Osteo-integration of plasma-spray, biomimetic octacalcium phosphate and carbonate-apatite coatings on titanium implants

The biomimetic approach of producing calcium-phosphate (Ca-P) coating on metal implants offers the possibility to form Ca-P phases that cannot be produced by using the plasma-spray (PS) technique. Furthermore, biomimetically produced coatings exhibit some important advantages in comparison to PS coatings like the ability to coat porous implants, and to incorporate biologically active agents, and the lack of delamination and particle release. In this study, PS coated Ti6Al4V implants are compared with biomimetic octacalcium phosphate (OCP) and carbonate-apatite (CA) coated implants by implantation in muscles and bony sites of New, Zealand White Rabbits. Previous reports have shown that coatings with high dissolution rate are highly bioactive and may ensure an early bone formation. However, the in vivo durability of the coating might. be an important parameter for the long-term bone fixation of an implant. This study shows a complete dissolution of OCP and CA and no dissolution of PS coating after 12 weeks of intramuscular implantation. Implantation in bone shows a similar bone growth in the early period of time for different coatings, and a more positive effect of the soluble coatings in the bone remodelling process. This results in a higher amount of bone after 12 weeks of implantation for biomimetically coated implants than for PS coated implants.