The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)


Age-related changes of the occlusal surface geometry in humans and great apes

ANN MARGVELASHVILI1,2, CHRISTOPH P. E. ZOLLIKOFER1 and MARCIA S. PONCE DE LEÓN1.

1Anthropological Institute and Museum, University of Zurich, 2Georgian National Museum

Thursday 8:45-9:00, Broadway III/IV Add to calendar

The surface formed by the dental arcades during occlusion – typically known as the “occlusal plane” – has a complex geometry, which is functionally relevant for the biomechanics of mastication. In dentistry, the geometry of the occlusal surface is defined by the curves of Spee and Wilson, which correspond to anteroposterior and transverse movements of the mandible, respectively. Here, we analyze how the geometry of the occlusal surface changes as a function of dental wear and subsequent compensatory mechanisms of the dentognathic system. We ask whether patterns of occlusal surface change are similar in humans and great apes. We used CT data of a sample of N=88 adult skulls of humans and great apes, and quantified occlusal surface geometry with 48 3D-landmarks. Results show that, with increasing dental wear, the occlusal surface changes its geometry from upward-concave to downward-concave. This pattern of in-vivo modification is largely similar in all the examined taxa. Overall, our study indicates that hominoids share a common set of masticatory mechanisms and compensatory dentognathic mechanisms causing occlusal surface change, irrespective of considerable differences between taxa in the architecture of the masticatory system, and in dietary adaptations.

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