Influence of a magnesium-fluoride coating of magnesium-based implants (MgCa0.8) on degradation in a rabbit model

MgCa0.8 cylinders (2.5 x 25 mm(2)) were coated with a magnesium-fluoride layer and implanted in the marrow cavities of both tibiae of 10 New Zealand White rabbits. The implantation duration was 3 and 6 months. The implants were clinically well tolerated. Micro-computed tomography revealed a new bone formation at the edges of the implants as well as an endosteal and periosteal remodeling. Using EDX-analysis, a calcium and phosphorus rich degradation layer could be found on the implant surface. It was covered by an incomplete layer containing fluoride. The analysis by weight before implantation and after 3 and 6 months, respectively, showed a slight decrease in volume in comparison to uncoated implants. When compared with uncoated implants, the mechanical properties of the coated implants exhibited a reduction in strength after 3 months. After 6 months, the strength of the coated implants was higher than that of uncoated cylinders.