The role of tooth enamel mechanical properties in primate dietary adaptation

Primate teeth adapt to the physical prop- erties of foods in a variety of ways including changes in oc- clusal morphology, enamel thickness, and overall size. We conducted a comparative study of extant primates to exam- ine whether their teeth also adapt to foods through varia- tion in the mechanical properties of the enamel. Nanoin- dentation techniques were used to map profiles of elastic modulus and hardness across tooth sections from the enamel-dentin junction to the outer enamel surface in a broad sample of primates including apes, Old World mon- keys, New World monkeys, and lemurs. The measured data profiles feature considerable overlap among species, indi- cating a high degree of commonality in mechanical proper- ties. These results suggest that differences in the load- bearing capacity of primate molar teeth are more a function of morphology—particularly tooth size and enamel thick- ness—than of underlying mechanical properties. Am J Phys Anthropol 148:171-177, 2012. V V C 2012 Wiley Periodicals, Inc.