The porous TiO2/
perlite composite
Ecopore is a synthetic
biomaterial with possible clinical application in bone substitution. In our previous work, we demonstrated that surface modification of
Ecopore with
fibronectin (FN) enhanced spreading and growth of human osteoblasts in vitro. In the present study, we implanted untreated, alkaline-etched and FN-coated
Ecopore cylinders into critical size defects of rabbit femora and applied pulsed polychrome sequence staining. After 6 weeks, sections of the implants were investigated via conventional and fluorescence microscopy. A partial ingrowth of bone matrix into the pore system of the
Ecopore implants was observed. At the contact zones, the bone appeared to be directly connected to the implant without detectable gaps. Defect healing was complete within 6 weeks, while fibrous tissue generation or
inflammation were absent in the implant modification groups, demonstrating basic
Ecopore biocompatibility. The mean bone apposition rates within the implant cross-section were 4.1+/-0.6 microm/day (p<0.001) in the FN-coated group and 3.3+/-0.5 microm/day (p<0.05) in the NaOH-etched group. In both treated
Ecopore modification groups, the apposition rates were significantly higher than in the non-modified control (2.9+/-0.6 microm/day), indicating bone growth stimulation by pre-treatment. Energy-dispersive X-ray analysis confirmed that significantly more bone tissue was formed inside the pores of the FN-coated implants compared to the unmodified control. The cross-sectional areas identified as ingrown bone amounted to 18.5+/-6.1% (p<0.05) in the FN group, 13.4+/-5.1% (p>0.05) in the NaOH-etched group and 10.2+/-5.5% in the unmodified group. In summary, we conclude that bone tissue tolerates
Ecopore well and that tissue ingrowth can be enhanced by etching and coating with FN.