Crystallographic Parameters Of Rod And Interrod Enamel Crystallites Differ Systematically*

Dental enamel has evolved to bear large masticatory forces, resist mechanical fatigue, and withstand wear over decades of use. Functional impairment or loss, as a consequence of developmental defects or tooth decay, has a dramatic impact on health and quality of life. Enamel formation and its degradation remain incompletely understood. This is in part due to its hierarchical architecture. Our objective was to test the hypothesis that crystallographic features of two microstructural features of ename, rod and interod enamel, differ as a consquence of their developmental origin. Towards this goal, we mapped crystallographic order/disorder by azimuthal autocorrelation of WAXS patterns recorded at 500 nm spot size and correlated this information with crystallite size, lattice parameters, and microstrain at each point. We find that there are ystematic variations in these parameters for rod and interrod crystallite populations that suggest differences in composition and imply that there are distinct crystallization environments during amelogenesis.