Organic compositional analysis of ancient maya tooth sealants and fillings

Abstract

One of the major unknowns regarding the ancient Maya practice of dental inlaying is the nature of the cement, used to affix small stones inside artificially drilled cavities on labial tooth surfaces. These cements endured the harsh buccal environment of a lifespan and secured the inlay firmly in the tooth even through centuries of subsequent postmortem decay. Beyond their adhesive properties, the sealant materials probably reduced cariogenic activity and periodontal infectious disease. Prior analysis of dental sealings was limited to the identification of inorganic components. Among the materials identified are hydroxyapatite and Portland cement-related compounds, materials that hardened and strengthened Maya dental adhesives. However, the substances that provided the agglutinant and resistance properties to the sealants and fillings remain unknown. The present study involved the analysis of the organic fraction of tooth sealants and fillings in samples from three Classic-period Maya archaeological sites, Holmul (Guatemala), Baking Pot (Belize), and the Copan Valley (Honduras). Attenuated total reflectance infrared spectroscopy (ATR-FTIR) and gas chromatography coupled to mass spectrometry (GC–MS) of eight dental specimens, revealed compositional variety and provide further clues as to the organic materials used in the sealing potions prepared by the ancient dental practitioners. Organic molecules suggest that vegetal resins from Pinaceae species, a probable Lamiaceae-derived essential oil, an Asteraceae preparation, and bitumen, were among the main ingredients. The results of these analyses further attest the chromatic properties of dental fillings and suggest the sealants may also have had antibacterial and anti-inflammatory properties. Overall, the results of this analysis highlight the high degree of sophistication of ancient Maya dental practice.