Meeting Abstract

61.1  Saturday, Jan. 5  The effects of tooth structure and loading on the distribution and magnitude of strain in durophagous teeth CROFTS, S; Univ. of Washington, Seattle croftss@uw.edu

A broad range of taxa, both extant and extinct, have teeth that are specialized to break hard prey items, including several elasmobranch lineages, bony fishes, mammals and reptiles. These teeth have two competing functional demands – to break the prey item and to avoid breakage themselves. While these teeth all serve the same general function, shapes ranges from broad flat plates, to more rounded teeth with stress concentrators, and even cupped shapes. Furthermore there are presumably different constraints on teeth, dependent on the frequency that they are used and replaced, and the specific hard prey. To better understand the functional constraints on tooth morphology, I digitally constructed four series of models that graded from one morphological extreme to another, covering the range of tooth morphologies seen in nature. These models varied in the degree of convexity and concavity of the occlusal surface, and the morphology of a stress concentrating cusp. Using finite element analysis (FEA), I applied different loading regimes to the models, to mimic different potential prey items. I measured maximum principal strain to determine which model teeth would be most likely to fracture, and where that fracture would be most likely to occur. Both the magnitude of strains and the distribution through the models changed with the morphology and with different loading regimes. This suggests different optimal shapes, where strain is lowest in the tooth, possibly dependent on prey type. Laser scans of the slightly domed teeth of the extinct placodont Placodus sp., were also analyzed and compared to the predicted optimal tooth shapes.