Meeting Abstract

39.3  Friday, Jan. 4  Three-diminesional finite element analysis of elasmobranch teeth WHITENACK, L.B.*; SIMKINS, D.C.; MOTTA, P.J.; Univ. of South Florida; Univ. of South Florida; Univ. of South Florida whitenac@mail.usf.edu

While teeth are a vital component of the shark feeding apparatus, their role in feeding has largely been ignored. Applying engineering techniques to shark tooth functional morphology may reveal insights into evolution undiscovered by traditional qualitative methods. The goal of this study is to explore the link between form and function for selachian teeth using Finite Element Analysis (FEA). We built three-dimensional FE models of individual teeth of various shark species to visualize stress distribution during puncture, draw, and holding. Initial results indicate that during puncture events, stress is concentrated at the tooth tip, decreasing greatly with distance from the tip. However, with increasing penetration the stress would rapidly dissipate as more of the cusp contacts the prey. In all cases, holding produces shear stresses between dentine and enamel. During draw, narrow teeth, such as those of Carcharhinus limbatus, concentrate stress along the edges and the dentine-enamel junction (DEJ), indicating that these teeth are better suited for puncture. Broader teeth, exemplified by C. leucas, show lower stress concentrations during draw than puncture, indicating that these teeth are better suited for draw. Notched teeth from Galeocerdo cuvier and Prionace glauca primarily concentrate stress at the notch and DEJ during both draw and puncture. However, G. cuvier exhibits less stress at the notch than P. glauca, indicating that not all notched teeth are functionally alike. Despite these stress concentrations, broken shark teeth are rarely seen. We therefore hypothesize that shark teeth have high safety factors, and their flexible attachment may further inhibit stress concentration at the DEJ by distributing stress through the collagenous Sharpeys fibers that anchor the tooth to the dental lamina.