Bone-implant interface mechanics of in vivo bio-inert ceramics.

We have previously demonstrated that there was no significant difference between the affinity of bone to bio-inert ceramics and stainless steel in a histological study. In this study, the bone-implant interface shear strength of alumina ceramics (Al2O3), zirconia ceramics (ZrO2), stainless steel (SUS316L) and sintered hydroxyapatite (HA) were compared in 19 dogs using a transcortical push-out model of the femur 4 and 12 wk after implantation. The interface shear strength of HA was significantly greater than that of alumina ceramics, zirconia ceramics and stainless steel (P < 0.001). There was no significant difference between bio-inert ceramics and stainless steel.