Three-dimensional
(3D) visualization of bone-implant interfaces
via electron tomography (ET) has contributed to the novel perspective
of nano-osseointegration and offers evidential support for nanoscaled
biomaterial surface modification. Conventional single-axis ET provides
a relatively large field of view of the human bone to titanium implant
interface showing bone structure arrangement near the interface. However,
the “missing wedge” associated with conventional single-axis
ET leads to artifacts and elongation in the reconstruction, limiting
the resolution and fidelity of reconstructions, as well as the ability
to extract quantitative information from nanostructured interfaces.
On-axis ET, performed by 180° rotation of a needle-shaped sample,
is a promising method to solve this problem. In this work, we present
the first application of on-axis ET for investigation of human bone
and laser-modified titanium implant interfaces without the missing
wedge. This work demonstrates a near artifact-free 3D visualization
of the nanotopographies of the implant surface oxide layer and bone
growth into these features. Complementary electron energy-loss spectroscopy
(EELS) mapping was used to illustrate the gradual intermixing of carbon
and calcium (characteristic elements of bone) with the nanoscaled
oxide layer of the implant surface. Ultimately, this approach serves
as direct evidence of nano-osseointegration and as a potential platform
to evaluate differently structured implant surfaces
