Is a blunt sword pointless? Tooth wear impacts puncture performance in Tasmanian devil canines.

As teeth wear, their shapes change and functional features can be dulled or lost, presumably making them less effective for feeding. However, we do not know the magnitude and effect of this wear. Using Tasmanian devil canines as a case study, we investigate the impact of wear on puncture in pointed teeth. We measured aspects of shape impacted by wear (tip sharpness, height, and volume) in teeth of varying wear followed by 3D printing real and theoretical forms to carry out physical puncture tests. Tooth wear acts in two ways: by blunting tooth tips, and decreasing height and volume, both of which impact performance. Sharper tips in unworn teeth decrease the force and energy required to puncture compared to blunter worn teeth, while taller unworn teeth provide the continuous energy necessary to propagate fracture relative to shorter worn teeth. These wear-modulated changes in shape necessitate more than twice the force to drive worn teeth into ductile food and decrease likelihood of puncture success.