The unique evolutionary adaptations of the large-scale morphology of teeth and the microscopic anatomical arrangement of its constituent parts culminate in a tool that optimizes its performance in mastication, defense and parasexual behavior. The hierarchical and composite nature of enamel, dentin and the whole tooth impart unique mechanical features and behaviors including anisotropy, heterogeneity and toughening mechanisms intended to prevent catastrophic failure. Investigations that aid a better understanding of the spatial variation in structural features (e.g., dentinal tubule density, mineral density) that contribute to mechanical behavior is warranted. In addition, quantification of the spatial variation and anisotropy in mechanical behavior of dog dentin as well as the geometry/morphology of the canine tooth is needed.

The central aim of this dissertation is to quantify the structural and morphological features and the mechanical behavior of teeth and characterize the relationship between them. The establishment of these relationships is a critical component in fully elucidating the association between form and function of teeth. Using nanoindentation, scanning electron microscope imagining, and micro-CT, we set out to quantify and characterize relationships between the spatial distribution of the dentin microstructure, mineral density and mechanical properties. Additionally, we created three-dimensional computer models to quantify morphology of the canine tooth in the domesticated dog (Canis lupus familiaris).

Our results demonstrate the presence of a spatial gradient in dentin microstructure, mineral density and mechanical properties with features of anisotropy. Microstructure and mineral density correlate with mechanical properties. However, other structural constituents (e.g., collagen) may also contribute to mechanical behavior and should be further explored. Many features of tooth geometry and morphology scale with body weight. In addition, we have demonstrated that some variance in canine tooth geometry and morphology is present among dog breeds. The work presented here will further inform investigations into form and function relationships of teeth. In addition, our results will contribute to the refinement of analytical models. Supported by future investigations, our results will contribute to the development of validation of future generic and patient-specific finite element models.