Texture Mapping Mature and Immature Enamel Using Synchrotron X-ray Diffraction

Objectives: Understanding the precise timings and progression of the maturation stage of enamel biomineralisation is of great interest to dental researchers is also essential for time-series archaeological studies where individuals' dietary, mobility, and migratory behaviours during childhood can be determined through the analysis of partially-mature dental enamel remains. Archaeological skeletal tissue collections containing children who died during enamel development provide a unique resource for the study human enamel maturation not available from clinical samples. We have used 2D synchrotron X-ray diffraction to map texture in intact sections of mature human enamel and compared this to the texture in immature enamel from archaeological samples to establish whether enamel maturation can be determined non-destructively by comparing the crystallographic texture patterns in mature and immature dental enamel samples.

Methods: High-resolution synchrotron radiation was used to collect 2D X-ray diffraction images across whole tooth crowns of intact sections of mature and partially mature enamel. The texture direction and magnitude were determined by interrogating the intensity pattern around the Debye ring of the 002 reflection to construct maps of the local orientation and magnitude of texture.

Results: Texture direction maps indicate a similar pattern of crystallite orientations in both mature and immature enamel; however the degree of texture was generally found to vary less in the immature enamel as compared to the fully mature enamel when observing a track from tooth surface to enamel-dentine junction.

Conclusion: Our results indicate that the differences in texture in mature and immature enamel can be quantified using synchrotron X-ray diffraction. Due to the complex growth patterns in enamel mineralization we have observed significant inter- and intra-tooth heterogeneities in enamel texture, therefore it will be necessary to characterize a larger number of tooth specimens in order to establish the precise texture markers of maturation.