A comparative in vivo study of strontium-functionalized and SLActive™ implant surfaces in early bone healing

• Main Authors: Offermanns V, Andersen OZ, Sillassen M, Almtoft KP, Andersen IH, Kloss F, Foss M
• Format: Article
• Language: English
• Published: Dove Medical Press 2018-04-01
• Series: International Journal of Nanomedicine
• Subjects: biofunctionalization; wettability; physical vapor deposition; bioactive; surface modification; bone
• Online Access: https://www.dovepress.com/a-comparative-in-vivo-study-of-strontium-functionalized-and-slactivetm-peer-reviewed-article-IJN

Vincent Offermanns,1 Ole Z Andersen,2 Michael Sillassen,2 Klaus P Almtoft,3 Inge H Andersen,3 Frank Kloss,4 Morten Foss2,5 1Department of Cranio-Maxillofacial and Oral Surgery, Medical University of Innsbruck, Innsbruck, Austria; 2Interdisciplinary Nanoscience Center (iNANO), Faculty of Science and Technology, Aarhus University, Aarhus, Denmark; 3Tribology Center, Danish Technological Institute, Aarhus, Denmark; 4Private Practice, Lienz, Austria; 5Department of Physics and Astronomy, Faculty of Science and Technology, Aarhus University, Aarhus, Denmark Purpose: Studies have shown that strontium-doped medical applications benefit bone metabolism leading to improved bone healing and osseointegration. Based on this knowledge, the aim of the study was to evaluate the performance of an implant surface, functionalized by a physical vapor deposition (PVD) coating (Ti-Sr-O), designed to yield predictable release of strontium. The Ti-Sr-O functionalized surface is compared to a routinely used, commercially available surface (SLActive™) with respect to bone-to-implant contact (BIC%) and new bone formation (BF%) in two defined regions of interest (ROI-I and ROI-II, respectively).Materials and methods: Ti-Sr-O functionalized, SLActive, and Grade 4 titanium implants were inserted in the femoral condyle of adult male New Zealand White rabbits. The PVD magnetron-sputtered Ti-Sr-O surface coating was characterized using scanning electron microscopy (SEM) for morphology and coating thickness. Strontium release and mechanical stability of the coating, under simulated insertion conditions, were evaluated. Furthermore, histomorphometrical BIC and BF were carried out 2 weeks after insertion.Results: Histomorphometry revealed increased bone formation of Ti-Sr-O with significant differences compared to SLActive and Grade 4 titanium in both regions of interest, ROI-I and ROI-II, at 0–250 µm and 250–500 µm distance from the implant surfaces. Analogous results of bone-to-implant contact were observed for the two modified surfaces. Conclusion: The results show that a nanopatterned Ti-Sr-O functionalized titanium surface, with sustained release of strontium, increases peri-implant bone volume and could potentially contribute to enhancement of bone anchorage of osseointegrated implants. Keywords: biofunctionalization, wettability, physical vapor deposition, bioactive, surface modification, bone