Enhanced osseointegration of endosseous implants by predictable sustained release properties of strontium

Studies have shown that strontium (Sr) incorporated into surfaces may enhance osseointegration. Thus, we suggested that a sustained Sr release from implant surfaces could improve bone healing. This study verifies and further investigates the effect of a novel TiSrO functionalized implant surface prepared from a magnetron co-sputtering platform with a continuous release of Sr. Materials and methods Four experimental TiSrO groups, which differed from each other in Sr contents and pre-wash procedures, were tested. Implants were prepared with a TiSrO coating by means of magnetron co-sputtering and compared to Grade 4 titanium. Composition, morphology and mechanical stability were analyzed; Sr-release data were gained from in vitro washout experiments. In vivo investigations were carried out in a rat model and analyzed histologically regarding bone-to-implant contact and new bone formation 30 days after implantation. Results Structural differences were detected between the two basis TiSrO coatings with 6.7 at.% and 8.9 at.% Sr, respectively. Different release profiles were observed with 8.9 at.% Sr coating exhibiting the highest long-term release of Sr. Median values of new bone formation and bone-to-implant contact was found to be 60.1% and 91.6%, respectively, for the best group compared to 16.6% and 70.6% for the Grade 4 titanium reference. The increase in new bone formation was found to correlate with the amount of Sr released in vitro. Conclusion The results show that sputtered TiSrO coatings with sustained release of Sr may improve osseointegration, and could thus have impact on practical applications for medical implants. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1099–1106, 2015.