FREIBURG, Germany: Thousands of different bacteria colonise the oral cavity, many of which remain unidentified. Researchers in Freiburg are now using a combined culture- and gene-based approach to determine which of these microorganisms contribute to periodontitis. The project, funded by the German Research Foundation, combines two methods that have been used successfully in gut microbiome research to analyse both the genetic material and the culturable bacteria. The aim is to gain a more precise understanding of how the composition of the oral microbiota differs between various states of health and periodontitis.