Comparison of microfocus- and synchrotron X-ray tomography for the analysis of osteointegration around Ti6Al4V implants.

Micro-computed tomography (microCT) provides quantitative three-dimensional information of bone around titanium implants similar to classical histology. The study, based on an animal model, containing cuboid-shaped biofunctionalised Ti6Al4V implants with surrounding bone after 4 weeks, is performed using 3 microCT-systems with X-ray tubes, one synchrotron-radiation-based microCT-system (SRmicroCT), and classical histology. Although the spatial resolution of the microCT-systems is comparable, only the results of SRmicroCT agree with results of classical histology. The X-ray tube sources give rise to huge artefacts in the tomograms (interface scattering, beam hardening), which impaired the quantitative analysis of bone up to about 200microm from the implant surface. Due to the non-destructive character of microCT the specimens can be subsequently examined by classical histology without restriction. The quantitative comparison of bone formation uncovers the strong dependence of the newly formed bone from the selected slice. This implies the necessity of 3D analysis. SRmicroCT and classical histology prove that surface modifications of the titanium implant significantly influence the bone formation. Using SRmicroCT, the preparation artefacts due to cutting and polishing are excluded.