Miyazaki Toshiki, Sasaki Takashi, Shirosaki Yuki, Yokoyama Ken'ichi, Kawashita Masakazu
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan.
Department of Applied Chemistry, Kyushu Institute of Technology, Kitakyushu, Japan.
Biomed Mater Eng. 2018;29(1):109-118. doi: 10.3233/BME-171716.
Although titanium (Ti) is clinically used for hard tissue reconstruction, it has low bone-bonding ability, i.e. bioactivity. Materials able to deposit apatite on their surfaces within the body is considered to exhibit bioactivity. Effects of the metallographic structure and machining process of Ti on its apatite-forming ability remains unclear. In this study, Ti substrates subjected to various preheating and machining processes were then subjected to NaOH and heat treatments. The apatite-forming abilities of resulting Ti were examined in simulated body fluid (SBF). Preheating of the Ti decreased its reactivity with NaOH solution. When quenched or annealed Ti was subjected to NaOH and heat treatments, the induction period for apatite formation in SBF slightly increased. This was attributed to a decrease in sodium titanate and increase in rutile on the Ti surface after the treatments. Substrates subjected to wire-electrical-discharge machining did not form apatite. This was attributed to the inhibition of PO43- adsorption on their surfaces following Ca2+ adsorption, which is an essential process for apatite nucleation. Contamination of Ti surface by components of the brass wire used in the machining contributed to the inhibition. The bioactivity of surface-modified Ti was therefore significantly affected by its thermal treatment and machining process.
尽管钛（Ti）在临床上用于硬组织重建，但其骨结合能力较低，即生物活性较低。能够在体内表面沉积磷灰石的材料被认为具有生物活性。钛的金相结构和加工工艺对其磷灰石形成能力的影响尚不清楚。在本研究中，对经过各种预热和加工工艺的钛基板进行了氢氧化钠和热处理。在模拟体液（SBF）中检测所得钛的磷灰石形成能力。钛的预热降低了其与氢氧化钠溶液的反应性。当淬火或退火的钛进行氢氧化钠和热处理时，SBF中磷灰石形成的诱导期略有增加。这归因于处理后钛表面钛酸钠的减少和金红石的增加。经过电火花线切割加工的基板未形成磷灰石。这归因于Ca2+吸附后其表面PO43-吸附的抑制，这是磷灰石成核的一个基本过程。加工中使用的黄铜丝成分对钛表面的污染导致了这种抑制。因此，表面改性钛的生物活性受到其热处理和加工工艺的显著影响。
