Paramonova Katya, UMCG Groningen, The Netherlands

Strength of oral biofilms: species-dependent or environment-dependent?

E. Paramonova, O. J. Kalmykowa, H.C. van der Mei, H.J. Busscher, P.K. Sharma
Department of Biomedical Engineering, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands, e-mail: e.paramonova@med.umcg.nl

In this study we investigate an influence of species composition and environmental hydrodynamic conditions on strength of oral biofilms. We use single species and multiple species biofilms of Streptococcus oralis, Streptococcus sanguis and Actinomyces naeslundii, and full dental plaque as model systems. Biofilms are grown in parallel plate flow chamber at different flow rates. Biofilms strength is measured by compression testing in a low load compression tester (LLCT). Compression tests are combined with confocal laser scanning microscopy (CLSM) to evaluate changes in biofilm architecture due to different hydrodynamic conditions and microbial composition. Single and multiple species biofilms grown at the same flow rates show similar behaviour in response to compression. This type of behaviour can be classified as viscoelastic. Biofilms of full dental plaque are more viscous compared to single and multiple species biofilms. When biofilms are grown at increased flow rates, their behaviour becomes more elastic. Based on CLSM analysis, species composition affects biofilm architecture: single species streptococci biofilms are densely-packed, but they become more loosely-bound with addition of Actinomyces naeslundii. Loosely-bound biofilms are more elastic during compression compared to densely-packed biofilms.