Iijima Masahiro, Muguruma Takeshi, Brantley William A, Okayama Miki, Yuasa Toshihiro, Mizoguchi Itaru
Division of Orthodontics and Dentofacial Orthopedics, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-tobetsu, Hokkaido, Japan.
Am J Orthod Dentofacial Orthop. 2008 Sep;134(3):333.e1-6; discussion 333-4. doi: 10.1016/j.ajodo.2008.03.012.
Titanium miniscrew implants are popular in orthodontics, but there is little information about their torsional performance.
Four brands of miniscrew implants (A-D) with 1.6-mm diameters were compared, with miniscrew A implants also having diameters of 1.2 to 2.0 mm. Nominal compositions of the implants were determined by x-ray fluorescence (n = 8). The miniscrews were loaded to failure in torsion, and the mean moment and twist angle were determined for each group (n = 8). Data were compared by ANOVA and the Tukey multiple range tests. Micro x-ray diffraction (n = 3) was used to identify phases in the implants, and the phases were also examined in etched cross-sections with a scanning electron microscope.
Miniscrew A and C implants were pure titanium, whereas miniscrew B and D implants contained small amounts of vanadium, aluminum, iron, and manganese. Only alpha-titanium peaks were detected for all implants by micro x-ray diffraction, but beta titanium was observed in the microstructures of miniscrew B and D implants, which had significantly higher torsional moments at failure.
Addition of small amounts of other elements to titanium yielded significantly improved torsional performance for miniscrew implants. Research to develop optimum compositions for mechanical properties and biocompatibility is needed.
钛微螺钉种植体在正畸领域很受欢迎，但关于其扭转性能的信息却很少。
比较了四种直径为1.6毫米的微螺钉种植体（A - D），其中微螺钉A种植体的直径还有1.2至2.0毫米。通过X射线荧光分析确定种植体的标称成分（n = 8）。将微螺钉加载至扭转破坏，测定每组的平均扭矩和扭转角度（n = 8）。数据通过方差分析和Tukey多重范围检验进行比较。使用微X射线衍射（n = 3）识别种植体中的相，并通过扫描电子显微镜在蚀刻的横截面中检查这些相。
微螺钉A和C种植体为纯钛，而微螺钉B和D种植体含有少量钒、铝、铁和锰。通过微X射线衍射在所有种植体中仅检测到α钛峰，但在微螺钉B和D种植体的微观结构中观察到β钛，其在破坏时具有明显更高的扭矩。
向钛中添加少量其他元素可显著提高微螺钉种植体的扭转性能。需要开展研究以开发具有最佳机械性能和生物相容性的成分。
