Phytoliths in dental calculus as a key for reconstructing ancient diets

Many plants contain siliceous precipitations which occur inside, on the surface or between the cells both of aerial and underground organs. Together with the calcareous ones, these siliceous deposits represent the so-called phytoliths. In nature, after the death of the plants and the decomposition of their portions, phytoliths are deposited into the soil or sediments where they may be preserved for a very long time. Moreover, phytoliths may be entrapped in the use-wear traces of many artefacts, for example on the surface of grinding stones, or in the dental calculus of humans and animals. In this last case, they provide a direct evidence of the plants that were consumed. Therefore, the analysis of dental calculus appears particularly suitable for reconstructing ancient diets; moreover, it is well established that the removal of dental plaque does not cause damage to the dental enamel. The identification of phytoliths and starch grains contained in dental calculus of nine individuals from the Eneolithic-Bronze Age site of Scoglietto (southern Tuscany, Italy) provided information about the plant use in the local diet. In particular, the analysis revealed the consumption of a remarkable variety of cereals.