Palaeoproteomic characterization of archaeological dental calculus reveals precarious periodontal health in pre-Roman Italy (7th–4th century BCE)

: Periodontitis, a chronic inflammatory disease affecting the tooth-supporting structures, is a key indicator of oral health in palaeopathology. While poor oral hygiene, systemic diseases, and genetics are well-established contributors, the dietary impact has often been underestimated. Clinical studies, however, link diets high in fermentable carbohydrates and meat to inflammation. We investigated periodontal disease by analyzing interdental septa in 63 individuals from elite and non-elite groups in pre-Roman Italy (7th-4th centuries BCE), a period of social stratification, intensified agriculture, and increased cereal consumption. Macroscopic analysis was combined with proteomics of dental calculus from 33 individuals. Of the 1890 septa considered, 23 % displayed signs of periodontitis, with significantly higher rates in males. Prevalence increased with age in both sexes. Proteomic findings identified Porphyromonas gingivalis, a key periodontal pathogen, in 10 of 19 well-preserved dental calculus samples. While plaque accumulation is the main trigger for periodontitis, our findings highlight the dietary role in disease susceptibility. Carbohydrate-rich foods adhere to teeth and nourish bacteria, worsening periodontal conditions. At the same time, greater access to animal protein, particularly among emerging elites, may have contributed to inflammation. We propose that a proinflammatory diet may have been a major contributor to the proliferation of pathogenic oral microbiota.