Thin Enamel coverings in large theropods?

[Chaos Soahc]

Many studies cite that theropods (tyrannosaurs included) had remarkably thin tooth enamel covering's. I wonder how this thin covering can handle the prodigious tooth pressures and bite forces created without breaking? 

[Chaos Soahc]

Here are my sources:

Gignac, P. M., & Erickson, G. M. (2017). The biomechanics behind extreme osteophagy in Tyrannosaurus rex. Scientific Reports, 7(1), 2012.

LeBlanc, A. R., Morrell, A. P., Sirovica, S., Al-Jawad, M., Labonte, D., D’Amore, D. C., ... & Addison, O. (2024). Iron-coated Komodo dragon teeth and the complex dental enamel of carnivorous reptiles. Nature Ecology & Evolution, 8(9), 1711-1722.

Can anyone explain this?

[Jura]

Well, based on the interpretations of Gignac et al. 2017, they handled those prodigious pressures just fine. I think that the way many of these papers word enamel thickness is misleading. Crocodylians and other reptiles don't have abnormally thin enamel. Rather, it's mammals that are the oddballs with their weirdly thick enamel.

[Thomas Richard Holtz]

Yes, what Jura points out is true! Mammals aren't really a good marker for "normal."

In fact, it might be argued that mammals with diphyodonty (that is, baby teeth and only one set of adult teeth) might need extra thickened enamel to allow functional teeth throughout their adult lives. In contrast, dinosaurs and other animals with polyphodonty (continuous tooth replacement throughout life) need not lay down as much enamel, as they will be getting rid of those teeth before they are too worn down.

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[Eric Snively]

Katlin Schroeder and colleagues documented heavy wear/damage on the enamel of certain theropods, in some reflecting lots of tooth-on-bone contact. A few tyrannosaur specimens have spalling with part of a tooth sheared away, similar to spalling in crocodylians. Paul Gignac accurately simulated how this would happen in Alligator teeth, with finite element engineering methods. Tooth shape and direction of forces minimize breakage of whole teeth, even when parts are damaged. As Tom and Jason say, the teeth would be replaced soon enough anyway.

Note that the pressures Gignac and Erickon caculated for Tyrannosaurus are not much greater than they discovered for crococylians. Most other researchers calculate much greater  potential greater bite forces in Tyrannosaurus (with linearly increased pressures), and as Paul Gignac said "We're ok with that." Classy science.

[Thomas Yazbek]

it's funny how the peristaltic way humans drink/can imbibe liquid foods has allowed us to keep on living when all our teeth have been lost. a toothless lion is dead.

Thomas Yazbeck

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