Effects of Surface Roughness and Maximum Load on the Mechanical Properties of Cancellous Bone Measured by Nanoindentation

Abstract

AbstractNanoindentation was used to assess the mechanical properties of lamellar and interlamellar tissue in dehydrated rabbit cancellous bone. The effects of surface roughness and maximum nanoindentation load on the measured mechanical properties were examined in two samples of differing surface roughness using maximum loads ranging from 250-3000 μN. As the ratio of indentation depth to surface roughness decreased below approximately 3:1, the variability in material properties increased substantially. At low loads, the indentation modulus of the lamellar bone was approximately 20% greater than that of the interlamellar bone, while at high loads the measured properties of both layers converged to an intermediate value. Relatively shallow indentations made on smooth surfaces revealed significant differences in the properties of lamellar and interlamellar bone that are consistent with microstructural observations of lamellar bone as more mineralized than interlamellar bone.