Exploring the biomechanics of taurodontism

Abstract

Taurodontism (i.e. enlarged pulp chamber with concomitant apical displacement of the root bi/trifurcation) is considered a dental anomaly with relatively low incidence in contemporary societies, but it represents a typical trait frequently found in Neandertal teeth. Four hypotheses can be envisioned to explain the high frequency in Neandertals: adaptation to a specific occlusal loading regime (biomechanical advantage), adaptation to a high attrition diet, pleiotropic or genetic drift effects. In this contribution we used finite element analysis (FEA) and advanced loading concepts based on macrowear information to evaluate whether taurodontism supplies some dental biomechanical advantages. Loads were applied to the digital model of the lower right first molar (RM 1 ) of the Neandertal specimen Le Moustier 1, as well as to the digital models of both a shortened and a hypertaurodontic version of Le Moustier RM 1 . Moreover, we simulated a scenario where an object is held between teeth and pulled in different directions to investigate whether taurodontism might be useful for para-masticatory activities. Our results do not show any meaningful difference among all the simulations, pointing out that taurodontism does not improve the functional biomechanics of the tooth and does not favour para-masticatory pulling activities. Therefore, taurodontism should be considered either an adaptation to a high attrition diet or most likely the result of pleiotropic or genetic drift effects. Finally, our results have important implications for modern dentistry during endodontic treatments, as we observed that filling the pulp chamber with dentine-like material increases tooth stiffness, and ultimately tensile stresses in the crown, thus favouring tooth failure.

Elucidating the evolution of hominid dentition in the age of phenomics, modularity, and quantitative genetics

“…Kupczik and Hublin (2010) report that the Neanderthal larger root-to-crown and dentine volumes relative to the Pleistocene or recent H. sapiens anatomy may be evidence of distinct occlusal loading. But a more recent finite element analysis explored various loads and strains to digital models of taurodont molars, but found no biomechanical differences between taurodont and non-taurodont molars, ruling out one possible source of selective advantage (Benazzi et al, 2014).…”

Mandibular molar root and pulp cavity morphology in Homo naledi and other Plio-Pleistocene hominins

“…The pulp tissue contains, among other things, odontoblasts, which deposit dentine at the periphery of the chamber during tooth development and in response to applied stimuli such as caries, trauma and wear (Berkovitz et al, 2002). It has been suggested that large pulp cavities of H. neanderthalensis may be an adaptation to a high-attrition dietary regimen because it allows for the deposition of secondary and tertiary dentine on the pulp walls following the loss of enamel and coronal dentine and thus prolongs tooth longevity (Blumberg et al, 1971;Constant and Grine, 2001; Kupczik and Hublin, 2010;Benazzi et al, 2015).…”

Dynamic Modelling of Tooth Deformation Using Occlusal Kinematics and Finite Element Analysis

“…In biology and palaeontology, dental biomechanics is the basis for understanding the relationship between tooth morphology, functional demands and constraints, and evolutionary adaptive processes in the masticatory apparatus of living and extinct animals [ 3 – 7 ]. One of the virtual and numerical tools of dental biomechanics is finite element (FE) analysis which is commonplace in dental industry [ 8 , 9 ] and has increasingly been used in evolutionary biological studies [ 7 , 10 – 14 ].…”