The mechanical properties and their dependence on temperature were determined by means of 3-point bending tests. The binary archwire materials were characterized by a two-phase structure (NiTi matrix and Ni3Ti4 precipitates).
The SEM analyses revealed abradant residues in virtually all archwires, while DSC revealed complex transformation properties. In addition to the martensitic and austenitic transformations, an R-phase transformation was also detected. The bending tests showed pronounced loading and unloading plateaus. The martensitic archwires (Neo Sentalloy F80, 35 degrees C Thermo-Active Copper NiTi) were found to have a lower strength than the martensitic-austenitic (Rematitan "Lite") and the austenitic archwires (Titanol SE S, Titanal). With increasing temperature (in the range from 22 degrees C to 60 degrees C) a linear rise in the plateau forces was recorded.
When assessing the quality of archwires, account should be taken of the surface quality, as it is this that determines corrosion resistance, biocompatibility and friction characteristics. The mechanical properties depend on the initial state; moderate plateau forces and plateau moments can only be achieved with martensitic archwires. In contrast to conventional steel alloys, the strength characteristics are heavily dependent on temperature and need to be known if NiTi archwires are to be used to optimal effect. In addition, the superelastic plateau is used only partially, if at all, when minimum leveling is required.
本研究旨在从转变行为、化学成分、表面形貌和力学性能（在22摄氏度、37摄氏度和60摄氏度的温度下）方面对五种选定的商用镍钛弓丝进行表征。
所研究的矩形正畸弓丝为尺寸0.016英寸×0.022英寸的Neo Sentalloy F80（美国纽约州中央伊斯利普的GAC公司）、35摄氏度热激活铜镍钛（美国加利福尼亚州格伦多拉的A公司/奥美科公司）、Rematitan“Lite”（德国普福尔茨海姆的登泰克公司）、Titanol SE S（德国普福尔茨海姆的福雷斯塔登特公司）和Titanal（美国加利福尼亚州圣马科斯的兰瑟公司）。使用分析扫描电子显微镜（XL3, EDAX SUTW蓝宝石探测器；荷兰埃因霍温的飞利浦公司）通过能量色散X射线光谱分析化学成分和表面形貌。通过差示扫描量热法（DSC；美国加利福尼亚州弗里蒙特的珀金埃尔默Pyris 1型，珀金埃尔默公司）在-80摄氏度至+80摄氏度的范围内测量转变温度。通过三点弯曲试验确定力学性能及其对温度的依赖性。二元弓丝材料具有两相结构（镍钛基体和Ni3Ti4析出物）。
扫描电子显微镜分析显示几乎所有弓丝中都存在磨损残留物，而差示扫描量热法显示出复杂的转变特性。除了马氏体和奥氏体转变外，还检测到R相转变。弯曲试验显示出明显的加载和卸载平台。发现马氏体弓丝（Neo Sentalloy F80、35摄氏度热激活铜镍钛）的强度低于马氏体-奥氏体弓丝（Rematitan“Lite”)和奥氏体弓丝（Titanol SE S、Titanal）。随着温度升高（在22摄氏度至60摄氏度范围内），记录到平台力呈线性上升。
在评估弓丝质量时，应考虑表面质量，因为正是表面质量决定了耐腐蚀性、生物相容性和摩擦特性。力学性能取决于初始状态；只有马氏体弓丝才能实现适度的平台力和平台力矩。与传统钢合金不同，强度特性强烈依赖于温度，如果要最佳地使用镍钛弓丝，就需要了解这一点。此外，在需要最小整平的情况下，超弹性平台即使使用也只是部分使用。
