Bonding strength of apatite layer formed on chemically treated tantalum metal

摘要

As a candidate for highly loaded bone substitute, tantalum metal has attractive features such as biocompatibility, high malleability and ductility. The present authors previously showed that NaOH and heat treatments make tantalum metal to form a bonelike apatite layer on its surface in a short period, although even the untreated tantalum metal forms the apatite in a long period. In the present study, bonding strength of the apatite layer, which was formed on the NaOH- and heat-treated tantalum metal, to the substrate was measured under tensile stress and compared with that of the apatite formed on the untreated substrate. The former showed much higher bonding strength than the latter. The higher bonding strength of the former was attributed to a graded structure at the apatite-substrate interface where the apatite gradually changes into the interior metal substrate.