Subvertical grooves of interproximal facets in neandertal posterior teeth

Abstract

Subvertical grooves, located on the interproximal facets of most Neandertal posterior teeth, are less frequently noted on the teeth of other hominids, including modern humans. These grooves, 0.1–0.5 mm in width, are strictly localized within the facet area. Scanning electron microscopic (SEM) examination of grooves present on Neandertal teeth from Caverna delle Fate (Liguria, Italy) and Genay (Côte d'Or, France) demonstrated that they were produced during the life of these individuals. Characteristics of the groove surface suggest an erosion‐abrasion mechanism of formation. These grooves, which developed in parts of the dentition exposed to marked stress, originated in areas characterized by changes in the orientation of enamel prism bundles (i.e., Hunter‐Schreger bands). Observations carried out on modern human molars showed a subvertical disposition of these bands near interproximal ridges facilitating subvertical microfractures. Possible correlations between enamel structure, masticatory stress, and interproximal groove formation in Neandertals are discussed.