Improved bone ingrowth and fixation with a thin calcium phosphate coating intended for complete resorption

Bonit® is claimed to be a resorbable electrochemically deposited calcium phosphate coating consisting mainly of brushite, which is a hydroxyapatite precursor. This study involved a comparison of Ti6Al4V screw‐shaped implants with and without a 15 ± 5 μm Bonit coating in rabbit tibia and femur, after 6 and 12 weeks of insertion. The biomechanical removal torque test showed significantly increased values for the coated implants after 12 weeks ( p < 0.05) but not after 6 weeks of integration. Higher bone‐implant contact was found for the coated implants in the tibia after 6 weeks and for both tibial and femoral screws after 12 weeks ( p < 0.05). There was no difference in the inflammatory reaction around the implants, and possible grains of the coating could be detected after 6 weeks, but not after 12 weeks of follow‐up. This unloaded short‐term study has shown promising results for the easily applicable and resorbable coat (Bonit) compared to uncoated titanium‐alloy implants. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007