Exploring the Effects of Tooth Wear on Functional Morphology: a Preliminary Study Using Dental Topographic Analysis

Mammalian tooth form reflects the material properties of foods. Much research has focused on relationships between aspects of dental morphology and diet. Understanding these relationships allows us to infer feeding adaptations from the teeth of fossil forms. Most such studies have focused on unworn (rather than worn) teeth because these are easier to characterize and compare among species. Nevertheless, tooth shape changes with wear, and most fossil teeth are worn. How does wear affect functional efficiency? Can dental morphology of worn teeth be used to infer diets of fossil species? The study described here presents a new way to examine the shapes of worn teeth so that we may begin to answer these important questions. Geographic information systems (GIS) were used to model teeth as topographic landscapes. A laser scanner generated a digital elevation model of the occlusal surface, and slope, angularity, surface area, relief, and modal aspect of each cusp, and other variables were quantified. Data on worn gorilla molars are given as an example. Although some aspects of morphology (e.g., surface area, occlusal relief) change with wear, others evidently do not. For example, cusp angularity showed no consistent change through the wear sequence, suggesting maintenance of some aspects of chewing efficiency. We conclude that this approach can be used to characterize and compare occlusal morphology in variably worn teeth. This will allow us to evaluate changes in chewing efficiency as teeth wear, a prerequisite to the inclusion of worn teeth in studies of mammalian dental functional anatomy. Peter Ungar, Department of Anthropology, Old Main 330, University of Arkansas, Fayetteville, Arkansas 72701, USA Malcolm Williamson, Center for Advanced Spatial Technologies, Ozark Hall 12, University of Arkansas, Fayetteville, Arkansas 72701, USA