On the evolution of the morphology and resilience of molar cusps in fossil hominid teeth.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35841750.
- Also identified by DOI 10.1016/j.jmbbm.2022.105357.
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Abstract
Teeth play an important role in evolutionary studies due to their good preservation and direct link to diet. The present work makes use of a previously generated database on molar teeth of fossil hominids which consists of cuspal enamel thickness d<sub>c</sub>, dentin horn angle φ and section width D, all measured on a given histological tooth section. These data are here interpreted with the aid of "fracture stress" Q<sub>F</sub> = P<sub>F</sub>/D<sup>2</sup> and geological age t, where P<sub>F</sub> is the occlusal force needed to cause cusp failure as determined from d<sub>c</sub> and φ. Q<sub>F</sub> is virtually a constant in non-hominins ("apes") while monotonically increasing toward present time in hominins. These two trends intersect at t = t<sub>s</sub> = 4.5 (0.11) mya, a value similar to other divergence estimates. Q<sub>F</sub> was fitted with a function f(t) which is proportional to (d<sub>c</sub>/D)<sup>2</sup>. The monotonic variation of Q<sub>F</sub> and in turn d<sub>c</sub>/D with t contrasts the more complex behavior generally characterizing other physical entities of fossil hominids. The increase in d<sub>c</sub>/D in hominins promotes tooth resilience and in turn life span. Finally, it is suggested that P<sub>F</sub> provides an upper bound to the maximum bite force produced by the jaw structure.
Medical subject headings
- Hominidae
- Tooth