An Experimental and Methodological Approach of Plant Fibres in Dental Calculus: The Case Study of the Early Neolithic Site of Cova del Pasteral (Girona, Spain)

Perishable organic raw materials such as plant fibres have been widely used since the time of the earliest human groups, although their poor preservation limits our knowledge of their use. Filling this gap requires a focused search for plant fibre evidence in non-perishable materials. Since teeth are sometimes used in fibre processing, evidence of fibres can be sought in mineralised bacterial plaque, and therefore, its analysis can potentially be useful in the study of plant–human relationships. Experimental protocols have been tested to improve the recovery of microremains in dental calculus, although these are typically focused on microremains other than plant fibres. This article investigates the possibility that plant fibres are identified less often in dental calculus because the corrosive agents used cause their disappearance. Ethylenediaminetetraacetic acid (EDTA) and hydrochloric acid agents at 0.2 and 0.5 M were applied for 5, 30, 90, and 170 h to six different modern plant fibres considering their use in archaeological craft activities and showed that none of the procedures affected their characteristics. After testing the same approach on medieval control dental calculus samples, a selected methodology (0.5 M EDTA) was applied to ancient dental calculus from the Neolithic site of Cova del Pasteral (La Cellera de Ter, NE Spain) as a case study to identify the plant fibres present in it.