Dental calculus is a mineralized plaque biofilm formed by microbiota of the oral microbiome. Until recently, the information potential of dental calculus for archaeological study was not fully realised and it was often discarded. However, it is now recognized that dental calculus entombs and preserves valuable microfossils and biomolecules within its matrix. While the analysis of calculus is usually destructive, judicious sampling of relatively small quantities of material can provide unique information on ancient health and diet. Additionally, dental calculus is not classified as human tissue, but as an ectopic growth, and in some cases may provide an alternative to the destructive analysis of human skeletal remains. We present a case study applying microscopy and shotgun proteomic methods to Roman Age individuals to demonstrate the potential of even minute quantities of dental calculus to entrap and preserve biomolecules related to diet, health and disease.