Bioactivation of titanium using calcium-hydroxide slurry

钛上的成骨活化一直是生物材料研究人员的主要兴趣，因此，各种表面改性技术已经被研究。在这些技术中，羟基磷灰石（HAP）涂层由于其良好的生物材料-骨固定能力是最成功的技术，羟基磷灰石涂层钛目前用于临床环境。然而，牙医和骨科医生指出，这种植入物在人体内放置较长时间后，有时会出现hap -钛界面断裂和涂层本身溶解的情况。我们最近开发了一种使用氢氧化钙浆料的化学涂层技术。其工艺流程为：将钛基材埋入氢氧化钙粉与水混合制成的氢氧化钙浆料中，随后将含有钛基材的浆料在空气中加热。我们发现，用这种方法处理钛板，在其表面形成钛酸钙涂层。在本研究中，研究了处理条件与表面层特性之间的关系。将表面修饰的钛棒手术植入大鼠硬组织，观察钛棒周围的成骨情况。我们初步研究了浆液加工中加热温度对涂层特性的影响。当加热温度超过600℃时，在其表面形成结晶的钛酸钙涂层，被涂层的钛可以在模拟体液中快速沉淀磷酸钙。当温度升高时，基材上同时形成较厚的二氧化钛层，导致涂层的附着力降低。其次，我们尝试通过在浆料中添加钠离子来提高涂层的生物相容性。将Ca(OH)_2与1m NaOH或NaCl溶液混合制备浆料，在基体上形成由钛酸钙和钛酸钠组成的复合涂层。复合涂层能更快地析出磷酸钙，但由于涂层较厚，会降低涂层的机械强度。最后，在600℃的加热温度下，将Ca(OH)_2浆液处理后的Ti棒手术植入大鼠体内。第7天，新骨迅速形成并与骨表面直接接触。少

The activation of osteogenesis on titanium has been a major interest for biomaterial researchers, and, thus, various surface modification techniques have been studied. Among these techniques, a hydroxyapatite (HAP) coating applied by the plasma-splaying process is the most successful technique due to its good biomaterial-bone fixation ability and HAP-coated titanium is currently used in clinical settings. However, dentists and orthopedists have pointed out that fracture at the HAP-titanium interface and dissolution of the coating itself sometimes occur after such implants have been in the human body for a long time. We recently developed a chemical coating technique using calcium-hydroxide slurry. The process is as follows: a titanium substrate is buried in calcium-hydroxide slurry prepared by a mixture of calcium-hydroxide powder with water, and, subsequently, the slurry containing the titanium substrate is heated in air. We revealed that, by treating a titanium plate with this proces … More s, a calcium titanate coating was formed on its surface. In the present study, the relationships between the treatment conditions and the characteristics of the surface layer were investigated. Furthermore, the surface-modified titanium rod was surgically inserted in hard tissue of rat, and osteogenesis around the rod was investigated.We initially investigated the effect of heating temperatures in the slurry processing upon characteristics of the coatings. When using the heating temperature beyond 600℃, a crystallized calcium titanate coating was formed on its surface, and the coated titanium can precipitate calcium phosphate in a simulated body fluid rapidly. When raising the temperature, thick titanium dioxide layer was simultaneously formed on the substrate, resulting in the decrease of the adhesion strength of the coating. We secondly attempted to improve biocompatibility of the coating by adding sodium ions in the slurry. When preparing the slurry by mixing Ca(OH)_2 with 1-M NaOH or NaCl solutions, a composite coating comprising calcium and sodium titanates were formed on the substrate. The composite coating could precipitate calcium phosphate more rapidly, although mechanical strength of the coating would decrease owing to the formation of the thick coating. Last, we surgically implanted the Ti rod treated with the Ca(OH)_2 slurry and with the heating temperature of 600℃, into a rat. At 7 days, new bone was formed vigorously and was in contact with the surface directly. Less