Bone tissue responses to Mg-incorporated oxidized implants and machine-turned implantsin the rabbit femur

Previous studies have demonstrated a significant improvement in the bone response to oxidized titanium implants. Little is known about the effects of specific oxide properties on the bone tissue responses to titanium implants. This study in-vestigated the bone tissue responses to magnesium (Mg)-incorporated oxidized titanium implants and machine-turned titani-um implants in the rabbit femur. The oxidized implants were prepared using micro arc oxidation (MAO) methods. Surface oxide properties were characterized by using various surface analytic techniques, involving scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and optical interferometry. Screw shaped titanium implants, 10 machine-turned implants (controls) and 10 Mg-incorporated im-plants (tests) were inserted in the femoral condyles of 10 New Zealand white rabbits. After a 6-week healing period, resonance frequency analyses and removal torque measurements of the Mg-incorporated oxidized implants demonstrated significant im-provements in implant integration with bone in comparison to machine-turned implants, p=0.007 and p=0.017, respectively. Bone growth in the pores of the oxidized implants was probably incomplete at a follow-up of 6 weeks, as indicated by SEM and EDS measurements. Mg-incorporated titanium implants significantly improved bone responses as compared with machine-turned control implants. Considering the differences and similarities of the surface oxide properties of controls and test im-plants, the enhanced bone responses to Mg-incorporated implants could be explained by the Mg surface chemistry of the test im-plants. (Journal of Applied Biomaterials and Biomechanics 2005; 3: 18-28).