チタンとTi-6Al-4V 合金を組み合わせたインプラントの曲げ特性と耐食性

抄録

Because implants frequently comprise two or three types of pieces which are composed of small parts, fracture is apt to occur. Therefore, to increase strength, implants fabricated of both JIS type-4 titanium (G4) and Ti-6Al-4V alloy (G5) combined are currently being used. However, when different metals are used in combination, it is important to clarify the release of metal ions due to galvanic action, and the strength of the implants.
In this study, implant bodies and abutments were produced using G4 and G5 by machining, and two-piece implants of G4 and G5 combined were fabricated. The maximum bending load at an inclination of 30° and amounts of titanium and vanadium released in 1% lactic acid solution were measured.
The tensile strength, elongation, yield strength, and hardness of G4 and G5 wires were measured. As a result, the tensile strength, yield strength, and hardness were higher for G5 than G4, and the elongation of G4 was greater than that of G5. The maximum bending load of implants fabricated in combination at the inclination of 30° was the highest with G5G5, and lowest with G4G4. No significant difference in the maximum bending load was noted between G4G5 and G5G4. The strain showed a similar tendency. The amount of titanium release was the lowest with G4G4 and G4G5, and highest with G5G5. The amount of vanadium release was the lowest with G4G5, second lowest with G5G4, and highest with G5G5. Furthermore, because galvanic action does not readily occur with the combined use of titanium and titanium alloy and there was no problem regarding the strength, it was suggested that the combined implants would have no problems in clinical use.