In recent years the scientific community has shown an increased significant interest in the relationship between biomechanics and diet in extant and extinct primates. Most of these conclusions were based on the analyses of cranial morphology or unworn teeth. However, while tooth morphology can suggest what type of food can be processed, dental wear can tell us how a tooth is used.
In this study, we examine the stress distribution in a digital model of a second mandibular molar of Pongo pygmaeus during occlusal loadings, taking into account the macrowear pattern. We combine together two different digital approaches: Finite Element Analysis (FEA) for the study of stress distribution and the Occlusal Fingerprint Analysis (OFA) for the examination of dental macrowear. The OFA results show a flat wear pattern characterized by large Phase II and large buccal phase I facets. On the contrary, the lingual phase I facets are less developed with the exception of facets 5 and 7 that form along the slopes of the metaconid cusp.
The FEA results indicate that the crenulated surface of the Pongo occlusal crown acts to reduce tensile stresses, which are of low magnitude and mainly concentrated on the occlusal grooves. The protostylid is shaped like a buttress to suffer the high tensile stresses that insist in the deep buccal groove.
The molar of Pongo seems to resists very well to crushing and grinding stresses (phase II facets), which are typical of a diet that includes hard food objects such as seeds, bark and unripe fruits. On the other hand, the stress distribution on the metaconid is slighter higher and probably related to a shearing action (where the forces are directed parallel to the contact plane). The low blunt cusps, the thick enamel, the crenulated occlusal surface and the protostylid are important dental features that concur to reduce the tensile stresses in orangutans molars. This novel computer-based approach, that integrates together recent developments in dental macrowear and FEA, can potentially become a valuable tool to advance our understanding of the diet, morphology and evolution of extinct hominin species.
|Conference||Annual Meeting of the European Society for the study of Human Evolution (ESHE 2014)|
|Abbreviated title||ESHE 2014|
|Period||18/09/14 → 20/09/14|