Imaging of the inner structure of cave bear teeth by novel non-destructive techniques

The potential of non-destructive imaging techniques, such as optical coherence tomography (OCT), X-ray micro-3D computed tomography (μ-CT) and terahertz (THz) imaging has been considered for structural and age diagnostic tasks in the field of paleontology. In particular OCT, a high-resolution, non-destructive and contactless technology for two and three dimensional (2D, 3D) imaging, was evaluated for the investigation of dental cementum microstructures, exemplified by cave bear teeth. OCT with a depth resolution in the micron range showed its ability to count the annual appositional lines consisting of cementum and thus to determine the age of the individual. As additional method also THz technology is presented which exhibits much larger penetration depths up to centimeters, but with a lower resolution, in contrast to OCT. Thus, THz imaging gives insight into the internal structure of the cave bear teeth on a larger scale. Furthermore, to complete the variety of considered non-destructive imaging techniques, μ-CT has been applied for analysis of the teeth structures, in comparison to OCT and THz imaging results. The combination of these complementary methods is well suited for the non-destructive characterization of teeth.