Bioactive TiOB‐Coating on Titanium Alloy Implants Enhances Osseointegration in a Rat Model

The surface properties of titanium alloy implants for improved osseointegration in orthopaedic and dental surgery have been modified by many technologies. Hydroxyapatite coatings with a facultative integration of growth factors deposited by plasma spraying showed improved osseointegration. Our approach in order to enhance osseointegration was carried out by a surface modification method of titanium alloy implants called plasma chemical oxidation (PCO). PCO is an electrochemical procedure that converts the nm‐thin natural occurring titanium‐oxide layer on an implant to a 5 µm thick ceramic coating (TiOB‐surface). Bioactive TiOB‐surfaces have a porous microstructure and were loaded with calcium and phosphorous, while bioinert TiOB‐surfaces with less calcium and phosphorous loadings are smooth. A rat tibial model with bilateral placement of titanium alloy implants was employed to analyze the bone response to TiOB‐surfaces in vivo. 64 rats were randomly assigned to four groups of implants: (i) pure titanium alloy (control), ii) titanium alloy, type III anodization, (iii) bioinert TiOB‐surface, and (iv) bioactive TiOB‐surface. Mechanical fixation was evaluated by pull out tests at 3 and 8 weeks. The bioactive TiOB‐surface showed significantly increased shear strength at 8 weeks compared to all other groups.