Tooth Wear Inclination in Great Ape Molars

Abstract

Primate dietary diversity is reflected in their dental morphology, with differences in size and shape of teeth. In particular, the tooth wear angle can provide insight into a species' ability to break down certain foods. To examine dietary and masticatory information, digitized polygon models of dental casts provide a basis for quantitative analysis of wear associated with tooth attrition. In this study, we analyze and compare the wear patterns of Pongo pygmaeus, Gorilla gorillagorilla and Pan troglodytes schweinfurthii lower molars, focusing on the degree of inclination of specific wear facets. The variation in wear angles appears to be indicative of jaw movements and the specific stresses imposed on food during mastication, reflecting thus the ecology of these species. Orangutans exhibit flatter wear angles, more typical of a diet consisting of hard and brittle foods, while gorillas show a wear pattern with a high degree of inclination, reflecting thus their more leafy diet. Chimpanzees, on the other hand, show intermediate inclinations, a pattern that could be related to their highly variable diet. This method is demonstrated to be a powerful tool for better understanding the relationship between food, mastication and tooth wear processes in living primates, and can be potentially used to reconstruct the diet of fossil species.

A functional analysis of Carabelli trait in Australian aboriginal dentition

“…It has been demonstrated in non‐human primates that a high degree of inclination of the occlusal surface, generates larger surface‐parallel loads on foods, which in turn induces shearing stress (Gordon, 1982; Spears & Crompton, 1996). Shearing wear is generally characterized by a higher inclination compared to grinding and crushing wear (Fiorenza, 2009, 2015; Fiorenza et al, 2018, 2019; Fiorenza et al, 2020; Fiorenza, Benazzi, & Kullmer, 2011; Knight‐Sadler & Fiorenza, 2017), and Carabelli occlusal contacts are not an exception to this rule. A steep molar cusp geometry is mechanically advantageous in processing tough and pliant foods (Gordon, 1982; Hartman, 1988; Luke & Lucas, 1983; Spears & Crompton, 1996).…”

“…It has been demonstrated in non-human primates that a high degree of inclination of the occlusal surface, generates larger surface-parallel loads on foods, which in turn induces shearing stress (Gordon, 1982;Spears & Crompton, 1996). Shearing wear is generally characterized by a higher inclination compared to grinding and crushing wear (Fiorenza, 2009(Fiorenza, , 2015Fiorenza et al, , 2019Fiorenza et al, 2020;Knight-Sadler & Fiorenza, 2017), and…”

A dental revolution: The association between occlusion and chewing behaviour

“…Second lower molars were selected for OFA as it has been shown to provide an effective representation of masticatory behaviours in primates [ 61 ]. OFA can only be effectively applied to moderately worn teeth because dental wear facet patterns are obliterated at more advanced stages of wear [ 39 ].…”

3D Data Analysis for Teeth Morphology Study

“…Application of 3D imaging and image processing techniques allows measurements beyond traditional odontometric parameters: maximal tooth crown dimensions in mesiodistal and bucco-lingual directions. And here angular measurements play a significant role due inclinations of dental cusp planes, including studies of dental wear is [25]. Regarding dental wear (or usually natural functional attrition of opposing and adjacent teeth) should be mentioned that it can change dental morphology substantially, thus 3D imaging and processing methods provide for studies of inner morphological structures located at the enamel-dentine junction [26,27].…”