Medical porous-surfaced implants have been shown to lead to higher bone/metal shear strength than other types of
fixation. A problem that has been identified with porous surface implants is the loss of physical properties.
Porous-surfaced titanium implants were fabricated by cylindrical explosive compaction method by using various pressure
transmitting media, i.e. water, grease or paraffin. The shear strengths between a Ti rod and Ti particles, surface
pore sizes and porosity ratios for the obtained Ti implants were measured. On the effect of transmitting media, the order
of value of surface pore size is as follows grease > paraffin > water. The diameter of pore size is in the range between 180
µm and 361 µm when using T6 powders and between 265 µm and 514 µm when using T10 particle, respectively and these
ranges are almost the same as the result of the pore size range of 50 to 400 µm by Bobyn et al.7). The obtained shear
strength between a Ti rod and Ti particles in implants were in the range of 130-230MPa and were higher than that of
bone itself (60MPa). On pressure transmitting media, the order of value on surface pore size for the shear strength was
grease ≧ paraffin > water. The surface of the implants showed the porous shape for favorable to bone tissue growth.
これまで，医療用表面多孔質インプラント材は骨との接合性に優れることが知られているが，インプラント材の多孔 質部の接合強度が低いことが問題点となっている。本研究はインプラント材の多孔質部の接合強が高く，かつ多孔性に 優れるインプラント材の開発を目指し，爆発圧縮技術の応用する表面多孔質インプラント材の作製について検討したも のである。特に衝撃圧力伝播媒体として，水，パラフィン，グリースについて，その効果を検討した。その結果，３種 の圧力伝播媒体について，インプラント材のTiロッドとTi粉末粒子とのせん断強度は140-240MPaで，骨自身のせん断 強度（60MPa）より十分強く，かつ，表面空隙サイズも150-500µmと広範囲に変化させることができ，骨組織を有効に 成長させうることが知られた。
Explosive compaction, Porous-surfaced implants, Titanium particle, Pressure transmitting medium, Plasma rotating electrode process