Researchers have discovered that tooth wear and tooth picking are responsible for dentoalveolar remodelling in 1.77 million-year-old hominin samples from Dmanisi, explaining the wide range of mandibular shape variation.1 Variation in cranial and dentoalveolar morphologies in early Pleistocene hominins is well known, but the reasons behind such diversity have been largely unexplored until now.

Increasing severity of tooth wear corresponded with increasing age, with moderate overall wear being recorded in the young adult Dmanisi, wear-induced pathological changes in the older adult and edentulousness in the senile individual. Due to continuous eruption, mesial drift and lingual tipping, tooth wear can have a pronounced effect on mandibular morphology and wear-related reshaping of the jawbones. Such mandibular shape variation is within the normal range of expected variation for a paleopopulation with light to heavy dental wear.

Significantly, horizontal scratches on teeth and local marginal periodontitis add to the growing evidence for habitual use of toothpicks during the period. The findings provide the earliest evidence of tooth-pick induced local periodontitis. The authors conclude that further research into age- and wear-related dentognathic changes is needed to assess the impact on remodelling patterns and variation in other fossil hominins.