Study of medieval plaque shows how oral microbiomes have changed
COPENHAGEN, Denmark: A number of recent studies have shown that dental calculus from archaeological samples could be a rich source for better understanding the dental health of our ancestors. Similarly, a new study of the calculus of remains buried in a Danish cemetery has shed light on the oral microbiomes of certain groups of medieval humans in the area.
A team from the University of Copenhagen led the study and sampled calculus from the remains of 21 humans buried circa 1100–1450 CE in the medieval cemetery of the village Tjærby, Denmark. A total of 3,671 proteins from 220 different protein groups were identified from the calculus, with approximately 85 to 95 per cent produced by bacteria from the oral microbiome.
Although all of the studied samples showed traces of bacteria associated with periodontal disease and dental caries, the team was able to divide the samples into two groups: one that was health-predisposed and the other more susceptible to oral disease. In the former group, there was just one case of periodontitis, whereas seven members of the latter group displayed signs of severe tooth decay. Since the two groups were more than likely to have had similar diets and oral health habits, the difference in oral health outcomes is likely to be attributed to differences in proteins, such as Streptococcus sanguinis, a relatively harmless bacteria that was far more prevalent in the former group’s oral microbiomes.
Despite these differences, the calculus samples that were used were found to be far more heterogeneous than samples gathered from modern Danish individuals. The study’s authors argued that the increased diversity of modern diets, combined with environmental and lifestyle factors, genetics, hygiene practices and different personal histories of antibiotics use were likely to be the main causes of the variety in modern oral microbiomes.
The study, titled “Quantitative metaproteomics of medieval dental calculus reveals individual oral health status”, was published online in Nature Communications on 20 November 2018.