Effect of Ca contamination on apatite formation in a Ti metal subjected to NaOH and heat treatments
Effect of Ca contamination on apatite formation in a Ti metal subjected to NaOH and heat treatments
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Ca 污染对经 NaOH 和热处理的 Ti 金属中磷灰石形成的影响
DOI：
10.1007/s10856-012-4837-6
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
T. Kokubo
中科院分区：
文献类型：
--
作者：
T. Kizuki;H. Takadama;T. Matsushita;Takashi Nakamura;T. Kokubo
长期以来，已知钛（Ti）金属通过在其预先经受NaOH和热处理并且结果在其表面上形成钛酸钠之后在活体中在其表面上形成的磷灰石层而结合到活体骨。这些治疗应用于全髋关节上的多孔钛金属层，所得关节自2007年以来一直在临床使用。它也已被证明，磷灰石形成的处理后的钛金属在活体中也发生在一个acellular模拟体液（SBF）的离子浓度几乎等于那些人的血浆，因此骨结合能力的处理后的钛金属可以使用SBF在体外进行评估。然而，最近发现，某些钛金属进行相同的NaOH和热处理显示磷灰石形成在SBF中，这是减少与在某些情况下使用的NaOH溶液的体积增加。这表明经处理的钛金属的骨结合能力随所用NaOH溶液的体积而变化。在本研究中，这种现象进行了系统的研究，使用商业NaOH试剂，被认为是在处理后的钛金属的表面层的结构和组成。结果发现，在NaOH处理过程中，随着NaOH溶液体积的增加，NaOH试剂中大量的钙污染物集中在Ti金属的表面上，并且这通过抑制Na离子从钛酸钠释放到周围流体中来抑制SBF中Ti金属上磷灰石的形成。即使Ca污染水平为NaOH试剂的0.0005%也足以抑制磷灰石形成。另一方面，另一种标称纯度仅为97%的NaOH试剂没有表现出任何这种抑制，因为它几乎不含Ca污染。这表明，必须仔细选择NaOH试剂，以获得可靠的骨结合钛金属植入物的NaOH和热处理。
It has long been known that titanium (Ti) metal bonds to living bone through an apatite layer formed on its surface in the living body after it had previously been subjected to NaOH and heat treatments and as a result had formed sodium titanate on its surface. These treatments were applied to a porous Ti metal layer on a total hip joint and the resultant joint has been in clinical use since 2007. It has been also demonstrated that the apatite formation on the treated Ti metal in the living body also occurred in an acelullar simulated body fluid (SBF) with ion concentrations nearly equal to those of the human blood plasma, and hence bone-bonding ability of the treated Ti metal can be evaluated using SBF in vitro. However, it was recently found that certain Ti metals subjected to the same NaOH and heat treatments display apatite formation in SBF which is decreased with the increasing volume of the NaOH solution used in some cases. This indicates that bone-bonding ability of the treated Ti metal varies with the volume of the NaOH solution used. In the present study, this phenomenon was systematically investigated using commercial NaOH reagents and is considered in terms of the structure and composition of the surface layers of the treated Ti metals. It was found that a larger amount of the calcium contamination in the NaOH reagent is concentrated on the surface of the Ti metal during the NaOH treatment with an increasing volume of the NaOH solution, and that this inhibited apatite formation on the Ti metal in SBF by suppressing Na ion release from the sodium titanate into the surrounding fluid. Even a Ca contamination level of 0.0005 % of the NaOH reagent was sufficient to inhibit apatite formation. On the other hand, another NaOH reagent with a nominal purity of just 97 % did not exhibit any such inhibition, since it contained almost no Ca contamination. This indicates that NaOH reagent must be carefully selected for obtaining reliable bone-bonding implants of Ti metal by the NaOH and heat treatments.
DOI：
10.1002/jbm.b.31309
发表时间：
2009-07-01
影响因子：
3.4
作者：
Kawanabe, Keiichi;Ise, Kentaro;Matsumoto, Tadami
通讯作者：
Matsumoto, Tadami