Macrowear and the mechanical behavior of enamel

Analysis of dental macrowear and microwear can provide valuable insights into diet and life-history of fossil and extant animals. However, studies have assumed implicitly that the mechanical behavior of wear surfaces are equal. The properties of enamel that influence mechanical behavior are known to vary throughout the cusp, suggesting that not all wear surfaces will have equivalent mechanical behavior and that different degrees of wear affect wear resistance. Previous studies have implicated the orientation of enamel prisms and crystallites with respect to the occlusal surface as a primary factor affecting wear resistance. Here, we investigate how mechanical behavior changes with macrowear using microscratch testing on a baboon molar and place our results within the context of changes in the microstructural features of enamel. Our results suggest that a moderate degree of wear confers the greatest wear resistance and identify microstructural features of enamel that are functionally important, warranting further investigation.