The leitmotiv for periodontal bacteria titre in dental calculus: An increase from Eneolithic age to present one

Aims: Periodontal bacteria are often associated with oral and systemic degenerative diseases. They normally reside in the oral cavity and, together with other microorganisms, are able to form a complex biofilm matrix in different oral sites, for example, on the tongue and in dental plaque/calculus, which are linked by salivary flux. In these conditions, dental calculi could represent an effective snapshot of the amount of these pathogens in the oral cavity and be an extraordinary approach for the comparison of the oral microbiological status of different populations from the past. Methods: The red complex bacteria Porphyromonas gingivalis, Tannerella Forsythia, Treponema pallidum and an orange group representing Fusobacterium nucleatum, were enumerated by a real time PCR procedure in DNA extracts from dental calculi belonging to Sardinian subjects referring to the: Copper Age, about 3000 BC, n = 25; Late Antique Period 8-9th century n = 5; 19th century n = 24; 20th century n= 50. The periodontal bacteria (Pb) titre % was normalised to total plaque bacteria by using the subsequent formula: % Pb = [Pb genome/Total bacterial genomes] *100. Results The results suggest that a significative increase% (P< 0.01) is evaluable in the modern era when Pb % is about 1000 fold more than in the Copper Age samples, especially for F. nucleatum and P. gingivalis. However, Pb titre appears constant until the industrial era (19th century), with no increase of pathogen titre in the plaque biofilm. Conclusions The increase of these microorganisms in the last century suggests a dramatic change in human oral ecology, which may be the result of an alimentary revolution that took place a 100 years ago. Orrù et al., JPNIM 2017